draft-ietf-ospf-manet-mpr-04.txt   rfc5449.txt 
Open Shortest Path (OSPF) E. Baccelli Network Working Group E. Baccelli
Internet-Draft P. Jacquet Request for Comments: 5449 P. Jacquet
Intended status: Experimental INRIA Category: Experimental INRIA
Expires: July 21, 2009 D. Nguyen D. Nguyen
CRC CRC
T. Clausen T. Clausen
LIX, Ecole Polytechnique, France LIX, Ecole Polytechnique
January 17, 2009 February 2009
OSPF MPR Extension for Ad Hoc Networks OSPF Multipoint Relay (MPR) Extension for Ad Hoc Networks
draft-ietf-ospf-manet-mpr-04
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Abstract Abstract
This document specifies an OSPFv3 interface type tailored for mobile This document specifies an OSPFv3 interface type tailored for mobile
ad hoc networks. This interface type is derived from the broadcast ad hoc networks. This interface type is derived from the broadcast
interface type, and denoted the "OSPFv3 MANET interface type". interface type, and is denoted the "OSPFv3 MANET interface type".
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 6 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5
3.1. MANET Characteristics . . . . . . . . . . . . . . . . . . 6 3.1. MANET Characteristics . . . . . . . . . . . . . . . . . . 5
3.2. OSPFv3 MANET Interface Characteristics . . . . . . . . . . 6 3.2. OSPFv3 MANET Interface Characteristics . . . . . . . . . . 5
4. Protocol Overview and Functioning . . . . . . . . . . . . . . 7 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6
4.1. Efficient Flooding using MPRs . . . . . . . . . . . . . . 7 4.1. Efficient Flooding Using MPRs . . . . . . . . . . . . . . 6
4.2. MPR Topology Reduction . . . . . . . . . . . . . . . . . . 7 4.2. MPR Topology-Reduction . . . . . . . . . . . . . . . . . . 6
4.3. Multicast Transmissions of Protocol Packets . . . . . . . 7 4.3. Multicast Transmissions of Protocol Packets . . . . . . . 7
4.4. MPR Adjacency Reduction . . . . . . . . . . . . . . . . . 8 4.4. MPR Adjacency-Reduction . . . . . . . . . . . . . . . . . 7
5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 8 5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Data Structures . . . . . . . . . . . . . . . . . . . . . 8 5.1. Data Structures . . . . . . . . . . . . . . . . . . . . . 7
5.1.1. N(i): Symmetric 1-hop Neighbor Set . . . . . . . . . . 8 5.1.1. N(i): Symmetric 1-Hop Neighbor Set . . . . . . . . . . 7
5.1.2. N2(i): Symmetric strict 2-hop Neighbor Set . . . . . . 9 5.1.2. N2(i): Symmetric Strict 2-Hop Neighbor Set . . . . . . 8
5.1.3. Flooding-MPR set . . . . . . . . . . . . . . . . . . . 9 5.1.3. Flooding-MPR Set . . . . . . . . . . . . . . . . . . . 8
5.1.4. Flooding-MPR-selector set . . . . . . . . . . . . . . 10 5.1.4. Flooding-MPR-Selector Set . . . . . . . . . . . . . . 9
5.1.5. Path-MPR set . . . . . . . . . . . . . . . . . . . . . 10 5.1.5. Path-MPR Set . . . . . . . . . . . . . . . . . . . . . 9
5.1.6. Path-MPR-selector set . . . . . . . . . . . . . . . . 11 5.1.6. Path-MPR-Selector Set . . . . . . . . . . . . . . . . 10
5.1.7. MPR set . . . . . . . . . . . . . . . . . . . . . . . 11 5.1.7. MPR Set . . . . . . . . . . . . . . . . . . . . . . . 10
5.1.8. MPR-selector set . . . . . . . . . . . . . . . . . . . 11 5.1.8. MPR-Selector Set . . . . . . . . . . . . . . . . . . . 10
5.2. Hello Protocol . . . . . . . . . . . . . . . . . . . . . . 11 5.2. Hello Protocol . . . . . . . . . . . . . . . . . . . . . . 10
5.2.1. Flooding-MPR Selection . . . . . . . . . . . . . . . . 12 5.2.1. Flooding-MPR Selection . . . . . . . . . . . . . . . . 11
5.2.2. Flooding-MPR Selection Signaling - FMPR TLV . . . . . 12 5.2.2. Flooding-MPR Selection Signaling - FMPR TLV . . . . . 11
5.2.3. Neighbor Ordering . . . . . . . . . . . . . . . . . . 12 5.2.3. Neighbor Ordering . . . . . . . . . . . . . . . . . . 12
5.2.4. Metric Signaling - METRIC-MPR TLV and PMPR TLV . . . . 13 5.2.4. Metric Signaling - METRIC-MPR TLV and PMPR TLV . . . . 12
5.2.5. Path-MPR Selection . . . . . . . . . . . . . . . . . . 13 5.2.5. Path-MPR Selection . . . . . . . . . . . . . . . . . . 12
5.2.6. Path-MPR Selection Signaling - PMPR TLV . . . . . . . 13 5.2.6. Path-MPR Selection Signaling - PMPR TLV . . . . . . . 12
5.2.7. Hello Packet Processing . . . . . . . . . . . . . . . 14 5.2.7. Hello Packet Processing . . . . . . . . . . . . . . . 13
5.3. Adjacencies . . . . . . . . . . . . . . . . . . . . . . . 14 5.3. Adjacencies . . . . . . . . . . . . . . . . . . . . . . . 13
5.3.1. Packets over 2-Way Links . . . . . . . . . . . . . . . 15 5.3.1. Packets over 2-Way Links . . . . . . . . . . . . . . . 14
5.3.2. Adjacency Conservation . . . . . . . . . . . . . . . . 15 5.3.2. Adjacency Conservation . . . . . . . . . . . . . . . . 14
5.4. Link State Advertisements . . . . . . . . . . . . . . . . 15 5.4. Link State Advertisements . . . . . . . . . . . . . . . . 14
5.4.1. LSA Flooding . . . . . . . . . . . . . . . . . . . . . 16 5.4.1. LSA Flooding . . . . . . . . . . . . . . . . . . . . . 15
5.4.2. Link State Acknowledgments . . . . . . . . . . . . . . 17 5.4.2. Link State Acknowledgments . . . . . . . . . . . . . . 17
5.5. Hybrid Routers . . . . . . . . . . . . . . . . . . . . . . 18 5.5. Hybrid Routers . . . . . . . . . . . . . . . . . . . . . . 18
5.6. Synch Routers . . . . . . . . . . . . . . . . . . . . . . 19 5.6. Synch Routers . . . . . . . . . . . . . . . . . . . . . . 18
5.7. Routing Table Computation . . . . . . . . . . . . . . . . 19 5.7. Routing Table Computation . . . . . . . . . . . . . . . . 18
6. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . . 19 6. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1. Flooding-MPR TLV . . . . . . . . . . . . . . . . . . . . 20 6.1. Flooding-MPR TLV . . . . . . . . . . . . . . . . . . . . 19
6.2. Metric-MPR TLV . . . . . . . . . . . . . . . . . . . . . . 20 6.2. Metric-MPR TLV . . . . . . . . . . . . . . . . . . . . . . 19
6.3. Path-MPR TLV . . . . . . . . . . . . . . . . . . . . . . 22 6.3. Path-MPR TLV . . . . . . . . . . . . . . . . . . . . . . . 22
7. Security Considerations . . . . . . . . . . . . . . . . . . . 25 7. Security Considerations . . . . . . . . . . . . . . . . . . . 24
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9.1. Normative References . . . . . . . . . . . . . . . . . . . 27 9.1. Normative References . . . . . . . . . . . . . . . . . . . 26
9.2. Informative References . . . . . . . . . . . . . . . . . . 27 9.2. Informative References . . . . . . . . . . . . . . . . . . 26
Appendix A. Flooding-MPR Selection Heuristic . . . . . . . . . . 28 Appendix A. Flooding-MPR Selection Heuristic . . . . . . . . . . 28
Appendix B. Path-MPR Selection Heuristic . . . . . . . . . . . . 29 Appendix B. Path-MPR Selection Heuristic . . . . . . . . . . . . 29
Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 30 Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 30
Appendix D. Acknowledgments . . . . . . . . . . . . . . . . . . . 30 Appendix D. Acknowledgments . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
This document specifies an extension of OSPFv3 [RFC5340] adapted to This document specifies an extension of OSPFv3 [RFC5340] that is
MANETs [RFC2501], and based on mechanisms providing: adapted to mobile ad hoc networks (MANETs) [RFC2501] and based on
mechanisms providing:
Flooding reduction: only a subset of all routers will be involved in Flooding-reduction: only a subset of all routers will be involved in
(re)transmissions during a flooding operation. (re)transmissions during a flooding operation.
Topology reduction: only a subset of links are advertised, hence Topology-reduction: only a subset of links are advertised, hence
both the number and the size of LSAs are decreased. both the number and the size of Link State Advertisements (LSAs)
are decreased.
Adjacency reduction: adjacencies are brought up only with a subset Adjacency-reduction: adjacencies are brought up only with a subset
of neighbors, for lower database synchronization overhead. of neighbors for lower database synchronization overhead.
These mechanisms are based on multipoint relays (MPR), a technique These mechanisms are based on multipoint relays (MPR), a technique
developed in OLSR [RFC3626]. developed in the Optimized Link State Routing Protocol (OLSR)
[RFC3626].
The extension specified in this document integrates into the OSPF The extension specified in this document integrates into the OSPF
framework by defining the OSPFv3 MANET interface type. While this framework by defining the OSPFv3 MANET interface type. While this
extension enables OSPFv3 to function efficiently on mobile ad hoc extension enables OSPFv3 to function efficiently on mobile ad hoc
networks, operation of OSPFv3 on other types of interfaces or networks, operation of OSPFv3 on other types of interfaces or
networks, or in areas without OSPFv3 MANET interfaces, remains networks, or in areas without OSPFv3 MANET interfaces, remains
unaltered. unaltered.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
This document uses OSPF terminology as defined in [RFC2328] and This document uses OSPF terminology as defined in [RFC2328] and
[RFC5340], LLS terminology as defined in [RFC4813], and introduces [RFC5340], and Link-Local Signaling (LLS) terminology as defined in
the following terminology to the OSPF nomenclature: [RFC4813]; it introduces the following terminology to the OSPF
nomenclature:
OSPFv3 MANET interface - the OSPFv3 interface type for MANETs, as OSPFv3 MANET interface - the OSPFv3 interface type for MANETs, as
specified in this document. specified in this document.
Additionally, the following terms are used in this document: Additionally, the following terms are used in this document:
MANET router - a router which has only OSPFv3 MANET interface(s). MANET router - a router that has only OSPFv3 MANET interfaces.
Wired router - a router which has only OSPFv3 interface of types Wired router - a router that has only OSPFv3 interface of types
other than OSPFv3 MANET interfaces. other than OSPFv3 MANET interfaces.
Hybrid router - a router which has OSPFv3 interfaces of several Hybrid router - a router that has OSPFv3 interfaces of several
types, including at least one of the OSPFv3 MANET interface type. types, including at least one of the OSPFv3 MANET interface type.
Neighbor - a router, reachable through an OSPFv3 interface (of any Neighbor - a router, reachable through an OSPFv3 interface (of any
type). type).
MANET neighbor - a neighbor, reachable through an OSPFv3 MANET MANET neighbor - a neighbor, reachable through an OSPFv3 MANET
interface. interface.
Symmetric 1-hop neighbor - a neighbor, in a state greater than or Symmetric 1-hop neighbor - a neighbor, in a state greater than or
equal to 2-Way (through an interface of any type). equal to 2-Way (through an interface of any type).
Symmetric strict 2-hop neighbor - a symmetric 1-hop neighbor of a Symmetric strict 2-hop neighbor - a symmetric 1-hop neighbor of a
symmetric 1-hop neighbor, which is not itself a symmetric 1-hop symmetric 1-hop neighbor, which is not itself a symmetric 1-hop
neighbor of this router. neighbor of the considered router.
Symmetric strict 2-hop neighborhood - the set formed by all the Symmetric strict 2-hop neighborhood - the set formed by all the
symmetric strict 2-hop neighbors of the considered router. symmetric strict 2-hop neighbors of the considered router.
Synch router - a router which brings up adjacencies with all of its Synch router - a router that brings up adjacencies with all of its
MANET neighbors. MANET neighbors.
Flooding-MPR - A router which is selected by its symmetric 1-hop Flooding-MPR - a router that is selected by its symmetric 1-hop
neighbor, router X, to retransmit all broadcast protocol packets neighbor, router X, to retransmit all broadcast protocol packets
that it receives from router X, provided that that broadcast that it receives from router X, provided that the broadcast
protocol packet is not a duplicate, and that the hop limit field protocol packet is not a duplicate and that the Hop Limit field of
of the protocol packet is greater than one. the protocol packet is greater than one.
Path-MPR - A router, which is selected by a symmetric 1-hop Path-MPR - a router that is selected by a symmetric 1-hop neighbor,
neighbor, X, as being on the shortest path from a router in the X, as being on the shortest path from a router in the symmetric
symmetric strict 2-hop neighborhood of router X and to the router strict 2-hop neighborhood of router X to router X.
X.
Multipoint Relay (MPR) - A router which is selected by its symmetric Multipoint relay (MPR) - a router that is selected by its symmetric
1-hop neighbor as either Flooding-MPR or as Path-MPR, or as both. 1-hop neighbor as either a Flooding-MPR, a Path-MPR, or both.
Flooding-MPR Selector - A router which has selected its symmetric Flooding-MPR-selector - a router that has selected its symmetric
1-hop neighbor, router X, as one of its Flooding-MPRs is a 1-hop neighbor, router X, as one of its Flooding-MPRs is a
Flooding-MPR selector of router X. Flooding-MPR-selector of router X.
Path-MPR Selector - A router which has selected its symmetric 1-hop Path-MPR-selector - a router that has selected its symmetric 1-hop
neighbor, router X, as one of its Path-MPRs is a Path-MPR selector neighbor, router X, as one of its Path-MPRs is a Path-MPR selector
of router X. of router X.
MPR Selector - A router which has selected its symmetric 1-hop MPR-selector - a router that has selected its symmetric 1-hop
neighbor, router X, as either one of its Flooding-MPRs or as one neighbor, router X, as either one of its Flooding-MPRs, one of its
of its Path-MPRs or as both is an MPR selector of router X. Path-MPRs, or both is an MPR-selector of router X.
3. Applicability Statement 3. Applicability Statement
The OSPFv3 MANET interface type, defined in this specification, The OSPFv3 MANET interface type, defined in this specification,
allows OSPFv3 to be deployed within an area where parts of that area allows OSPFv3 to be deployed within an area where parts of that area
are a mobile ad hoc network (MANET) with moderate mobility are a mobile ad hoc network (MANET) with moderate mobility
properties. properties.
3.1. MANET Characteristics 3.1. MANET Characteristics
MANETs [RFC2501] are networks in which a dynamic network topology is MANETs [RFC2501] are networks in which a dynamic network topology is
a frequently expected condition, often due to router mobility and/or a frequently expected condition, often due to router mobility and/or
to varying quality of wireless links - the latter of which also to varying quality of wireless links -- the latter of which also
generally entails bandwidth scarcity and interference issues between generally entails bandwidth scarcity and interference issues between
neighbors. neighbors.
Moreover, MANETs often exhibit "semi-broadcast" properties, i.e. that Moreover, MANETs often exhibit "semi-broadcast" properties, i.e., a
a router R that makes a transmission within a MANET can only assume router R that makes a transmission within a MANET can only assume
that transmission to be received by a subset of the total number of that transmission to be received by a subset of the total number of
routers within that MANET. Further, if two routers, R1 and R2, each routers within that MANET. Further, if two routers, R1 and R2, each
make a transmission, each of these transmissions is not guaranteed to make a transmission, neither of these transmissions is guaranteed to
be received by the same subset of routers within the MANET - and this be received by the same subset of routers within the MANET -- even if
even if each of R1 and R2 can mutually receive transmissions from R1 and R2 can mutually receive transmissions from each other.
each other.
These characteristics are incompatible with several OSPFv3 These characteristics are incompatible with several OSPFv3
mechanisms, including, but not limited to, existing mechanisms for mechanisms, including, but not limited to, existing mechanisms for
control traffic reduction, such as flooding reduction, topology control-traffic reduction, such as flooding-reduction, topology-
reduction and adjacency reduction (e.g. Designated Router). reduction, and adjacency-reduction (e.g., Designated Router).
3.2. OSPFv3 MANET Interface Characteristics 3.2. OSPFv3 MANET Interface Characteristics
An interface of the OSPFv3 MANET interface type is the point of An interface of the OSPFv3 MANET interface type is the point of
attachment of an OSPFv3 router to a network which may have MANET attachment of an OSPFv3 router to a network that may have MANET
characteristics. That is, an interface of the OSPFv3 MANET interface characteristics. That is, an interface of the OSPFv3 MANET interface
type is able to accommodate the MANET characteristics described in type is able to accommodate the MANET characteristics described in
Section 3.1. An OSPFv3 MANET interface type is not prescribing a set Section 3.1. An OSPFv3 MANET interface type is not prescribing a set
of behaviors or expectations that the network is required to have. of behaviors or expectations that the network is required to satisfy.
Rather, it is describing operating conditions under which protocols Rather, it is describing operating conditions under which protocols
on an interface towards that network must be able to function (i.e. on an interface towards that network must be able to function (i.e.,
the protocols are required to be able to operate correctly when faced the protocols are required to be able to operate correctly when faced
with the characteristics as described in Section 3.1). As such, the with the characteristics described in Section 3.1). As such, the
OSPFv3 MANET interface type is a generalization of other OSPFv3 OSPFv3 MANET interface type is a generalization of other OSPFv3
interface types; for example a protocol operating correctly over an interface types; for example, a protocol operating correctly over an
OSPFv3 MANET interface would also operate correctly over an OSPFv3 OSPFv3 MANET interface would also operate correctly over an OSPFv3
broadcast interface (whereas the inverse would not necessarily be broadcast interface (whereas the inverse would not necessarily be
true). true).
Efficient OSPFv3 operation over MANETs relies on control traffic Efficient OSPFv3 operation over MANETs relies on control-traffic
reduction, and using mechanisms appropriate for semi-broadcast. The reduction and on using mechanisms appropriate for semi-broadcast.
OSPFv3 MANET interface type, defined in this document, allows The OSPFv3 MANET interface type, defined in this document, allows
networks with MANET characteristics into the OSPFv3 framework by networks with MANET characteristics into the OSPFv3 framework by
integrating mechanisms (flooding reduction, topology reduction and integrating mechanisms (flooding-reduction, topology-reduction, and
adjacency reduction) derived from solutions standardized by the MANET adjacency-reduction) derived from solutions standardized by the MANET
working group. working group.
4. Protocol Overview and Functioning 4. Protocol Overview and Functioning
The OSPFv3 MANET interface type, defined in this specification, makes The OSPFv3 MANET interface type, defined in this specification, makes
use of flooding reduction, topology reduction and adjacency use of flooding-reduction, topology-reduction, and adjacency-
reduction, all based on multipoint relaying (MPR) - a technique reduction, all based on MPR, a technique derived from [RFC3626], as
derived from [RFC3626], as standardized in the MANET working group. standardized in the MANET working group. Multicast transmissions of
Multicast transmissions of protocol packets are used when possible. protocol packets are used when possible.
4.1. Efficient Flooding using MPRs 4.1. Efficient Flooding Using MPRs
OSPFv3 MANET interfaces use a flooding reduction mechanism denoted OSPFv3 MANET interfaces use a flooding-reduction mechanism, denoted
MPR flooding [MPR], whereby only a subset of MANET neighbors (those MPR flooding [MPR], whereby only a subset of MANET neighbors (those
selected as Flooding-MPR) participate in a flooding operation. This selected as Flooding-MPR) participate in a flooding operation. This
reduces the number of (re)transmissions necessary for a flooding reduces the number of (re)transmissions necessary for a flooding
operation [MPR-analysis], while retaining resilience to transmission operation [MPR-analysis], while retaining resilience against
errors (inherent when using wireless links), and obsolete two-hop transmission errors (inherent when using wireless links) and against
neighbor information (e.g. as caused by router mobility) obsolete two-hop neighbor information (e.g., as caused by router
[MPR-robustness]. mobility) [MPR-robustness].
4.2. MPR Topology Reduction 4.2. MPR Topology-Reduction
OSPFv3 MANET interfaces use a topology reduction mechanism denoted OSPFv3 MANET interfaces use a topology-reduction mechanism, denoted
MPR topology reduction, whereby only necessary links to MANET MPR topology-reduction, whereby only necessary links to MANET
neighbors (those identified by Path-MPR selection as belonging to neighbors (those identified by Path-MPR selection as belonging to
shortest paths) are included in LSAs. Routers in a MANET shortest paths) are included in LSAs. Routers in a MANET
periodically generate and flood Router-LSAs describing their periodically generate and flood Router-LSAs describing their
selection of such links to their Path-MPRs. Such links are reported selection of such links to their Path-MPRs. Such links are reported
as point-to-point links. This reduces the size of LSAs originated by as point-to-point links. This reduces the size of LSAs originated by
routers on a MANET [MPR-topology], while retaining classic OSPF routers on a MANET [MPR-topology], while retaining classic OSPF
properties: optimal paths using synchronized adjacencies (if properties: optimal paths using synchronized adjacencies (if
synchronized paths are preferred over non-synchronized paths of equal synchronized paths are preferred over non-synchronized paths of equal
cost). cost).
4.3. Multicast Transmissions of Protocol Packets 4.3. Multicast Transmissions of Protocol Packets
OSPFv3 MANET interfaces employ multicast transmissions, when OSPFv3 MANET interfaces employ multicast transmissions when possible,
possible, thereby taking advantage of inherent broadcast capabilities thereby taking advantage of inherent broadcast capabilities of the
of the medium, if present (with wireless interfaces, this can often medium, if present (with wireless interfaces, this can often be the
be the case [RFC2501]). In particular, LSA acknowledgments are sent case [RFC2501]). In particular, LSA acknowledgments are sent via
via multicast over these interfaces, and retransmissions over the multicast over these interfaces, and retransmissions over the same
same interfaces are considered as implicit acknowledgments. Jitter interfaces are considered as implicit acknowledgments. Jitter
management, such as delaying packet (re)transmission, can be employed management, such as delaying packet (re)transmission, can be employed
in order to allow several packets to be bundled into a single in order to allow several packets to be bundled into a single
transmission, which may avoid superfluous retransmissions due to transmission, which may avoid superfluous retransmissions due to
packet collisions [RFC5148]. packet collisions [RFC5148].
4.4. MPR Adjacency Reduction 4.4. MPR Adjacency-Reduction
Adjacencies over OSPFv3 MANET interfaces are required to be formed Adjacencies over OSPFv3 MANET interfaces are required to be formed
only with a subset of the neighbors of that OSPFv3 MANET interface. only with a subset of the neighbors of that OSPFv3 MANET interface.
No Designated Router or Backup Designated Router are elected on an No Designated Router or Backup Designated Router are elected on an
OSPFv3 MANET interface. Rather, adjacencies are brought up over an OSPFv3 MANET interface. Rather, adjacencies are brought up over an
OSPFv3 MANET interface only with MPRs and MPR Selectors. Only a OSPFv3 MANET interface only with MPRs and MPR selectors. Only a
small subset of routers in the MANET (called Synch routers) are small subset of routers in the MANET (called Synch routers) are
required to bring up adjacencies with all their MANET neighbors. required to bring up adjacencies with all their MANET neighbors.
This reduces the amount of control traffic needed for database This reduces the amount of control traffic needed for database
synchronization, while ensuring that LSAs still describe only synchronization, while ensuring that LSAs still describe only
synchronized adjacencies. synchronized adjacencies.
5. Protocol Details 5. Protocol Details
This section complements [RFC5340] and specifies the information that This section complements [RFC5340] and specifies the information that
must be maintained, processed and transmitted by routers which must be maintained, processed, and transmitted by routers that
operate one or more OSPFv3 MANET interfaces. operate one or more OSPFv3 MANET interfaces.
5.1. Data Structures 5.1. Data Structures
In addition to the values used in [RFC5340], the type field in the In addition to the values used in [RFC5340], the Type field in the
interface data structure can take a new value, "MANET". Furthermore, interface data structure can take a new value, "MANET". Furthermore,
and in addition to the protocol structures defined by [RFC5340], and in addition to the protocol structures defined by [RFC5340],
routers which operate one or more MANET interfaces make use of the routers that operate one or more MANET interfaces make use of the
data structures described below. data structures described below.
5.1.1. N(i): Symmetric 1-hop Neighbor Set 5.1.1. N(i): Symmetric 1-Hop Neighbor Set
The Symmetric 1-hop Neighbor set N(i) records router IDs of the set The Symmetric 1-hop Neighbor set N(i) records router IDs of the set
of symmetric 1-hop neighbors of the router on interface i. More of symmetric 1-hop neighbors of the router on interface i. More
precisely, N(i) records tuples of the form: precisely, N(i) records tuples of the form:
(1_HOP_SYM_id, 1_HOP_SYM_time) (1_HOP_SYM_id, 1_HOP_SYM_time)
where: where:
1_HOP_SYM_id: is the router ID of the symmetric 1-hop neighbor of 1_HOP_SYM_id: is the router ID of the symmetric 1-hop neighbor of
this router over the interface i. this router over interface i.
1_HOP_SYM_time: specifies the time at which the tuple expires and 1_HOP_SYM_time: specifies the time at which the tuple expires and
MUST be removed from the set. MUST be removed from the set.
For convenience throughout this document, N will denote the union of For convenience throughout this document, N will denote the union of
all N(i) sets, for all MANET interfaces on the router. all N(i) sets for all MANET interfaces on the router.
5.1.2. N2(i): Symmetric strict 2-hop Neighbor Set 5.1.2. N2(i): Symmetric Strict 2-Hop Neighbor Set
The Symmetric strict 2-hop Neighbor set N2(i) records links between The Symmetric strict 2-hop Neighbor set N2(i) records links between
routers in N(i) and their symmetric 1-hop neighbors, excluding: routers in N(i) and their symmetric 1-hop neighbors, excluding:
(i) the router performing the computation, (i) the router performing the computation, and
(ii) all routers in N(i). (ii) all routers in N(i).
More precisely, N2(i) records tuples of the form: More precisely, N2(i) records tuples of the form:
(2_HOP_SYM_id, 1_HOP_SYM_id, 2_HOP_SYM_time) (2_HOP_SYM_id, 1_HOP_SYM_id, 2_HOP_SYM_time)
where: where:
2_HOP_SYM_id: is the router ID of a symmetric strict 2-hop neighbor. 2_HOP_SYM_id: is the router ID of a symmetric strict 2-hop neighbor.
1_HOP_SYM_id: is the router ID of the symmetric 1-hop neighbor of 1_HOP_SYM_id: is the router ID of the symmetric 1-hop neighbor of
this router through which the symmetric strict 2-hop neighbor can this router through which the symmetric strict 2-hop neighbor can
be reached. be reached.
2_HOP_SYM_time: specifies the time at which the tuple expires and 2_HOP_SYM_time: specifies the time at which the tuple expires and
MUST be removed from the set. MUST be removed from the set.
For convenience throughout this document, N2 will denote the union of For convenience throughout this document, N2 will denote the union of
all N2(i) sets, for all MANET interfaces on the router. all N2(i) sets for all MANET interfaces on the router.
5.1.3. Flooding-MPR set 5.1.3. Flooding-MPR Set
The Flooding-MPR set on interface i records router IDs of a subset of The Flooding-MPR set on interface i records router IDs of a subset of
the routers listed in N(i), selected such that through this subset, the routers listed in N(i), selected such that, through this subset,
each router listed in N2(i) is reachable in 2 hops by this router. each router listed in N2(i) is reachable in 2 hops by this router.
There is one Flooding-MPR set per MANET interface. More precisely, There is one Flooding-MPR set per MANET interface. More precisely,
the Flooding-MPR set records tuples of the form: the Flooding-MPR set records tuples of the form:
(Flooding_MPR_id, Flooding_MPR_time) (Flooding_MPR_id, Flooding_MPR_time)
where: where:
Flooding_MPR_id: is the router ID of the symmetric 1-hop neighbor of Flooding_MPR_id: is the router ID of the symmetric 1-hop neighbor of
this router, selected as Flooding-MPR. this router that is selected as Flooding-MPR.
Flooding_MPR_time: specifies the time at which the tuple expires and Flooding_MPR_time: specifies the time at which the tuple expires and
MUST be removed from the set. MUST be removed from the set.
Flooding-MPR selection is detailed in Section 5.2.1. Flooding-MPR selection is detailed in Section 5.2.1.
5.1.4. Flooding-MPR-selector set 5.1.4. Flooding-MPR-Selector Set
The Flooding-MPR-selector set on interface i records router IDs of The Flooding-MPR-selector set on interface i records router IDs of
the set of symmetric 1-hop neighbors of this router on interface i the set of symmetric 1-hop neighbors of this router on interface i
that have selected this router as Flooding-MPR. There is one that have selected this router as their Flooding-MPR. There is one
Flooding-MPR-selector set per MANET interface. More precisely, the Flooding-MPR-selector set per MANET interface. More precisely, the
Flooding-MPR-selector set records tuples of the form: Flooding-MPR-selector set records tuples of the form:
(Flooding_MPR_SELECTOR_id, Flooding_MPR_SELECTOR_time) (Flooding_MPR_SELECTOR_id, Flooding_MPR_SELECTOR_time)
where: where:
Flooding_MPR_SELECTOR_id: is the router ID of the symmetric 1-hop Flooding_MPR_SELECTOR_id: is the router ID of the symmetric 1-hop
neighbor of this router, that has selected this router as neighbor of this router, that has selected this router as its
Flooding-MPR. Flooding-MPR.
Flooding_MPR_SELECTOR_time: specifies the time at which the tuple Flooding_MPR_SELECTOR_time: specifies the time at which the tuple
expires and MUST be removed from the set. expires and MUST be removed from the set.
Flooding-MPR selection is detailed in Section 5.2.1. Flooding-MPR selection is detailed in Section 5.2.1.
5.1.5. Path-MPR set 5.1.5. Path-MPR Set
The Path-MPR set records router IDs of routers in N, that provide The Path-MPR set records router IDs of routers in N that provide
shortest paths from routers in N2 and to this router. There is one shortest paths from routers in N2 to this router. There is one Path-
Path-MPR set per router. More precisely, the Path-MPR set records MPR set per router. More precisely, the Path-MPR set records tuples
tuples of the form: of the form:
(Path_MPR_id, Path_MPR_time) (Path_MPR_id, Path_MPR_time)
where: where:
Path_MPR_id: is the router ID of the symmetric 1-hop neighbor of Path_MPR_id: is the router ID of the symmetric 1-hop neighbor of
this router, selected as Path-MPR. this router, selected as Path-MPR.
Path_MPR_time: specifies the time at which the tuple expires and Path_MPR_time: specifies the time at which the tuple expires and
MUST be removed from the set. MUST be removed from the set.
Path-MPR selection is detailed in Section 5.2.5. Path-MPR selection is detailed in Section 5.2.5.
5.1.6. Path-MPR-selector set 5.1.6. Path-MPR-Selector Set
The Path-MPR-selector set records router IDs of the set of symmetric The Path-MPR-selector set records router IDs of the set of symmetric
1-hop neighbors over any MANET interface that have selected this 1-hop neighbors over any MANET interface that have selected this
router as Path-MPR. There is one Path-MPR-selector set per router. router as their Path-MPR. There is one Path-MPR-selector set per
More precisely, the Path-MPR-selector set records tuples of the form: router. More precisely, the Path-MPR-selector set records tuples of
the form:
(Path_MPR_SELECTOR_id, Path_MPR_SELECTOR_time) (Path_MPR_SELECTOR_id, Path_MPR_SELECTOR_time)
where: where:
Path_MPR_SELECTOR_id: is the router ID of the symmetric 1-hop Path_MPR_SELECTOR_id: is the router ID of the symmetric 1-hop
neighbor of this router, that has selected this router as Path- neighbor of this router that has selected this router as its Path-
MPR. MPR.
Path_MPR_SELECTOR_time: specifies the time at which the tuple Path_MPR_SELECTOR_time: specifies the time at which the tuple
expires and MUST be removed from the set. expires and MUST be removed from the set.
Path-MPR selection is detailed in Section 5.2.5. Path-MPR selection is detailed in Section 5.2.5.
5.1.7. MPR set 5.1.7. MPR Set
The MPR set is the union of the Flooding-MPR set(s) and the Path-MPR The MPR set is the union of the Flooding-MPR set(s) and the Path-MPR
set. There is one MPR set per router. set. There is one MPR set per router.
5.1.8. MPR-selector set 5.1.8. MPR-Selector Set
The MPR-Selector Set is the union of the Flooding-MPR-selector set(s) The MPR-selector set is the union of the Flooding-MPR-selector set(s)
and the Path-MPR-selector set. There is one MPR-selector set per and the Path-MPR-selector set. There is one MPR-selector set per
router. router.
5.2. Hello Protocol 5.2. Hello Protocol
On OSPFv3 MANET interfaces, packets are sent, received and processed On OSPFv3 MANET interfaces, packets are sent, received, and processed
as defined in [RFC5340] and [RFC2328], augmented for MPR selection as as defined in [RFC5340] and [RFC2328], and augmented for MPR
detailed in this section. selection as detailed in this section.
All additional signaling for OSPFv3 MANET interfaces is done through All additional signaling for OSPFv3 MANET interfaces is done through
inclusion of TLVs within an LLS block [RFC4813], appended to Hello inclusion of TLVs within an LLS block [RFC4813], which is appended to
packets. If an LLS block is not already present, an LLS block MUST Hello packets. If an LLS block is not already present, an LLS block
be created and appended to the Hello packets. MUST be created and appended to the Hello packets.
Hello packets sent over an OSPFv3 MANET interface MUST have the L bit Hello packets sent over an OSPFv3 MANET interface MUST have the L bit
of the OSPF Options field set, as per [RFC4813], indicating the of the OSPF Options field set, as per [RFC4813], indicating the
presence of an LLS block. presence of an LLS block.
This document defines and employs the following TLVs in Hello packets This document defines and employs the following TLVs in Hello packets
sent over OSPFv3 MANET interfaces: sent over OSPFv3 MANET interfaces:
FMPR - signaling Flooding-MPR selection; FMPR - signaling Flooding-MPR selection;
skipping to change at page 12, line 22 skipping to change at page 11, line 29
Section 6. Section 6.
5.2.1. Flooding-MPR Selection 5.2.1. Flooding-MPR Selection
The objective of Flooding-MPR selection is for a router to select a The objective of Flooding-MPR selection is for a router to select a
subset of its neighbors such that a packet, retransmitted by these subset of its neighbors such that a packet, retransmitted by these
selected neighbors, will be received by all routers 2 hops away. selected neighbors, will be received by all routers 2 hops away.
This property is called the Flooding-MPR "coverage criterion". The This property is called the Flooding-MPR "coverage criterion". The
Flooding-MPR set of a router is computed such that, for each OSPFv3 Flooding-MPR set of a router is computed such that, for each OSPFv3
MANET interface, it satisfies this criterion. The information MANET interface, it satisfies this criterion. The information
required to perform this calculation (i.e. link sensing and required to perform this calculation (i.e., link sensing and
neighborhood information) is acquired through periodic exchange of neighborhood information) is acquired through periodic exchange of
OSPFv3 Hello packets. OSPFv3 Hello packets.
Flooding-MPRs are computed by each router which operates at least one Flooding-MPRs are computed by each router that operates at least one
OSPFv3 MANET interface. The smaller the Flooding-MPR set is, the OSPFv3 MANET interface. The smaller the Flooding-MPR set is, the
lower the overhead will be. However, while it is not essential that lower the overhead will be. However, while it is not essential that
the Flooding-MPR set is minimal, the "coverage criterion" MUST be the Flooding-MPR set is minimal, the "coverage criterion" MUST be
satisfied by the selected Flooding-MPR set. satisfied by the selected Flooding-MPR set.
The willingness of a neighbor router to act as Flooding-MPR MAY be The willingness of a neighbor router to act as Flooding-MPR MAY be
taken into consideration by a heuristic for Flooding-MPR selection. taken into consideration by a heuristic for Flooding-MPR selection.
An example heuristic taking willingness into account is given in An example heuristic that takes willingness into account is given in
Appendix A. Appendix A.
5.2.2. Flooding-MPR Selection Signaling - FMPR TLV 5.2.2. Flooding-MPR Selection Signaling - FMPR TLV
A router MUST signal its Flooding-MPRs set to its neighbors, through A router MUST signal its Flooding-MPRs set to its neighbors by
including an FMPR TLV in generated Hello packets. Inclusion of this including an FMPR TLV in generated Hello packets. Inclusion of this
FMPR TLV signals the list of symmetric 1-hop neighbors that the FMPR TLV signals the list of symmetric 1-hop neighbors that the
sending router has selected as Flooding-MPR, as well as the sending router has selected as Flooding-MPRs, as well as the
willingness of the sending router to be elected Flooding-MPR by other willingness of the sending router to be elected Flooding-MPR by other
routers. The FMPR TLV structure is detailed in Section 6.1. routers. The FMPR TLV structure is detailed in Section 6.1.
5.2.3. Neighbor Ordering 5.2.3. Neighbor Ordering
Neighbors listed in the Hello packets sent over OSPFv3 MANET Neighbors listed in the Hello packets sent over OSPFv3 MANET
interfaces MUST be included in the order as given below: interfaces MUST be included in the order as given below:
1. symmetric 1-hop neighbors which are selected as Flooding-MPRs; 1. symmetric 1-hop neighbors that are selected as Flooding-MPRs;
2. other symmetric 1-hop neighbors; 2. other symmetric 1-hop neighbors;
3. other 1-hop neighbors. 3. other 1-hop neighbors.
This ordering allows correct interpretation of an included FMPR TLV. This ordering allows correct interpretation of an included FMPR TLV.
5.2.4. Metric Signaling - METRIC-MPR TLV and PMPR TLV 5.2.4. Metric Signaling - METRIC-MPR TLV and PMPR TLV
Hello packets sent over OSPFv3 MANET interfaces MUST advertise the Hello packets sent over OSPFv3 MANET interfaces MUST advertise the
costs of links towards ALL the symmetric MANET neighbors of the costs of links towards ALL the symmetric MANET neighbors of the
sending router. If the sending router has more than one OSPFv3 MANET sending router. If the sending router has more than one OSPFv3 MANET
interfaces, links to ALL the symmetric MANET neighbors over ALL the interface, links to ALL the symmetric MANET neighbors over ALL the
OSPFv3 MANET interfaces of that router MUST have their costs OSPFv3 MANET interfaces of that router MUST have their costs
advertised. advertised.
The costs of the links between the router and each of its MANET The costs of the links between the router and each of its MANET
neighbors on the OSPFv3 MANET interface over which the Hello packet neighbors on the OSPFv3 MANET interface over which the Hello packet
is sent MUST be signaled through including METRIC-MPR TLVs. The is sent MUST be signaled by including METRIC-MPR TLVs. The METRIC-
METRIC-MPR TLV structure is detailed in Section 6.2. MPR TLV structure is detailed in Section 6.2.
Moreover, the lowest cost from each MANET neighbor towards the router Moreover, the lowest cost from each MANET neighbor towards the router
(regardless of over which interface) MUST be specified in the (regardless of over which interface) MUST be specified in the
included PMPR TLV. Note that the lowest cost can be over an included PMPR TLV. Note that the lowest cost can be over an
interface which is not an OSPFv3 MANET interface. interface that is not an OSPFv3 MANET interface.
5.2.5. Path-MPR Selection 5.2.5. Path-MPR Selection
A router which has one or more OSPFv3 MANET interface(s) MUST select A router that has one or more OSPFv3 MANET interfaces MUST select a
a Path-MPR set from among routers in N. Routers in the Path-MPR set Path-MPR set from among routers in N. Routers in the Path-MPR set of
of a router are those which take part in the shortest (with respect a router are those that take part in the shortest (with respect to
to the metrics used) path from routers in N2 and to this router. A the metrics used) path from routers in N2 to this router. A
heuristic for Path-MPR selection is given in Appendix B. heuristic for Path-MPR selection is given in Appendix B.
5.2.6. Path-MPR Selection Signaling - PMPR TLV 5.2.6. Path-MPR Selection Signaling - PMPR TLV
A router MUST signal its Path-MPR set to its neighbors, through A router MUST signal its Path-MPR set to its neighbors by including a
including a PMPR TLV in generated Hello packets. PMPR TLV in generated Hello packets.
A PMPR TLV MUST contain a list of IDs of all symmetric 1-hop A PMPR TLV MUST contain a list of IDs of all symmetric 1-hop
neighbors of all OSPFv3 MANET interfaces of the router. These IDs neighbors of all OSPFv3 MANET interfaces of the router. These IDs
MUST be included in the PMPR TLV in the order as given below: MUST be included in the PMPR TLV in the order as given below:
1. Neighbors which are both adjacent AND are selected as Path-MPR 1. Neighbors that are both adjacent AND selected as Path-MPR for any
for any OSPFv3 MANET interface of the router generating the Hello OSPFv3 MANET interface of the router generating the Hello packet.
packet.
2. Neighbors which are adjacent over any OSPFv3 MANET interface of 2. Neighbors that are adjacent over any OSPFv3 MANET interface of
the router generating the Hello packet. the router generating the Hello packet.
3. Symmetric 1-hop neighbors on any OSPFv3 MANET interface of the 3. Symmetric 1-hop neighbors on any OSPFv3 MANET interface of the
router generating the Hello packet, which have not been router generating the Hello packet that have not been previously
previously included in this PMPR TLV. included in this PMPR TLV.
The list of neighbor IDs is followed by a list of costs for the links The list of neighbor IDs is followed by a list of costs for the links
from these neighbors and to the router generating the Hello packet from these neighbors to the router generating the Hello packet
containing this PMPR TLV, as detailed in Section 5.2.4. The PMPR TLV containing this PMPR TLV, as detailed in Section 5.2.4. The PMPR TLV
structure is detailed in Section 6.3. structure is detailed in Section 6.3.
5.2.7. Hello Packet Processing 5.2.7. Hello Packet Processing
In addition to the processing specified in [RFC5340], N and N2 MUST In addition to the processing specified in [RFC5340], N and N2 MUST
be updated when received Hello packets indicate changes to the be updated when received Hello packets indicate changes to the
neighborhood of an OSPFv3 MANET interface i. In particular, if a neighborhood of an OSPFv3 MANET interface i. In particular, if a
received Hello packet signals that a tuple in N (or N2) is to be received Hello packet signals that a tuple in N (or N2) is to be
deleted, the deletion is done immediately, without waiting for the deleted, the deletion is done immediately, without waiting for the
tuple to expire. Note that N2 records not only 2-hop neighbors tuple to expire. Note that N2 records not only 2-hop neighbors
listed in received Hellos, but also 2-hop neighbors listed in the listed in received Hellos but also 2-hop neighbors listed in the
appended PMPR TLVs. appended PMPR TLVs.
The Flooding-MPR set MUST be recomputed when either of N(i) or N2(i) The Flooding-MPR set MUST be recomputed when either of N(i) or N2(i)
has changed. The Path-MPR set MUST be recomputed when either of N or has changed. The Path-MPR set MUST be recomputed when either of N or
N2 has changed. Moreover, the Path-MPR set MUST be recomputed if N2 has changed. Moreover, the Path-MPR set MUST be recomputed if
appended LLS information signals change with respect to one or more appended LLS information signals change with respect to one or more
link cost(s). link costs.
The Flooding-MPR selector set and the Path-MPR selector set MUST be The Flooding-MPR-selector set and the Path-MPR-selector set MUST be
updated upon receipt of a Hello packet containing LLS information updated upon receipt of a Hello packet containing LLS information
indicating changes in the list of neighbors that has selected the indicating changes in the list of neighbors that has selected the
router as MPR. router as MPR.
If a Hello with the S bit set is received on a OSPFv3 MANET interface If a Hello with the S bit set is received on an OSPFv3 MANET
of a router, from a non-adjacent neighbor, the router MUST transition interface of a router, from a non-adjacent neighbor, the router MUST
this neighbor's state to ExStart. transition this neighbor's state to ExStart.
5.3. Adjacencies 5.3. Adjacencies
Adjacencies are brought up between OSPFv3 MANET interfaces as Adjacencies are brought up between OSPFv3 MANET interfaces as
described in [RFC5340] and [RFC2328]. However, in order to reduce described in [RFC5340] and [RFC2328]. However, in order to reduce
the control traffic overhead over the OSPFv3 MANET interfaces, a the control-traffic overhead over the OSPFv3 MANET interfaces, a
router which has one or more such OSPFv3 MANET interface(s) MAY bring router that has one or more such OSPFv3 MANET interfaces MAY bring up
up adjacencies with only subset of its MANET neighbors. adjacencies with only a subset of its MANET neighbors.
Over an OSPFv3 MANET interface, a router MUST bring up adjacencies Over an OSPFv3 MANET interface, a router MUST bring up adjacencies
with all MANET neighbors which are included in its MPR set and its with all MANET neighbors that are included in its MPR set and its
MPR Selector set; this ensures that beyond the first hop, routes use MPR-selector set; this ensures that, beyond the first hop, routes use
synchronized links (if synchronized paths are preferred over non- synchronized links (if synchronized paths are preferred over non-
synchronized paths of equal cost). A router MAY bring up adjacencies synchronized paths of equal cost). A router MAY bring up adjacencies
with other MANET neighbors, at the expense of additional with other MANET neighbors, at the expense of additional
synchronization overhead. synchronization overhead.
5.3.1. Packets over 2-Way Links 5.3.1. Packets over 2-Way Links
When a router does not form a full adjacency with a MANET neighbor, When a router does not form a full adjacency with a MANET neighbor,
the state of that neighbor does not progress beyond 2-Way (as defined the state of that neighbor does not progress beyond 2-Way (as defined
in [RFC2328]). A router can send protocol packets, such as LSAs, to in [RFC2328]). A router can send protocol packets, such as LSAs, to
a MANET neighbor in 2-Way state. Therefore, any packet received from a MANET neighbor in 2-Way state. Therefore, any packet received from
a symmetric MANET neighbor MUST be processed. a symmetric MANET neighbor MUST be processed.
As with the OSPF broadcast interface [RFC2328], the next hop in the As with the OSPF broadcast interface [RFC2328], the next hop in the
forwarding table MAY be a neighbor that is not adjacent. However, forwarding table MAY be a neighbor that is not adjacent. However,
when a data packet has travelled beyond its first hop, the MPR when a data packet has travelled beyond its first hop, the MPR-
selection process guarantees that subsequent hops in the SPT will be selection process guarantees that subsequent hops in the shortest
over adjacencies (if synchronized paths are preferred over non- path tree (SPT) will be over adjacencies (if synchronized paths are
synchronized paths of equal cost). preferred over non-synchronized paths of equal cost).
5.3.2. Adjacency Conservation 5.3.2. Adjacency Conservation
Adjacencies are torn down according to [RFC2328]. When the MPR set Adjacencies are torn down according to [RFC2328]. When the MPR set
or MPR selector set is updated (due to changes in the neighborhood), or MPR-selector set is updated (due to changes in the neighborhood),
and when a neighbor was formerly, but is no longer, in the MPR set or and when a neighbor was formerly, but is no longer, in the MPR set or
the MPR selector set, then the adjacency with that neighbor is kept, the MPR-selector set, then the adjacency with that neighbor is kept
unless the change causes the neighbor to cease being a symmetric unless the change causes the neighbor to cease being a symmetric
1-hop neighbor. 1-hop neighbor.
When a router receives Hello packets from a symmetric 1-hop neighbor When a router receives Hello packets from a symmetric 1-hop neighbor
which ceases to list this router as being adjacent (see that ceases to list this router as being adjacent (see
Section 5.2.6), the state of that neighbor MUST be changed to (i) Section 5.2.6), the state of that neighbor MUST be changed to:
2-Way if the neighbor is not in the MPR set or the MPR selector set,
or (ii) ExStart if the neighbor is in the MPR set or the MPR selector 1. 2-Way if the neighbor is not in the MPR set or MPR-selector set,
set, or if the neighbor or the router itself is a Synch router. or
2. ExStart if either the neighbor is in the MPR set or MPR-selector
set, or the neighbor or the router itself is a Synch router.
5.4. Link State Advertisements 5.4. Link State Advertisements
Routers generate Router-LSAs periodically, using the format specified Routers generate Router-LSAs periodically, using the format specified
in [RFC5340] and [RFC2328]. in [RFC5340] and [RFC2328].
Routers which have one or more OSPFv3 MANET interface(s) MUST include Routers that have one or more OSPFv3 MANET interfaces MUST include
the following links in the Router-LSAs that they generate: the following links in the Router-LSAs that they generate:
o links to all neighbors that are in the Path-MPR set; AND o links to all neighbors that are in the Path-MPR set, AND
o links to all neighbors that are in the Path-MPR Selector set. o links to all neighbors that are in the Path-MPR-selector set.
Routers which have one or more OSPFv3 MANET interface(s) MAY list Routers that have one or more OSPFv3 MANET interfaces MAY list other
other links they have through those OSPFv3 MANET interfaces, at the links they have through those OSPFv3 MANET interfaces, at the expense
expense of larger LSAs. of larger LSAs.
In addition, routers which have one or more OSPFv3 MANET interface(s) In addition, routers that have one or more OSPFv3 MANET interfaces
MUST generate updated Router-LSAs when either of the following MUST generate updated Router-LSAs when either of the following
occurs: occurs:
o a new adjacency has been brought up, reflecting a change in the o a new adjacency has been brought up, reflecting a change in the
MPR set; Path-MPR set;
o a new adjacency has been brought up, reflecting a change in the o a new adjacency has been brought up, reflecting a change in the
MPR Selector set; Path-MPR-selector set;
o a formerly adjacent and advertised neighbor ceases to be adjacent; o a formerly adjacent and advertised neighbor ceases to be adjacent;
o the cost of a link to (or from) an advertised neighbor has o the cost of a link to (or from) an advertised neighbor has
changed. changed.
5.4.1. LSA Flooding 5.4.1. LSA Flooding
An originated LSA is flooded according to [RFC5340], out all An originated LSA is flooded, according to [RFC5340], out all
interfaces concerned by the scope of this LSA. interfaces concerned by the scope of this LSA.
Link State Updates received on an interface of a type other than Link State Updates received on an interface of a type other than
OSPFv3 MANET interface are processed and flooded according to OSPFv3 MANET interface are processed and flooded according to
[RFC2328] and [RFC5340], over every interface. If a Link State [RFC2328] and [RFC5340], over every interface. If a Link State
Update was received on an OSPFv3 MANET interface, it is processed as Update was received on an OSPFv3 MANET interface, it is processed as
follows: follows:
1. Consistency checks are performed on the received packet according 1. Consistency checks are performed on the received packet according
to [RFC2328] and [RFC5340], and the Link State Update packet is to [RFC2328] and [RFC5340], and the Link State Update packet is
thus associated with a particular neighbor and a particular area. thus associated with a particular neighbor and a particular area.
2. If the Link State Update was received from a router other than a 2. If the Link State Update was received from a router other than a
symmetric 1-hop neighbor, the Link State Update MUST be discarded symmetric 1-hop neighbor, the Link State Update MUST be discarded
without further processing. without further processing.
3. Otherwise, for each LSA contained in Link State Updates received 3. Otherwise, for each LSA contained in Link State Updates received
over an OSPFv3 MANET interface, the following steps replace steps over an OSPFv3 MANET interface, the following steps replace steps
1 to 5 of section 13.3 of [RFC2328]. 1 to 5 of Section 13.3 of [RFC2328].
1. If an LSA exists in the Link State Database, with the same (1) If an LSA exists in the Link State Database, with the same
Link State ID, LS Type and Advertising Router values as the Link State ID, LS Type, and Advertising Router values as the
received LSA, and if the received LSA is not newer (see received LSA, and if the received LSA is not newer (see
section 13.1 of [RFC2328]), then the received LSA MUST NOT be Section 13.1 of [RFC2328]), then the received LSA MUST NOT
processed, except for acknowledgment as described in be processed, except for acknowledgment as described in
Section 5.4.2. Section 5.4.2.
2. Otherwise, the LSA MUST be attributed a scope according to (2) Otherwise, the LSA MUST be attributed a scope according to
its type, as specified in section 3.5 of [RFC5340]. its type, as specified in Section 3.5 of [RFC5340].
3. If the scope of the LSA is link local or reserved, the LSA (3) If the scope of the LSA is link local or reserved, the LSA
MUST NOT be flooded on any interface. MUST NOT be flooded on any interface.
4. Otherwise: (4) Otherwise:
+ If the scope of the LSA is the area, the LSA MUST be + If the scope of the LSA is the area, the LSA MUST be
flooded on all the OSPFv3 interfaces of the router in that flooded on all the OSPFv3 interfaces of the router in
area according to the default flooding algorithm described that area, according to the default flooding algorithm
in Section 5.4.1.1. described in Section 5.4.1.1.
+ Otherwise, the LSA MUST be flooded on all the OSPFv3 + Otherwise, the LSA MUST be flooded on all the OSPFv3
interfaces of the router according to the default flooding interfaces of the router according to the default
algorithm described in Section 5.4.1.1. flooding algorithm described in Section 5.4.1.1.
5.4.1.1. Default LSA Flooding Algorithm 5.4.1.1. Default LSA Flooding Algorithm
The default LSA flooding algorithm is as follows: The default LSA flooding algorithm is as follows:
1. The LSA MUST be installed in the Link State Database. 1. The LSA MUST be installed in the Link State Database.
2. The Age of the LSA MUST be increased by InfTransDelay. 2. The Age of the LSA MUST be increased by InfTransDelay.
3. The LSA MUST be retransmitted over all OSPFv3 interfaces of types 3. The LSA MUST be retransmitted over all OSPFv3 interfaces of types
other than OSPFv3 MANET interface. other than OSPFv3 MANET interface.
4. If the sending OSPFv3 interface is a Flooding-MPR selector of 4. If the sending OSPFv3 interface is a Flooding-MPR-selector of
this router, then the LSA MUST also be retransmitted over all this router, then the LSA MUST also be retransmitted over all
OSPFv3 MANET interfaces concerned by the scope, with the OSPFv3 MANET interfaces concerned by the scope, with the
multicast address all_SPF_Routers. multicast address all_SPF_Routers.
Note that MinLSArrival SHOULD be set to a value that is appropriate Note that MinLSArrival SHOULD be set to a value that is appropriate
to dynamic topologies: LSA updating may need to be more frequent in to dynamic topologies: LSA updating may need to be more frequent in
MANET parts of an OSPF network than in other parts of an OSPF MANET parts of an OSPF network than in other parts of an OSPF
network. network.
5.4.2. Link State Acknowledgments 5.4.2. Link State Acknowledgments
When a router receives an LSA over an OSPFv3 MANET interface, the When a router receives an LSA over an OSPFv3 MANET interface, the
router MUST proceed to acknowledge the LSA as follows: router MUST proceed to acknowledge the LSA as follows:
1. If the LSA was not received from an adjacent neighbor, the router 1. If the LSA was not received from an adjacent neighbor, the router
MUST NOT acknowledge it. MUST NOT acknowledge it.
2. Otherwise, if the LSA was received from an adjacent neighbor and 2. Otherwise, if the LSA was received from an adjacent neighbor and
if the LSA is already in the Link State Database (i.e. the LSA if the LSA is already in the Link State Database (i.e., the LSA
has already been received and processed), then the router MUST has already been received and processed), then the router MUST
send an acknowledgment for this LSA on all OSPFv3 MANET send an acknowledgment for this LSA on all OSPFv3 MANET
interfaces, to the multicast address all_SPF_Routers. interfaces to the multicast address all_SPF_Routers.
3. Otherwise, if the LSA is not already in the Link State Database: 3. Otherwise, if the LSA is not already in the Link State Database:
1. If the router decides to retransmit the LSA (as part of the 1. If the router decides to retransmit the LSA (as part of the
flooding procedure), the router MUST NOT acknowledge it, as flooding procedure), the router MUST NOT acknowledge it, as
this retransmission will be considered as an implicit this retransmission will be considered as an implicit
acknowledgment. acknowledgment.
2. Otherwise, if the router decides to not retransmit the LSA 2. Otherwise, if the router decides to not retransmit the LSA
(as part of the flooding procedure), the router MUST send an (as part of the flooding procedure), the router MUST send an
explicit acknowledgment for this LSA on all OSPFv3 MANET explicit acknowledgment for this LSA on all OSPFv3 MANET
interfaces, to the multicast address all_SPF_Routers. interfaces to the multicast address all_SPF_Routers.
If a router sends an LSA on an OSPFv3 MANET interface, it expects If a router sends an LSA on an OSPFv3 MANET interface, it expects
acknowledgments (explicit or implicit) from all adjacent neighbors. acknowledgments (explicit or implicit) from all adjacent neighbors.
In the case where the router did not generate, but simply relays, the In the case where the router did not generate, but simply relays, the
LSA, then the router MUST expect acknowledgments (explicit or LSA, then the router MUST expect acknowledgments (explicit or
implicit) only from adjacent neighbors that have not previously implicit) only from adjacent neighbors that have not previously
acknowledged this LSA. If a router detects that some adjacent acknowledged this LSA. If a router detects that some adjacent
neighbor has not acknowledged the LSA, then that router MUST neighbor has not acknowledged the LSA, then that router MUST
retransmit the LSA. retransmit the LSA.
If, due to the MPR flooding reduction mechanism employed for LSA If, due to the MPR flooding-reduction mechanism employed for LSA
Flooding as described in Section 5.4.1, a router decides to not relay flooding as described in Section 5.4.1, a router decides to not relay
an LSA, the router MUST still expect acknowledgments of this LSA an LSA, the router MUST still expect acknowledgments of this LSA
(explicit or implicit) from adjacent neighbors that have not (explicit or implicit) from adjacent neighbors that have not
previously acknowledged this LSA. If a router detects that some previously acknowledged this LSA. If a router detects that some
adjacent neighbor has not acknowledged the LSA, then the router MUST adjacent neighbor has not acknowledged the LSA, then the router MUST
retransmit the LSA. retransmit the LSA.
Note that it may be beneficial to aggregate several acknowledgments Note that it may be beneficial to aggregate several acknowledgments
in the same transmission, taking advantage of native multicasting (if in the same transmission, taking advantage of native multicasting (if
available). A timer wait MAY thus be used before any acknowledgment available). A timer wait MAY thus be used before any acknowledgment
transmission. transmission.
Additionally, jitter [RFC5148] on packet (re)transmission MAY be used Additionally, jitter [RFC5148] on packet (re)transmission MAY be used
in order to increase the opportunities to bundle several packets in order to increase the opportunities to bundle several packets
together in each transmission. together in each transmission.
5.5. Hybrid Routers 5.5. Hybrid Routers
In addition to the operations described in Section 5.2, Section 5.3 In addition to the operations described in Section 5.2, Section 5.3
and Section 5.4, hybrid routers MUST: and Section 5.4, Hybrid routers MUST:
o select ALL their MANET neighbors as Path-MPRs. o select ALL their MANET neighbors as Path-MPRs.
o list adjacencies over OSPFv3 interfaces of types other than OSPFv3 o list adjacencies over OSPFv3 interfaces of types other than OSPFv3
MANET interface, as specified in [RFC5340] and [RFC2328], in MANET interface, as specified in [RFC5340] and [RFC2328], in
generated Router-LSAs. generated Router-LSAs.
5.6. Synch Routers 5.6. Synch Routers
In a network with no hybrid routers, at least one Synch router MUST In a network with no Hybrid routers, at least one Synch router MUST
be selected. A Synch router MUST: be selected. A Synch router MUST:
o set the S bit in the PMPR TLV appended to the Hello packets it o set the S bit in the PMPR TLV appended to the Hello packets it
generates; AND generates, AND
o become adjacent with ALL MANET neighbors. o become adjacent with ALL MANET neighbors.
A proposed heuristic for selection of Sync routers is as follows: A proposed heuristic for selection of Sync routers is as follows:
o A router which has a MANET interface and an ID that is higher than o A router that has a MANET interface and an ID that is higher than
the ID of all of its current neighbors, and whose ID is higher the ID of all of its current neighbors, and whose ID is higher
than any other ID present in Router-LSAs currently in its Link than any other ID present in Router-LSAs currently in its Link
State Database selects itself as Synch router. State Database selects itself as Synch router.
Other heuristics are possible, however any heuristic for selecting Other heuristics are possible; however, any heuristic for selecting
Synch routers MUST ensure the presence of at least one sync or hybrid Synch routers MUST ensure the presence of at least one Synch or
router in the network. Hybrid router in the network.
5.7. Routing Table Computation 5.7. Routing Table Computation
When routing table (re)computation occurs, in addition to the When routing table (re)computation occurs, in addition to the
processing of the Link State Database defined in [RFC5340] and processing of the Link State Database defined in [RFC5340] and
[RFC2328], routers which have one or more MANET interfaces MUST take [RFC2328], routers that have one or more MANET interfaces MUST take
into account links between themselves and MANET neighbors that are in into account links between themselves and MANET neighbors that are in
state 2-Way or higher (as data and protocol packets may be sent, state 2-Way or higher (as data and protocol packets may be sent,
received and processed over these links too). Thus, the connectivity received, and processed over these links too). Thus, the
matrix used to compute routes MUST reflect links between the root and connectivity matrix used to compute routes MUST reflect links between
all its neighbors in state 2-Way and higher, as well as links the root and all its neighbors in state 2-Way and higher, as well as
described in the Link State Database. links described in the Link State Database.
6. Packet Formats 6. Packet Formats
OSPFv3 packets are as defined by [RFC5340] and [RFC2328]. Additional OSPFv3 packets are as defined by [RFC5340] and [RFC2328]. Additional
LLS signaling [RFC4813] is used in Hello packets sent over OSPFv3 LLS signaling [RFC4813] is used in Hello packets sent over OSPFv3
MANET interfaces, as detailed in this section. MANET interfaces, as detailed in this section.
This specification uses network byte order (most significant octet This specification uses network byte order (most significant octet
first) for all fields. first) for all fields.
skipping to change at page 20, line 22 skipping to change at page 19, line 31
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=FMPR | Length | | Type=FMPR | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Willingness | # Sym. Neigh. | # Flood MPR | Reserved | | Willingness | # Sym. Neigh. | # Flood MPR | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Flooding-MPR TLV (FMPR) Figure 1: Flooding-MPR TLV (FMPR)
where: where:
Willingness - is an 8 bit unsigned integer field which specifies the Willingness - is an 8-bit unsigned integer field that specifies the
willingness of the router to flood link state information on willingness of the router to flood link-state information on
behalf of other routers. It can be set to any integer value from behalf of other routers. It can be set to any integer value from
1 to 6. By default, a router SHOULD advertise a willingness of 1 to 6. By default, a router SHOULD advertise a willingness of
WILL_DEFAULT = 3. WILL_DEFAULT = 3.
# Sym. Neigh. - is an 8 bit unsigned integer field which specifies # Sym. Neigh. - is an 8-bit unsigned integer field that specifies
the number of symmetric 1-hop neighbors. These symmetric 1-hop the number of symmetric 1-hop neighbors. These symmetric 1-hop
neighbors are listed first among the neighbors in a Hello packet. neighbors are listed first among the neighbors in a Hello packet.
# Flood MPR - is an 8 bit unsigned integer field which specifies the # Flood MPR - is an 8-bit unsigned integer field that specifies the
number of neighbors selected as Flooding-MPR. These Flooding-MPRs number of neighbors selected as Flooding-MPR. These Flooding-MPRs
are listed first among the symmetric 1-hop neighbors. are listed first among the symmetric 1-hop neighbors.
Reserved - is an 8 bit field which SHOULD be cleared ('0') on Reserved - is an 8-bit field that SHOULD be cleared ('0') on
transmission and SHOULD be ignored on reception. transmission and SHOULD be ignored on reception.
6.2. Metric-MPR TLV 6.2. Metric-MPR TLV
A TLV of Type METRIC-MPR is defined for signaling costs of links to A TLV of Type METRIC-MPR is defined for signaling costs of links to
neighbors, shown in Figure 2. neighbors, shown in Figure 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 21, line 20 skipping to change at page 20, line 20
| Reserved |U|R| Cost 0 | | Reserved |U|R| Cost 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost 1 | Cost 2 | | Cost 1 | Cost 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : : :
: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost n | Padding | | Cost n | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Metric TLV (METRIC-MPR). Figure 2: Metric TLV (METRIC-MPR)
where: where:
Reserved - is a 14 bit field which SHOULD be cleared ('0') on Reserved - is a 14-bit field that SHOULD be cleared ('0') on
transmission and SHOULD be ignored on reception. transmission and SHOULD be ignored on reception.
R - is a binary flag, cleared ('0') if the costs advertised in the R - is a binary flag, cleared ('0') if the costs advertised in the
TLV are direct (i.e. the costs of the links from the router to the TLV are direct (i.e., the costs of the links from the router to
neighbors), set ('1') if the costs advertised are reverse (i.e. the neighbors), or set ('1') if the costs advertised are reverse
the costs of the links from the neighbors to the router). (i.e., the costs of the links from the neighbors to the router).
By default, R is cleared ('0').
U - is a binary flag, cleared ('0') if each the cost for each link U - is a binary flag, cleared ('0') if the cost for each link from
from the sending router and to each advertised neighbor is the sending router and to each advertised neighbor is explicitly
explicitly included (shown in Figure 3), set ('1') if a single included (shown in Figure 3), or set ('1') if a single metric
metric value is included which applies to all links (shown in value is included that applies to all links (shown in Figure 4).
Figure 4).
Cost n - is an 8 bit unsigned integer field which specifies the cost Cost n - is an 8-bit unsigned integer field that specifies the cost
of the link, in the direction specified by the R flag, between of the link, in the direction specified by the R flag, between
this router and the neighbor listed at the n-th position in the this router and the neighbor listed at the n-th position in the
Hello packet, when counting from the beginning of the Hello packet Hello packet when counting from the beginning of the Hello packet
and with the first neighbor being at position 0. and with the first neighbor being at position 0.
Padding - is a 16 bit field which SHOULD be cleared ('0') on Padding - is a 16-bit field that SHOULD be cleared ('0') on
transmission and SHOULD be ignored on reception. Padding is transmission and SHOULD be ignored on reception. Padding is
included in order that the TLV is 32bit aligned. Padding MUST be included in order that the TLV is 32-bit aligned. Padding MUST be
included when the TLV contains an even number of Cost fields, and included when the TLV contains an even number of Cost fields and
MUST NOT be included otherwise. MUST NOT be included otherwise.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=METRIC-MPR | Length | | Type=METRIC-MPR | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |0|R| Cost 0 | | Reserved |0|R| Cost 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost 1 | Cost 2 | | Cost 1 | Cost 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Metric Advertisement TLV (METRIC-MPR) example with Figure 3: Metric Advertisement TLV (METRIC-MPR) example with explicit
explicit individual link costs (U=0) and an odd number of Costs (and, individual link costs (U=0) and an odd number of Costs (and, hence,
hence, no padding). no padding).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=METRIC-MPR | Length | | Type=METRIC-MPR | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |1|R| Cost | | Reserved |1|R| Cost |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Metric Advertisement TLV (METRIC-MPR) example with a Figure 4: Metric Advertisement TLV (METRIC-MPR) example with a single
single and uniform link cost (U=1) (and, hence, no padding). and uniform link cost (U=1) (and, hence, no padding).
6.3. Path-MPR TLV 6.3. Path-MPR TLV
A TLV of Type PMPR is defined for signaling Path-MPR selection, shown A TLV of Type PMPR is defined for signaling Path-MPR selection, shown
in Figure 1, as well as the link cost associated with these Path- in Figure 1, as well as the link cost associated with these Path-
MPRs. MPRs.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 23, line 29 skipping to change at page 22, line 35
| Cost 0 | Cost 1 | | Cost 0 | Cost 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : : :
: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost n | Padding | | Cost n | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Path-MPR TLV (PMPR) Figure 5: Path-MPR TLV (PMPR)
# Sym Neigh. - is an 8 bit unsigned integer field which specifies # Sym Neigh. - is an 8-bit unsigned integer field that specifies the
the number of symmetric 1-hop MANET neighbors of all OSPFv3 MANET number of symmetric 1-hop MANET neighbors of all OSPFv3 MANET
interfaces of the router, listed in the PMPR TLV. interfaces of the router, listed in the PMPR TLV.
# Adj. Neigh. - is an 8 bit unsigned integer field which specifies # Adj. Neigh. - is an 8-bit unsigned integer field that specifies
the number of adjacent neighbors. These adjacent neighbors are the number of adjacent neighbors. These adjacent neighbors are
listed first among the symmetric 1-hop MANET neighbors of all listed first among the symmetric 1-hop MANET neighbors of all
OSPFv3 MANET interface of the router in the PMPR TLV. OSPFv3 MANET interfaces of the router in the PMPR TLV.
# Path-MPR - is an 8 bit unsigned integer field which specifies the # Path-MPR - is an 8-bit unsigned integer field that specifies the
number of MANET neighbors selected as Path-MPR. These Path-MPRs number of MANET neighbors selected as Path-MPR. These Path-MPRs
are listed first among the adjacent MANET neighbors in the PMPR are listed first among the adjacent MANET neighbors in the PMPR
TLV. TLV.
Reserved - is a 6 bit field which SHOULD be cleared ('0') on Reserved - is a 6-bit field that SHOULD be cleared ('0') on
transmission and SHOULD be ignored on reception. transmission and SHOULD be ignored on reception.
S - is a binary flag, cleared ('0') if the router brings up
adjacencies only with neighbors in its MPR set and MPR selector
set as per Section 5.3, set ('1') if the router brings up
adjacencies with all MANET neighbors as a Synch router -- as per
Section 5.6.
U - is a binary flag, cleared ('0') if the cost for each link from U - is a binary flag, cleared ('0') if the cost for each link from
each advertised neighbor in the PMPR TLV and to the sending router each advertised neighbor in the PMPR TLV and to the sending router
is explicitly included (as shown in Figure 6), set ('1') if a is explicitly included (as shown in Figure 6), or set ('1') if a
single metric value is included which applies to all links (as single metric value is included that applies to all links (as
shown in Figure 7). shown in Figure 7).
Neighbor ID - is a 32 bit field which specifies the router ID of a S - is a binary flag, cleared ('0') if the router brings up
adjacencies only with neighbors in its MPR set and MPR-selector
set, as per Section 5.3, or set ('1') if the router brings up
adjacencies with all MANET neighbors as a Synch router, as per
Section 5.6.
Neighbor ID - is a 32-bit field that specifies the router ID of a
symmetric 1-hop neighbor of an OSPFv3 MANET interface of the symmetric 1-hop neighbor of an OSPFv3 MANET interface of the
router. router.
Cost n - is a 16 bit unsigned integer field which specifies the cost Cost n - is a 16-bit unsigned integer field that specifies the cost
of the link in the direction from the nth listed advertised of the link in the direction from the n-th listed advertised
neighbor in the PMPR TLV and towards this router. A default value neighbor in the PMPR TLV and towards this router. A default value
of 0xFFFF (i.e. infinity) MUST be advertised, unless information of 0xFFFF (i.e., infinity) MUST be advertised unless information
received via Hello packets from the neighbor specifies otherwise, received via Hello packets from the neighbor specifies otherwise,
in which case the received information MUST be advertised. If a in which case the received information MUST be advertised. If a
neighbor is reachable via more than one interface, the cost neighbor is reachable via more than one interface, the cost
advertised MUST be the minimum of the costs by which that neighbor advertised MUST be the minimum of the costs by which that neighbor
can be reached. can be reached.
Padding - is a 16 bit field which SHOULD be cleared ('0') on Padding - is a 16-bit field that SHOULD be cleared ('0') on
transmission and SHOULD be ignored on reception. Padding is transmission and SHOULD be ignored on reception. Padding is
included in order that the PMPR TLV is 32bit aligned. Padding included in order that the PMPR TLV is 32-bit aligned. Padding
MUST be included when the TLV contains an odd number of Cost MUST be included when the TLV contains an odd number of Cost
fields, and MUST NOT be included otherwise. fields and MUST NOT be included otherwise.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=PMPR | Length | | Type=PMPR | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| # Adj. Neigh | # Path-MPR | Reserved |0|S| | # Sym Neigh | # Adj. Neigh | # Path-MPR | Reserved |0|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID | | Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID | | Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : : :
: : : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost 1 | Cost 2 | | Cost 1 | Cost 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 25, line 34 skipping to change at page 24, line 34
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Path-MPR TLV (PMPR) with explicit individual link costs Figure 6: Path-MPR TLV (PMPR) with explicit individual link costs
(U=0) and an even number of Cost fields (hence, no padding). (U=0) and an even number of Cost fields (hence, no padding).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=PMPR | Length | | Type=PMPR | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| # Adj. Neigh | # Path-MPR | Reserved |1|S| | # Sym Neigh | # Adj. Neigh | # Path-MPR | Reserved |1|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID | | Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID | | Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cost | Padding | | Cost | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Path-MPR TLV (PMPR) with a single and uniform link cost Figure 7: Path-MPR TLV (PMPR) with a single and uniform link cost
(U=1) (hence, padding included). (U=1) (hence, padding included).
skipping to change at page 26, line 9 skipping to change at page 25, line 9
[RFC4593] describes generic threats to routing protocols, whose [RFC4593] describes generic threats to routing protocols, whose
applicability to OSPFv3 [RFC5340] is not altered by the presence of applicability to OSPFv3 [RFC5340] is not altered by the presence of
OSPFv3 MANET interfaces. As such, the OSPFv3 MANET interface type OSPFv3 MANET interfaces. As such, the OSPFv3 MANET interface type
does not introduce new security threats to [RFC5340]. does not introduce new security threats to [RFC5340].
However, the use of a wireless medium and the lack of infrastructure, However, the use of a wireless medium and the lack of infrastructure,
as enabled by the use of the OSPFv3 MANET interface type, may render as enabled by the use of the OSPFv3 MANET interface type, may render
some of the attacks described in [RFC4593] easier to undertake. some of the attacks described in [RFC4593] easier to undertake.
For example, control traffic sniffing and control traffic analysis For example, control-traffic sniffing and control-traffic analysis
are simpler tasks with wireless than with wires, as it is sufficient are simpler tasks with wireless than with wires, as it is sufficient
to be somewhere within radio range in order to "listen" to wireless to be somewhere within radio range in order to "listen" to wireless
traffic. Inconspicuous wiretapping of the right cable(s) is not traffic. Inconspicuous wiretapping of the right cable(s) is not
necessary. necessary.
In a similar fashion, physical signal interference is also a simpler In a similar fashion, physical signal interference is also a simpler
task with wireless than with wires, as it is sufficient to emit from task with wireless than with wires, as it is sufficient to emit from
somewhere within radio range in order to be able to disrupt the somewhere within radio range in order to be able to disrupt the
communication medium. No complex wire connection is required. communication medium. No complex wire connection is required.
Other types of interference (including not forwarding packets), Other types of interference (including not forwarding packets),
spoofing, and different types of falsification or overloading (as spoofing, and different types of falsification or overloading (as
described in [RFC4593]) are also threats to which routers using described in [RFC4593]) are also threats to which routers using
OSPFv3 MANET interfaces may be subject. In these cases, the lack of OSPFv3 MANET interfaces may be subject. In these cases, the lack of
pre-determined infrastructure or authority, enabled by the use of predetermined infrastructure or authority, enabled by the use of
OSPFv3 MANET interfaces, may facilitate such attacks by making it OSPFv3 MANET interfaces, may facilitate such attacks by making it
easier to forge legitimacy. easier to forge legitimacy.
Moreover, the consequence zone of a given threat, and its consequence Moreover, the consequence zone of a given threat, and its consequence
period (as defined in [RFC4593]), may also be slightly altered over period (as defined in [RFC4593]), may also be slightly altered over
the wireless medium, compared to the same threat over wired networks. the wireless medium, compared to the same threat over wired networks.
Indeed, mobility and the fact that radio range spans "further" than a Indeed, mobility and the fact that radio range spans "further" than a
mere cable may expand the consequence zone in some cases, while the mere cable may expand the consequence zone in some cases; meanwhile,
more dynamic nature of MANET topologies may decrease the consequence the more dynamic nature of MANET topologies may decrease the
period, as harmful information (or lack of information) will tend to consequence period, as harmful information (or lack of information)
be replaced quicker by legitimate information. will tend to be replaced quicker by legitimate information.
8. IANA Considerations 8. IANA Considerations
This document defines three LLS TLVs, for which allocation of type This document defines three LLS TLVs, for which type values have been
values are requested from the LLS TLV type registry defined in allocated from the LLS TLV type registry defined in [RFC4813].
[RFC4813].
+------------+------------+--------------+ +------------+------------+--------------+
| Mnemonic | Type Value | Name | | Mnemonic | Type Value | Name |
+------------+------------+--------------+ +------------+------------+--------------+
| FMPR | tbd | Flooding-MPR | | FMPR | 3 | Flooding-MPR |
| METRIC-MPR | tbd | Metric-MPR | | METRIC-MPR | 4 | Metric-MPR |
| PMPR | tbd | Path-MPR | | PMPR | 5 | Path-MPR |
+------------+------------+--------------+ +------------+------------+--------------+
Table 1: LLS TLV Type Assignments Table 1: LLS TLV Type Assignments
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, BCP 14, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF version 2", RFC 2328, 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
April 1998.
[RFC5340] Moy, J., Coltun, R., Ferguson, D., and A. Lindem, [RFC4813] Friedman, B., Nguyen, L., Roy, A., Yeung, D., and
"OSPF for IPv6", RFC 5340, 2008. A. Zinin, "OSPF Link-Local Signaling", RFC 4813,
March 2007.
[RFC4813] Zinin, A., Friedman, B., Roy, A., Nguyen, L., and [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem,
D. Yeung, "OSPF Link Local Signaling", RFC 4813, "OSPF for IPv6", RFC 5340, July 2008.
2007.
9.2. Informative References 9.2. Informative References
[RFC2501] Macker, J. and S. Corson, "MANET Routing Protocol [MPR] Qayyum, A., Viennot, L., and A. Laouiti,
Performance Issues and Evaluation Considerations",
RFC 2501, January 1999.
[RFC3626] Clausen, T. and P. Jacquet, "The Optimized Link
State Routing Protocol", RFC 3626, October 2003.
[RFC5148] Adamson, B., Dearlove, C., and T. Clausen, "Jitter
Considerations in MANETs", RFC 5148, 2008.
[MPR] Qayyum, A., Viennot, L., and A. Laouiti,,
"Multipoint Relaying for Flooding Broadcast "Multipoint Relaying for Flooding Broadcast
Messages in Mobile Wireless Networks", Proceedings Messages in Mobile Wireless Networks", Proceedings
of HICSS , 2002. of HICSS , 2002.
[MPR-analysis] Ngyuen, D. and P. Minet, "Analysis of MPR Selection
in the OLSR Protocol", 2nd Int. Workshop on
Performance Analysis and Enhancement of
Wireless Networks, 2007.
[MPR-robustness] Adjih, C., Baccelli, E., Clausen, T., and P. [MPR-robustness] Adjih, C., Baccelli, E., Clausen, T., and P.
Jacquet, "On the Robustness and Stability of Jacquet, "On the Robustness and Stability of
Connected Dominated Sets", INRIA Research Connected Dominated Sets", INRIA Research
Report RR-5609, 2005. Report RR-5609, 2005.
[MPR-analysis] Ngyuen, D. and P. Minet, "Analysis of MPR Selection
in the OLSR Protocol", 2nd Int. Workshop on
Performance Analysis and Enhancement of Wireless
Networks , 2007.
[MPR-topology] Baccelli, E., Clausen, T., and P. Jacquet, "Partial [MPR-topology] Baccelli, E., Clausen, T., and P. Jacquet, "Partial
Topology in an MPR-based Solution for Wireless OSPF Topology in an MPR-based Solution for Wireless OSPF
on Mobile Ad Hoc Networks", INRIA Research on Mobile Ad Hoc Networks", INRIA Research
Report RR-5619, 2005. Report RR-5619, 2005.
[RFC2501] Corson, S. and J. Macker, "Mobile Ad hoc Networking
(MANET): Routing Protocol Performance Issues and
Evaluation Considerations", RFC 2501,
February 1999.
[RFC3626] Clausen, T. and P. Jacquet, "Optimized Link State
Routing Protocol (OLSR)", RFC 3626, October 2003.
[RFC4593] Barbir, A., Murphy, S., and Y. Yang, "Generic [RFC4593] Barbir, A., Murphy, S., and Y. Yang, "Generic
Threats to Routing Protocols", RFC 4593, 2006. Threats to Routing Protocols", RFC 4593,
October 2006.
[RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter
Considerations in Mobile Ad Hoc Networks (MANETs)",
RFC 5148, February 2008.
Appendix A. Flooding-MPR Selection Heuristic Appendix A. Flooding-MPR Selection Heuristic
The following specifies a proposed heuristic for selection of The following specifies a proposed heuristic for selection of
Flooding-MPRs on interface i. It constructs a Flooding-MPR set that Flooding-MPRs on interface i. It constructs a Flooding-MPR set that
enables a router to reach routers in the 2-hop neighborhood through enables a router to reach routers in the 2-hop neighborhood through
relaying by one Flooding-MPR router. relaying by one Flooding-MPR router.
The following terminology will be used in describing the heuristics: The following terminology will be used in describing the heuristics:
D(Y) is the degree of a 1-hop neighbor, router Y (where Y is a member D(Y) is the degree of a 1-hop neighbor, router Y (where Y is a member
of N(i), defined as the number of neighbors of router Y, EXCLUDING of N(i), defined as the number of neighbors of router Y, EXCLUDING
all the members of N(i) and EXCLUDING the router performing the all the members of N(i) and EXCLUDING the router performing the
computation. The proposed heuristic can then be described as computation. The proposed heuristic can then be described as
follows. Begin with an empty Flooding-MPR set. Then: follows. Begin with an empty Flooding-MPR set. Then:
1. Calculate D(Y), where Y is a member of N(i), for all routers in 1. Calculate D(Y), where Y is a member of N(i), for all routers in
N(i). N(i).
2. Add to the Flooding-MPR set those routers in N(i), which are the 2. Add to the Flooding-MPR set those routers in N(i) that are the
only routers to provide reachability to a router in N2(i). For only routers to provide reachability to a router in N2(i). For
example, if router B in N2(i) can be reached only through a example, if router B in N2(i) can be reached only through a
router A in N(i), then add router A to the Flooding-MPR set. router A in N(i), then add router A to the Flooding-MPR set.
Remove the routers from N2(i) which are now covered by a router Remove the routers from N2(i) that are now covered by a router in
in the Flooding-MPR set. the Flooding-MPR set.
3. While there exist routers in N2(i) which are not covered by at 3. While there exist routers in N2(i) that are not covered by at
least one router in the Flooding-MPR set: least one router in the Flooding-MPR set:
1. For each router in N(i), calculate the reachability, i.e. the 1. For each router in N(i), calculate the reachability, i.e.,
number of routers in N2(i) which are not yet covered by at the number of routers in N2(i) that are not yet covered by at
least one router in the Flooding-MPR set, and which are least one router in the Flooding-MPR set, and that are
reachable through this 1-hop neighbor; reachable through this 1-hop neighbor;
2. Select as a Flooding-MPR the neighbor with highest 2. Select as a Flooding-MPR the neighbor with the highest
willingness among the routers in N(i) with non-zero willingness among the routers in N(i) with non-zero
reachability. In case of a tie among routers with same reachability. In case of a tie among routers with the same
willingness, select the router which provides reachability to willingness, select the router that provides reachability to
the maximum number of routers in N2(i). In case of another the maximum number of routers in N2(i). In case of another
tie between routers also providing the same amount of tie between routers also providing the same amount of
reachability, select as Flooding-MPR the router whose D(Y) is reachability, select as Flooding-MPR the router whose D(Y) is
greater. Remove the routers from N2(i) which are now covered greater. Remove the routers from N2(i) that are now covered
by a router in the Flooding-MPR set. by a router in the Flooding-MPR set.
4. As an optimization, consider in increasing order of willingness 4. As an optimization, consider in increasing order of willingness
each router Y in the Flooding-MPR set: if all routers in N2(i) each router Y in the Flooding-MPR set: if all routers in N2(i)
are still covered by at least one router in the Flooding-MPR set are still covered by at least one router in the Flooding-MPR set
when excluding router Y, then router Y MAY be removed from the when excluding router Y, then router Y MAY be removed from the
Flooding-MPR set. Flooding-MPR set.
Other algorithms, as well as improvements over this algorithm, are Other algorithms, as well as improvements over this algorithm, are
possible. Different routers may use different algorithms possible. Different routers may use different algorithms
independently. However, the algorithm used MUST provide the router independently. However, the algorithm used MUST provide the router
with a Flooding-MPR set that fulfills the flooding coverage with a Flooding-MPR set that fulfills the flooding coverage
criterion, i.e. it MUST select a Flooding-MPR set such that any 2-hop criterion, i.e., it MUST select a Flooding-MPR set such that any
neighbor is covered by at least one Flooding-MPR router. 2-hop neighbor is covered by at least one Flooding-MPR router.
Appendix B. Path-MPR Selection Heuristic Appendix B. Path-MPR Selection Heuristic
The following specifies a proposed heuristic for calculating a Path- The following specifies a proposed heuristic for calculating a Path-
MPR set that enables a router to reach routers in the 2-hop MPR set that enables a router to reach routers in the 2-hop
neighborhood through shortest paths via routers in its Path-MPR set. neighborhood through shortest paths via routers in its Path-MPR set.
The following terminology will be used for describing this heuristic: The following terminology will be used for describing this heuristic:
A - The router performing the Path-MPR set calculation. A - The router performing the Path-MPR set calculation.
B, C, D, .... - Other routers in the network. B, C, D, .... - Other routers in the network.
cost(A, B) - The cost of the path through the direct link, from A to cost(A, B) - The cost of the path through the direct link, from A to
B. B.
dist(C, A) - The cost of the shortest path from C to A. dist(C, A) - The cost of the shortest path from C to A.
A cost matrix is populated with the values of the costs of links A cost matrix is populated with the values of the costs of links
originating from router A (available locally) and by values listed in originating from router A (available locally) and with values listed
Hello packets received from neighbor routers. More precisely, the in Hello packets received from neighbor routers. More precisely, the
cost matrix is populated as follows: cost matrix is populated as follows:
1. The coefficients of the cost matrix are set by default to 0xFFFF 1. The coefficients of the cost matrix are set by default to 0xFFFF
(maximal value, i.e. infinity). (maximal value, i.e., infinity).
2. The coefficient cost(A,B) of the cost matrix for a link from 2. The coefficient cost(A,B) of the cost matrix for a link from
router A to a neighbor B (the direct cost for this link) is set router A to a neighbor B (the direct cost for this link) is set
to the minimum cost over all interfaces that feature router B as to the minimum cost over all interfaces that feature router B as
a symmetric 1-hop neighbor. The reverse cost for this link, a symmetric 1-hop neighbor. The reverse cost for this link,
cost(B,A), is set at the value received in Hello packets from cost(B,A), is set at the value received in Hello packets from
router B. If router B is reachable through several interfaces at router B. If router B is reachable through several interfaces at
the same time, cost(B,A) is set as the minimum cost advertised by the same time, cost(B,A) is set as the minimum cost advertised by
router B for its links towards router A. router B for its links towards router A.
3. The coefficients of the cost matrix concerning the link between 3. The coefficients of the cost matrix concerning the link between
two neighbors of A, routers C and B, are populated at the two neighbors of A, routers C and B, are populated at the
reception of their Hello packets. The cost (B,C) is set to the reception of their Hello packets. The cost (B,C) is set to the
value advertised by the Hello packets from B, and respectively, value advertised by the Hello packets from B, and, respectively,
the cost (C,B) is set to the value advertised in Hello packets the cost (C,B) is set to the value advertised in Hello packets
from C. from C.
4. The coefficients of the cost matrix, cost(B,C) for a link that 4. The coefficients cost(B,C) of the cost matrix for a link that
connects a neighbor B to a 2-hop neighbor C is obtained via the connects a neighbor B to a 2-hop neighbor C are obtained via the
Hello packets received from router B. In this case cost(B,C) and Hello packets received from router B. In this case, cost(B,C)
cost(C,B) are respectively set to the values advertised by router and cost(C,B) are respectively set to the values advertised by
B for the direct cost and reverse cost for node C. router B for the direct cost and reverse cost for node C.
Once the cost matrix is populated, the proposed heuristic can then be Once the cost matrix is populated, the proposed heuristic can then be
described as follows. Begin with an empty Path-MPR set. Then: described as follows. Begin with an empty Path-MPR set. Then:
1. Using the cost matrix and the Dijkstra algorithm, compute the 1. Using the cost matrix and the Dijkstra algorithm, compute the
router distance vector, i.e. the shortest distance for each pair router distance vector, i.e., the shortest distance for each pair
(X,A) where X is in N or N2 minimizing the sum of the cost of the (X,A) where X is in N or N2 minimizing the sum of the cost of the
path between X and A. path between X and A.
2. Compute N' as the subset of N made of the elements X such that 2. Compute N' as the subset of N made of the elements X such that
cost(X,A)=dist(X,A). cost(X,A)=dist(X,A).
3. Compute N2' as the subset of N and N2 made of the elements Y that 3. Compute N2' as the subset of N and N2 made of the elements Y that
do not belong to N' and such that there exist X in N' such do not belong to N' and such that there exist X in N' such
cost(Y,X)+cost(X,A)=dist(Y,A). cost(Y,X)+cost(X,A)=dist(Y,A).
4. Compute the MPR selection algorithm presented in Appendix A with 4. Compute the MPR selection algorithm presented in Appendix A with
N' instead of N(i) and N2' instead of N2(i). The resulting MPR N' instead of N(i) and N2' instead of N2(i). The resulting MPR
set is the Path-MPR set. set is the Path-MPR set.
Other algorithms, as well as improvements over this algorithm, are Other algorithms, as well as improvements over this algorithm, are
possible. Different routers may use different algorithms possible. Different routers may use different algorithms
independently. However, the algorithm used MUST provide the router independently. However, the algorithm used MUST provide the router
with a Path-MPR set that fulfills the path coverage criterion, i.e. with a Path-MPR set that fulfills the path coverage criterion, i.e.,
it MUST select a Path-MPR set such that for any element of N or N2 it MUST select a Path-MPR set such that for any element of N or N2
that is not in the Path-MPR set, there exists a shortest path that that is not in the Path-MPR set, there exists a shortest path that
goes from this element to the router through a neighbor selected as goes from this element to the router through a neighbor selected as
Path-MPR (unless the shortest path is only one hop). Path-MPR (unless the shortest path is only one hop).
Appendix C. Contributors Appendix C. Contributors
The authors would like to thank Cedric Adjih, Acee Lindem, Padma The authors would like to thank Cedric Adjih, Acee Lindem, Padma
Pillay-Esnault and Laurent Viennot for their contributions to this Pillay-Esnault, and Laurent Viennot for their contributions to this
document. document.
Appendix D. Acknowledgments Appendix D. Acknowledgments
The authors would like to thank Juan Antonio Cordero Fuertes, Ulrich The authors would like to thank Juan Antonio Cordero Fuertes, Ulrich
Herberg and Richard Ogier for reviewing this document. Herberg, and Richard Ogier for reviewing this document.
Authors' Addresses Authors' Addresses
Emmanuel Baccelli Emmanuel Baccelli
INRIA INRIA
Phone: +33 1 69 33 55 11 Phone: +33 1 69 33 55 11
EMail: Emmanuel.Baccelli@inria.fr EMail: Emmanuel.Baccelli@inria.fr
URI: http://www.emmanuelbaccelli.org/ URI: http://www.emmanuelbaccelli.org/
skipping to change at page 31, line 27 skipping to change at page 31, line 27
Phone: +33 1 3963 5263 Phone: +33 1 3963 5263
EMail: Philippe.Jacquet@inria.fr EMail: Philippe.Jacquet@inria.fr
Dang-Quan Nguyen Dang-Quan Nguyen
CRC CRC
Phone: +1-613-949-8216 Phone: +1-613-949-8216
EMail: dang.nguyen@crc.ca EMail: dang.nguyen@crc.ca
Thomas Heide Clausen Thomas Heide Clausen
LIX, Ecole Polytechnique, France LIX, Ecole Polytechnique
Phone: +33 6 6058 9349 Phone: +33 6 6058 9349
EMail: T.Clausen@computer.org EMail: T.Clausen@computer.org
URI: http://www.thomasclausen.org/ URI: http://www.thomasclausen.org/
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