draft-ietf-manet-olsrv2-02.txt   draft-ietf-manet-olsrv2-03.txt 
Mobile Ad hoc Networking (MANET) T. Clausen Mobile Ad hoc Networking (MANET) T. Clausen
Internet-Draft LIX, Ecole Polytechnique, France Internet-Draft LIX, Ecole Polytechnique, France
Expires: December 28, 2006 C. Dearlove Expires: August 5, 2007 C. Dearlove
BAE Systems Advanced Technology BAE Systems Advanced Technology
Centre Centre
P. Jacquet P. Jacquet
Project Hipercom, INRIA Project Hipercom, INRIA
The OLSRv2 Design Team The OLSRv2 Design Team
MANET Working Group MANET Working Group
June 26, 2006 February 2007
The Optimized Link-State Routing Protocol version 2 The Optimized Link State Routing Protocol version 2
draft-ietf-manet-olsrv2-02 draft-ietf-manet-olsrv2-03
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Abstract Abstract
This document describes version 2 of the Optimized Link State Routing This document describes version 2 of the Optimized Link State Routing
(OLSRv2) protocol for mobile ad hoc networks. The protocol embodies (OLSRv2) protocol for mobile ad hoc networks. The protocol embodies
an optimization of the classical link state algorithm tailored to the an optimization of the classical link state algorithm tailored to the
requirements of a mobile wireless LAN. requirements of a mobile ad hoc network (MANET).
The key optimization of OLSRv2 is that of multipoint relays, The key optimization of OLSRv2 is that of multipoint relays,
providing an efficient mechanism for network-wide broadcast of link- providing an efficient mechanism for network-wide broadcast of link
state information (i.e. reducing the cost of performing a network- state information (i.e. reducing the cost of performing a network-
wide link-state broadcast). A secondary optimization is that OLSRv2 wide link state broadcast). A secondary optimization is that OLSRv2
employs partial link-state information: each node maintains employs partial link state information: each node maintains
information about all destinations, but only a subset of links. This information about all destinations, but only a subset of links.
allows that only select nodes diffuse link-state advertisements (i.e. Consequently, only selected nodes diffuse link state advertisements
reduces the number of network-wide link-state broadcasts) and that (thus reducing the number of network-wide link state broadcasts) and
these advertisements contain only a subset of links (i.e. reduces the these advertisements contain only a subset of links (thus reducing
size of each network-wide link-state broadcast). The partial link- the size of network-wide link state broadcasts). The partial link
state information thus obtained still allows each OLSRv2 node to at state information thus obtained still allows each OLSRv2 node to at
all times maintain optimal (in terms of number of hops) routes to all all times maintain optimal (in terms of number of hops) routes to all
destinations in the network. destinations in the network.
OLSRv2 imposes minimum requirements to the network by not requiring OLSRv2 imposes minimum requirements on the network by not requiring
sequenced or reliable transmission of control traffic. Furthermore, sequenced or reliable transmission of control traffic. Furthermore,
the only interaction between OLSRv2 and the IP stack is routing table the only interaction between OLSRv2 and the IP stack is routing table
management. management.
OLSRv2 is particularly suitable for large and dense networks as the OLSRv2 is particularly suitable for large and dense networks as the
technique of MPRs works well in this context. technique of MPRs works well in this context.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2. Applicability Statement . . . . . . . . . . . . . . . . . 6 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 8
2. Protocol Overview and Functioning . . . . . . . . . . . . . . 8 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 9
2.1. Protocol Extensibility . . . . . . . . . . . . . . . . . . 10 5. Local Information Base . . . . . . . . . . . . . . . . . . . . 11
3. Processing and Forwarding Repositories . . . . . . . . . . . . 11 5.1. Local Attached Network Set . . . . . . . . . . . . . . . . 11
3.1. Received Set . . . . . . . . . . . . . . . . . . . . . . . 11 6. Processing and Forwarding Repositories . . . . . . . . . . . . 12
3.2. Fragment Set . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Received Set . . . . . . . . . . . . . . . . . . . . . . . 12
3.3. Processed Set . . . . . . . . . . . . . . . . . . . . . . 12 6.2. Processed Set . . . . . . . . . . . . . . . . . . . . . . 12
3.4. Forwarded Set . . . . . . . . . . . . . . . . . . . . . . 12 6.3. Forwarded Set . . . . . . . . . . . . . . . . . . . . . . 13
3.5. Relay Set . . . . . . . . . . . . . . . . . . . . . . . . 12 6.4. Relay Set . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Packet Processing and Message Forwarding . . . . . . . . . . . 14 7. Packet Processing and Message Forwarding . . . . . . . . . . . 14
4.1. Actions when Receiving an OLSRv2 Packet . . . . . . . . . 14 7.1. Actions when Receiving an OLSRv2 Packet . . . . . . . . . 14
4.2. Actions when Receiving an OLSRv2 Message . . . . . . . . . 14 7.2. Actions when Receiving an OLSRv2 Message . . . . . . . . . 14
4.3. Message Considered for Processing . . . . . . . . . . . . 15 7.3. Message Considered for Processing . . . . . . . . . . . . 15
4.4. Message Considered for Forwarding . . . . . . . . . . . . 17 7.4. Message Considered for Forwarding . . . . . . . . . . . . 15
5. Information Repositories . . . . . . . . . . . . . . . . . . . 20 8. Information Repositories . . . . . . . . . . . . . . . . . . . 18
5.1. Neighborhood Information Base . . . . . . . . . . . . . . 20 8.1. Neighborhood Information Base . . . . . . . . . . . . . . 18
5.1.1. Link Set . . . . . . . . . . . . . . . . . . . . . . . 20 8.1.1. Link Set . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.2. MPR Set . . . . . . . . . . . . . . . . . . . . . . . 21 8.1.2. MPR Set . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.3. MPR Selector Set . . . . . . . . . . . . . . . . . . . 21 8.1.3. MPR Selector Set . . . . . . . . . . . . . . . . . . . 19
5.2. Topology Information Base . . . . . . . . . . . . . . . . 21 8.2. Topology Information Base . . . . . . . . . . . . . . . . 19
5.2.1. Advertised Neighbor Set . . . . . . . . . . . . . . . 21 8.2.1. Advertised Neighbor Set . . . . . . . . . . . . . . . 19
5.2.2. ANSN History Set . . . . . . . . . . . . . . . . . . . 22 8.2.2. ANSN History Set . . . . . . . . . . . . . . . . . . . 20
5.2.3. Topology Set . . . . . . . . . . . . . . . . . . . . . 22 8.2.3. Topology Set . . . . . . . . . . . . . . . . . . . . . 20
5.2.4. Attached Network Set . . . . . . . . . . . . . . . . . 23 8.2.4. Attached Network Set . . . . . . . . . . . . . . . . . 20
5.2.5. Routing Set . . . . . . . . . . . . . . . . . . . . . 23 8.2.5. Routing Set . . . . . . . . . . . . . . . . . . . . . 21
6. OLSRv2 Control Message Structures . . . . . . . . . . . . . . 24 9. Control Message Structures . . . . . . . . . . . . . . . . . . 22
6.1. General OLSRv2 Message TLVs . . . . . . . . . . . . . . . 24 9.1. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 22
6.1.1. VALIDITY_TIME TLV . . . . . . . . . . . . . . . . . . 24 9.1.1. HELLO Message TLVs . . . . . . . . . . . . . . . . . . 23
6.2. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 25 9.1.2. HELLO Message Address Block TLVs . . . . . . . . . . . 23
6.2.1. HELLO Message OLSRv2 Message TLVs . . . . . . . . . . 26 9.2. TC Messages . . . . . . . . . . . . . . . . . . . . . . . 24
6.2.2. HELLO Message OLSRv2 Address Block TLVs . . . . . . . 26 9.2.1. TC Message TLVs . . . . . . . . . . . . . . . . . . . 24
6.3. TC Messages . . . . . . . . . . . . . . . . . . . . . . . 27 9.2.2. TC Message Address Block TLVs . . . . . . . . . . . . 25
6.4. TC Message: OLSRv2 Address Block TLVs . . . . . . . . . . 27 10. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 26
7. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 29 10.1. HELLO Message: Transmission . . . . . . . . . . . . . . . 26
7.1. HELLO Message: Transmission . . . . . . . . . . . . . . . 29 11. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 27
8. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 30 11.1. Populating the MPR Selector Set . . . . . . . . . . . . . 27
8.1. Populating the MPR Selector Set . . . . . . . . . . . . . 30 11.2. Symmetric Neighborhood and 2-Hop Neighborhood Changes . . 28
8.2. Symmetric Neighborhood and 2-Hop Neighborhood Changes . . 31 12. TC Message Generation . . . . . . . . . . . . . . . . . . . . 29
9. TC Message Generation . . . . . . . . . . . . . . . . . . . . 32 12.1. TC Message: Transmission . . . . . . . . . . . . . . . . . 30
9.1. TC Message: Transmission . . . . . . . . . . . . . . . . . 33 13. TC Message Processing . . . . . . . . . . . . . . . . . . . . 32
10. TC Message Processing . . . . . . . . . . . . . . . . . . . . 34 13.1. Initial TC Message Processing . . . . . . . . . . . . . . 32
10.1. Single TC Message Processing . . . . . . . . . . . . . . . 34 13.1.1. Populating the ANSN History Set . . . . . . . . . . . 32
10.1.1. Populating the ANSN History Set . . . . . . . . . . . 35 13.1.2. Populating the Topology Set . . . . . . . . . . . . . 33
10.1.2. Populating the Topology Set . . . . . . . . . . . . . 35 13.1.3. Populating the Attached Network Set . . . . . . . . . 34
10.1.3. Populating the Attached Network Set . . . . . . . . . 36 13.2. Completing TC Message Processing . . . . . . . . . . . . . 34
10.2. Completed TC Message Processing . . . . . . . . . . . . . 37 13.2.1. Purging the Topology Set . . . . . . . . . . . . . . . 35
10.2.1. Purging the Topology Set . . . . . . . . . . . . . . . 37 13.2.2. Purging the Attached Network Set . . . . . . . . . . . 35
10.2.2. Purging the Attached Network Set . . . . . . . . . . . 37 14. Populating the MPR Set . . . . . . . . . . . . . . . . . . . . 36
11. Populating the MPR Set . . . . . . . . . . . . . . . . . . . . 38 15. Populating Derived Sets . . . . . . . . . . . . . . . . . . . 37
12. Populating Derived Sets . . . . . . . . . . . . . . . . . . . 39 15.1. Populating the Relay Set . . . . . . . . . . . . . . . . . 37
12.1. Populating the Relay Set . . . . . . . . . . . . . . . . . 39 15.2. Populating the Advertised Neighbor Set . . . . . . . . . . 37
12.2. Populating the Advertised Neighbor Set . . . . . . . . . . 39 16. Routing Table Calculation . . . . . . . . . . . . . . . . . . 38
13. Routing Table Calculation . . . . . . . . . . . . . . . . . . 40 17. Proposed Values for Constants . . . . . . . . . . . . . . . . 42
14. Proposed Values for Constants . . . . . . . . . . . . . . . . 44 17.1. Neighborhood Discovery Constants . . . . . . . . . . . . . 42
14.1. Neighborhood Discovery Constants . . . . . . . . . . . . . 44 17.2. Message Intervals . . . . . . . . . . . . . . . . . . . . 42
14.2. Message Intervals . . . . . . . . . . . . . . . . . . . . 44 17.3. Holding Times . . . . . . . . . . . . . . . . . . . . . . 42
14.3. Holding Times . . . . . . . . . . . . . . . . . . . . . . 44 17.4. Jitter Times . . . . . . . . . . . . . . . . . . . . . . . 42
14.4. Willingness . . . . . . . . . . . . . . . . . . . . . . . 44 17.5. Willingness . . . . . . . . . . . . . . . . . . . . . . . 42
15. Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 45 18. Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 43
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44
16.1. Multicast Addresses . . . . . . . . . . . . . . . . . . . 46 19.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 44
16.2. Message Types . . . . . . . . . . . . . . . . . . . . . . 46 19.2. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 44
16.3. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 46 20. References . . . . . . . . . . . . . . . . . . . . . . . . . . 46
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 48 20.1. Normative References . . . . . . . . . . . . . . . . . . . 46
17.1. Normative References . . . . . . . . . . . . . . . . . . . 48 20.2. Informative References . . . . . . . . . . . . . . . . . . 46
17.2. Informative References . . . . . . . . . . . . . . . . . . 48 Appendix A. Node Configuration . . . . . . . . . . . . . . . . . 47
Appendix A. Example Heuristic for Calculating MPRs . . . . . . . 49 Appendix B. Protocol and Port Number . . . . . . . . . . . . . . 48
Appendix B. Heuristics for Generating Control Traffic . . . . . 52 Appendix C. Example Heuristic for Calculating MPRs . . . . . . . 49
Appendix C. Protocol and Port Number . . . . . . . . . . . . . . 53 Appendix D. Packet and Message Layout . . . . . . . . . . . . . 52
Appendix D. Packet and Message Layout . . . . . . . . . . . . . 54 Appendix D.1. Packet and Message Options . . . . . . . . . . . . . 52
Appendix D.1. OLSRv2 Packet Format . . . . . . . . . . . . . . . . 54 Appendix D.2. Example HELLO Message . . . . . . . . . . . . . . . 54
Appendix E. Node Configuration . . . . . . . . . . . . . . . . . 59 Appendix D.3. Example TC Message . . . . . . . . . . . . . . . . . 55
Appendix F. Jitter . . . . . . . . . . . . . . . . . . . . . . . 60 Appendix E. Time TLVs . . . . . . . . . . . . . . . . . . . . . 58
Appendix G. Security Considerations . . . . . . . . . . . . . . 63 E.1. Representing Time . . . . . . . . . . . . . . . . . . . . 58
Appendix G.1. Confidentiality . . . . . . . . . . . . . . . . . . 63 E.2. General Time TLV Structure . . . . . . . . . . . . . . . . 58
Appendix G.2. Integrity . . . . . . . . . . . . . . . . . . . . . 63 E.3. Message TLVs . . . . . . . . . . . . . . . . . . . . . . . 60
Appendix G.3. Interaction with External Routing Domains . . . . . 64 E.3.1. VALIDITY_TIME TLV . . . . . . . . . . . . . . . . . . 60
Appendix G.4. Node Identity . . . . . . . . . . . . . . . . . . . 65 E.3.2. INTERVAL_TIME TLV . . . . . . . . . . . . . . . . . . 60
Appendix H. Flow and Congestion Control . . . . . . . . . . . . 66 Appendix F. Message Jitter . . . . . . . . . . . . . . . . . . . 61
Appendix I. Contributors . . . . . . . . . . . . . . . . . . . . 67 F.1. Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Appendix J. Acknowledgements . . . . . . . . . . . . . . . . . . 68 F.1.1. Periodic message generation . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 69 F.1.2. Externally triggered message generation . . . . . . . 62
Intellectual Property and Copyright Statements . . . . . . . . . . 70 F.1.3. Message forwarding . . . . . . . . . . . . . . . . . . 63
F.1.4. Maximum Jitter Determination . . . . . . . . . . . . . 64
Appendix G. Security Considerations . . . . . . . . . . . . . . 65
Appendix G.1. Confidentiality . . . . . . . . . . . . . . . . . . 65
Appendix G.2. Integrity . . . . . . . . . . . . . . . . . . . . . 65
Appendix G.3. Interaction with External Routing Domains . . . . . 66
Appendix G.4. Node Identity . . . . . . . . . . . . . . . . . . . 67
Appendix H. Flow and Congestion Control . . . . . . . . . . . . 68
Appendix I. Contributors . . . . . . . . . . . . . . . . . . . . 69
Appendix J. Acknowledgements . . . . . . . . . . . . . . . . . . 70
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 71
Intellectual Property and Copyright Statements . . . . . . . . . . 72
1. Introduction 1. Introduction
The Optimized Link State Routing protocol version 2 (OLSRv2) is an The Optimized Link State Routing protocol version 2 (OLSRv2) is an
update to OLSRv1 as published in RFC3626 [1]. Compared to RFC3626, update to OLSRv1 as published in RFC3626 [1]. Compared to RFC3626,
OLSRv2 retains the same basic mechanisms and algorithms, while OLSRv2 retains the same basic mechanisms and algorithms, while
providing an even more flexible signaling framework and some providing a more flexible signaling framework and some simplification
simplification of the messages being exchanged. Also, OLSRv2 takes of the messages being exchanged. Also, OLSRv2 accommodates both IPv4
care to accommodate both IPv4 and IPv6 addresses in a compact and IPv6 addresses in a compact manner.
fashion.
OLSRv2 is developed for mobile ad hoc networks. It operates as a OLSRv2 is developed for mobile ad hoc networks. It operates as a
table driven, proactive protocol, i.e. it exchanges topology table driven, proactive protocol, i.e. it exchanges topology
information with other nodes of the network regularly. Each node information with other nodes in the network regularly. Each node
selects a set of its neighbor nodes as "MultiPoint Relays" (MPRs). selects a set of its neighbor nodes as "MultiPoint Relays" (MPRs).
Only nodes that are selected as such MPRs are then responsible for Control traffic may be diffused through the network using hop by hop
forwarding control traffic intended for diffusion into the entire forwarding; a node only needs to forward control traffic directly
network. MPRs provide an efficient mechanism for flooding control received from its MPR selectors (nodes which have selected it as an
MPR). MPRs thus provide an efficient mechanism for diffusing control
traffic by reducing the number of transmissions required. traffic by reducing the number of transmissions required.
Nodes selected as MPRs also have a special responsibility when Nodes selected as MPRs also have a special responsibility when
declaring link state information in the network. Indeed, the only declaring link state information in the network. A sufficient
requirement for OLSRv2 to provide shortest path routes to all requirement for OLSRv2 to provide shortest path routes to all
destinations is that MPR nodes declare link-state information for destinations is that nodes declare link state information for their
their MPR selectors. Additional available link-state information may MPR selectors, if any. Additional available link state information
be utilized, e.g. for redundancy. may be transmitted, e.g. for redundancy. Thus, as well as being used
to facilitate efficient flooding, MPRs are also allow the reduction
Nodes which have been selected as multipoint relays by some neighbor of the number and size of link state messages. MPRs are also thus
node(s) announce this information periodically in their control used as intermediate nodes in multi-hop route calculations.
messages. Thereby a node announces to the network that it has
reachability to the nodes which have selected it as an MPR. Thus, as
well as being used to facilitate efficient flooding, MPRs are also
used for route calculation from any given node to any destination in
the network.
A node selects MPRs from among its one hop neighbors with A node selects MPRs from among its one hop neighbors connected by
"symmetric", i.e. bi-directional, linkages. Therefore, selecting "symmetric", i.e. bi-directional, links. Therefore, selecting routes
routes through MPRs automatically avoids the problems associated with through MPRs automatically avoids the problems associated with data
data packet transfer over uni-directional links (such as the problem packet transfer over uni-directional links (such as the problem of
of not getting link-layer acknowledgments for data packets at each not getting link layer acknowledgments at each hop, for link layers
hop, for link-layers employing this technique for unicast traffic). employing this technique).
OLSRv2 is developed to work independently from other protocols. OLSRv2 is developed to work independently from other protocols.
Likewise, OLSRv2 makes no assumptions about the underlying link- (Parts of OLSRv2 have been published separately as [3] and [4] for
layer. However, OLSRv2 may use link-layer information and wider use.) Likewise, OLSRv2 makes no assumptions about the
notifications when available and applicable. underlying link layer. However, OLSRv2 may use link layer
information and notifications when available and applicable, as
described in [4].
OLSRv2, as OLSRv1, inherits the concept of forwarding and relaying OLSRv2, as OLSRv1, inherits its concept of forwarding and relaying
from HIPERLAN (a MAC layer protocol) which is standardized by ETSI from HIPERLAN (a MAC layer protocol) which is standardized by ETSI
[6]. [6], [7].
1.1. Terminology 2. Terminology
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [2]. document are to be interpreted as described in RFC2119 [2].
MANET specific terminology is to be interpreted as described in [3] MANET specific terminology is to be interpreted as described in [3]
and [4]. and [4].
Additionally, this document uses the following terminology: Additionally, this document uses the following terminology:
node - A MANET router which implements the Optimized Link State Node - A MANET router which implements the Optimized Link State
Routing protocol version 2 as specified in this document. Routing protocol version 2 as specified in this document.
OLSRv2 interface - A MANET interface, running OLSRv2. OLSRv2 interface - A MANET interface, running OLSRv2.
symmetric strict 2-hop neighbor - A symmetric 2-hop neighbor which is Symmetric strict 2-hop neighbor - A symmetric 2-hop neighbor which
not a symmetric 1-hop neighbor and is not a 2-hop neighbor only is not a symmetric 1-hop neighbor and is not a 2-hop neighbor only
through a symmetric 1-hop neighbor with willingness WILL_NEVER. through a symmetric 1-hop neighbor with willingness WILL_NEVER.
(If node Z is a symmetric 2-hop neighbor of node X then there is a
node Y such that node Z is a symmetric 1-hop neighbor of node Y
and node Y is a symmetric 1-hop neighbor of node X. If node Z is a
symmetric strict 2-hop neighbor of node X then there is such a
node Y with willingness which is not WILL_NEVER.)
symmetric strict 2-hop neighborhood - The set of the symmetric strict Symmetric strict 2-hop neighborhood - The set of the symmetric
2-hop neighbors of node X. strict 2-hop neighbors of a node.
multipoint relay (MPR) - A node which is selected by its symmetric Multipoint relay (MPR) - A node which is selected by its symmetric
1-hop neighbor, node X, to "re-transmit" all the broadcast 1-hop neighbor, node X, to "re-transmit" all the broadcast
messages that it receives from node X, provided that the message messages that it receives from node X, provided that the message
is not a duplicate, and that the hop limit field of the message is is not a duplicate, and that the hop limit field of the message is
greater than one. greater than one.
MPR selector - A node which has selected its symmetric 1-hop MPR selector - A node which has selected its symmetric 1-hop
neighbor, node X, as one of its MPRs is an MPR selector of node X. neighbor, node X, as one of its MPRs is an MPR selector of node X.
1.2. Applicability Statement 3. Applicability Statement
OLSRv2 is a proactive routing protocol for mobile ad hoc networks OLSRv2 is a proactive routing protocol for mobile ad hoc networks
(MANETs) [7], [8]. It is well suited to large and dense networks of (MANETs). The larger and more dense a network, the more optimization
mobile nodes, as the optimization achieved using the MPRs works well can be achieved by using MPRs compared to the classic link state
in this context. The larger and more dense a network, the more algorithm. OLSRv2 enables hop-by-hop routing, i.e. each node using
optimization can be achieved as compared to the classic link state its local information provided by OLSRv2 to route packets.
algorithm. OLSRv2 uses hop-by-hop routing, i.e. each node uses its
local information to route packets.
As OLSRv2 continuously maintains routes to all destinations in the As OLSRv2 continuously maintains routes to all destinations in the
network, the protocol is beneficial for traffic patterns where the network, the protocol is beneficial for traffic patterns where the
traffic is random and sporadic between a large subset of nodes, and traffic is random and sporadic between a large subset of nodes, and
where the [source, destination] pairs are changing over time: no where the [source, destination] pairs are changing over time: no
additional control traffic need be generated in this situation since additional control traffic need be generated in this situation since
routes are maintained for all known destinations at all times. Also, routes are maintained for all known destinations at all times. Also,
since routes are maintained continuously, traffic is subject to no since routes are maintained continuously, traffic is subject to no
delays due to buffering/route-discovery. This continued route delays due to buffering or to route discovery.
maintenance may be done using periodic message exchange, as detailed
in this specification, or triggered by external events if available.
OLSRv2 supports nodes which have multiple interfaces which OLSRv2 supports nodes which have multiple interfaces which
participate in the MANET. OLSRv2, additionally, supports nodes which participate in the MANET using OLSRv2. As described in [4], each
have non-MANET interfaces which can serve as (if configured to do so) OLSRv2 interface may have one or more network addresses (which may
gateways towards other networks. have prefix lengths). OLSRv2, additionally, supports nodes which
have non-OLSRv2 interfaces which can serve as gateways towards other
networks.
The message exchange format, contained in previous versions of this OLSRv2 uses the format specified in [3] for all messages and packets.
specification, has been factored out to an independent specification OLSRv2 is thereby able to allow for extensions via "external" and
[3], which is used for carrying OLSRv2 control signals. OLSRv2 is "internal" extensibility. External extensibility allows a protocol
thereby able to allow for extensions via "external" and "internal" extension to specify and exchange new message types, which can be
extensibility. External extensibility implies that a protocol forwarded and delivered correctly even by nodes which do not support
extension may specify and exchange new message types, formatted that extension. Internal extensibility allows a protocol extension
according to [3], which can be forwarded and delivered correctly. to define additional attributes to be carried embedded in the
Internal extensibility implies that a protocol extension may define standard OLSRv2 control messages detailed in this specification (or
additional attributes to be carried embedded in the standard OLSRv2 any new message types defined by other protocol extensions) using the
control messages detailed in this specification, using the TLV TLV mechanism specified in [3], while still allowing nodes not
mechanism specified in [3], while OLSRv2 control messages with supporting that extension to forward messages including the extension
additional attributes can still be correctly understood by all OLSRv2 and process messages ignoring the extension.
nodes.
The OLSRv2 neighborhood discovery protocol using HELLO messages has The OLSRv2 neighborhood discovery protocol using HELLO messages is
likewise been factored out to an independent specification [4]. This specified in [4]; note that all references to MANET interfaces in [4]
refer to OLSRv2 interfaces when using [4] as part of OLSRv2. This
neighborhood discovery protocol serves to ensure that each OLSRv2 neighborhood discovery protocol serves to ensure that each OLSRv2
node has available continuously updated information repositories node has available continuously updated information repositories
describing the node's 1-hop and 2-hop neighbors. [4] uses the message describing the node's 1-hop and symmetric 2-hop neighbors. This
format specified in [3], and hence is extensible as described above. neighborhood discovery protocol, which also uses [3], is extended in
this document by the addition of MPR information.
2. Protocol Overview and Functioning 4. Protocol Overview and Functioning
OLSRv2 is a proactive routing protocol for mobile ad hoc networks. OLSRv2 is a proactive routing protocol for mobile ad hoc networks.
The protocol inherits the stability of a link state algorithm and has The protocol inherits the stability of a link state algorithm and has
the advantage of having routes immediately available when needed due the advantage of having routes immediately available when needed due
to its proactive nature. OLSRv2 is an optimization over the to its proactive nature. OLSRv2 is an optimization of the classical
classical link state protocol, tailored for mobile ad hoc networks. link state protocol, tailored for mobile ad hoc networks. The main
The main tailoring and optimizations of OLSRv2 are: tailoring and optimizations of OLSRv2 are:
o periodic, unacknowledged transmission of all control messages; o periodic, unacknowledged transmission of all control messages;
o optimized flooding for global link-state information diffusion; o optimized flooding for global link state information diffusion;
o partial topology maintenance - each node knows only a subset of o partial topology maintenance - each node knows only a subset of
the links in the network, sufficient for a minimum hop route to the links in the network, sufficient for a minimum hop route to
all destinations. all destinations.
The optimized flooding and partial topology maintenance are based on
the concept on MultiPoint Relays (MPRs), selected independently by
nodes based on the symmetric 1-hop and 2-hop neighbor information
maintained using [4].
Using the message exchange format [3] and the neighborhood discovery Using the message exchange format [3] and the neighborhood discovery
protocol [4], OLSRv2 also contains the following main components: protocol [4], OLSRv2 also contains the following main components:
o a TLV, to be included within the HELLO messages of [4], allowing a o A TLV, to be included within the HELLO messages of [4], allowing a
node to signal MPR selection; node to signal MPR selection.
o an optimized flooding mechanism for global information exchange, o An optimized flooding mechanism for global information exchange,
denoted "MPR flooding"; denoted "MPR flooding".
o a specification of global signaling, denoted TC (Topology Control) o A specification of global signaling, denoted TC (Topology Control)
messages. TC messages in OLSRv2 serve to: messages. TC messages in OLSRv2 serve to:
* inject link-state information into the entire network; * inject link state information into the entire network;
* inject addresses of hosts and networks for which they may serve * inject addresses of hosts and networks for which they may serve
as a gateway into the entire network. as a gateway into the entire network.
TC messages are emitted periodically, thereby allowing nodes to TC messages are emitted periodically, thereby allowing nodes to
continuously track global changes in the network. continuously track global changes in the network. Incomplete TC
messages may be used to report additions to advertised information
The use of [4] allows a node to continuously track changes to its without repeating unchanged information. Some TC messages may be
local topology up to two hops away. This allows a node to make flooded over only part of the network, allowing a node to ensure
provisions for ensuring optimized flooding, denoted "MPR flooding", that nearer nodes are kept more up to date than distant nodes.
as well as injection of link-state information into the network.
This is done through the notion of MultiPoint Relays (MPRs).
The idea of MPRs is to minimize the overhead of flooding messages in Each node in the network selects an MPR Set. The MPR Set of a node X
the network by reducing redundant retransmissions of messages in the
same region. Each node in the network selects an MPR Set, a set of
nodes in its symmetric 1-hop neighborhood which may retransmit its
messages. The 1-hop neighbors of a node which are not in its MPR set
receive and process broadcast messages, but do not retransmit
broadcast messages received from that node. The MPR Set of a node X
may be any subset of its symmetric 1-hop neighborhood such that every may be any subset of its symmetric 1-hop neighborhood such that every
node in its symmetric strict 2-hop neighborhood has a symmetric link node in the symmetric strict 2-hop neighborhood of node X has a
to a node in the MPR Set of node X. The MPR Set of a node may thus be symmetric link to a node in the MPR Set of node X. The MPR Set of a
said to "cover" the node's symmetric strict 2-hop neighborhood. The node may thus be said to "cover" the node's symmetric strict 2-hop
smaller a MPR Set, the fewer times messages are forwarded and the neighborhood. Each node also maintains information about the set of
less resulting control traffic overhead. [8] gives an analysis and symmetric 1-hop neighbors that have selected it as MPR. This set is
example of MPR selection algorithms. Note that as long as the called the MPR Selector Set of the node.
condition above is satisfied, any algorithm selecting MPR Sets is
acceptable in terms of implementation interoperability.
Each node maintains information about the set of symmetric 1-hop
neighbors that have selected it as MPR. This set is called the MPR
Selector Set of the node. A node obtains this information from an
MPR TLV which is inserted into the HELLO message exchange of [4].
Each node also maintains a Relay Set, which is the set of nodes for Note that as long as the condition above is satisfied, any algorithm
which a node is to relay broadcast traffic. The Relay Set is derived selecting MPR Sets is acceptable in terms of implementation
from the MPR Selector Set in that the Relay Set MUST contain all the interoperability. However if smaller MPR Sets are selected then the
nodes in the MPR Selector set and MAY contain additional nodes. greater the efficiency gains that are possible. Note that [8] gives
an analysis and example of MPR selection algorithms.
Using the MPR flooding mechanism, link-state information can be In OLSRv2, actual efficiency gains are based on the sizes of each
injected into the network. For this purpose, a node maintains an node's Relay Set, the set of symmetric 1-hop neighbors for which it
Advertised Neighbor Set which MUST contain all the nodes in the MPR is to relay broadcast traffic, and its Advertised Neighbor Set, the
selector set and MAY contain additional nodes. If the Advertised set of symmetric 1-hop neighbors for which it is to advertise link
Neighbor Set of a node is non-empty, it is reported in TC messages state information into the network in TC messages. Each of these
generated by that node. If the Advertised Neighbor Set is empty, TC sets MUST contain all the nodes in the MPR Selector Set and MAY
messages are not generated by that node, unless needed for gateway contain additional nodes. If the Advertised Neighbor Set is empty,
TC messages are not generated by that node, unless needed for gateway
reporting, or for a short period to accelerate the removal of reporting, or for a short period to accelerate the removal of
unwanted links. unwanted links.
OLSRv2 is designed to work in a completely distributed manner and OLSRv2 is designed to work in a completely distributed manner and
does not depend on any central entity. The protocol does not require does not depend on any central entity. The protocol does not require
reliable transmission of control messages: each node sends control reliable transmission of control messages: each node sends control
messages periodically, and can therefore sustain a reasonable loss of messages periodically, and can therefore sustain a reasonable loss of
some such messages. Such losses may occur frequently in radio some such messages. Such losses may occur frequently in radio
networks due to collisions or other transmission problems. networks due to collisions or other transmission problems. OLSRv2
may use "jitter", randomized adjustments to message transmission
times, to reduce the incidence of collisions.
OLSRv2 does not require sequenced delivery of messages. Each control OLSRv2 does not require sequenced delivery of messages. Each control
message contains a sequence number which is incremented for each message contains a sequence number which is incremented for each
message. Thus the recipient of a control message can, if required, message. Thus the recipient of a control message can, if required,
easily identify which information is more recent - even if messages easily identify which information is more recent - even if messages
have been re-ordered while in transmission. have been re-ordered while in transmission.
OLSRv2 does not require any changes to the format of IP packets, any OLSRv2 does not require any changes to the format of IP packets, any
existing IP stack can be used as is: OLSRv2 only interacts with existing IP stack can be used as is: OLSRv2 only interacts with
routing table management. OLSR sends its control messages using UDP. routing table management. OLSR sends its control messages using UDP.
2.1. Protocol Extensibility 5. Local Information Base
OLSRv2 uses the neighborhood discovery mechanism of [4], and
specifies additionally one message type, TC, and a number of TLVs.
All messages exchanged by [4] and by OLSRv2 use and comply with the
extensible message exchange format of [3], thus OLSR provides both
"external" extensibility (addition of new message types as in OLSRv1
[1]) and "internal" extensibility (addition of information to
existing messages through TLVs) as described in [3].
Those nodes which do not recognize a new message type ("external
extensibility") will ignore this message type for processing, but
will correctly forward the message, if specified in the message
header. Those nodes which do not recognize a newly defined TLV type
ignore the added TLV, but process (if the message type is recognized)
the message correctly, as well as forwards the message, if specified
in the message header.
3. Processing and Forwarding Repositories A node maintains a Local Information Base that records information
about its OLSRv2 interfaces, and its non-OLSRv2 interfaces that can
serve as gateways to other networks. The former is maintained using
a Local Interface Set, as described in [4]. The latter is maintained
using a Local Attached Network Set. All addresses in the Local
Information Base have an associated prefix length; if an address
otherwise does not have a prefix length then it is set equal to the
address length. Two addresses are considered equal if and only if
their associated prefix lengths are also equal.
The following data structures are employed in order to ensure that a The Local Information Base is not modified by this protocol. This
message is processed at most once and is forwarded at most once per protocol may respond to changes of this Local Information Base which
interface of a node, and that fragmented content is treated MUST reflect corresponding changes in the node's status. It is not
correctly. the responsibility of OLSRv2 to maintain routes to networks recorded
in the Local Attached Network Set in that node.
3.1. Received Set 5.1. Local Attached Network Set
Each node maintains, for each OLSRv2 interface, a set of signatures A node's Local Attached Network Set records its local non-OLSRv2
of messages, which have been received over that interface, in the interfaces. that can act as gateways to other networks. It consists
form of "Received Tuples": of Local Attached Network Tuples:
(RX_type, RX_orig_addr, RX_seq_number, RX_time) (AL_net_addr, AL_dist)
where: where:
RX_type is the received message type, or zero if the received message AL_net_addr is the network address of an attached network which can
sequence number is not type-specific; be reached via this node.
RX_orig_addr is the originator address of the received message; AL_dist is the number of hops to the network with address
AL_net_addr from this node.
RX_seq_number is the message sequence number of the received message; Attached networks with AL_dist == 0 MUST be local to this node and
MUST NOT be attached to any other node. Attached networks with
AL_dist > 0 MAY be attached to other nodes.
RX_time specifies the time at which this Received Tuple expires and Attached networks with AL_dist > 0 MUST be advertised in TC messages
*MUST* be removed. generated by this node, this may result in the node originating TC
messages when it has no other reason to do so. Attached networks
with AL_dist == 0 MAY be advertised in HELLO messages (which causes
the MPRs of this node to advertise them in their TC messages) or MAY
be advertised in TC messages; they MUST be advertised in one type of
message and SHOULD NOT be advertised in both. If a node is sending
TC messages for any other reason, then advertising attached networks
in TC messages is more efficient. A node MAY decide which form of
advertisement to use depending on its circumstances.
In a node, this is denoted the "Received Set" for that interface. 6. Processing and Forwarding Repositories
3.2. Fragment Set The following data structures are employed in order to ensure that a
message is processed at most once and is forwarded at most once per
interface of a node.
Each node stores messages containing fragmented content until all 6.1. Received Set
fragments are received and the message processing can be completed,
in the form of "Fragment Tuples":
(FG_message, FG_time) A node's Received Sets, one per OLSRv2 interface, each record the
signatures of messages which have been received over that interface.
Each consists of Received Tuples:
(RX_type, RX_orig_addr, RX_seq_number, RX_time)
where: where:
FG_message is the message containing fragmented content; RX_type is the received message type, or zero if the received
message sequence number is not type-specific;
FG_time specifies the time at which this Fragment Tuple expires and RX_orig_addr is the originator address of the received message;
MUST be removed.
In a node, this is denoted the "Fragment Set". RX_seq_number is the message sequence number of the received
message;
3.3. Processed Set RX_time specifies the time at which this Tuple expires and MUST be
removed.
Each node maintains a set of signatures of messages which have been 6.2. Processed Set
processed by the node, in the form of "Processed Tuples":
A node's Processed Set records signatures of messages which have been
processed by the node. It consists of Processed Tuples:
(P_type, P_orig_addr, P_seq_number, P_time) (P_type, P_orig_addr, P_seq_number, P_time)
where: where:
P_type is the processed message type, or zero if the processed P_type is the processed message type, or zero if the processed
message sequence number is not type-specific; message sequence number is not type-specific;
P_orig_addr is the originator address of the processed message; P_orig_addr is the originator address of the processed message;
P_seq_number is the message sequence number of the processed message; P_seq_number is the message sequence number of the processed
message;
P_time specifies the time at which this Processed Tuple expires and
*MUST* be removed.
In a node, this is denoted the "Processed Set". P_time specifies the time at which this Tuple expires and MUST be
removed.
3.4. Forwarded Set 6.3. Forwarded Set
Each node maintains a set of signatures of messages which have been A node's Forwarded Set records signatures of messages which have been
retransmitted/forwarded by the node, in the form of "Forwarded processed by the node. It consists of Forwarded Tuples:
Tuples":
(FW_type, FW_orig_addr, FW_seq_number, FW_time) (F_type, F_orig_addr, F_seq_number, F_time)
where: where:
FW_type is the forwarded message type, or zero if the forwarded F_type is the forwarded message type, or zero if the forwarded
message sequence number is not type-specific; message sequence number is not type-specific;
FW_orig_addr is the originator address of the forwarded message; F_orig_addr is the originator address of the forwarded message;
FW_seq_number is the message sequence number of the forwarded F_seq_number is the message sequence number of the forwarded
message; message;
FW_time specifies the time at which this Forward Tuple expires and F_time specifies the time at which this Tuple expires and MUST be
*MUST* be removed. removed.
In a node, this is denoted the "Forwarded Set".
3.5. Relay Set 6.4. Relay Set
Each node maintains a set of neighbor interface addresses for which A node's Relay Set records the neighbor interface addresses for which
it is to relay flooded messages, in the form of "Relay Tuples": it is to relay flooded messages. It consists of Relay Tuples:
(RY_iface_addr) (RY_iface_addr)
where: where:
RY_iface_addr is the address of a neighbor interface for which the RY_iface_addr is the address of a neighbor interface for which the
node SHOULD relay flooded messages. This MUST include a prefix node SHOULD relay flooded messages. This MUST include a prefix
length. length.
In a node, this is denoted the "Relay Set". 7. Packet Processing and Message Forwarding
4. Packet Processing and Message Forwarding
On receiving a basic packet, as defined in [3], a node examines each On receiving a packet, as defined in [3], a node examines the packet
of the message headers. If the message type is known to the node, header and each of the message headers. If the message type is known
the message is processed locally according to the specifications for to the node, the message is processed locally according to the
that message type. The message is also independently evaluated for specifications for that message type. The message is also
forwarding. independently evaluated for forwarding.
4.1. Actions when Receiving an OLSRv2 Packet 7.1. Actions when Receiving an OLSRv2 Packet
On receiving a packet, a node MUST perform the following tasks: On receiving a packet, a node MUST perform the following tasks:
1. The packet may be fully parsed on reception, or the packet and 1. The packet MAY be fully parsed on reception, or the packet and
its messages may be parsed only as required. (It is possible to its messages MAY be parsed only as required. (It is possible to
parse the packet header, or determine its absence, without parse the packet header, or determine its absence, without
parsing any messages. It is possible to divide the packet into parsing any messages. It is possible to divide the packet into
messages without even fully parsing their headers. It is messages without even fully parsing their headers. It is
possible to determine whether a message is to be forwarded, and possible to determine whether a message is to be forwarded, and
to forward it, without parsing its body. It is possible to to forward it, without parsing its body. It is possible to
determine whether a message is to be processed without parsing determine whether a message is to be processed without parsing
its body. It is possible to determine if that processing may be its body.)
delayed because the message is a fragment by inspecting the first
few octets of the message body without fully parsing it.)
2. If parsing fails at any point the relevant entity (packet or 2. If parsing fails at any point the relevant entity (packet or
message) MUST be silently discarded, other parts of the packet message) MUST be silently discarded, other parts of the packet
(up to the whole packet) MAY be silently discarded; (up to the whole packet) MAY be silently discarded;
3. Otherwise if the packet header is present and it contains a 3. Otherwise if the packet header is present and it contains a
packet TLV block, then each TLV in it is processed according to packet TLV block, then each TLV in it is processed according to
its type; its type if recognized, otherwise the TLV is ignored;
4. Otherwise each message in the packet, if any, is treated 4. Otherwise each message in the packet, if any, is treated
according to Section 4.2. according to Section 7.2.
4.2. Actions when Receiving an OLSRv2 Message 7.2. Actions when Receiving an OLSRv2 Message
A node MUST perform the following tasks for each received OLSRv2 A node MUST perform the following tasks for each received OLSRv2
message: message:
1. If the received OLSRv2 message header cannot be correctly parsed 1. If the received OLSRv2 message header cannot be correctly parsed
according to the specification in [3], or if the node recognizes according to the specification in [3], or if the node recognizes
from the originator address of the message that the message is from the originator address of the message that the message is
one which the receiving node itself originated, then the message one which the receiving node itself originated, then the message
MUST be silently discarded; MUST be silently discarded;
2. Otherwise: 2. Otherwise:
1. If the received message is of a known type then the message 1. If the received message is of a known type then the message
is considered for processing according to Section 4.3, AND; is considered for processing according to Section 7.3, AND;
2. If for the received message (<hop-limit> + <hop-count>) > 1, 2. If for the received message (<hop-limit> + <hop-count>) > 1,
then the message is considered for forwarding according to then the message is considered for forwarding according to
Section 4.4. Section 7.4.
4.3. Message Considered for Processing 7.3. Message Considered for Processing
If a message (the "current message") is considered for processing, If a message (the "current message") is considered for processing,
the following tasks MUST be performed: the following tasks MUST be performed:
1. If an entry exists in the Processed Set where: 1. If an entry exists in the Processed Set where:
* P_type == the message type of the current message, or 0 if the * P_type == the message type of the current message, or 0 if the
typedep bit in the message semantics octet (in the message typedep bit in the message semantics octet (in the message
header) of the current message is cleared ('0'), AND; header) of the current message is cleared ('0'), AND;
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+ P_type = the message type of the current message, or 0 if + P_type = the message type of the current message, or 0 if
the typedep bit in the message semantics octet (in the the typedep bit in the message semantics octet (in the
message header) of the current message is cleared ('0'); message header) of the current message is cleared ('0');
+ P_orig_addr = originator address of the current message; + P_orig_addr = originator address of the current message;
+ P_seq_number = sequence number of the current message; + P_seq_number = sequence number of the current message;
+ P_time = current time + P_HOLD_TIME. + P_time = current time + P_HOLD_TIME.
2. If the current message does not contain a valid message TLV 2. Process the message according to its type.
with Type == FRAGMENTATION (or if it does and the indicated
number of fragments is one) then process the message fully
according to its type.
3. Otherwise:
1. If the current message does not contain a valid message
TLV with Type == CONT_SEQ_NUM then the current message
MUST be silently discarded;
2. Otherwise if the current message is "partially or wholly
self-contained", as indicated by the notselfcont bit in
the Value field of the TLV with Type == FRAGMENTATION
being cleared ('0'), then process the current message as
far as possible according to its type;
3. If the Fragment Set includes any Fragment Tuples with:
- either the typedepseq bit in the Value field of the
TLV with Type == FRAGMENTATION in the current message
is cleared ('0') OR message type of FG_message ==
message type of current message, AND;
- originator address of FG_message == originator address
of current message, AND;
- content sequence number (the Value field of the
message TLV with Type == CONT_SEQ_NUM) of FG_message
== content sequence number of current message; AND
- either fragment number (from the Value field of the
TLV with Type == FRAGMENTATION) in FG_message ==
fragment number of current message OR number of
fragments (from the Value field of the TLV with Type
== FRAGMENTATION) of FG_message != number of fragments
of current message;
then remove these Fragment Tuples from the Fragment Set;
4. If the Fragment Set includes Fragment Tuples containing
all the remaining fragments of the same overall message
as the current message, i.e. if the number of Fragment
Tuples such that:
- either the typedepseq bit in the Value field of the
TLV with Type == FRAGMENTATION in the current message
is cleared ('0') OR message type of FG_message ==
message type of current message, AND;
- originator address of FG_message == originator address
of current message, AND;
- content sequence number (the Value field of the
message TLV with Type == CONT_SEQ_NUM) of FG_message
== content sequence number of current message
is equal to (number of fragments of current message, less
one) then all of these Fragment Tuples are removed from
the Fragment Set and their messages processed according
to their type (taking account of any previous processing
of any which are partially or wholly self-contained);
5. Otherwise, a Fragment Tuple is added to the Fragment Set
with
- FG_message = current message;
- FG_time = current time + FG_HOLD_TIME;
possibly replacing a previously received instance of the
same fragment.
4.4. Message Considered for Forwarding 7.4. Message Considered for Forwarding
If a message is considered for forwarding, and it is either of a If a message is considered for forwarding, and it is either of a
message type defined in this document or of an unknown message type, message type defined in this document or of an unknown message type,
then it MUST use the following algorithm. A message type not defined then it MUST use the following algorithm. A message type not defined
in this document MAY specify the use of this, or another algorithm. in this document MAY specify the use of this, or another algorithm.
(Such an other algorithm MAY use the Received Set for the receiving (Such an other algorithm MAY use the Received Set for the receiving
interface, it SHOULD use the Forwarded Set similarly to the following interface, it SHOULD use the Forwarded Set similarly to the following
algorithm.) algorithm.)
If a message is considered for forwarding according to this If a message is considered for forwarding according to this
algorithm, the following tasks MUST be performed: algorithm, the following tasks MUST be performed:
1. If the sending interface (as indicated by the source interface of 1. If the sending interface (as indicated by the source interface of
the IP datagram containing the message) does not match (taking the IP datagram containing the message) does not match (taking
into account any address prefix of) any N_neighbor_iface_addr in into account any address prefix of) any N_neighbor_iface_addr in
any Symmetric Neighbor Tuple, then the message MUST be silently any Symmetric Neighbor Tuple, then the message MUST be silently
discarded. discarded.
2. Otherwise: 2. Otherwise:
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cleared ('0'); cleared ('0');
- RX_orig_addr = originator address of the message; - RX_orig_addr = originator address of the message;
- RX_seq_number = sequence number of the message; - RX_seq_number = sequence number of the message;
- RX_time = current time + RX_HOLD_TIME. - RX_time = current time + RX_HOLD_TIME.
2. If an entry exists in the Forwarded Set where: 2. If an entry exists in the Forwarded Set where:
- FW_type == the message type, or 0 if the typedep bit - F_type == the message type, or 0 if the typedep bit in
in the message semantics octet (in the message header) the message semantics octet (in the message header) is
is cleared ('0'); cleared ('0');
- F_orig_addr == the originator address of the received
- FW_orig_addr == the originator address of the received
message, AND; message, AND;
- FW_seq_number == the sequence number of the received - F_seq_number == the sequence number of the received
message. message.
then the message MUST be silently discarded. then the message MUST be silently discarded.
3. Otherwise if a Relay Tuple exists whose RY_iface_addr 3. Otherwise if a Relay Tuple exists whose RY_iface_addr
matches (taking into account any address prefix) the matches (taking into account any address prefix) the
sending interface (as indicated by the source interface sending interface (as indicated by the source interface
of the IP datagram containing the message): of the IP datagram containing the message):
1. Create an entry in the Forwarded Set with: 1. Create an entry in the Forwarded Set with:
o FW_type = the message type, or 0 if the typedep o F_type = the message type, or 0 if the typedep bit
bit in the message semantics octet (in the message in the message semantics octet (in the message
header) is cleared ('0'); header) is cleared ('0');
o FW_orig_addr = originator address of the message; o F_orig_addr = originator address of the message;
o FW_seq_number = sequence number of the message;
o FW_time = current time + FW_HOLD_TIME. o F_seq_number = sequence number of the message;
o F_time = current time + F_HOLD_TIME.
2. The message header is modified as follows: 2. The message header is modified as follows:
o Decrement <hop-limit> in the message header by 1; o Decrement <hop-limit> in the message header by 1;
o Increment <hop-count> in the message header by 1; o Increment <hop-count> in the message header by 1;
3. Transmit the message on all OLSRv2 interfaces of the 3. Transmit the message on all OLSRv2 interfaces of the
node. node.
Messages are retransmitted in the format specified by [3] with the Messages are retransmitted in the format specified by [3] with the
ALL-MANET-NEIGHBORS address (see Section 16.1) as destination IP ALL-MANET-NEIGHBORS address (see [4]) as destination IP address.
address.
5. Information Repositories 8. Information Repositories
The purpose of OLSRv2 is to determine the Routing Set, which may be The purpose of OLSRv2 is to determine the Routing Set, which may be
used to update IP's Routing Table, providing "next hop" routing used to update IP's Routing Table, providing "next hop" routing
information for IP datagrams. In order to accomplish this, OLSRv2 information for IP datagrams. In order to accomplish this, OLSRv2
uses a number of protocol sets: the Neighborhood Information Base, uses a number of protocol sets: the Neighborhood Information Base,
provided by [4], is in OLSRv2 augmented by information allowing MPR provided by [4], is in OLSRv2 augmented by information allowing MPR
selection and signaling. Additionally, OLSRv2 specifies a Topology selection and signaling. Additionally, OLSRv2 specifies a Topology
Information Base, which describes the information used for and Information Base, which describes the information used for and
acquired through TC message exchange - in other words: the topology acquired through TC message exchange - in other words: the Topology
base represents the network topology graph as seen from each node. Information Base represents the network topology graph as seen from
each node.
Addresses (other than originator addresses) recorded in the Addresses (other than originator addresses) recorded in the
Neighborhood Information Base and the Topology Information Base MUST Neighborhood Information Base and the Topology Information Base MUST
all be recorded with prefix lengths, in order to allow comparison all be recorded with prefix lengths, in order to allow comparison
with addresses received in HELLO and TC messages. For the Topology with addresses received in HELLO and TC messages.
Information Base this applies to A_neighbor_iface_addr,
T_dest_iface_addr, T_last_iface_addr, AN_net_addr, AN_gw_iface_addr,
R_dest_addr, R_dest_addr, R_next_iface_addr and R_local_iface_addr,
but not AH_orig_addr. For the Neighborhood Information Base see [4].
5.1. Neighborhood Information Base 8.1. Neighborhood Information Base
The neighborhood information base stores information about links The Neighborhood Information Base stores information about links
between local interfaces and interfaces on adjacent nodes. In between local interfaces and interfaces on adjacent nodes. In
addition to the sets described in [4], OLSRv2 adds an element to each addition to the sets described in [4], OLSRv2 adds an element to each
Link Tuple to allow a node to record the willingness of a 1-hop Link Tuple to allow a node to record the willingness of a 1-hop
neighbor node to be selected as an MPR. Also, OLSRv2 adds an MPR Set neighbor node to be selected as an MPR. Also, OLSRv2 adds an MPR Set
and an MPR Selector Set to the Neighborhood Information Base. The and an MPR Selector Set to the Neighborhood Information Base. The
MPR Set is used by a node to record which of its symmetric 1-hop MPR Set is used by a node to record which of its symmetric 1-hop
neighbors are selected as MPRs, and the MPR Selector Set is used by a neighbors are selected as MPRs, and the MPR Selector Set is used by a
node to record which of its symmetric 1-hop neighbors have selected node to record which of its symmetric 1-hop neighbors have selected
it as MPR. Thus the MPR Set is used, in addition to what is it as MPR. Thus, in addition to what is specified in [4], the MPR
specified in [4], when generating HELLO messages, and the MPR Set is used when generating HELLO messages, and the MPR Selector Set
Selector Set is populated, in addition to what is specified in [4] is populated when processing HELLO messages.
when processing HELLO messages.
5.1.1. Link Set 8.1.1. Link Set
The Link Tuples, specified in [4] are augmented by an element, Link Tuples are as specified in [4], augmented with:
L_willingness:
L_willingness is the node's willingness to be selected as an MPR; L_willingness is the node's willingness to be selected as an MPR;
The remaining elements of the Link Tuples are as specified in [4]. 8.1.2. MPR Set
5.1.2. MPR Set A node's MPR Set contains OLSRv2 interface addresses with which the
node has a symmetric link and which are of 1-hop symmetric neighbors
which the node has selected as MPRs:
A node maintains a set of all of the OLSRv2 interface addresses with (MP_neighbor_iface_addr)
which the node has a symmetric link and which are of 1-hop symmetric
neighbors which the node has selected as MPRs. This is denoted the
"MPR Set".
5.1.3. MPR Selector Set 8.1.3. MPR Selector Set
A node maintains a set of "MPR Selector Tuples" containing all of the A node's MPR Selector Set records the nodes which have selected this
OLSRv2 interface addresses with which the node has a symmetric link node as an MPR. It consists of MPR Selector Tuples:
and which are of 1-hop symmetric neighbors which have selected the
node as an MPR.
(MS_neighbor_iface_addr, MS_time) (MS_neighbor_iface_addr, MS_time)
MS_neighbor_iface_addr specifies an OLSRv2 interface address with where:
which the node has a symmetric link and which is of a 1-hop
symmetric neighbor which has selected the node as an MPR;
MS_time specifies the time at which this MPR Selector Tuple expires MS_neighbor_iface_addr is an OLSRv2 interface address with which
and *MUST* be removed. this node has a symmetric link and which is of a 1-hop symmetric
neighbor which has selected this node as an MPR;
In a node, the set of MPR Selector Tuples is denoted the "MPR MS_time specifies the time at which this Tuple expires and MUST be
Selector Set". removed.
5.2. Topology Information Base 8.2. Topology Information Base
The Topology Information Base stores information, required for the The Topology Information Base stores information, required for the
generation and processing of TC messages. The Advertised Neighbor generation and processing of TC messages. The Advertised Neighbor
Set contains OLSRv2 interface addresses of symmetric 1-hop neighbors Set contains OLSRv2 interface addresses of symmetric 1-hop neighbors
which are to be reported in TC messages. The Topology Set and which are to be reported in TC messages. The Topology Set and
Attached Network Set both record information received through TC Attached Network Set both record information received through TC
messages. Thus the Advertised Neighbor Set is used for generating TC messages. Thus the Advertised Neighbor Set is used for generating TC
messages, while the Topology Set and Attached Network Set are messages, while the Topology Set and Attached Network Set are
populated when processing TC messages. populated when processing TC messages.
Additionally, a Routing Set is maintained, derived from the Additionally, a Routing Set is maintained, derived from the
information recorded in the Neighborhood Information Base, Topology information recorded in the Neighborhood Information Base, Topology
Set and Attached Network Set. Set and Attached Network Set.
5.2.1. Advertised Neighbor Set 8.2.1. Advertised Neighbor Set
A node maintains a set of OLSRv2 interface addresses of symmetric A node's Advertised Neighbor Set contains OLSRv2 interface addresses
1-hop neighbors, which are to be advertised through TC messages: of symmetric 1-hop neighbors which are to be advertised through TC
messages:
(A_neighbor_iface_addr) (A_neighbor_iface_addr)
For this set, an Advertised Neighbor Set Sequence Number (ANSN) is
In addition, an Advertised Neighbor Set Sequence Number (ANSN) is
maintained. Each time the Advertised Neighbor Set is updated, the maintained. Each time the Advertised Neighbor Set is updated, the
ANSN MUST be incremented. The ANSN MUST also be incremented if any ANSN MUST be incremented. The ANSN MUST also be incremented if there
locally advertised attached networks are added or removed. is a change to the set of Local Attached Network Tuples that are to
be advertised in the node's TC messages.
5.2.2. ANSN History Set 8.2.2. ANSN History Set
A node records a set of "ANSN History Tuples", recording information A node's ANSN History Set records information about the freshness of
about the freshness of the topology information received from each the topology information received from each other node. It consists
other node: of ANSN History Tuples:
(AH_orig_addr, AH_seq_number, AH_time) (AH_orig_addr, AH_seq_number, AH_time)
AH_orig_addr is the originator address of a received TC message; where:
AH_orig_addr is the originator address of a received TC message,
note that this does not include a prefix length;
AH_seq_number is the highest ANSN in any TC message received which AH_seq_number is the highest ANSN in any TC message received which
originated from AH_orig_addr; originated from AH_orig_addr;
AH_time is the time at which this ANSN History Tuple expires and AH_time is the time at which this Tuple expires and MUST be removed.
*MUST* be removed.
In a node, the set of ANSN History Tuples is denoted the "ANSN
History Set".
5.2.3. Topology Set 8.2.3. Topology Set
Each node in the network maintains topology information about the A node's Topology Set records topology information about the network.
network in the form of "Topology Tuples": It consists of Topology Tuples:
(T_dest_iface_addr, T_last_iface_addr, T_seq_number, T_time) (T_dest_iface_addr, T_last_iface_addr, T_seq_number, T_time)
where:
T_dest_iface_addr is an OLSRv2 interface address of a destination T_dest_iface_addr is an OLSRv2 interface address of a destination
node, which may be reached in one hop from the node with the node, which may be reached in one hop from the node with the
OLSRv2 interface address T_last_iface_addr; OLSRv2 interface address T_last_iface_addr;
T_last_iface_addr is, conversely, an OLSRv2 interface address of a T_last_iface_addr is, conversely, an OLSRv2 interface address of a
node which is the last hop on a path towards the node with OLSRv2 node which is the last hop on a path towards the node with OLSRv2
interface address T_dest_iface_addr. Typically, the node with interface address T_dest_iface_addr.
OLSRv2 interface address T_last_iface_addr is a MPR of the node
with OLSRv2 interface address T_dest_iface_addr;
T_seq_number is the highest received ANSN associated with the T_seq_number is the highest received ANSN associated with the
information contained in this Topology Tuple; information contained in this Topology Tuple;
T_time specifies the time at which this Topology Tuple expires and T_time specifies the time at which this Tuple expires and MUST be
*MUST* be removed. removed.
In a node, the set of Topology Tuples is denoted the "Topology Set".
5.2.4. Attached Network Set 8.2.4. Attached Network Set
Each node in the network maintains information about attached A node's Attached Network Set records information about networks
networks in the form of "Attached Network Tuples": attached to other nodes. It consists of Attached Network Tuples:
(AN_net_addr, AN_gw_iface_addr, AN_seq_number, AN_time) (AN_net_addr, AN_gw_iface_addr, AN_dist, AN_seq_number, AN_time)
where:
AN_net_addr is the network address (including prefix length) of an AN_net_addr is the network address of an attached network, which may
attached network, which may be reached via the node with the be reached via the node with the OLSRv2 interface address
OLSRv2 interface address AN_gw_iface_addr; AN_gw_iface_addr;
AN_gw_iface_addr is the address of an OLSRv2 interface of a node AN_gw_iface_addr is the address of an OLSRv2 interface of a node
which can act as gateway to the network identified by AN_net_addr; which can act as gateway to the network with address AN_net_addr;
AN_dist is the number of hops to the network with address
AL_net_addr from the node with address AN_gw_iface_addr.
AN_seq_number is the highest received ANSN associated with the AN_seq_number is the highest received ANSN associated with the
information contained in this Attached Network Tuple; information contained in this Attached Network Tuple;
AN_time specifies the time at which this Attached Network Tuple AN_time specifies the time at which this Tuple expires and MUST be
expires and *MUST* be removed. removed.
In a node, the set of Attached Network Tuples is denoted the
"Attached Network Set".
5.2.5. Routing Set 8.2.5. Routing Set
A node records a set of "Routing Tuples" describing the selected path A node's Routing Set records the selected path to each destination
to each destination in the network for which a route is known: for which a route is known. It consists of Routing Tuples:
(R_dest_addr, R_next_iface_addr, R_dist, R_local_iface_addr) (R_dest_addr, R_next_iface_addr, R_dist, R_local_iface_addr)
where:
R_dest_addr is the address of the destination, either the address of R_dest_addr is the address of the destination, either the address of
an OLSRv2 interface of a destination node, or the network address an OLSRv2 interface of a destination node, or the network address
of an attached network; of an attached network;
R_next_iface_addr is the OLSRv2 interface address of the "next hop" R_next_iface_addr is the OLSRv2 interface address of the "next hop"
on the selected path to the destination; on the selected path to the destination;
R_dist is the number of hops on the selected path to the destination; R_dist is the number of hops on the selected path to the
destination;
R_local_iface_addr is the address of the local interface over which a
packet MUST be sent to reach the destination.
In a node, the set of Routing Tuples is denoted the "Routing Set". R_local_iface_addr is the address of the local interface over which
a packet MUST be sent to reach the destination.
6. OLSRv2 Control Message Structures 9. Control Message Structures
Nodes using OLSRv2 exchange information through messages. One or Nodes using OLSRv2 exchange information through messages. One or
more messages sent by a node at the same time are combined into a more messages sent by a node at the same time SHOULD be combined into
packet. These messages may have originated at the sending node, or a single packet. These messages may have originated at the sending
have originated at another node and forwarded by the sending node. node, or have originated at another node and are forwarded by the
Messages with different originators may be combined in the same sending node. Messages with different originators may be combined in
packet. the same packet.
The packet and message format used by OLSRv2 is defined in [3]. The packet and message format used by OLSRv2 is defined in [3].
However this specification contains some options which are not used However this specification contains some options which are not used
by OLSRv2. In particular (using the syntactical elements defined in by OLSRv2. In particular (using the syntactical entities defined in
the packet format specification): [3]):
o All OLSRv2 packets, not limited to those defined in this document, o All OLSRv2 packets, not limited to those defined in this document,
include a <packet-header>. include a <packet-header>.
o All OLSRv2 packets, not limited to those defined in this document, o All OLSRv2 packets, not limited to those defined in this document,
have the pseqnum bit of <packet-semantics> cleared ('0'), i.e. have the pseqnum bit of <packet-semantics> cleared ('0'), i.e.
they include a packet sequence number. they include a packet sequence number.
o OLSRv2 packets MAY include packet TLVs, however OLSRv2 itself does o OLSRv2 packets MAY include packet TLVs, however OLSRv2 itself does
not specify any packet TLVs. not specify any packet TLVs.
o All OLSRv2 messages, not limited to those defined in this o All OLSRv2 messages, not limited to those defined in this
document, include a full <msg-header> and hence have the noorig document, include a full <msg-header> and hence have the noorig
and nohops bits of <msg-semantics> cleared ('0'). and nohops bits of <msg-semantics> cleared ('0').
o All OLSRv2 message defined in this document have the typedep bit, o All OLSRv2 message defined in this document have the typedep bit
and all reserved bits of <msg-semantics> cleared ('0'). of <msg-semantics> cleared ('0').
Other options defined in [3] may be freely used, in particular any Other options defined in [3] may be freely used, in particular any
other values of <packet-semantics> or <tlv-semantics> consistent with other values of <packet-semantics>, <addr-semantics> or <tlv-
its specification. semantics> consistent with its specification.
OLSRv2 messages are sent using UDP, see Appendix C.
The remainder of this section defines, within the framework of [3], The remainder of this section defines, within the framework of [3],
message types and TLVs specific to OLSRv2. message types and TLVs specific to OLSRv2.
6.1. General OLSRv2 Message TLVs 9.1. HELLO Messages
This document specifies two message TLVs, which can be applied to any
OLSRv2 control messages, VALIDITY_TIME and INTERVAL_TIME.
6.1.1. VALIDITY_TIME TLV
All OLSRv2 messages specified in this document MUST include a
VALIDITY_TIME TLV, specifying a period following receipt of a
message, after which the receiving node MUST consider the message
content to no longer be valid (unless repeated in a later message).
The validity time of a message MAY be specified to depend on the
distance from the originator (i.e. the <hop-count> field in the
message header as defined in [3]). Thus, a VALIDITY_TIME TLV's value
field MAY contain a sequence of pairs (time, hop limit) in increasing
hop limit order; it MUST contain a final default value.
This is an extended, and compatible, version of the VALIDITY_TIME TLV
defined in [4].
Thus, an instance of a VALIDITY_TIME TLV MAY have the following value
field:
<t_1><hl_1><t_2><hl_2> ... <t_i><hl_i> .... <t_n><hl_n><t_default>
Which would mean that the message carrying this VALIDITY_TIME TLV
would have the following validity times:
o <t_1> in the interval from 0 (exclusive) to <hl_1> (inclusive)
hops away from the originator;
o <t_i> in the interval from <hl_(i-1)> (exclusive) to <hl_i>
(inclusive) hops away from the originator;
o <t_default> in the interval from <hl_n> (exclusive) to 255
(inclusive) hops away from the originator.
The VALIDITY_TIME message TLV specification is given in Table 1.
+----------------+------+-------------------+-----------------------+
| Name | Type | Length | Value |
+----------------+------+-------------------+-----------------------+
| VALIDITY_TIME | TBD | (2*n+1) * 8 bits | {<time><hop_limit>}* |
| | | | <t_default> |
+----------------+------+-------------------+-----------------------+
Table 1
where n is the number of (time, hop_limit) pairs in the TLV (i.e. is
equal to (<length>-1)/2, where <length> is the length of the TLV
value field) and where <time> and <t_default> are represented as
specified in [3].
6.2. HELLO Messages
A HELLO message in OLSRv2 is generated as specified in [4]. A HELLO message in OLSRv2 is generated as specified in [4].
Additionally, an OLSRv2 node: Additionally, an OLSRv2 node:
o MUST include TLV(s) with Type == MPR associated with all OLSRv2 o MUST include TLV(s) with Type == MPR associated with all OLSRv2
interface addresses included in the HELLO message with a TLV with interface addresses included in the HELLO message with a TLV with
Type == LINK_STATUS and Value == SYMMETRIC if that address is also Type == LINK_STATUS and Value == SYMMETRIC if that address is also
included in the node's MPR Set (if there is more than one copy of included in the node's MPR Set (if there is more than one copy of
the address, this applies to the specific copy of the address to the address, this applies to the specific copy of the address to
which the TLV is associated); which the LINK_STATUS TLV is associated);
o MUST NOT include any TLVs with Type == MPR associated with any o MUST NOT include any TLVs with Type == MPR associated with any
other addresses; other addresses;
o MAY include a message TLV with Type == WILLINGNESS, indicating the o MAY include a message TLV with Type == WILLINGNESS, indicating the
node's willingness to be selected as MPR. node's willingness to be selected as an MPR.
6.2.1. HELLO Message OLSRv2 Message TLVs 9.1.1. HELLO Message TLVs
In a HELLO message, a node MAY include a WILLINGNESS message TLV as In a HELLO message, a node MAY include a WILLINGNESS message TLV as
specified in Table 2. specified in Table 1.
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
| WILLINGNESS | TBD | 8 bits | The node's | | WILLINGNESS | TBD | 8 bits | The node's |
| | | | willingness to be | | | | | willingness to be |
| | | | selected as MPR, any | | | | | selected as MPR; |
| | | | unused bits (based on | | | | | unused bits (based on |
| | | | the maximum | | | | | the maximum |
| | | | willingness value | | | | | willingness value |
| | | | WILL_ALWAYS) are | | | | | WILL_ALWAYS) are |
| | | | RESERVED and SHOULD | | | | | RESERVED and SHOULD |
| | | | be set to zero. | | | | | be set to zero |
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
Table 2 Table 1
A node's willingness to be selected as MPR ranges from WILL_NEVER A node's willingness to be selected as MPR ranges from WILL_NEVER
(indicating that a node MUST NOT be selected as MPR by any node) to (indicating that a node MUST NOT be selected as MPR by any node) to
WILL_ALWAYS (indicating that a node MUST always be selected as MPR). WILL_ALWAYS (indicating that a node MUST always be selected as MPR).
If a node does not advertise a Willingness TLV in HELLO messages, the If a node does not advertise a Willingness TLV in HELLO messages, the
node MUST be assumed to have a willingness of WILL_DEFAULT. node MUST be assumed to have a willingness of WILL_DEFAULT.
6.2.2. HELLO Message OLSRv2 Address Block TLVs 9.1.2. HELLO Message Address Block TLVs
In a HELLO message, a node MAY include MPR address block TLV(s) as In a HELLO message, a node MAY include MPR address block TLV(s) as
specified in Table 3. specified in Table 2.
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+----------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+----------------------+
| MPR | TBD | 0 bits | No value, i.e. | | MPR | TBD | 0 bits | None |
| | | | novalue bit ([3]) set | +----------------+------+-------------------+----------------------+
+----------------+------+-------------------+-----------------------+
Table 3 Table 2
6.3. TC Messages 9.2. TC Messages
A TC message MUST contain: A TC message MUST contain:
o a message TLV with Type == CONT_SEQ_NUM, as specified in [3]; o A message TLV with Type == CONT_SEQ_NUM, as specified in
Section 9.2.1.
o a message TLV with Type == VALIDITY_TIME, as specified in o A message TLV with Type == VALIDITY_TIME, as specified in
Section 6.1.1; Appendix E.
o a first address block containing all of the node's OLSRv2 o A first address block containing all of the node's OLSRv2
interface addresses. This is similar to the Local Interface Block interface addresses. This is similar to the Local Interface Block
specified in [4], however these addresses MUST be included in the included in HELLO messages as specified in [4], however in a TC
same order in all copies of a given TC message, regardless of message these addresses MUST be included in the same order in all
which interface it is transmitted on, and no OTHER_IF address copies of a given TC message, regardless of which OLSRv2 interface
block TLV(s) are required; it is transmitted on, and no OTHER_IF address block TLVs are
required.
o additional address block(s) containing all addresses in the o Additional address block(s) containing all addresses in the
Advertised Address Set and Attached Network Set, the latter (only) Advertised Address Set and selected addresses in the Local
with associated GATEWAY address block TLV(s), as specified in Attached Network Set, the latter (only) with associated GATEWAY
Section 6.4, both with associated PREFIX_LENGTH TLV(s), as address block TLV(s), as specified in Section 9.2.2.
specified in [3], as necessary.
A TC message MAY contain: A TC message MAY contain:
o a message TLV INTERVAL_TIME, as specified in [4]. o A message TLV with Type == INTERVAL_TIME, as specified in
Appendix E.
6.4. TC Message: OLSRv2 Address Block TLVs o A message TLV with Type == INCOMPLETE, as specified in
Section 9.2.1.
9.2.1. TC Message TLVs
In a TC message, a node MUST include a CONT_SEQ_NUM message TLV, and
MAY contain an INCOMPLETE message TLV, as specified in Table 3.
+----------------+------+-------------------+-----------------------+
| Name | Type | Length | Value |
+----------------+------+-------------------+-----------------------+
| CONT_SEQ_NUM | TBD | 8 bits | The ANSN contained in |
| | | | the Advertised |
| | | | Neighbor Set |
| | | | |
| INCOMPLETE | TBD | 0 bits | None |
+----------------+------+-------------------+-----------------------+
Table 3
9.2.2. TC Message Address Block TLVs
In a TC message, a node MAY include GATEWAY address block TLV(s) as In a TC message, a node MAY include GATEWAY address block TLV(s) as
specified in Table 4. specified in Table 4.
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
| GATEWAY | TBD | 0 bits | No value, i.e. | | GATEWAY | TBD | 8 bits | Number of hops to |
| | | | novalue bit ([3]) set | | | | | attached network |
+----------------+------+-------------------+-----------------------+ +----------------+------+-------------------+-----------------------+
Table 4 Table 4
7. HELLO Message Generation 10. HELLO Message Generation
An OLSRv2 HELLO message is composed as defined in [4], with the An OLSRv2 HELLO message is composed as defined in [4], with the
following TLVs added: following additions:
o a message TLV with Type == WILLINGNESS and Value == the node's o A message TLV with Type == WILLINGNESS and Value == the node's
willingness to act as an MPR, MAY be included in the message; willingness to act as an MPR, MAY be included.
o for each symmetric 1-hop neighbor OLSRv2 interface address which o For each address which is included in the message with an
is included in the HELLO message with an associated TLV with Type associated TLV with Type == LINK_STATUS, and is of an MPR (i.e. is
== LINK_STATUS and is selected as an MPR (i.e. is present in the an MP_neighbor_iface_addr), an address TLV with Type == MPR MUST
MPR Set), an address TLV with Type == MPR MUST be included, this be included; this TLV MUST be associated with the same copy of the
SHOULD be associated with the same copy of the address as the TLV address as is the TLV with Type == LINK_STATUS.
with Type == LINK_STATUS;
o for each 1-hop neighbor OLSRv2 interface address which is included o For address which is included in the message and is not of an MPR
in the HELLO message but is not selected as an MPR (i.e. is not (i.e. is not an MP_neighbor_iface_addr) or is not associated with
present in the MPR Set), an address TLV with Type == MPR MUST NOT a TLV with Type == LINK_STATUS, an address TLV with Type == MPR
be included. MUST NOT be included.
7.1. HELLO Message: Transmission o For each Local Attached Tuple with AL_dist == 0, a node MAY
include AL_net_addr in the Local Interface Block of the message,
with an associated TLV with Type == OTHER_IF.
Messages are retransmitted in the packet/message format specified by 10.1. HELLO Message: Transmission
[3] with the ALL-MANET-NEIGHBORS address as destination IP address
and with TTL (IPv4) or hop limit (IPv6) equal to 1.
8. HELLO Message Processing HELLO messages are included in packets as specified in [3]. These
packets may contain other messages, including TC messages.
11. HELLO Message Processing
Subsequent to the processing of HELLO messages, as specified in [4], Subsequent to the processing of HELLO messages, as specified in [4],
the node MUST: the node MUST:
1. Determine the willingness of the originating node to be an MPR 1. Determine the willingness of the originating node to be an MPR
by: by:
* if the HELLO message contains a message TLV with Type == * if the HELLO message contains a message TLV with Type ==
WILLINGNESS then the willingness is the value of that TLV, WILLINGNESS then the willingness is the value of that TLV,
ignoring the reserved bits in that field; ignoring the reserved bits in that field;
* otherwise the willingness is WILL_DEFAULT. * otherwise the willingness is WILL_DEFAULT.
2. Update each Link Tuple whose L_neighbor_iface_addr is present in 2. Update each Link Tuple for which any address in its
the Local Interface Block of the HELLO message, with: L_neighbor_iface_addr_list is present in the Local Interface
Block of the HELLO message, with:
* L_willingness = the willingness of the originating node; * L_willingness = the willingness of the originating node.
3. Update its MPR Selector Set, according to Section 8.1. 3. Update its MPR Selector Set, according to Section 11.1.
8.1. Populating the MPR Selector Set 11.1. Populating the MPR Selector Set
On receiving a HELLO message, a node MUST: On receiving a HELLO message:
1. If a node finds one of its own interface addresses with an 1. If a node finds one of its OLSRv2 interface addresses with an
associated TLV with Type == MPR in the HELLO message (indicating associated TLV with Type == MPR in the HELLO message (indicating
that the originator node has selected the receiving node as an that the originator node has selected the receiving node as an
MPR), the MPR Selector Set MUST be updated as follows: MPR), the MPR Selector Set MUST be updated as follows:
1. For each address, henceforth neighbor address, in the Local 1. For each address, henceforth neighbor address, in the Local
Interface Block of the received HELLO message, where the Interface Block of the received HELLO message, where the
neighbor address is present as an N_neighbor_iface_addr in a neighbor address is present as an N_neighbor_iface_addr in a
Symmetric Neighbor Tuple with N_STATUS == SYMMETRIC: Symmetric Neighbor Tuple with N_STATUS == SYMMETRIC:
1. If there exists no MPR Selector Tuple with: 1. If there exists no MPR Selector Tuple with:
skipping to change at page 30, line 51 skipping to change at page 28, line 4
- MS_neighbor_iface_addr == neighbor address - MS_neighbor_iface_addr == neighbor address
then a new MPR Selector Tuple is created with: then a new MPR Selector Tuple is created with:
- MS_neighbor_iface_addr = neighbor address - MS_neighbor_iface_addr = neighbor address
2. The MPR Selector Tuple (new or otherwise) with: 2. The MPR Selector Tuple (new or otherwise) with:
- MS_neighbor_iface_addr == neighbor address - MS_neighbor_iface_addr == neighbor address
is then modified as follows: is then modified as follows:
- MS_time = current time + validity time - MS_time = current time + validity time
2. Otherwise if a node finds one of its own interface addresses with 2. Otherwise if a node finds one of its own interface addresses with
an associated TLV with Type == LINK_STATUS and Value == SYMMETRIC an associated TLV with Type == LINK_STATUS and Value == SYMMETRIC
in the HELLO message (indicating, since there is no TLV with Type in the HELLO message, the MPR Selector Set MUST be updated as
== MPR, that originator node has de-selected the receiving node follows:
as an MPR), the MPR Selector Set MUST be updated as follows:
1. All MPR Selector Tuples whose N_neighbor_iface_addr is in the 1. All MPR Selector Tuples whose MS_neighbor_iface_addr is in
Local Interface Block of the HELLO message are removed. the Local Interface Block of the HELLO message are removed.
MPR Selector Tuples are also removed upon expiration of MS_time, or MPR Selector Tuples are also removed upon expiration of MS_time, or
upon symmetric link breakage as described in Section 8.2. upon symmetric link breakage as described in Section 11.2.
8.2. Symmetric Neighborhood and 2-Hop Neighborhood Changes 11.2. Symmetric Neighborhood and 2-Hop Neighborhood Changes
A node MUST also perform the following: A node MUST also perform the following:
1. If a Link Tuple with L_STATUS == SYMMETRIC is removed, or its 1. If a Link Tuple with L_STATUS == SYMMETRIC is removed, or its
L_STATUS changes from SYMMETRIC to HEARD or LOST, and if that L_STATUS changes from SYMMETRIC to HEARD or LOST, and for each
Link Tuple's L_neighbor_iface_addr is an MS_iface_addr of an MPR address in that Link Tuple's L_neighbor_iface_addr_list, if it is
Selector Tuple, then that MPR Selector Tuple MUST be removed. an MS_neighbor_iface_addr of an MPR Selector Tuple, then that MPR
Selector Tuple MUST be removed.
2. If any of: 2. If any of:
* a Link Tuple is added with L_STATUS == SYMMETRIC, OR; * a Link Tuple is added with L_STATUS == SYMMETRIC, OR;
* a Link Tuple with L_STATUS == SYMMETRIC is removed, or its * a Link Tuple with L_STATUS == SYMMETRIC is removed, or its
L_STATUS changes from SYMMETRIC to HEARD or LOST, or vice L_STATUS changes from SYMMETRIC to HEARD or LOST, or vice
versa, OR; versa, OR;
* a 2-Hop Neighbor Tuple is added or removed, OR; * a 2-Hop Neighbor Tuple is added or removed, OR;
* the Neighbor Address Association Set is changed such that the * the Neighbor Address Association Set is changed such that the
subset of any NA_neighbor_iface_addr_list consisting of those subset of any NA_neighbor_iface_addr_list consisting of those
addresses which are the L_neighbor_iface_addr of a Link Tuple addresses which are in the L_neighbor_iface_addr_list of a
with L_STATUS == SYMMETRIC is changed, including the cases of Link Tuple with L_STATUS == SYMMETRIC is changed, including
removal or addition of a Neighbor Address Association Tuple the cases of removal or addition of a Neighbor Address
containing any such addresses; Association Tuple containing any such addresses;
then the MPR Set MUST be recalculated. then the MPR Set MUST be recalculated.
An additional HELLO message MAY be sent when the MPR Set changes, in An additional HELLO message MAY be sent when the MPR Set changes, in
addition to the cases specified in [4], and subject to the same addition to the cases specified in [4], and subject to the same
constraints. constraints.
9. TC Message Generation 12. TC Message Generation
A node with one or more OLSRv2 interfaces, and with a non-empty A node with one or more OLSRv2 interfaces, and with a non-empty
Advertised Neighbor Set or which acts as a gateway to an associated Advertised Neighbor Set or which acts as a gateway to an associated
network which is to be advertised in the MANET, MUST generate TC network which is to be advertised in the MANET, MUST generate TC
messages. A node with an empty Advertised Neighbor Set and which is messages. A node with an empty Advertised Neighbor Set and which is
not acting as such a gateway SHOULD also generate "empty" TC messages not acting as such a gateway SHOULD also generate "empty" TC messages
for a period A_HOLD_TIME after it last generated a non-empty TC for a period A_HOLD_TIME after it last generated a non-empty TC
message. TC messages (non-empty and empty) are generated according message. TC messages (non-empty and empty) are generated according
to the following: to the following:
1. the TC message MUST contain a message TLV with Type == 1. The message hop count MUST be set to zero.
CONT_SEQ_NUM and Value == ANSN from the Advertised Neighbor Set;
2. the TC message MUST contain a message TLV with Type == 2. The message hop limit MAY be set to any positive value, this
VALIDITY_TIME and Value == T_HOLD_TIME as specified in SHOULD be at least two. A node MAY:
Section 6.1.1;
3. the TC message MAY contain a message TLV with Type == * use the same hop limit in all TC messages, this MUST be at
INTERVAL_TIME and Value == TC_INTERVAL as specified in [4]; least equal to the network diameter in hops, a value of 255 is
RECOMMENDED in this case; OR
4. the TC message MUST contain the addresses of all of its OLSRv2 * use different hop limits in TC messages, this MUST regularly
include messages with hop limit at least equal to the network
diameter, a value of 255 is RECOMMENDED for these messages;
other hop limits SHOULD use a regular pattern with a regular
interval at any given number of hops distance.
3. The message MUST contain a message TLV with Type == CONT_SEQ_NUM
and Value == ANSN from the Advertised Neighbor Set.
4. The message MUST contain a message TLV with Type ==
VALIDITY_TIME, as specified in Appendix E.2. If all TC messages
are sent with the same hop limit (usually 255) then this TLV MUST
have Value == T_HOLD_TIME. If TC messages are sent with
different hop limits, then this TLV MUST specify times which vary
with the number of hops distance appropriate to the chosen
pattern of TC message hop limits, these times SHOULD be
appropriate multiples of T_HOLD_TIME.
5. The message MAY contain a message TLV with Type == INTERVAL_TIME,
as specified in Appendix E.2. If all TC messages are sent with
the same hop limit (usually 255) then this TLV MUST have Value ==
TC_INTERVAL. If TC messages are sent with different hop limits,
then this TLV MUST specify times which vary with the number of
hops distance appropriate to the chosen pattern of TC message hop
limits, these times SHOULD be appropriate multiples of
TC_INTERVAL.
6. The message MUST contain the addresses of all of its OLSRv2
interfaces in its first address block, note that the TC message interfaces in its first address block, note that the TC message
generated on all OLSRv2 interfaces MUST be identical (including generated on all OLSRv2 interfaces MUST be identical (including
having identical message sequence number) and hence these having identical message sequence number) and hence these
addresses are not ordered or otherwise identified according to addresses are not ordered or otherwise identified according to
the interface on which the TC message is transmitted; the interface on which the TC message is transmitted.
5. the TC message MUST contain, in address blocks other than its 7. The message MUST contain, in address blocks other than its first:
first:
1. A_neighbor_iface_addr from each Advertised Neighbor Tuple; 1. A_neighbor_iface_addr from each Advertised Neighbor Tuple;
2. the addresses of all associated hosts and networks for which 2. AL_net_addr from each Local Attached Neighbor Tuple with
this node is to act as a gateway and which is to be AL_dist > 0, each associated with a TLV with Type == GATEWAY
advertised in the MANET, each associated with a TLV with Type and Value == AL_dist.
== GATEWAY.
6. the TC message MAY be fragmented, only by its originator. It 8. The message MAY contain, in address blocks other than its first:
SHOULD be fragmented only if necessary; if the TC message is
fragmented, a FRAGMENTATION TLV MUST be included, and each
fragment SHOULD be indicated as "partially or wholly self
contained" in it, and MUST indicate that the content sequence
number (ANSN) is message type specific.
9.1. TC Message: Transmission 1. AL_net_addr from each Local Attached Neighbor Tuple with
AL_dist == 0, each associated with a TLV with Type == GATEWAY
and Value == 0.
12.1. TC Message: Transmission
TC messages are generated and transmitted periodically on all OLSRv2 TC messages are generated and transmitted periodically on all OLSRv2
interfaces, with a default interval between two consecutive TC interfaces, with a default interval between two consecutive TC
emissions by the same node of TC_INTERVAL. TC messages MAY be emissions by the same node of TC_INTERVAL.
generated in response to a change of contents (a change in ANSN, due
to a change in the Advertised Neighbor Set or the advertised locally
attached networks) but a node must respect a minimum interval of
TC_MIN_INTERVAL between generated TC messages.
TC messages SHOULD be generated with a message hop limit [3] greater TC messages MAY be generated in response to a change of contents,
than or equal to the expected network diameter (by default with a hop indicated by a change in ANSN. In this case a node MAY send a
limit of 255). complete TC message, and if so MAY re-start its TC message schedule.
Alternatively a node MAY send only new content in its address blocks
(with appropriate associated TLVs) in which case it MUST include a
message TLV with Type == INCOMPLETE, and MUST NOT re-start its TC
message schedule. This TC message MUST include its usual message
TLVs. Note that a node cannot report removal of advertised content
using an incomplete TC message.
TC messages are transmitted with the ALL-MANET-NEIGHBORS multicast When sending a TC message in response to a change of contents, a node
address as destination IP address and are forwarded according to the must respect a minimum interval of TC_MIN_INTERVAL between generated
specification in Section 4.4. TC messages. Sending an incomplete TC message MUST NOT cause the
interval between complete TC messages to be increased, and thus a
node MUST NOT send an incomplete TC message if within TC_MIN_INTERVAL
of the next scheduled complete TC message.
10. TC Message Processing The generation of TC messages, whether scheduled or triggered by a
change of contents, and the forwarding of TC messages, MAY be
jittered as described in Appendix F. The values of MAXJITTER used
SHOULD be:
When according to Section 4.3 a TC message is to be processed o TP_MAXJITTER for periodic TC message generation;
according to its type, this means that processing is carried out
according to Section 10.1 and Section 10.2. The timing of this
processing depends on whether the TC message is a fragment, and if so
whether it is "partially or wholly self-contained":
o if the message is not a fragment, then first Section 10.1 and then o TT_MAXJITTER for triggered TC message generation;
Section 10.2 are carried out when the message is received;
o if the message is a fragment which is "partially or wholly self- o TF_MAXJITTER for TC message forwarding;
contained", then processing according to Section 10.1 is carried
out when the message is received, and processing according to
Section 10.2 is carried out when all matching fragments have been
received and all processing according to Section 10.1 has been
carried out;
o if the message is a fragment which is not "partially or wholly TC messages are included in packets as specified in [3]. These
self-contained", then processing according to Section 10.1 is packets may contain other messages, including HELLO messages and TC
carried out when all matching fragments have been received, and messages with different originator addresses. TC messages are
processing according to Section 10.2 is carried out when all forwarded according to the specification in Section 7.4.
matching fragments have been received and all processing according
to Section 10.1 has been carried out. 13. TC Message Processing
When according to Section 7.3 a TC message is to be processed
according to its type, this means that:
o if the message does not contain a message TLV with Type ==
INCOMPLETE, then processing according to Section 13.1 and then
according to Section 13.2 is carried out;
o if the message contains a message TLV with Type == INCOMPLETE,
then only processing according to Section 13.1 is carried out.
For all processing purposes, "ANSN" is defined as being the value of For all processing purposes, "ANSN" is defined as being the value of
the message TLV with Type == CONT_SEQ_NUM in the TC message. If a TC the message TLV with Type == CONT_SEQ_NUM in the TC message. If a TC
message has no such TLV then the processing of Section 10.1 and message has no such TLV then it MUST NOT be processed.
Section 10.2 MUST NOT be carried out. (Note that if the message is a
fragment it will have already been discarded according to
Section 4.3.) If more than one TC message is processed according to
Section 10.2 then these must have the same ANSN to be recognized as
fragments of the same message.
10.1. Single TC Message Processing 13.1. Initial TC Message Processing
For the purpose of this section, note the following: For the purposes of this section, note the following:
o "validity time" is calculated from the VALIDITY_TIME message TLV o "validity time" is calculated from the VALIDITY_TIME message TLV
in the TC message according to the specification in Section 6.1.1; in the TC message according to the specification in Appendix E.2;
o "originator address" refers to the originator address in the TC o "originator address" refers to the originator address in the TC
message header; message header;
o comparisons of sequence numbers are carried out as specified in o comparisons of sequence numbers are carried out as specified in
Section 15. Section 18.
The TC message is processed as follows: The TC message is processed as follows:
1. the ANSN History Set is updated according to Section 10.1.1; if 1. the ANSN History Set is updated according to Section 13.1.1; if
the TC message is indicated as discarded in that processing then the TC message is indicated as discarded in that processing then
the following steps are not carried out; the following steps are not carried out;
2. the Topology Set is updated according to Section 10.1.2; 2. the Topology Set is updated according to Section 13.1.2;
3. the Attached Network Set is updated according to Section 10.1.3. 3. the Attached Network Set is updated according to Section 13.1.3.
10.1.1. Populating the ANSN History Set 13.1.1. Populating the ANSN History Set
The node MUST update its ANSN History Set as follows: The node MUST update its ANSN History Set as follows:
1. if there is an ANSN History Tuple with: 1. If there is an ANSN History Tuple with:
* AH_orig_addr == originator address; AND * AH_orig_addr == originator address; AND
* AH_seq_number > ANSN * AH_seq_number > ANSN
then the TC message MUST be discarded; then the TC message MUST be discarded.
2. otherwise create a new ANSN History Tuple with: 2. Otherwise
* AH_orig_addr = originator address; 1. If there is no ANSN History Tuple such that:
* AH_seq_number = ANSN; + AH_orig_addr == originator address;
* AH_time = current time + validity time. then create a new ANSN History Tuple with:
possibly replacing an existing ANSN History Tuple with the same + AH_orig_addr = originator address.
AH_orig_addr.
10.1.2. Populating the Topology Set 2. This ANSN History Tuple (existing or new) is then modified as
follows:
The node SHOULD update its Topology Set as follows: + AH_seq_number = ANSN;
1. for each address, henceforth local address, in the first address + AH_time = current time + validity time.
13.1.2. Populating the Topology Set
The node MUST update its Topology Set as follows:
1. For each address, henceforth local address, in the first address
block in the TC message: block in the TC message:
1. for each address, henceforth advertised address, in an 1. For each address, henceforth advertised address, in an
address block other than the first in the TC message, and address block other than the first in the TC message, and
which does not have an associated TLV with Type == GATEWAY: which does not have an associated TLV with Type == GATEWAY:
1. if there is a Topology Tuple with: 1. If there is no Topology Tuple such that:
T_dest_iface_addr == advertised address; AND
T_last_iface_addr == local address
then update this Topology Tuple to have: - T_dest_iface_addr == advertised address; AND
T_seq_number = ANSN; - T_last_iface_addr == local address
T_time = current time + validity time then create a new Topology Tuple with:
2. otherwise create a new Topology Tuple with: - T_dest_iface_addr = advertised address;
T_dest_iface_addr = advertised address; - T_last_iface_addr = local address.
T_last_iface_addr = local address; 2. This Topology Tuple (existing or new) is then modified as
follows:
T_seq_number = ANSN; - T_seq_number = ANSN;
T_time = current time + validity time. - T_time = current time + validity time.
10.1.3. Populating the Attached Network Set 13.1.3. Populating the Attached Network Set
The node SHOULD update its Attached Network Set as follows: The node MUST update its Attached Network Set as follows:
1. for each address, henceforth gateway address, in the first 1. For each address, henceforth gateway address, in the first
address block in the TC message: address block in the TC message:
1. for each address, henceforth network address, in an address 1. For each address, henceforth network address, in an address
block other than the first in the TC message, and which has block other than the first in the TC message, and which has
an associated TLV with Type == GATEWAY: an associated TLV with Type == GATEWAY:
1. if there is a Attached Network Tuple with: 1. If there is no Attached Network Tuple such that:
AN_net_addr == network address; AND - AN_net_addr == network address; AND
AN_gw_iface_addr == gateway address - AN_gw_iface_addr == gateway address
then update this Attached Network Tuple to have: then create a new Attached Network Tuple with:
AN_seq_number = ANSN; - AN_net_addr = network address;
AN_time = current time + validity time - AN_gw_iface_addr = gateway address.
2. otherwise create a new Attached Network Tuple with: 2. This Attached Network Tuple (existing or new) is then
modified as follows:
AN_net_addr = network address; - AN_dist = the value of the associated GATEWAY TLV;
AN_gw_iface_addr = gateway address
AN_seq_number = ANSN; - AN_seq_number = ANSN;
AN_time = current time + validity time - AN_time = current time + validity time.
10.2. Completed TC Message Processing 13.2. Completing TC Message Processing
The TC message(s) are processed as follows: The TC message is processed as follows:
1. the Topology Set is updated according to Section 10.2.1; 1. the Topology Set is updated according to Section 13.2.1;
2. the Attached Network Set is updated according to Section 10.2.2. 2. the Attached Network Set is updated according to Section 13.2.2.
10.2.1. Purging the Topology Set 13.2.1. Purging the Topology Set
The Topology Set MUST be updated as follows: The Topology Set MUST be updated as follows:
1. for each address, henceforth local address, in the first address 1. for each address, henceforth local address, in the first address
block of any of the TC messages, all Topology Tuples with: block of the TC message, all Topology Tuples with:
T_last_iface_addr == local address; AND * T_last_iface_addr == local address; AND
T_seq_number < ANSN * T_seq_number < ANSN
MUST be removed. MUST be removed.
10.2.2. Purging the Attached Network Set 13.2.2. Purging the Attached Network Set
The Attached Network Set MUST be updated as follows: The Attached Network Set MUST be updated as follows:
1. for each address, henceforth local address, in the first address 1. for each address, henceforth local address, in the first address
block of any of the TC messages, all Attached Network Tuples block of the TC message, all Attached Network Tuples with:
with:
AN_gw_iface_addr == local address; AND * AN_gw_iface_addr == local address; AND
AN_seq_number < ANSN * AN_seq_number < ANSN
MUST be removed. MUST be removed.
11. Populating the MPR Set 14. Populating the MPR Set
Each node MUST select, from among its symmetric 1-hop neighbors, a Each node MUST select, from among its symmetric 1-hop neighbors, a
subset of nodes as MPRs. This subset MUST be selected such that a subset of nodes as MPRs. This subset MUST be selected such that a
message transmitted by the node, and retransmitted by all its MPRs, message transmitted by the node, and retransmitted by all its MPRs,
will be received by all of its symmetric strict 2-hop neighbors. will be received by all of its symmetric strict 2-hop neighbors.
Each node selects its MPR Set individually, utilizing the information Each node selects its MPR Set individually, utilizing the information
in the Symmetric Neighbor Set, the 2-Hop Neighbor Set and the in the Symmetric Neighbor Set, the 2-Hop Neighbor Set and the
Neighborhood Address Association Set. Initially these sets will be Neighborhood Address Association Set. Initially these sets will be
empty, as will be the MPR Set. A node SHOULD recalculate its MPR Set empty, as will be the MPR Set. A node SHOULD recalculate its MPR Set
skipping to change at page 38, line 37 skipping to change at page 36, line 37
while reducing the number of retransmissions that will occur in a while reducing the number of retransmissions that will occur in a
region. Thus, the concept of MPR is an optimization of a classical region. Thus, the concept of MPR is an optimization of a classical
flooding mechanism. While it is not essential that the MPR Set is flooding mechanism. While it is not essential that the MPR Set is
minimal, it is essential that all symmetric strict 2-hop neighbors minimal, it is essential that all symmetric strict 2-hop neighbors
can be reached through the selected MPR nodes. A node MUST select an can be reached through the selected MPR nodes. A node MUST select an
MPR Set such that any strict 2-hop neighbor is "covered" by at least MPR Set such that any strict 2-hop neighbor is "covered" by at least
one MPR node. A node MAY select additional MPRs beyond the minimum one MPR node. A node MAY select additional MPRs beyond the minimum
set. Keeping the MPR Set small ensures that the overhead of OLSRv2 set. Keeping the MPR Set small ensures that the overhead of OLSRv2
is kept at a minimum. is kept at a minimum.
Appendix A contains an example heuristic for selecting MPRs. Appendix C contains an example heuristic for selecting MPRs.
12. Populating Derived Sets 15. Populating Derived Sets
The Relay Set and the Advertised Neighbor Set of OLSRv2 are denoted The Relay Set and the Advertised Neighbor Set of OLSRv2 are denoted
derived sets, since updates to these sets are not directly a function derived sets, since updates to these sets are not directly a function
of message exchanges, but rather are derived from updates to other of message exchanges, but rather are derived from updates to other
sets, in particular the MPR Selector Set. sets, in particular the MPR Selector Set.
12.1. Populating the Relay Set 15.1. Populating the Relay Set
The Relay Set contains the set of neighbor addresses, for which a The Relay Set contains the set of OLSRv2 interface addresses of those
node is supposed to relay broadcast traffic. This set SHOULD at symmetric 1-hop neighbors for which a node is supposed to relay
least contain all addresses in the MPR Selector Set. This set MAY broadcast traffic. This set MUST at least contain all addresses in
contain additional symmetric 1-hop neighbor addresses. the MPR Selector Set (i.e. all MS_neighbor_iface_addr). This set MAY
contain additional symmetric 1-hop neighbor OLSRv2 interface
addresses.
12.2. Populating the Advertised Neighbor Set 15.2. Populating the Advertised Neighbor Set
The Advertised Neighbor Set contains the set of OLSRv2 interface The Advertised Neighbor Set contains the set of OLSRv2 interface
addresses of those 1-hop neighbors to which a node advertises a addresses of those 1-hop neighbors to which a node advertises a
symmetric link in TC messages. This set SHOULD at least contain all symmetric link in TC messages. This set MUST at least contain all
of the OLSRv2 interface addresses of the nodes in the MPR Selector addresses in the MPR Selector Set (i.e. all MS_neighbor_iface_addr).
Set (i.e. all addresses associated with an MPR Selector node through This set MAY contain additional symmetric 1-hop neighbor OLSRv2
the Neighborhood Address Association Set, that is, appearing in the interface addresses.
same NA_neighbor_iface_addr_list as any MS_neighbor_iface_addr).
This set MAY also contain OLSRv2 interface addresses of other
symmetric 1-hop neighbors.
Whenever an address is removed from the Advertised Neighbor Set, the Whenever an address is added to or removed from the Advertised
ANSN MUST be incremented. Whenever an address is added to the Neighbor Set, the ANSN MUST be incremented.
Advertised Neighbor Set, the ANSN MUST be incremented.
13. Routing Table Calculation 16. Routing Table Calculation
The Routing Set is updated when a change (an entry appearing or The Routing Set is updated when a change (an entry appearing or
disappearing, or changing between SYMMETRIC and LOST) is detected in: disappearing, or changing between SYMMETRIC and LOST) is detected in:
o the Link Set, OR; o the Link Set, OR;
o the Neighbor Address Association Set, OR; o the Neighbor Address Association Set, OR;
o the 2-Hop Neighbor Set, OR; o the 2-Hop Neighbor Set, OR;
o the Topology Set, OR; o the Topology Set, OR;
o the Attached Network Set. o the Attached Network Set.
Note that some changes to these sets do not necessitate a change to Note that some changes to these sets do not necessitate a change to
the Routing Set, in particular changes to the Link Set which do not the Routing Set, in particular changes to the Link Set which do not
involve Link Tuples with L_STATUS == SYMMETRIC (either before or involve Link Tuples with L_STATUS == SYMMETRIC (either before or
after the change), similar changes to the Neighbor Address after the change), and similar changes to the Neighbor Address
Association Set. A node MAY avoid updating the Routing Set in such Association Set. A node MAY avoid updating the Routing Set in such
cases. cases.
Updates to the Routing Set does not generate or trigger any messages Updates to the Routing Set do not generate or trigger any messages to
to be transmitted. The state of the Routing Set SHOULD, however, be be transmitted. The state of the Routing Set SHOULD, however, be
reflected in the IP routing table by adding and removing entries from reflected in the IP routing table by adding and removing entries from
the routing table as appropriate. the routing table as appropriate.
To construct the Routing Set of node X, a shortest path algorithm is To construct the Routing Set of node X, a shortest path algorithm is
run on the directed graph containing run on the directed graph containing
o the arcs X -> Y where there exists a Link Tuple with Y as o the arcs X -> Y where there exists a Link Tuple with Y in the
L_neighbor_iface_addr and L_STATUS == SYMMETRIC (i.e. Y is a L_neighbor_iface_addr_list and L_STATUS == SYMMETRIC (i.e. Y is a
symmetric 1-hop neighbor of X), AND; symmetric 1-hop neighbor of X), AND;
o the arcs Y -> Z where Y is added as above and the Link Tuple with o the arcs Y -> Z where Y is added as above and the Link Tuple with
Y as L_neighbor_iface_addr has L_willingness not equal to Y in its L_neighbor_iface_addr_list has L_willingness not equal to
WILL_NEVER, and there exists a 2-Hop Neighbor Tuple with Y as WILL_NEVER, and there exists a 2-Hop Neighbor Tuple with Y as
N2_neighbor_iface_addr and Z as N2_2hop_iface_addr (i.e. Z is a N2_neighbor_iface_addr and Z as N2_2hop_iface_addr (i.e. Z is a
symmetric 2-hop neighbor of Z through Y, which does not have symmetric 2-hop neighbor of Z through Y, which does not have
willingness WILL_NEVER), AND; willingness WILL_NEVER), AND;
o the arcs U -> V, where there exists a Topology Tuple with U as o the arcs U -> V, where there exists a Topology Tuple with U as
T_last_iface_addr and V as T_dest_iface_addr (i.e. this is an T_last_iface_addr and V as T_dest_iface_addr (i.e. this is an
advertised link in the network). advertised link in the network).
The graph is complemented with: The graph is complemented with:
o arcs Y -> W where there exists a Link Tuple with Y as o arcs Y -> W where there exists a Link Tuple with Y in its
L_neighbor_iface_addr and L_STATUS == SYMMETRIC and a Neighborhood L_neighbor_iface_addr_list and L_STATUS == SYMMETRIC and a
Address Association Tuple with Y and W both contained in Neighborhood Address Association Tuple with Y and W both contained
NA_neighbor_iface_addr_list (i.e. Y and W are both addresses of in its NA_neighbor_iface_addr_list (i.e. Y and W are both
the same symmetric 1-hop neighbor), AND; addresses of the same symmetric 1-hop neighbor), AND;
o arcs U -> T where there exists an Attached Network Tuple with U as o arcs U -> T where there exists an Attached Network Tuple with U as
AN_net_addr and T as AN_gw_iface_addr (i.e. U is a gateway to AN_net_addr and T as AN_gw_iface_addr (i.e. U is a gateway to
network T). network T).
The following procedure is given as an example for (re-)calculating The following procedure is given as an example for calculating the
the Routing Set using a variation of Dijkstra's algorithm. Thus: Routing Set using a variation of Dijkstra's algorithm. Thus:
1. All Routing Tuples are removed. 1. All Routing Tuples are removed.
2. For each Link Tuple with L_STATUS == SYMMETRIC, a new Routing 2. For each Link Tuple with L_STATUS == SYMMETRIC, and for each
Tuple is added with: address (henceforth neighbor address) in that Link Tuple's
L_neighbor_iface_addr_list, a new Routing Tuple is added with:
* R_dest_addr = L_neighbor_iface_addr of the Link Tuple; * R_dest_addr = neighbor address;
* R_next_iface_addr = L_neighbor_iface_addr of the Link Tuple; * R_next_iface_addr = neighbor address;
* R_dist = 1; * R_dist = 1;
* R_local_iface_addr = L_local_iface_addr of the Link Tuple. * R_local_iface_addr = neighbor address.
3. For each Neighbor Address Association Tuple, for which two 3. For each Neighbor Address Association Tuple, for which two
addresses A1 and A2 are in NA_neighbor_iface_addr_list where: addresses A1 and A2 are in NA_neighbor_iface_addr_list where:
* there is a Routing Tuple with: * there is a Routing Tuple with:
+ R_dest_addr == A1 + R_dest_addr == A1
* and there is no Routing Tuple with: * and there is no Routing Tuple with:
skipping to change at page 42, line 45 skipping to change at page 40, line 47
willingness, MPR selectors are preferred over non-MPR willingness, MPR selectors are preferred over non-MPR
selectors. selectors.
2. After the above iteration has completed, if h == 1, for each 2. After the above iteration has completed, if h == 1, for each
2-Hop Neighbor Tuple where: 2-Hop Neighbor Tuple where:
+ N2_2hop_iface_addr is not equal to R_dest_addr of any + N2_2hop_iface_addr is not equal to R_dest_addr of any
Routing Tuple, AND; Routing Tuple, AND;
+ N2_neighbor_iface_addr has a willingness (i.e. the + N2_neighbor_iface_addr has a willingness (i.e. the
L_willingness of the Link Tuple of which L_willingness of the Link Tuple whose
L_neighbor_iface_addr == N2_neighbor_iface_addr) which is L_neighbor_iface_addr_list contains
not equal to WILL_NEVER; N2_neighbor_iface_addr) which is not equal to WILL_NEVER;
a Routing Tuple is added with: a Routing Tuple is added with:
+ R_dest_addr = N2_2hop_iface_addr of the 2-Hop Neighbor + R_dest_addr = N2_2hop_iface_addr of the 2-Hop Neighbor
Tuple; Tuple;
+ R_next_iface_addr = R_next_iface_addr of the Routing Tuple + R_next_iface_addr = R_next_iface_addr of the Routing Tuple
in which R_dest_addr == N2_neighbor_iface_addr; in which R_dest_addr == N2_neighbor_iface_addr;
+ R_dist = 2; + R_dist = 2;
+ R_local_iface_addr = R_local_iface_addr of the Routing + R_local_iface_addr = R_local_iface_addr of the Routing
Tuple in which R_dest_addr == N2_neighbor_iface_addr. Tuple in which R_dest_addr == N2_neighbor_iface_addr.
5. For each Attached Network Tuple, if 5. For each Attached Network Tuple, if
skipping to change at page 43, line 26 skipping to change at page 41, line 30
* AN_gw_iface_addr is equal to R_dest_addr of a Routing Tuple; * AN_gw_iface_addr is equal to R_dest_addr of a Routing Tuple;
then a new Routing Tuple MUST be added, with: then a new Routing Tuple MUST be added, with:
* R_dest_addr = AN_net_addr; * R_dest_addr = AN_net_addr;
* R_next_iface_addr = R_next_iface_addr of the Routing Tuple * R_next_iface_addr = R_next_iface_addr of the Routing Tuple
whose R_dest_addr == AN_gw_iface_addr; whose R_dest_addr == AN_gw_iface_addr;
* R_dist = R_dist of the Routing Tuple whose R_dest_addr == * R_dist = (R_dist of the Routing Tuple whose R_dest_addr ==
AN_gw_iface_addr; AN_gw_iface_addr) + AN_dist;
* R_local_iface_addr = R_local_iface_addr of the Routing Tuple * R_local_iface_addr = R_local_iface_addr of the Routing Tuple
whose R_dest_addr == AN_gw_iface_addr. whose R_dest_addr == AN_gw_iface_addr.
If more than one Attached Network Tuple has the same AN_net_addr, If more than one Attached Network Tuple has the same AN_net_addr,
then more than one Routing Tuple MUST NOT be added, and the added then more than one Routing Tuple MUST NOT be added, and the added
Routing Tuple MUST have minimum R_dist. Routing Tuple MUST have minimum R_dist.
14. Proposed Values for Constants 17. Proposed Values for Constants
This section list the values for the constants used in the This section list the values for the constants used in the
description of the protocol. description of the protocol. These proposed values are appropriate
to the case where all TC messages are sent with the same hop limit
(usually 255).
14.1. Neighborhood Discovery Constants 17.1. Neighborhood Discovery Constants
The constants HELLO_INTERVAL, REFRESH_INTERVAL, HELLO_MIN_INTERVAL, The constants HELLO_INTERVAL, REFRESH_INTERVAL, HELLO_MIN_INTERVAL,
H_HOLD_TIME, L_HOLD_TIME, N_HOLD_TIME and C are used as in [4]. H_HOLD_TIME, L_HOLD_TIME, N_HOLD_TIME, HP_MAXJITTER, HT_MAXJITTER and
C are used as in [4].
14.2. Message Intervals 17.2. Message Intervals
o TC_INTERVAL = 5 seconds o TC_INTERVAL = 5 seconds
o TC_MIN_INTERVAL = TC_INTERVAL/4 o TC_MIN_INTERVAL = TC_INTERVAL/4
14.3. Holding Times 17.3. Holding Times
o T_HOLD_TIME = 3 x TC_INTERVAL o T_HOLD_TIME = 3 x TC_INTERVAL
o A_HOLD_TIME = T_HOLD_TIME o A_HOLD_TIME = T_HOLD_TIME
o P_HOLD_TIME = 30 seconds o P_HOLD_TIME = 30 seconds
o FG_HOLD_TIME = 30 seconds
o RX_HOLD_TIME = 30 seconds o RX_HOLD_TIME = 30 seconds
o FW_HOLD_TIME = 30 seconds o F_HOLD_TIME = 30 seconds
14.4. Willingness 17.4. Jitter Times
o TP_MAXJITTER = HP_MAXJITTER
o TT_MAXJITTER = HT_MAXJITTER
o TF_MAXJITTER = TT_MAXJITTER
17.5. Willingness
o WILL_NEVER = 0 o WILL_NEVER = 0
o WILL_DEFAULT = 3 o WILL_DEFAULT = 3
o WILL_ALWAYS = 7 o WILL_ALWAYS = 7
15. Sequence Numbers 18. Sequence Numbers
Sequence numbers are used in OLSRv2 with the purpose of discarding Sequence numbers are used in OLSRv2 with the purpose of discarding
"old" information, i.e. messages received out of order. However with "old" information, i.e. messages received out of order. However with
a limited number of bits for representing sequence numbers, wrap- a limited number of bits for representing sequence numbers, wrap-
around (that the sequence number is incremented from the maximum around (that the sequence number is incremented from the maximum
possible value to zero) will occur. To prevent this from interfering possible value to zero) will occur. To prevent this from interfering
with the operation of OLSRv2, the following MUST be observed when with the operation of OLSRv2, the following MUST be observed when
determining the ordering of sequence numbers. determining the ordering of sequence numbers.
The term MAXVALUE designates in the following one more than the The term MAXVALUE designates in the following one more than the
largest possible value for a sequence number. For a 16 bit sequence largest possible value for a sequence number. For a 16 bit sequence
number (as are those defined in this specification) MAXVALUE is number (as are those defined in this specification) MAXVALUE is
65536. 65536.
The sequence number S1 is said to be "greater than" the sequence The sequence number S1 is said to be "greater than" the sequence
number S2 if: number S2 if:
o S1 > S2 AND S1 - S2 <= MAXVALUE/2 OR o S1 > S2 AND S1 - S2 < MAXVALUE/2 OR
o S2 > S1 AND S2 - S1 > MAXVALUE/2 o S2 > S1 AND S2 - S1 > MAXVALUE/2
When sequence numbers S1 and S2 differ by MAXVALUE/2 their ordering
cannot be determined. In this case, which should not occur, either
ordering may be assumed.
Thus when comparing two messages, it is possible - even in the Thus when comparing two messages, it is possible - even in the
presence of wrap-around - to determine which message contains the presence of wrap-around - to determine which message contains the
most recent information. most recent information.
16. IANA Considerations 19. IANA Considerations
16.1. Multicast Addresses
A well-known multicast address, ALL-MANET-NEIGHBORS, must be
registered and defined for both IPv6 and IPv4. The addressing scope
is link-local, i.e. this address is similar to the all nodes/routers
multicast address of IPv6 in that it targets all OLSRv2 capable nodes
adjacent to the originator of an IP datagram.
16.2. Message Types 19.1. Message Types
OLSRv2 defines one message type, which must be allocated from the OLSRv2 defines one message type, which must be allocated from the
"Assigned Message Types" repository of [3] "Assigned Message Types" repository of [3].
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description | | Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| TC | TBD | Topology Control (global signaling) | | TC | TBD | Topology Control (global signaling) |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
Table 5 Table 5
16.3. TLV Types 19.2. TLV Types
OLSRv2 defines one Message TLV type, which must be allocated from the OLSRv2 defines three message TLV types, which must be allocated from
"Assigned message TLV Types" repository of [3] the "Assigned message TLV Types" repository of [3].
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description | | Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| WILLINGNESS | TBD | Specifies a node's willingness to | | WILLINGNESS | TBD | Specifies the originating node's |
| | | act as a relay and to partake in | | | | willingness to act as a relay and to |
| | | network formation | | | | partake in network formation |
| | | |
| CONT_SEQ_NUM | TBD | Specifies a content sequence number |
| | | for this message |
| | | |
| INCOMPLETE | TBD | Specifies that this message is |
| | | incomplete |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
Table 6 Table 6
OLSRv2 defines one Address Block TLV type, which must be allocated
from the "Assigned address block TLV Types" repository of [3] OLSRv2 defines two Address Block TLV types, which must be allocated
from the "Assigned address block TLV Types" repository of [3].
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description | | Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
| MPR | TBD | Specifies that a given address is | | MPR | TBD | Specifies that a given address is |
| | | selected as MPR | | | | selected as MPR |
| | | |
| GATEWAY | TBD | Specifies that a given address is |
| | | reached via a gateway on the |
| | | originating node |
+--------------------+-------+--------------------------------------+ +--------------------+-------+--------------------------------------+
Table 7 Table 7
17. References 20. References
17.1. Normative References 20.1. Normative References
[1] Clausen, T. and P. Jacquet, "The Optimized Link State Routing [1] Clausen, T. and P. Jacquet, "The Optimized Link State Routing
Protocol", RFC 3626, October 2003. Protocol", RFC 3626, October 2003.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, BCP 14, March 1997. Levels", RFC 2119, BCP 14, March 1997.
[3] Clausen, T., Dean, J., Dearlove, C., and C. Adjih, "Generalized [3] Clausen, T., Dean, J., Dearlove, C., and C. Adjih, "Generalized
MANET Packet/Message Format", work in MANET Packet/Message Format", work in
progress draft-ietf-manet-packetbb-01.txt, June 2006. progress draft-ietf-manet-packetbb-03.txt, January 2007.
[4] Clausen, T., Dean, J., and C. Dearlove, "MANET Neighborhood [4] Clausen, T., Dean, J., and C. Dearlove, "MANET Neighborhood
Discovery Protocol (NHDP)", work in Discovery Protocol (NHDP)", work in
progress draft-ietf-manet-nhdp-00.txt, June 2006. progress draft-ietf-manet-nhdp-01.txt, February 2007.
17.2. Informative References 20.2. Informative References
[5] Atkins, D., Stallings, W., and P. Zimmermann, "PGP Message [5] Atkins, D., Stallings, W., and P. Zimmermann, "PGP Message
Exchange Formats", RFC 1991, August 1996. Exchange Formats", RFC 1991, August 1996.
[6] ETSI, "ETSI STC-RES10 Committee. Radio equipment and systems: [6] ETSI, "ETSI STC-RES10 Committee. Radio equipment and systems:
HIPERLAN type 1, functional specifications ETS 300-652", HIPERLAN type 1, functional specifications ETS 300-652",
June 1996. June 1996.
[7] Jacquet, P., Minet, P., Muhlethaler, P., and N. Rivierre, [7] Jacquet, P., Minet, P., Muhlethaler, P., and N. Rivierre,
"Increasing reliability in cable free radio LANs: Low level "Increasing reliability in cable free radio LANs: Low level
forwarding in HIPERLAN.", 1996. forwarding in HIPERLAN.", 1996.
[8] Qayuum, A., Viennot, L., and A. Laouiti, "Multipoint relaying: [8] Qayyum, A., Viennot, L., and A. Laouiti, "Multipoint relaying:
An efficient technique for flooding in mobile wireless An efficient technique for flooding in mobile wireless
networks.", 2001. networks.", 2001.
Appendix A. Example Heuristic for Calculating MPRs Appendix A. Node Configuration
OLSRv2 does not make any assumption about node addresses, other than
that each node is assumed to have at least one unique and routable IP
address for each interface that it has which participates in the
MANET.
When applicable, a recommended way of connecting an OLSRv2 network to
an existing IP routing domain is to assign an IP prefix (under the
authority of the nodes/gateways connecting the MANET with the routing
domain) exclusively to the OLSRv2 area, and to configure the gateways
statically to advertise routes to that IP sequence to nodes in the
existing routing domain.
Appendix B. Protocol and Port Number
Packets in OLSRv2 are communicated using UDP. Port 698 has been
assigned by IANA for exclusive usage by the OLSR (v1 and v2)
protocol.
Appendix C. Example Heuristic for Calculating MPRs
The following specifies a proposed heuristic for selection of MPRs. The following specifies a proposed heuristic for selection of MPRs.
In graph theory terms, MPR computation is a "set cover" problem, In graph theory terms, MPR computation is a "set cover" problem,
which is a difficult optimization problem, but for which an easy and which is a difficult optimization problem, but for which an easy and
efficient heuristics exist: the so-called "Greedy Heuristic", a efficient heuristics exist: the so-called "Greedy Heuristic", a
variant of which is described here. In simple terms, MPR computation variant of which is described here. In simple terms, MPR computation
constructs an MPR Set that enables a node to reach any symmetric constructs an MPR Set that enables a node to reach any symmetric
2-hop neighbors by relaying through an MPR node. 2-hop neighbors by relaying through an MPR node.
skipping to change at page 52, line 5 skipping to change at page 52, line 5
interfaces on node 'a'. interfaces on node 'a'.
o In a multiple interface scenario MPRs are selected for each o In a multiple interface scenario MPRs are selected for each
interface of the selecting node, providing full coverage of all interface of the selecting node, providing full coverage of all
2-hop nodes accessible through that interface. The overall MPR 2-hop nodes accessible through that interface. The overall MPR
Set is then the union of these sets. These sets do not however Set is then the union of these sets. These sets do not however
have to be selected independently, if a node is selected as an MPR have to be selected independently, if a node is selected as an MPR
for one interface it may be automatically added to the MPR for one interface it may be automatically added to the MPR
selection for other interfaces. selection for other interfaces.
Appendix B. Heuristics for Generating Control Traffic
A node creates HELLO messages and TC messages as specified in
Section 7 and Section 9, the former being a modification of the
specification in [4]. The heuristics for creation of HELLO messages
in [4] remain applicable, with the division of the address TLVs with
Type == LINK_STATUS and Value == SYMMETRIC into separate ranges with
and without an associated TLV with Type == MPR. The heuristics for
collection of addresses are also generally applicable to TC messages,
excepting that the first address block is not sorted as the Local
Interface Block of a HELLO message is, and that other addresses
recorded in TC messages are divided into those with and without a TLV
with Type == GATEWAY. These should be ordered so that the range of
addresses without that TLV is continuous (and it is suggested that
the range without is also continuous).
Appendix C. Protocol and Port Number
Packets in OLSRv2 are communicated using UDP. Port 698 has been
assigned by IANA for exclusive usage by the OLSR (v1 and v2)
protocol.
Appendix D. Packet and Message Layout Appendix D. Packet and Message Layout
This section specifies the translation from the abstract descriptions This appendix illustrates the translation from the abstract
of packets employed in the protocol specification, and the bit-layout descriptions of packets employed in the protocol specification, and
packets actually exchanged between the nodes. the bit-layout packets actually exchanged between the nodes.
Appendix D.1. OLSRv2 Packet Format Appendix D.1. Packet and Message Options
The basic layout of an OLSRv2 packet is as described in [3]. However The basic layout of an OLSRv2 packet is as described in [3]. However
the following points should be noted. the following points should be noted.
In the following figures, reserved bits marked Reserved or Resv MUST
be cleared ('0'). Octets indicated as Padding are optional and MAY
be omitted; if not omitted they SHOULD be used to pad to a 32 bit
boundary and MUST all be zero.
OLSRv2 uses only packets with a packet header including a packet OLSRv2 uses only packets with a packet header including a packet
sequence number, either with or without a packet TLV block. Thus all sequence number, either with or without a packet TLV block. Thus all
OLSRv2 packets have the layout of either OLSRv2 packets have the layout of either
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |0|0| Packet Sequence Number | |0 0 0 0 0 0 0 0| Reserved |0|0| Packet Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
skipping to change at page 55, line 28 skipping to change at page 53, line 28
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
: ... : : ... :
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Message + Padding | | Message + Padding |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The reserved bits marked Resv SHOULD be cleared ('0'). The octets
indicated as Padding are optional and MAY be omitted; if not omitted
they SHOULD be used to pad to a 32 bit boundary and MUST all be zero.
OLSRv2 uses only messages with a complete message header. Thus all OLSRv2 uses only messages with a complete message header. Thus all
OLSRv2 messages, plus padding if any, have the following layout. OLSRv2 messages, plus padding if any, have the following layout.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|0|0| Message Size | | Message Type | Resv |N|0|0| Message Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address | | Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number | | Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Message Body | | Message Body |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding | | | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The reserved bits marked Resv SHOULD be cleared ('0'). In standard
OLSRv2 messages (HELLO and TC) the type dependent sequence number bit In standard OLSRv2 messages (HELLO and TC) the type dependent
marked N SHOULD also be cleared ('0'). sequence number bit marked N MUST be cleared ('0').
The layouts of the message body, address block, TLV block and TLV are The layouts of the message body, address block, TLV block and TLV are
as in [3], allowing all options. Standard (HELLO and TC) messages as in [3], allowing all options. Standard (HELLO and TC) messages
contain a first address block which contains local interface address contain a first address block which contains local interface address
information, all other address blocks contain neighbor interface information, all other address blocks contain neighbor interface
address information (or for a TC message address information for address information (or for a TC message address information for
which it is a gateway) specific to the message type. which it is a gateway) specific to the message type.
Appendix D.2. Example HELLO Message
An example HELLO message, using IPv4 (four octet) addresses is as An example HELLO message, using IPv4 (four octet) addresses is as
follows. The overall message length is 56 octets (it does not need follows. The overall message length is 58 octets. The message has a
padding). The message has a hop limit of 1 and a hop count of 0, as hop limit of 1 and a hop count of 0, as sent by its originator.
sent by its originator.
The message has a message TLV block with content length 12 octets The message has a message TLV block with content length 12 octets
containing three message TLVs. These TLVs represent message validity containing three message TLVs. These TLVs represent message validity
time, message interval time and willingness. Each uses a TLV with time, message interval time and willingness. Each uses a TLV with
semantics value 4, indicating no start and stop indexes are included, semantics value 4, indicating no start and stop indexes are included,
and each has a value length of 1 octet. and each has a value length of 1 octet.
The first address block contains a 1 local interface address, with The first address block contains 1 local interface address. The
head length 4. This is equal to the address length, thus no tail or semantics octet 2 indicates it has no tail section. It has head
mid sections of the address are included. This address block has no length 4, this is equal to the address length, it thus has no mid
TLVs (the TLV block content length is 0 octets). section. This address block has no TLVs (TLV block content length is
0 octets).
The second, and last, address block reports 4 neighbor interface The second, and last, address block includes 4 neighbor interface
addresses, with address head length 3 octets, and no tail octet (zero addresses. The semantics octet 2 indicates they have no tail
tail length). Thus each mid address section is of length one octet. section. The addresses have head length 3 octets, thus each mid
The following address TLV block (content length 11 octets) includes section is of length one octet. The following address TLV block
two TLVs. (content length 11 octets) includes two TLVs.
The first of these TLVs reports the link status of all four neighbors The first of these TLVs reports the link status of all four neighbors
in a single multivalue TLV, the first two addresses are HEARD, the in a single multivalue TLV, the first two addresses are HEARD, the
last two addresses are SYMMETRIC. The TLV semantics value of 12 last two addresses are SYMMETRIC. The TLV semantics octet value of
indicates, in addition to that this is a multivalue TLV, that no 20 indicates, in addition to that this is a multivalue TLV, that no
start index and stop index are included, hence values for all start index and stop index are included, hence values for all
addresses are included. The TLV value length of 4 octets indicates addresses are included. The TLV value length of 4 octets indicates
one octet per value per address. one octet per value per address.
The second of these TLV indicates that the last address (start index The second of these TLVs indicates that the last address (start index
3, stop index 3) is an MPR. This TLV has no value, or value length, 3, stop index 3) is an MPR. This TLV has no value, or value length,
fields, as indicated by its semantics octet being equal to 1. fields, as indicated by its semantics octet being equal to 2.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HELLO |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0| | HELLO |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address | | Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0| Message Sequence Number | |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0| Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| VALIDITY_TIME |0 0 0 0 0 1 0 0| |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| VALIDITY_TIME |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 0 0 1 0 0| |0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1| Value | WILLINGNESS |0 0 0 0 0 1 0 0| |0 0 0 0 0 0 0 1| Value | WILLINGNESS |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1| Value |0 0 0 0 0 0 0 1|0 0 0 0 0 1 0 0| |0 0 0 0 0 0 0 1| Value |0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Head | |0 0 0 0 0 1 0 0| Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 1 0 0|0 0 0 0 0 0 1 1| | Head (cont) |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Head | Mid | |0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 1| Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Mid | Mid |0 0 0 0 0 0 0 0| | Head (cont) | Mid | Mid | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 1 0 1 1| LINK_STATUS |0 0 0 0 1 1 0 0|0 0 0 0 0 1 0 0| | Mid |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| LINK_STATUS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HEARD | HEARD | SYMMETRIC | SYMMETRIC | |0 0 0 1 0 1 0 0|0 0 0 0 0 1 0 0| HEARD | HEARD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPR |0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 1|0 0 0 0 0 0 1 1| | SYMMETRIC | SYMMETRIC | MPR |0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 1|0 0 0 0 0 0 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Appendix D.3. Example TC Message
An example TC message, using IPv4 (four octet) addresses, is as An example TC message, using IPv4 (four octet) addresses, is as
follows. The overall message length is 64 octets, it also does not follows. The overall message length is 67 octets.
need padding.
The message has a message TLV block with content length 13 octets The message has a message TLV block with content length 13 octets
containing three TLVs. The first TLV is a content sequence number containing three TLVs. The first two TLVs are validity and interval
TLV used to carry the 2 octet ANSN. The semantics value is 4 times as for the HELLO message above. The third TLV is a content
indicating that no index fields are included. The other two TLVs are sequence number TLV used to carry the 2 octet ANSN. The semantics
validity and interval times as for the HELLO message above. value is also 4.
The message has three address blocks. The first address block The message has three address blocks. The first address block
contains 3 local interface addresses (with common head length 2 contains 3 local interface addresses (with semantics octet 2, hence
octets) and has a TLV block with content length 0 octets. no tail section, head length 2 octets, and hence mid sections with
length two octets) and has no TLVs (TLV block content length 0
octets).
The other two address blocks contain neighbor interface addresses. The other two address blocks contain neighbor interface addresses.
The first contains 3 addresses (semantics octet 2, no tail section,
The first contains 3 addresses and has an empty TLV block (content head length 2 octets, hence mid sections length two octets) and has
length 0 octets). The second contains 1 address. The head octet no TLVs (TLV block content length 0 octets). The second contains 1
(hex 82) indicates a head length of two octets and the presence of a address, with semantics octet 4 indicating that the tail section,
tail octet. The tail octet (hex 82) indicates a tail length of two length 2 octets, consists of zero valued octets (not included). The
octets, all zero bits and not included. The following TLV block following TLV block (content length 6 octets) includes two TLVs, the
(content length 6 octets) includes two TLVs, the first (semantics first (semantics value 4 indicating no indexes are needed) indicates
value 4 indicating no indexes are needed) indicates that the address that the address has a netmask, with length given by the value (of
has a netmask, with length given by the value (of length 1 octet) of length 1 octet) of 16. Thus this address is Head.0.0/16. The second
16. Thus this address is Head.0.0/16. The second TLV indicates that TLV indicates that the originating node is a gateway to this network,
the originating node is a gateway to this network, the TLV semantics at a given number of hops distance. The TLV semantics value of 4
value of 5 indicates that neither indexes nor value are needed. indicates that no indexes are needed.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TC |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0| | TC |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address | | Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number | | Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1| CONT_SEQ_NUM |0 0 0 0 0 1 0 0| |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1| VALIDITY_TIME |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0| Value (ANSN) | VALIDITY_TIME | |0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1| Value | INTERVAL_TIME | |0 0 0 0 0 0 0 1| Value | CONT_SEQ_NUM |0 0 0 0 0 1 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1| Value |0 0 0 0 0 0 1 1| |0 0 0 0 0 0 1 0| Value (ANSN) |0 0 0 0 0 0 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0| Head | Mid | | 0x02 |0 0 0 0 0 0 1 0| Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) | Mid | Mid | | Mid | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 1| | Mid |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0| Head | Mid | |0 0 0 0 0 0 1 1| 0x02 |0 0 0 0 0 0 1 0| Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) | Mid | Mid | | Head (cont) | Mid | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 1| | Mid (cont) | Mid |0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 0 0 0 0 0 1 0| Head |1 0 0 0 0 0 1 0| |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 1 0 0|0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| PREFIX_LENGTH |0 0 0 0 0 1 0 0| | Head |0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1|0 0 0 1 0 0 0 0| GATEWAY |0 0 0 0 0 1 0 1| |0 0 0 0 0 1 1 1| PREFIX_LENGTH |0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1 0 0 0 0| GATEWAY |0 0 0 0 0 1 0 0| Number Hops |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Appendix E. Node Configuration Appendix E. Time TLVs
OLSRv2 does not make any assumption about node addresses, other than This appendix specifies a general time TLV structure for expressing
that each node is assumed to have at least one a unique and routable either single time values or a set of time values with each value
IP address for each interface that it has which participates in the associated with a range of distances. Furthermore, using this
MANET. general time TLV structure, this document specifies the INTERVAL_TIME
and VALIDITY_TIME TLVs, which are used by OLSRv2.
When applicable, a recommended way of connecting an OLSRv2 network to E.1. Representing Time
an existing IP routing domain is to assign an IP prefix (under the
authority of the nodes/gateways connecting the MANET with the routing
domain) exclusively to the OLSRv2 area, and to configure the gateways
statically to advertise routes to that IP sequence to nodes in the
existing routing domain.
Appendix F. Jitter This document specifies a TLV structure in which time values are each
represented in an 8 bit time code, one or more of which may be used
in a TLV's value field. Of these 8 bits, the least significant four
bits represent the mantissa (a), and the most significant four bits
represent the exponent (b), so that:
In a wireless network, simultaneous packet transmission by nearby o time value = (1 + a/16) * 2^b * C
nodes is undesirable as, depending on the medium access control and
other lower layer mechanisms, the interference between these messages
may cause at best increased delay, and at worst complete packet loss
by both nodes. This is often particularly true when using a
broadcast mechanism, such as is used by OLSRv2 packets.
The problems of simultaneous packet transmission in OLSRv2 are o time code = 16 * b + a
increased by the following features of the protocol:
o If two nodes send packets containing regularly scheduled messages All nodes in the network MUST use the same value of C, which will be
of the same type at the same time, then if, as is typical, they specified in seconds, hence so will be all time values. Note that
are using the same message interval, further transmissions of ascending values of the time code represent ascending time values,
these messages will also be at the same time, and will also time values may thus be compared by comparison of time codes.
interfere. This node synchronization could even result in
complete operational failure of these nodes.
o OLSRv2 allows nodes to respond to changes in their circumstances, An algorithm for computing the time code representing the smallest
usually changes in the neighborhood, with immediate messages of representable time value not less than the time value t is:
appropriate types. Nearby nodes will have overlapping
neighborhoods, and may respond to the same change in
circumstances. For example a single link failure can result in a
node having to change its MPR Set, and then two or more of its
neighbors having changed MPR status responding simultaneously with
revised TC messages, whose packets may interfere.
o When a node sends such a responsive message, there is no apparent 1. find the largest integer b such that t/C >= 2^b;
reason why it should not restart its message schedule of the
appropriate type of message. This results in nodes responding to
the same change not just sending single simultaneous packets, but
becoming synchronized.
o Nodes also forward messages they receive from other nodes. Two 2. set a = 16 * (t / (C * 2^b) - 1), rounded up to the nearest
nearby nodes will thus commonly receive and forward the same integer;
message. The consequent packet transmissions can easily interfere
with each other.
Because interference can easily occur, is self-reinforcing, and is 3. if a == 16 then set b = b + 1 and set a = 0;
anything from undesirable to catastrophic, mechanisms to minimize it,
and to break synchronization of nodes, SHOULD be used in OLSRv2.
These all make a deliberate adjustment to the timing, known as
"jitter". Three cases exist:
o When a node generates a control message periodically, it would 4. if a and b are in the range 0 and 15 then the required time value
normally wait for a delay equal to MESSAGE_INTERVAL (e.g. can be represented by the time code 16 * b + a, otherwise it can
HELLO_INTERVAL for HELLO messages or TC_INTERVAL for TC messages) not.
between two transmissions of messages of that type. This delay
SHOULD be mitigated by subtracting a jitter time, so that the
delay between consecutive transmissions of a messages of the same
type SHOULD be equal to MESSAGE_INTERVAL - jitter, where jitter is
a random value whose generation is discussed below. Note that
this is a deliberately asymmetric process. It ensures that the
message interval does not exceed MESSAGE_INTERVAL (which leaves
MESSAGE_INTERVAL an appropriate value for reporting in an
INTERVAL_TIME message TLV) and also allows different nodes to
become completely desynchronized as each interval is based on the
previous actual transmission time, not on a fixed clock of period
MESSAGE_INTERVAL.
o When a node responds to an externally triggered change in The minimum time value that can be represented in this manner is C.
circumstances, it SHOULD delay the transmission of a message in The maximum time value that can be represented in this manner is
response by a random jitter time. It MAY restart its schedule of 63488 * C.
messages of the appropriate type based on that new time. If such
a message is delayed due to the need to respect the appropriate
MESSAGE_MIN_INTERVAL (e.g. HELLO_MIN_INTERVAL for HELLO messages
or TC_MIN_INTERVAL for TC messages) then the node MAY reduce this
minimum interval by a jitter time as the normal message interval
is reduced (thus allowing MESSAGE_MIN_INTERVAL to equal
MESSAGE_INTERVAL even when using jitter).
o When a node forwards a message, it SHOULD delay the message E.2. General Time TLV Structure
retransmission by a random jitter time.
In the first and second cases above, the maximum jitter time may be A Time TLV may be a packet, message or address block TLV. If it is a
specified by a parameter MAXJITTER. It is necessary only that this packet or message TLV then it must be a single value TLV as defined
be significantly less than each MESSAGE_INTERVAL, and less than each in [3]; if it is an address block TLV then it may be single value or
MESSAGE_MIN_INTERVAL. Normally the actual value of the jitter multivalue TLV. The specific Time TLVs specified in this document,
(reduction in message interval or delay of responsive message) SHOULD in Appendix E.3 are message, and hence single value, TLVs. Note that
be uniformly generated in the interval 0 <= jitter <= MAXJITTER, even a single value Time TLV may contain a multiple octet <value>
however this may be modified as indicated below. field.
In the third case above, a message SHOULD be delayed by a jitter The purpose of a single value Time TLV is to allow a single time
value which is significantly less than the originating node's message value to be determined by a node receiving an entity containing the
interval. This MAY be available in an INTERVAL_TIME message TLV in Time TLV, based on its distance from the entity's originator. The
the message to be forwarded. If not so available, a node MAY Time TLV may contain information that allows that time value to be a
estimate an acceptable maximum jitter by any other means available to function of distance, and thus different receiving nodes may
it, which may be by use of its own MAXJITTER parameter for as long as determine different time values. If a receiving node will not be
this works. In a network in which this is likely to be unsuccessful, able to determine its distance from the originating node, then the
nodes SHOULD include an INTERVAL_TIME message TLV in messages which form of this Time TLV with a single time code in a <value> field (or
are to be forwarded. single value subfield) SHOULD be used.
In all cases, as well as constraints imposed by message intervals and The <value> field of a single value Time TLV is specified, using the
message minimum intervals, the maximum jitter delay SHOULD only be as regular expression syntax of [3], by:
large as is required to achieve the required objective of minimizing
interference due to synchronization. This is because all jitter, and
forwarding jitter in particular, is undesirable for otherwise ideal
functioning of the network.
Because of differing parameters, or due to responsive messages with a <value> = {<time><distance>}*<time>
small minimum message interval, a node may receive a message from an
originating node while still waiting to forward an earlier message of
the same type originating from the same node. The forwarding node
SHOULD NOT allow forwarding jitter delay to reorder these messages.
A node MAY discard the earlier message, transmitting the later
message no later than the earlier message was due to be
retransmitted, if, and only if, it can guarantee that this will not
have any adverse effect.
OLSRv2 messages are transmitted in potentially multi-message packets. where:
Whilst a packet is a hop by hop construct and it is the messages in
it which are forwarded, if a number of messages are received in the <time> is an 8 bit field containing a time code as defined in
same packet, they SHOULD (if their maximum jitter delays are Appendix E.1.
compatible) be permitted to be forwarded in the same new packet.
This may be accomplished by generating the same random delay for all <distance> is an 8 bit field specifying a distance from the message
messages received in a single packet. Furthermore, the opportunity originator, in hops.
to combine messages to be forwarded from different sources, and
locally generated messages in a single packet SHOULD be allowed even A single value <value> field thus consists of an odd number of
when this means adjusting (forwards or backwards) the strictly octets; with a repetition factor of n in the regular expression
uniformly generated random jitter times, however these SHOULD NOT be syntax it contains 2n+1 octets, thus the <length> field of a single
allowed to exceed their maximum value, nor allow a message interval value Time TLV, which MUST always be present, is given by:
to be exceeded, nor compromise the purpose of jitter. (It is for
this reason that messages in the same packet should be given the same o <length> = 2n+1
random jitter, as giving them independent jitter values but then, for
example, allowing all to be sent with the earliest would reduce the A single value <value> field may be thus represented by:
mean jitter delay.)
<t_1><d_1><t_2><d_2> ... <t_i><d_i> ... <t_n><d_n><t_default>
<d_1>, ... <d_n>, if present, MUST be a strictly increasing sequence.
Then, at the receiving node's distance from the originator node, the
time value indicated is that represented by the time code:
o <t_1>, if n > 0 and distance <= <d_1>;
o <t_i+1>, if n > 1 and <d_i> < distance <= <d_i+1> for some i such
that 1 <= i < n;
o <t_default> otherwise, i.e. if n == 0 or distance > <d_n>.
In a multivalue Time TLV, each single value subfield of the
multivalue Time TLV is defined as above. Note that [3] requires that
each single value subfield has the same length (i.e. the same value
of n) but they need not use the same values of <d_1> to <d_n>.
E.3. Message TLVs
Two message TLVs are defined, for signaling message validity time
(VALIDITY_TIME) and message interval (INTERVAL_TIME).
E.3.1. VALIDITY_TIME TLV
A VALIDITY TIME TLV is a message TLV that defines the validity time
of the information carried in the message in which the TLV is
contained. After this time the receiving node MUST consider the
message content to no longer be valid (unless repeated in a later
message). The validity time of a message MAY be specified to depend
on the distance from its originator. (This is appropriate if
messages are sent with different hop limits, so that receiving nodes
at greater distances receive information less frequently and must
treat is as valid for longer.)
A VALIDITY_TIME TLV is an example of a Time TLV specified as in
Appendix E.1.
E.3.2. INTERVAL_TIME TLV
An INTERVAL_TIME TLV is a message TLV that defines the maximum time
before another message of the same type as this message from the same
originator should be received. This interval time MAY be specified
to depend on the distance from the originator. (This is appropriate
if messages are sent with different hop limits, so that receiving
nodes at greater distances have an increased interval time.)
An INTERVAL_TIME TLV is an example of a Time TLV specified as in
Appendix E.1.
Appendix F. Message Jitter
Since NHDP employs periodic message transmission in order to detect
neighborhoods, and since NHDP is a building block for MANET routing
protocols employing other triggered or periodic message exchanges,
this appendix presents global concerns pertaining to jittering of
MANET control traffic.
F.1. Jitter
In order to prevent nodes in a MANET from simultaneous transmission,
whilst retaining the MANET characteristic of maximum node autonomy, a
randomization of the transmission time of packets by nodes, known as
jitter, MAY be employed. Three jitter mechanisms, which target
different aspects of this problem, MAY be employed, with the aim of
reducing the likelihood of simultaneous transmission, and, if it
occurs, preventing it from continuing.
Three cases exist:
o Periodic message generation;
o Externally triggered message generation;
o Message forwarding.
Each of these cases uses a parameter, denoted MAXJITTER, for the
maximum timing variation that it introduces. If more than one of
these cases is used by a protocol, it MAY use the same or a different
value of MAXJITTER for each case. It also MAY use the same or
different values of MAXJITTER according to message type, and under
different circumstances - in particular if other parameters (such as
message interval) vary.
Issues relating to the value of MAXJITTER are considered in
Appendix F.1.4.
F.1.1. Periodic message generation
When a node generates a message periodically, two successive messages
will be separated by a well-defined interval, denoted
MESSAGE_INTERVAL. A node MAY maintain more than one such interval,
e.g. for different message types or in different circumstances (such
as backing off transmissions to avoid congestion). Jitter MAY be
applied by reducing this delay by a random amount, so that the delay
between consecutive transmissions of a messages of the same type is
equal to (MESSAGE_INTERVAL - jitter), where jitter is the random
value.
Subtraction of the random value from the message interval ensures
that the message interval never exceeds MESSAGE_INTERVAL, and does
not adversely affect timeouts or other mechanisms which may be based
on message late arrival or failure to arrive. By basing the message
transmission time on the previous transmission time, rather than by
jittering a fixed clock, nodes can become completely desynchronized,
which minimizes their probability of repeated collisions. This is
particularly useful when combined with externally triggered message
generation and rescheduling.
The jitter value SHOULD be taken from a uniform distribution between
zero and MAXJITTER.
Note that a node will know its own MESSAGE_INTERVAL value and can
readily ensure that any MAXJITTER value used satisfies the conditions
in Appendix F.1.4.
F.1.2. Externally triggered message generation
An internal or external condition or event MAY trigger message
generation by a node. Depending upon the protocol, this condition
MAY trigger generation of a single message, initiation of a new
periodic message schedule, or rescheduling of existing periodic
messaging. Collision between externally triggered messages is made
more likely if more than one node is likely to respond to the same
event. To reduce this likelihood, an externally triggered message
MAY be jittered by delaying it by a random duration; an internally
triggered message MAY also be so jittered if appropriate. This delay
SHOULD be generated uniformly in an interval between zero and
MAXJITTER. If periodically transmitted messages are rescheduled,
then this SHOULD be based on this delayed time, with subsequent
messages treated as described in Appendix F.1.1.
When messages are triggered, whether or not they are also
periodically transmitted, a protocol MAY impose a minimum interval
between messages of the same type, denoted MESSAGE_MIN_INTERVAL. It
is however appropriate to also allow this interval to be reduced by
jitter, so that when a message is transmitted the next message is
allowed after a time (MESSAGE_MIN_INTERVAL - jitter), where jitter
SHOULD be generated uniformly in an interval between zero and
MAXJITTER (using a value of MAXJITTER appropriate to periodic message
transmission). This is because otherwise, when external triggers are
more frequent than MESSAGE_MIN_INTERVAL, it takes the role of
MESSAGE_INTERVAL and the arguments applying to jittering of the
latter also apply to the former. This also permits
MESSAGE_MIN_INTERVAL to equal MESSAGE_INTERVAL even when jitter is
used.
F.1.3. Message forwarding
When a node forwards a message, it may be jittered by delaying it by
a random duration. This delay SHOULD be generated uniformly in an
interval between zero and MAXJITTER.
Unlike the cases of periodically generated and externally triggered
messages, a node is not automatically aware of the message
originator's value of MESSAGE_INTERVAL, which is required to select a
value of MAXJITTER which is known to be valid. This may require
prior agreement as to the value (or minimum value) of
MESSAGE_INTERVAL, may be by inclusion in the message of
MESSAGE_INTERVAL (the time until the next relevant message, rather
than the time since the last message) or be by any other protocol
specific mechanism, which may include estimation of the value of
MESSAGE_INTERVAL based on received message times.
For several possible reasons (differing parameters, message
rescheduling, extreme random values) a node may receive a message
while still waiting to forward an earlier message of the same type
originating from the same node. This is possible without jitter, but
may occur more often with it. The appropriate action to take is
protocol specific (typically to discard the earlier message or to
forward both, possible modifying timing to maintain message order).
In many cases, including [1] and protocols using the full
functionality of [3], messages are transmitted hop by hop in
potentially multi-message packets, and some or all of those messages
may need to be forwarded. For efficiency this should be in a single
packet, and hence the forwarding jitter of all messages received in a
single packet should be the same. (This also requires that a single
value of MAXJITTER is used in this case.) For this to have the
intended uniform distribution it is necessary to choose a single
random jitter for all messages. It is not appropriate to give each
message a random jitter and then to use the smallest of these jitter
values, as that produces a jitter with a non-uniform distribution and
a reduced mean value.
In addition, the protocol may permit messages received in different
packets to be combined, possibly also with locally generated messages
(periodically generated or triggered). However in this case the
purpose of the jitter will be accomplished by choosing any of the
independently scheduled times for these events as the single
forwarding time; this may have to be the earliest time to achieve all
constraints. This is because without combining messages, a
transmission was due at this time anyway.
F.1.4. Maximum Jitter Determination
In considering how the maximum jitter (one or more instances of
parameter MAXJITTER) may be determined, the following points may be
noted:
o While jitter may resolve the problem of simultaneous
transmissions, the timing changes (in particular the delays) it
introduces will otherwise only have a negative impact on a well-
designed protocol. Thus MAXJITTER should always be minimized,
subject to acceptably achieving its intent.
o When messages are periodically generated, all of the following
that are relevant apply to each instance of MAXJITTER:
* it MUST NOT be greater than MESSAGE_INTERVAL/2;
* it SHOULD be significantly less than MESSAGE_INTERVAL;
* it MUST NOT be greater than MESSAGE_MIN_INTERVAL;
* it SHOULD NOT be greater than MESSAGE_MIN_INTERVAL/2.
o As well as the decision as to whether to use jitter being
dependent on the medium access control and lower layers, the
selection of the MAXJITTER parameter should be appropriate to
those mechanisms.
o As jitter is intended to reduce collisions, greater jitter, i.e.
an increased value of MAXJITTER, is appropriate when the chance of
collisions is greater. This is particularly the case with
increased node density, where node density should be considered
relative to (the square of) the interference range rather than
useful signal range.
o The choice of MAXJITTER used when forwarding messages may also
take into account the expected number of times that the message
may be sequentially forwarded, up to the network diameter in hops.
Appendix G. Security Considerations Appendix G. Security Considerations
Currently, OLSRv2 does not specify any special security measures. As Currently, OLSRv2 does not specify any special security measures. As
a proactive routing protocol, OLSRv2 makes a target for various a proactive routing protocol, OLSRv2 makes a target for various
attacks. The various possible vulnerabilities are discussed in this attacks. The various possible vulnerabilities are discussed in this
section. section.
Appendix G.1. Confidentiality Appendix G.1. Confidentiality
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multipoint transmission. It is therefore important that the multipoint transmission. It is therefore important that the
authentication mechanism employed permits that any receiving node can authentication mechanism employed permits that any receiving node can
validate the authenticity of a message. As an analogy, given a block validate the authenticity of a message. As an analogy, given a block
of text, signed by a PGP private key, then anyone with the of text, signed by a PGP private key, then anyone with the
corresponding public key can verify the authenticity of the text. corresponding public key can verify the authenticity of the text.
Appendix G.3. Interaction with External Routing Domains Appendix G.3. Interaction with External Routing Domains
OLSRv2 does, through the use of TC messages, provide a basic OLSRv2 does, through the use of TC messages, provide a basic
mechanism for injecting external routing information to the OLSRv2 mechanism for injecting external routing information to the OLSRv2
domain. Appendix E also specifies that routing information can be domain. Appendix A also specifies that routing information can be
extracted from the topology table or the routing table of OLSRv2 and, extracted from the topology table or the routing table of OLSRv2 and,
potentially, injected into an external domain if the routing protocol potentially, injected into an external domain if the routing protocol
governing that domain permits. governing that domain permits.
Other than as described in Appendix E, when operating nodes, Other than as described in Appendix A, when operating nodes,
connecting OLSRv2 to an external routing domain, care MUST be taken connecting OLSRv2 to an external routing domain, care MUST be taken
not to allow potentially insecure and untrustworthy information to be not to allow potentially insecure and untrustworthy information to be
injected from the OLSRv2 domain to external routing domains. Care injected from the OLSRv2 domain to external routing domains. Care
MUST be taken to validate the correctness of information prior to it MUST be taken to validate the correctness of information prior to it
being injected as to avoid polluting routing tables with invalid being injected as to avoid polluting routing tables with invalid
information. information.
A recommended way of extending connectivity from an existing routing A recommended way of extending connectivity from an existing routing
domain to an OLSRv2 routed MANET is to assign an IP prefix (under the domain to an OLSRv2 routed MANET is to assign an IP prefix (under the
authority of the nodes/gateways connecting the MANET with the exiting authority of the nodes/gateways connecting the MANET with the exiting
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Appendix G.4. Node Identity Appendix G.4. Node Identity
OLSRv2 does not make any assumption about node addresses, other than OLSRv2 does not make any assumption about node addresses, other than
that each node is assumed to have at least one a unique and routable that each node is assumed to have at least one a unique and routable
IP address for each interface that it has which participates in the IP address for each interface that it has which participates in the
MANET. MANET.
Appendix H. Flow and Congestion Control Appendix H. Flow and Congestion Control
TBD Due to its proactive nature, the OLSRv2 protocol has a natural
control over the flow of its control traffic. Nodes transmit control
messages at predetermined rates specified and bounded by message
intervals.
OLSRv2 employs [4] for local signalling, embedding MPR selection
advertisement through a simple address block TLV, and node
willingness advertisement (if any) as a single message TLV. OLSRv2
local signalling, therefore, shares the characteristics and
constraints of [4].
Furthermore, the MPR optimization greatly constrains global
signalling overhead from link state diffusion in two ways. First,
the messages that advertise the topology need only contain MPR
selectors, reducing their size as compared to full link state.
Second, the cost of diffusing these messages throughout the network
is greatly reduced as compared to when using classic flooding, since
only MPRs need to forward broadcast messages. In dense networks, the
reduction of control traffic can be of several orders of magnitude
compared to routing protocols using classical flooding [8]. This
feature naturally provides more bandwidth for useful data traffic and
pushes further the frontier of congestion.
Since the control traffic is continuous and periodic, it keeps the
quality of the links used in routing more stable. However, using
certain OLSRv2 options, some control messages (HELLO messages or TC
messages) may be intentionally sent in advance of their deadline in
order to increase the responsiveness of the protocol to topology
changes. This may cause a small, temporary and local increase of
control traffic, however this is at all times bounded by the use of
minimum message intervals.
Appendix I. Contributors Appendix I. Contributors
This specification is the result of the joint efforts of the This specification is the result of the joint efforts of the
following contributors -- listed alphabetically. following contributors -- listed alphabetically.
o Cedric Adjih, INRIA, France, <Cedric.Adjih@inria.fr> o Cedric Adjih, INRIA, France, <Cedric.Adjih@inria.fr>
o Emmanuel Baccelli, Hitachi Labs Europe, France, o Emmanuel Baccelli, Hitachi Labs Europe, France,
<Emmanuel.Baccelli@inria.fr> <Emmanuel.Baccelli@inria.fr>
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o Monden Kazuya, Hitachi SDL, Japan, <monden@sdl.hitachi.co.jp> o Monden Kazuya, Hitachi SDL, Japan, <monden@sdl.hitachi.co.jp>
o Kenichi Mase, Niigata University, Japan, <mase@ie.niigata-u.ac.jp> o Kenichi Mase, Niigata University, Japan, <mase@ie.niigata-u.ac.jp>
o Ryuji Wakikawa, KEIO University, Japan, <ryuji@sfc.wide.ad.jp> o Ryuji Wakikawa, KEIO University, Japan, <ryuji@sfc.wide.ad.jp>
Appendix J. Acknowledgements Appendix J. Acknowledgements
The authors would like to acknowledge the team behind OLSRv1, The authors would like to acknowledge the team behind OLSRv1,
specified in RFC3626, including Anis Laouiti, Pascale Minet, Laurent specified in RFC3626, including Anis Laouiti, Pascale Minet, Laurent
Viennot (all at INRIA, France), and Amir Qayuum (Center for Advanced Viennot (all at INRIA, France), and Amir Qayyum (Center for Advanced
Research in Engineering, Pakistan) for their contributions. Research in Engineering, Pakistan) for their contributions.
The authors would like to gratefully acknowledge the following people The authors would like to gratefully acknowledge the following people
for intense technical discussions, early reviews and comments on the for intense technical discussions, early reviews and comments on the
specification and its components: Li Li (CRC), Louise Lamont (CRC), specification and its components: Li Li (CRC), Louise Lamont (CRC),
Joe Macker (NRL), Alan Cullen (BAE Systems), Philippe Jacquet Joe Macker (NRL), Alan Cullen (BAE Systems), Philippe Jacquet
(INRIA), Khaldoun Al Agha (LRI), Richard Ogier (SRI), Song-Yean Cho (INRIA), Khaldoun Al Agha (LRI), Richard Ogier (SRI), Song-Yean Cho
(Samsung Software Center), Shubhranshu Singh (Samsung AIT) and the (Samsung Software Center), Shubhranshu Singh (Samsung AIT) and the
entire IETF MANET working group. entire IETF MANET working group.
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Philippe Jacquet Philippe Jacquet
Project Hipercom, INRIA Project Hipercom, INRIA
Phone: +33 1 3963 5263 Phone: +33 1 3963 5263
Email: philippe.jacquet@inria.fr Email: philippe.jacquet@inria.fr
URI: http://hipercom.inria.fr/test/Jacquet.htm URI: http://hipercom.inria.fr/test/Jacquet.htm
The OLSRv2 Design Team The OLSRv2 Design Team
MANET Working Group MANET Working Group
Intellectual Property Statement Full Copyright Statement
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
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Internet Society. Administrative Support Activity (IASA).
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