Mobile Ad hoc Networking (MANET)                              T. Clausen
Internet-Draft                          LIX, Ecole Polytechnique, France
Expires: February 2, September 7, 2006                                   C. Dearlove
                                         BAE Systems Advanced Technology
                                                                  Centre
                                                  The OLSRv2 Design Team
                                                     MANET Working Group
                                                           March 6, 2006                                    August 2005

          The Optimized Link-State Routing Protocol version 2
                       draft-ietf-manet-olsrv2-00
                       draft-ietf-manet-olsrv2-01

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Copyright Notice

   Copyright (C) The Internet Society (2005). (2006).

Abstract

   This document describes version 2 of the Optimized Link State Routing
   (OLSRv2) protocol for mobile ad hoc networks.  The protocol is an
   optimization of the classical link state algorithm tailored to the
   requirements of a mobile wireless LAN.

   The key optimization of OLSRv2 is that of multipoint relays,
   providing an efficient mechanism for network-wide broadcast of link-
   state information.  A secondary optimization is, that OLSRv2 employs
   partial link-state information: each node maintains information of
   all destinations, but only a subset of links.  This allows that only
   select nodes diffuse link-state advertisements (i.e. reduces the
   number of network-wide broadcasts) and that these advertisements
   contain only a subset of links (i.e. reduces the size of each
   network-wide broadcast).  The partial link-state information thus
   obtained allows each OLSRv2 node to at all times maintain optimal (in
   terms of number of hops) routes to all destinations in the network.

   OLSRv2 imposes minimum requirements to the network by not requiring
   sequenced or reliable transmission of control traffic.  Furthermore,
   the only interaction between OLSRv2 and the IP stack is routing table
   management.

   OLSRv2 is particularly suitable for large and dense networks as the
   technique of MPRs works well in this context.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
     1.1   Terminology  . . . . . . . . . . . . . . . . . . . . . . .  6
     1.2   Applicability Statement  . . . . . . . . . . . . . . . . .  7
   2.  Protocol Overview and Functioning  . . . . . . . . . . . . . .  8
   3.  OLSRv2 Signaling Framework  9
     2.1   Protocol Extensibility . . . . . . . . . . . . . . . . . . 11
     3.1   OLSRv2 Packet Format
   3.  Processing and Forwarding Repositories . . . . . . . . . . . . 13
     3.1   Received Message Set . . . . . . . 11
     3.2   OLSR Messages . . . . . . . . . . . . 13
     3.2   Fragment Set . . . . . . . . . . 12
       3.2.1   Address Blocks . . . . . . . . . . . . . 13
     3.3   Processed Set  . . . . . . . 13
       3.2.2   TLVs . . . . . . . . . . . . . . . 14
     3.4   Forwarded Set  . . . . . . . . . . 14
     3.3   Message Content Fragmentation . . . . . . . . . . . . 14
     3.5   Relay Set  . . 15
   4.  Packet Processing and Message Forwarding . . . . . . . . . . . 17
     4.1   Processing and Forwarding Repositories . . . . . . . . . . 17
       4.1.1   Received . 14
   4.  Packet Processing and Message Set Forwarding . . . . . . . . . . . 16
     4.1   Actions when Receiving an OLSRv2 Packet  . . . . . . 17
       4.1.2   Processed Set . . . 16
     4.2   Actions when Receiving an OLSRv2 Message . . . . . . . . . 16
     4.3   Message Considered for Processing  . . . . . . . . 17
       4.1.3   Forwarded Set . . . . 16
     4.4   Message Considered for Forwarding  . . . . . . . . . . . . 18
   5.  Information Repositories . . . . 18
       4.1.4   Relay Set . . . . . . . . . . . . . . . 21
     5.1   Neighborhood Information Base  . . . . . . . 18
     4.2   Fragment Set . . . . . . . 21
       5.1.1   Link Set . . . . . . . . . . . . . . . . 18
     4.3   Actions when Receiving an OLSRv2-Packet . . . . . . . 21
       5.1.2   2-Hop Neighbor Set . . 19
     4.4   Actions when Receiving an OLSRv2-Message . . . . . . . . . 19
     4.5   Message Considered for Processing . . . . . . . 22
       5.1.3   Neighborhood Address Association Set . . . . . 20
     4.6   Message Considered for Forwarding . . . . 23
       5.1.4   MPR Set  . . . . . . . . 21
   5.  Information Repositories . . . . . . . . . . . . . . . 23
       5.1.5   MPR Selector Set . . . . 23
     5.1   Local Link  Information Base . . . . . . . . . . . . . . . 23
       5.1.1   Link
       5.1.6   Advertised Neighbor Set  . . . . . . . . . . . . . . . 23
     5.2   Topology Information Base  . . . . . . . . 23
       5.1.2   2-hop Neighbor Set . . . . . . . . 24
       5.2.1   Topology Set . . . . . . . . . . . . 24
       5.1.3   Neighborhood Address Association Set . . . . . . . . . 24
       5.1.4   MPR
       5.2.2   Attached Network Set . . . . . . . . . . . . . . . . . 24
       5.2.3   Routing Set  . . . . . . 24
       5.1.5   Advertised Neighbor Set . . . . . . . . . . . . . . . 25
     5.2   Topology Information Base  . .
   6.  OLSRv2 Control Message Structures  . . . . . . . . . . . . . . 25
   6. 26
     6.1   General OLSRv2 Control Messages  . Message TLVs  . . . . . . . . . . . . . . . 26
       6.1.1   VALIDITY_TIME TLV  . . . 26
     6.1   HELLO Messages . . . . . . . . . . . . . . . 26
       6.1.2   INTERVAL_TIME TLV  . . . . . . . 26
     6.2   TC Messages . . . . . . . . . . . 27
     6.2   Local Interface Blocks . . . . . . . . . . . . 26
     6.3   MA Messages . . . . . . 28
     6.3   HELLO Messages . . . . . . . . . . . . . . . . . 26
   7.  Populating the MPR Set . . . . . 28
       6.3.1   HELLO Message: Message TLVs  . . . . . . . . . . . . . 29
       6.3.2   HELLO Message: Address Blocks TLVs . . 27
   8.  Populating the Advertised Neighbor Set . . . . . . . . 29
     6.4   TC Messages  . . . . 28
   9.  HELLO Message Generation . . . . . . . . . . . . . . . . . . . 29
     9.1 30
   7.  HELLO Message: Message TLVs Generation . . . . . . . . . . . . . . . 29
     9.2 . . . . 31
     7.1   HELLO Message: Address Blocks and Address TLVs Transmission  . . . . . . 29
   10. . . . . . . . . . 33
   8.  HELLO Message Processing . . . . . . . . . . . . . . . . . . 31
     10.1 . 34
     8.1   Populating the Link Set  . . . . . . . . . . . . . . . . . 31
     10.2 34
     8.2   Populating the 2-Hop Neighbor Set  . . . . . . . . . . . . 33
     10.3 36
     8.3   Populating the Relay MPR Selector Set  . . . . . . . . . . . . . . . . . 34
     10.4 37
     8.4   Neighborhood and 2-hop 2-Hop Neighborhood Changes  . . . . . . . 34
   11. 38
   9.  TC Message Generation  . . . . . . . . . . . . . . . . . . . 36
     11.1 . 40
     9.1   TC Message: Message TLVs Transmission . . . . . . . . . . . . . . . . . 36
     11.2 41
   10.   TC Message: Address Blocks and Address TLVs Message Processing  . . . . . . . 36
   12.   TC Message Processing . . . . . . . . . . . . 42
     10.1  Checking Freshness & Validity of a TC message  . . . . . . 42
     10.2  Updating the Topology Set  . 37
   13.   MA Message Generation . . . . . . . . . . . . . . . 43
     10.3  Purging Old Entries from the Topology Set  . . . . 39
   14.   MA Message Processing . . . . 44
     10.4  Updating the Attached Networks Set . . . . . . . . . . . . 44
     10.5  Purging Old Entries from the Attached Network Set  . . . 40
   15.   Routing Table Calculation . 45
     10.6  Processing Unfragmented TC Messages  . . . . . . . . . . . 45
     10.7  Processing Partially or Wholly Self-Contained
           Fragmented TC Messagess  . . . . . 41
   16.   Proposed Values for Constants . . . . . . . . . . . . 45
   11.   Populating the MPR Set . . . 44
     16.1  Message Types . . . . . . . . . . . . . . . . 47
   12.   Populating Derived Sets  . . . . . . 44
     16.2  Message Intervals . . . . . . . . . . . . 48
     12.1  Populating the Relay Set . . . . . . . . 44
     16.3  Holding Times . . . . . . . . . 48
     12.2  Populating the Advertised Neighbor Set . . . . . . . . . . 48
   13.   Populating the Neighborhood Address Association Set  . . . 44
     16.4  Willingness . 49
   14.   Routing Table Calculation  . . . . . . . . . . . . . . . . . 50
   15.   Proposed Values for Constants  . . . . . 44
   17.   Representing Time . . . . . . . . . . 53
     15.1  Message Intervals  . . . . . . . . . . . 45
   18.   IANA Considerations . . . . . . . . . 53
     15.2  Holding Times  . . . . . . . . . . . 46
   A.  Example Heuristic for Calculating MPRs . . . . . . . . . . . 53
     15.3  Willingness  . 47
   B.  Example Algorithms for Generating Control Traffic . . . . . . 50
     B.1   Example Algorithm for Generating HELLO messages . . . . . 50
     B.2   Example Algorithm for Generating TC messages . . . . . . . 51
   C.  Protocol and Port Number . . . . 53
     15.4  Time . . . . . . . . . . . . . . . 53
   D.  OLSRv2 Packet and Message Layout . . . . . . . . . . . . 54
   16.   Representing Time  . . . 54
     D.1   General OLSR Packet Format . . . . . . . . . . . . . . . . 54
       D.1.1   Message TLVs . . 55
   17.   IANA Considerations  . . . . . . . . . . . . . . . . . . . 55
       D.1.2   Address Block . 56
     17.1  Multicast Addresses  . . . . . . . . . . . . . . . . . . . 55
       D.1.3   Address Block 56
     17.2  Message Types  . . . . . . . . . . . . . . . . . . . . . . 56
     17.3  TLV Types  . . . . . . . . . . . . . . . . . . 57
     D.2   Layout of OLSRv2 Specified Messages . . . . . . 56
   18.   References . . . . . . . . . . . . . . . . . . . . . . . . . 57
       D.2.1   Layout of HELLO Messages
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 58
       D.2.2   Layout of TC messages
   A.  Example Heuristic for Calculating MPRs . . . . . . . . . . . . 59
   B.  Example Algorithms for Generating Control Traffic  . . . . 58
   E.  Node Configuration . . 62
     B.1   Example Algorithm for Generating HELLO messages  . . . . . 62
     B.2   Example Algorithm for Generating TC messages . . . . . . . 63
   C.  Protocol and Port Number . . . . . . . . . . 60
     E.1   IPv6 Specific Considerations . . . . . . . . . 65
   D.  Packet and Message Layout  . . . . . . 60
   F.  Security Considerations . . . . . . . . . . . . 66
     D.1   OLSRv2 Packet Format . . . . . . . 61
     F.1   Confidentiality . . . . . . . . . . . . 66
   E.  Node Configuration . . . . . . . . . 61
     F.2   Integrity . . . . . . . . . . . . . 73
   F.  Security Considerations  . . . . . . . . . . . 61
     F.3   Interaction with External Routing Domains . . . . . . . . 62
     F.4   Node Identity 74
     F.1   Confidentiality  . . . . . . . . . . . . . . . . . . . . . 74
     F.2   Integrity  . 63
   G.  Flow and Congestion Control . . . . . . . . . . . . . . . . . 64
   H.  Sequence Numbers . . . . . . 74
     F.3   Interaction with External Routing Domains  . . . . . . . . 75
     F.4   Node Identity  . . . . . . . . . 65
   I.  References . . . . . . . . . . . . . 76
   G.  Flow and Congestion Control  . . . . . . . . . . . . . . 66
   J.  Contributors . . . 77
   H.  Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 67
   K.  Acknowledgements 78
   I.  Contributors . . . . . . . . . . . . . . . . . . . . . . . 68
       Author's Address . . 79
   J.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 68 80
       Intellectual Property and Copyright Statements . . . . . . . . 69 81

1.  Introduction

   The Optimized Link State Routing Protocol version 2 (OLSRv2) is an
   update to OLSRv1 as published in RFC3626 [11]. [1].  Compared to RFC3626,
   OLSRv2 retains the same basic mechanisms and algorithms, while
   providing an even more flexible signaling framework and some
   simplification of the messages being exchanged.  Also, OLSRv2 takes
   care to accomodate both IPv4 and IPv6 addresses in a compact fashion.

   OLSRv2 is developed for mobile ad hoc networks.  It operates as a
   table driven, proactive protocol, i.e., i.e. it exchanges topology
   information with other nodes of the network regularly.  Each node
   selects a set of its neighbor nodes as "multipoint relays" (MPR). "MultiPoint Relays" (MPRs).
   In OLSRv2, only nodes that are selected as such MPRs are then
   responsible for forwarding control traffic intended for diffusion
   into the entire network.  MPRs provide an efficient mechanism for
   flooding control traffic by reducing the number of transmissions
   required.

   Nodes,

   Nodes selected as MPRs, MPRs also have a special responsibility when
   declaring link state information in the network.  Indeed, the only
   requirement for OLSRv2 to provide shortest path routes to all
   destinations is that MPR nodes declare link-state information for
   their MPR selectors.  Additional available link-state information may
   be utilized, e.g., for redundancy.

   Nodes which have been selected as multipoint relays by some neighbor
   node(s) announce this information periodically in their control
   messages.  Thereby a node announces to the network, network that it has
   reachability to the nodes which have selected it as an MPR.  Then,
   aside from  Thus, as
   well as being used to facilitate efficient flooding, MPRs are also
   used for route calculation from any given node to any destination in
   the network.

   A node selects MPRs from among its one hop neighbors with
   "symmetric", i.e., bi-directional, linkages.  Therefore, selecting
   the route through MPRs automatically avoids the problems associated
   with data packet transfer over uni-directional links (such as the
   problem of not getting link-layer acknowledgments for data packets at
   each hop, for link-layers employing this technique for unicast
   traffic).

   OLSRv2 is developed to work independently from other protocols.
   Likewise, OLSRv2 makes no assumptions about the underlying link-
   layer.  However, OLSRv2 may use link-layer information and
   notifications when available and applicable.

   OLSRv2, as OLSRv1, inherits the concept of forwarding and relaying
   from HIPERLAN (a MAC layer protocol) which is standardized by ETSI
   [3].
   [5].

1.1  Terminology

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [5]. [2].

   Additionally, this document uses the following terminology:

   node - a MANET router which implements the Optimized Link State
      Routing protocol as specified in this document.

   OLSRv2 interface - A network device participating in a MANET running
      OLSRv2.  A node may have several OLSRv2 interfaces, each interface
      assigned an unique one or more IP address. addresses.

   neighbor - A node X is a neighbor of node Y if node Y can hear node X
      (i.e., a link exists from an OLSRv2 interface on node X to an
      OLSRv2 interface on node Y).  A neighbor may also be called a
      1-hop neighbor.

   2-hop neighbor - A node X is a 2-hop neighbor of node Y if node X is
      a neighbor of a neighbor of node Y.

   strict 2-hop Y, but is not node Y itself.

   strict 2-hop neighbor - a 2-hop neighbor which is (i) not the node
      itself, (ii) not a neighbor of
      the node, and (iii) is not a 2-hop neighbor only through a neighbor with
      willingness WILL_NEVER.

   multipoint relay (MPR) - A node which is selected by its 1-hop
      neighbor, node X, to "re-transmit" all the broadcast messages that
      it receives from node X, provided that the message is not a
      duplicate, and that the time to live field of the message is
      greater than one.

   multipoint relay selector (MPR selector, MS) - A node which has
      selected its 1-hop neighbor, node X, as one of its multipoint relay,
      relays, will be called an MPR selector of node X.

   link - A link is a pair of OLSRv2 interfaces from two different
      nodes, where at least one interface is able to hear (i.e. receive
      traffic from) the other.  A node is said to have a link to another
      node when one of its interfaces has a link to one of the
      interfaces of the other node.

   symmetric link - A link where both interfaces have verified they are able to hear (i.e.
      receive messages from) the other.

   asymmetric link - A link which is not symmetric.

   symmetric 1-hop neighborhood - The symmetric 1-hop neighborhood of
      any node X is the set of nodes which have at least one symmetric
      link to node X.

   symmetric 2-hop neighborhood - The symmetric 2-hop neighborhood of
      node X is the set of nodes, excluding node X itself, which have a
      symmetric link to the symmetric 1-hop neighborhood of X.

   symmetric strict 2-hop neighborhood - The symmetric strict 2-hop
      neighborhood of node X is the set of nodes in its symmetric 2-hop
      neighborhood that are neither in its symmetric 1-hop neighborhood
      nor reachable only through a symmetric 1-hop neighbor of node X
      with willingness WILL_NEVER.

1.2  Applicability Statement

   OLSRv2 is a proactive routing protocol for mobile ad hoc networks
   (MANETs) [1], [2]. [6], [7].  It is well suited to large and dense networks of
   mobile nodes, as the optimization achieved using the MPRs works well
   in this context.  The larger and more dense a network, the more
   optimization can be achieved as compared to the classic link state
   algorithm.  OLSRv2 uses hop-by-hop routing, i.e., each node uses its
   local information to route packets.

   As OLSRv2 continuously maintains routes to all destinations in the
   network, the protocol is beneficial for traffic patterns where the
   traffic is random and sporadic between a large subset of nodes, and
   where the [source, destination] pairs are changing over time: no
   additional control traffic is need be generated in this situation since
   routes are maintained for all known destinations at all times.  Also,
   since routes are maintained continously, traffic is subject to no
   delays due to buffering/route-discovery.  This continued route
   maintenance may be done using periodic message exchange, as detailed
   in this specification, or triggered by external events if available.

   OLSRv2 supports nodes which have multiple interfaces which
   participate in the MANET.  OLSRv2, additionally, supports nodes which
   have non-MANET interfaces which can serve as (if configured to do so)
   gateways towards other networks.

   The message exchange format, contained in previous versions of this
   specification, has been factored out to an independant specification
   [4], which is used for carrying OLSRv2 control signals.  OLSRv2 is
   thereby able to accommodate for extensions via "external" and
   "internal" extensibility.  External extensibility implies that a
   protocol extension may specify and exchange new message types which
   can be forwarded and delivered correctly according to [4].  Internal
   extensibility implies, that a protocol extension may define
   additional attributes to be carried embedded in the OLSRv2 control
   messages, detailed in this specification, while these OLSRv2 control
   messages with additional attributes can still be correctly understood
   by all OLSRv2 nodes.

2.  Protocol Overview and Functioning

   OLSRv2 is a proactive routing protocol for mobile ad hoc networks.
   The protocol inherits the stability of a link state algorithm and has
   the advantage of having routes immediately available when needed due
   to its proactive nature.  OLSRv2 is an optimization over the
   classical link state protocol, tailored for mobile ad hoc networks.
   The main tailoring and optimizations of OLSRv2 are:

   o  periodic, unacknowledged transmission of all control messages;

   o  optimized flooding for global link-state information diffusion;

   o  partial topology maintenance -- each node will know of all
      destinations and a subset of links in the network.

   More specifically, OLSRv2 consists of the following main components:

   o  A general and flexible signaling framework, allowing for
      information exchange between OLSRv2 nodes.  This framework allows
      for both local information exchange (between neighboring nodes)
      and global information exchange using an optimized flooding
      mechanism denoted "MPR flooding".

   o  A specification of local signaling, denoted HELLO messages.  HELLO
      messages in OLSRv2 serve to:

      *  discover links to adjacent OLSR nodes;

      *  perform bidirectionality check on the discovered links;

      *  advertise neighbors and hence discover 2-hop neighbors;

      *  signal MPR selection.

      HELLO messages are emitted periodically, thereby allowing nodes to
      continuously track changes in their local neighborhoods.

   o  A specification of global signaling, denoted TC messages.  TC
      messages in OLSRv2 serve to:

      *  inject link-state information into the entire network.

      *  inject addresses of hosts and networks for which they may serve
         as a gateway into the entire network.

      *  allow nodes with multiple interface addresses to ensure that
         nodes within two hops can associate these addresses with a
         single node for efficient MPR Set determination.

      TC messages are emitted periodically, thereby allowing nodes to
      continuously track global changes in the network.

   Thus, through periodic exchange of HELLO messages, a node is able to
   acquire and maintain information about its immediate neighborhood.
   This includes information about immediate neighbors, as well as nodes
   which are two hops away.  By HELLO messages being exchanged
   periodically, a node learns about changes in the neighborhood (new
   nodes emerging, old nodes disappearing) without requiring explicit
   mechanisms for doing so.

   Based on the local topology information, acquired through the
   periodic exchange of HELLO messages, an OLSRv2 node is able to make
   provisions for ensuring optimized flooding, denoted "MPR flooding",
   as well as injection of link-state information into the network.
   This is done through the notion of Multipoint Relays.

   The idea of multipoint relays is to minimize the overhead of flooding
   messages in the network by reducing redundant retransmissions in the
   same region.  Each node in the network selects a set of nodes in its
   symmetric 1-hop neighborhood which may retransmit its messages.  This
   set of selected neighbor nodes is called the "Multipoint Relay" (MPR)
   Set of that node.  The neighbors of node N which are *NOT* in its MPR
   set, receive and process broadcast messages but do not retransmit
   broadcast messages received from node N. The MPR set Set of a node is
   selected such that it covers (in terms of radio range) all symmetric
   strict 2-hop nodes.  The MPR set Set of N, denoted as MPR(N), is then an
   arbitrary subset of the symmetric 1-hop neighborhood of N which
   satisfies the following condition: every node in the symmetric strict
   2-hop neighborhood of N MUST have a symmetric link towards MPR(N).
   The smaller a MPR set, Set, the less control traffic overhead results from
   the routing protocol. [2] [7] gives an analysis and example of MPR
   selection algorithms.  Notice, that as long as the condition above is
   satisfied, any algorithm selecting MPR sets Sets is acceptable in terms of
   implementation interoperability.

   Each node maintains information about the set of neighbors that have
   selected it as MPR.  This set is called the "Multipoint Relay
   Selector set" Set" (MPR Selector Set) of a node.  A node obtains this
   information from periodic HELLO messages received from the neighbors.

   A broadcast message, intended to be diffused in the whole network,
   coming from any of the MPR selectors of
   Each node N also maintains a Relay Set, which is the set of nodes for
   which a node is to relay broadcast traffic.  The Relay Set is derived
   from the MPR Selector Set in that the Relay Set MUST contain all the
   nodes in the MPR Selector set and MAY contain additional nodes.

   A broadcast message, intended to be diffused in the whole network,
   coming from any of the nodes in the Relay Set of node N is assumed to
   be retransmitted by node N, if N has not received it yet.  This set
   can change over time (i.e., (e.g., when a node selects another MPR Set) and
   is indicated by the selector nodes in their HELLO messages.

   Using the MPR flooding mechanism, link-state information can be
   injected into the network using TC messages: network.  For this purpose, a node evaluates
   periodically if it is required to generate TC messages and, if so, maintains an
   Advertised Neighbor Set which information is to be included MUST contain all the nodes in these the MPR
   selector set and MAY contain additional nodes.  If the Advertised
   Neighbor Set of a node is non-empty, TC messages. messages, containing the
   links between the node and the nodes in the Advertised Neighbor Set,
   are not generated, unless needed for gateway reporting or multiple
   interface address association (if the latter case only, with minimal
   scope).

   OLSRv2 is designed to work in a completely distributed manner and
   does not depend on any central entity.  The protocol does NOT REQUIRE not require
   reliable transmission of control messages: each node sends control
   messages periodically, and can therefore sustain a reasonable loss of
   some such messages.  Such losses occur frequently in radio networks
   due to collisions or other transmission problems.

   Also, OLSRv2 does NOT REQUIRE not require sequenced delivery of messages.  Each
   control message contains a sequence number which is incremented for
   each message.  Thus the recipient of a control message can, if
   required, easily identify which information is more recent - even if
   messages have been re-ordered while in transmission.  Furthermore,
   OLSRv2 provides support for protocol extensions such as sleep mode
   operation, multicast-routing etc.  Such extensions may be introduced
   as additions to the protocol without breaking backwards compatibility
   with earlier versions.

   OLSRv2 does NOT REQUIRE not require any changes to the format of IP packets.
   Thus any existing IP stack can be used as is: OLSRv2 only interacts
   with routing table management.

3.  OLSR sends its own control messages
   using UDP.

2.1  Protocol Extensibility

   This specification defines and uses two OLSRv2 Signaling Framework

   In OLSRv2, signaling serves as a way message types, HELLO
   and TC.  As for a node OLSRv1 [1] extensions to express its
   relationships with other nodes -- or more precisely, a control-
   message in OLSRv2 states that "the address X has the following
   special relationship with addresses W, Y and Z". may define new
   message types to carry additional information.  This "special
   relationship" may be advertisement of an adjacency between interface
   X and interfaces WYZ, advertisement of an associated cost,
   advertisement of selection
   considered as designated router etc.

   In an OLSRv2 MANET, signaling may be either "local", intended only
   for nodes adjacent "external" extensibility.  New message types are
   divided into two ranges, those which may be added by standards
   actions (with types up to the originator of the signal or "global",
   intended 127) and those made available for all nodes in the private/
   local use (with types 128 to 255).

   All new messages must be syntactically OLSRv2 MANET.

   In this section, the general mechanism employed messages, as defined in
   [4].  (Some additional constraints to that specification are added
   for all OLSRv2
   signaling is described.

   This section provides abstract descriptions of message- packets and messages, requiring full packet
   formats.  In the complementary Appendix D, a graphical representation
   of OLSRv2 control messages and packets can be found.

3.1  OLSRv2 Packet Format

   OLSRv2 messages are carried in a general packet format, allowing:

   o  piggybacking of several independent messages (originated message
   headers.)  Note that if it is required to include one or
      forwarded) more blocks
   of unstructured data in such a message (possibly as its only content)
   this may be achieved by including each block as a single transmission;

   o  external extensibility -- i.e. new message TLV
   block, with an appropriately defined message TLV.  (Like message
   types, TLV types can are divided into those up to 127 which may be introduced added
   by standards action, and those from 128 to 255 available for auxiliary functions, while still being delivered private/
   local use.)

   A network may contain nodes both aware of, and unaware of, any new
   message types.  The originator of a message can control whether a
   message flooded through the network is forwarded
      correctly even by nodes not capable of interpreting the message;

   o  controlled-scope diffusion which are
   unaware of messages.

   The packet format is inherited directly from OLSRv1 [11] and conforms
   to the following specification:

   packet = <packet-length><packet seq. number>{<message>}+

   with message type, thus reaching all nodes in the usual notion of "+" indicating "one network,
   or more" occurrences of
   the preceding element, and the elements defined thus:

   <packet-length> is an 16 bit field, only flooded by nodes which specifies the length (in
      octets) of recognise the packet;
   <packet seq. number> is message type.

   OLSRv2 also supports an 16 bit field, which specifies the packet
      sequence number (PSN), alternative, and more powerful, extension
   mechanism which MUST be be incremented was not supported by one each
      time a new OLSRv2 packet is transmitted.  "Wrap-around" is handled
      as described in Appendix H.  A separate Packet Sequence Number is
      maintained for each OLSRv2 interface such OLSRv1, that packets transmitted
      over of adding new
   information to an interface are sequentially enumerated.

   <message> is the message as already defined in Section 3.2.

3.2  OLSR Messages

   Signals in OLSRv2 are carried through "messages".  The primary
   content of a message is type, whilst still leaving
   the predefined information unchanged and usable, including by a set of addresses about node
   which does not recognise the
   originating node wishes to convey new information.  These addresses  This may be divided into one or more address blocks.  Each address SHALL
   appear only once in considered
   to be "internal" extensibility of a message.  Each address block

   The mechanism for this extensibility is followed by
   zero or more TLVs, explained with more details in Section 3.2.2,
   which convey information (e.g. cost, link-status, ...) about the
   addresses use of TLV (type-length-
   value) structures in that address block.  A the message MAY also contain zero or
   more TLVs, format defined in [4] to carry
   information associated with either the whole message.

   Message content MAY (e.g. due to size limitations) be fragmented.
   Each fragment is transmitted such that it makes up a syntactically
   correct message (i.e. all headers are set as if each fragment is a
   message in its own right, and each message contains all message
   TLVs).  Content fragmentation is detailed in Section 3.3.

   A message has the following general layout

   message    = <msg-header><tlv-block>{<addr-block><tlv-block>}*

   msg-header = <type><vtime><msg-size><originator-address>
                <ttl><hopcount><msg-seq-number>

   <tlv-block>  = <tlv-length><tlv>* whole, or with
   one or more addresses carried in the usual notion message.  The messages defined
   in this specification carry two types of "*" indicating "zero or more" occurrences addresses, those of the preceding element,
   originating node's own interfaces participating in OLSRv2, and the elements defined thus:

   <tlv-length> is a 16 bit field, which contains the total length (in
      octets) those
   of the immediately following TLV(s).  If no TLV follows,
      this field contains zero;

   <tlv> is a TLV, providing information regarding the entire message neighbouring nodes or
      the address block networks to which it follows.  TLVs are specified in
      Section 3.2.2;
   <addr-block> is has a block of addresses, with route.  (New
   message types may define other relationships to addresses which the originator of they
   carry.)  All information associated with these addresses, or the
   message has as a special relationship.  Address blocks are
      specified whole, in Section 3.2.1;

   <type> messages defined in this specification is an 8 bit field, in
   TLV format; additional TLVs may be defined and added to these
   messages.

   Those nodes which specifies do not recognise newly defined TLV types ignore the type of message;

   <vtime>
   added TLVs.  (This is an 8 bit field, which specifies for how long time after
      reception a node MUST consider facilitated by that the information contained TLVs defined in this
   specification, or in [4], have the
      message as valid, unless a more recent update to the information
      is received.  The encoding of vtime is lowest type numbers and that TLVs
   must be included in type order, as specified in Section 17;

   <msg-size> [4].)  It is an 16 bit field, which specifies the size of the <msg-
      header>
   important that newly defined TLV types permit this behaviour.

3.  Processing and the Forwarding Repositories

   The following <msg-body>, counted data-structures are employed in octets;

   <originator-address> order to ensure that a
   message is the address of an processed at most once and is forwarded at most once per
   interface of the a node,
      which originated the message. and that fragmented content is treated
   correctly.

3.1  Received Message Set

   Each node SHOULD select one
      interface address and MUST utilize this address consistently as
      "originator address" maintains, for all messages each OLSRv2 interface it generates;

   <ttl> is an 8 bit field, which contains the maximum number of hops possesses, a
      message will be transmitted.  Before a message set of
   signatures of messages, which have been received over that interface,
   in the form of "Received Tuples":

      (RX_type, RX_addr, RX_seq_number, RX_time)

   where:

   RX_type is retransmitted, the Time To Live MUST be decremented by 1.  When a node receives a received message with a Time To Live equal to 0 type, or 1, zero if the received message MUST NOT
      be retransmitted under any circumstances.  Normally, a node would
      sequence number is not receive a message with a TTL of zero.

   <hopcount> type-specific.

   RX_addr is an 8 bit field, which contains the number originator address of hops a
      message has attained.  Before a message is retransmitted, the Hop
      Count MUST be incremented by 1.  Initially, this received message;

   RX_seq_number is set to '0' by the originator message sequence number of the received message;

   <msg-seq-number> is a 16 bit field,

   RX_time specifies the time at which contains this record expires and *MUST* be
      removed.

   In a unique number,
      generated by node, this is denoted the originator "Received Message Set" for that
   interface.

3.2   Fragment Set

   Each node to uniquely identify each stores messages containing fragmented content until all
   fragments are received and the message processing can be completed,
   in the network.  "Wrap-around" form of "Fragment Tuples":

      (FG_message, FG_time)

   where:

   FG_message is handled as described in
      Appendix H.

   TLVs associated with a the message or an address block SHALL be included
   in numerically ascending order within each TLV block.  Note that containing fragmented content;

   FG_time specifies the time at which this
   means that all TLVs defined in record expires and MUST be
      removed.

   In a node, this document appear before all other
   TLVs in that TLV block.

3.2.1  Address Blocks

   An address block represents is denoted the "Fragment Set".

3.3  Processed Set

   Each node maintains a set of addresses in a compact form.
   Assuming that an address can be specified as a sequence of bits signatures of messages which have been
   processed by the node, in the form  'head:tail', then an address-block is a set of addresses
   sharing "Processed Tuples":

      (P_type, P_addr, P_seq_number, P_time)

   where:

   P_type is the same 'head' and having different 'tails'.  Specifically,
   an address block conforms to processed message type, or zero if the following specification:

   address-block = {<head-length><head><nb tails>{<tail>*}}

   with processed
      message sequence number is not type-specific.

   P_addr is the usual notion of "*" indicating "zero or more" occurrences originator address of the preceding element, and the elements defined thus:

   <head-length> processed message;

   P_seq_number is the message sequence number of "common leftmost bits" in a set of
      addresses, akin to a "prefix", however with the only restriction
      on the head-length that 0 <= head-length <= the length of processed message;

   P_time specifies the
      address;

   <head> time at which this record expires and *MUST* be
      removed.

   In a node, this is denoted the longest sequence "Processed Set".

3.4  Forwarded Set

   Each node maintains a set of leftmost bits, signatures of messages which have been
   retransmitted/forwarded by the addresses node, in the address block have in common.  Akin to a prefix;

   <nb tails> form of "Forwarded
   Tuples":

      (FW_type, FW_addr, FW_seq_number, FW_time)

   where:

   FW_type is the forwarded message type, or zero if the forwarded
      message sequence number is not type-specific.

   FW_addr is the originator address of tails which follows;

   <tail> the forwarded message;

   FW_seq_number is the message sequence number of bits which, when concatenated to the head,
      makes up a single, complete, unique address.

   This representation aims forwarded
      message;

   FW_time specifies the time at providing which this record expires and *MUST* be
      removed.

   In a flexible, yet compact, way of
   representing sets of interface addresses.

3.2.2  TLVs

   A TLV node, this is denoted the "Forwarded Set".

3.5  Relay Set

   Each node maintains a carrier set of information, relative to a message or to neighbor interface addresses in an address block.  A TLV, associated to an address-
   block, specifies some attribute(s), for which associate with address(ses)
   in the address-block.  In order
   it is to provide relay flooded messages, in the largest amount form of
   flexibility to benefit from address aggregation as described in
   Section 3.2.1, a TLV associated to an address block can apply to:

   o  a single address in "Relay Tuples":

      (RY_if_addr)

   where:

   RY_if_addr is the address block;

   o  all addresses in the address block;

   o  any continuous sequence of addresses in a neighbor interface for which the address block;

   Specifically, node
      SHOULD relay flooded messages.

   In a TLV conforms to node, this is denoted the following specification:

   tlv = <type><length><index-start><index-stop><value>

   where "Relay Set".

4.  Packet Processing and Message Forwarding

   Upon receiving a basic packet, a node examines each of the elements are defined thus:

   <type> is an 8 bit field, which specifies message
   headers.  If the message type of is known to the TLV.  The
      two most significant bits are allocated with node, the following
      semantics:

   bit 7 message is
   processed locally according to the "user" bit.  Types with this bit unset are defined in
      this specification or can be allocated via standards action.
      Types with this bit set are reserved specifications for private/local use.

   bit 6 that message
   type.  The message is the "multivalue" bit.  TLVs with types with this bit unset
      include also independently evaluated for forwarding.

4.1  Actions when Receiving an OLSRv2 Packet

   Upon receiving a single value, which applies to each of packet, a node MUST perform the addresses
      defined by <index-start> and <index-stop>.  TLVs with types with
      this bit set include separate values for each of following task:

   1.  If the addresses in packet contains no messages (i.e. the interval defined by <index-start> and <index-stop>;

   <length> packet length is an 8 bit field which specifies
       less than or equal to the length, counted in
      octets, size of the data contained in <value>.  If packet header) or if the multivalue bit
      is set, this
       packet cannot be parsed into messages, the packet MUST be an integral multiple of (<index-stop>-<index-
      start>+1);

   <index-start>
       silently discarded.

   2.  Otherwise, each message in the packet is treated according to
       Section 4.2.

4.2  Actions when Receiving an 8 bit field.  For a TLV associated with an
      address block, specifies OLSRv2 Message

   A node MUST perform the index of the first address in the
      address-block (starting at zero), following tasks for which this TLV applies.  For
      a TLV associated with a message, this field SHALL each received OLSRv2
   message:

   1.  If the received OLSRv2 message header cannot be set correctly parsed
       according to zero;

   <index-stop> the specification in [4], or if the originator
       address of the message is an 8 bit field.  For a TLV associated with an interface address
      block, specifies the index of the last address in receiving
       node then the address-
      block (starting at zero) for which this TLV applies.  For a TLV
      associated with a message, this field SHALL message MUST be set to zero;

   <value> contains a payload, silently discarded;

   2.  Otherwise:

       1.  If the message is of a known type then the length specified in <length>,
      which message is to be processed
           considered for processing according to the specification indexed by
      the <type> field. Section 4.3;

       2.  If this is a TLV for an address block the received message TTL > 0, and if either the
      multivalue bit is set, this field
           message is divided into (<index-stop>-
      <index-start>+1) equal-sized fields which are applied in turn to
      each address described by <index-start> and <index-stop>

   Two of a known type, or more TLVs bit 3 of the same type SHALL NOT apply to message semantics
           octet in the same
   address.

3.3  Message Content Fragmentation

   An OLSRv2 message MAY be larger than header is desirable to include, with
   the OLSR packet and other headers (UDP, IP) clear, as indicated in a MAC frame.  In this
   case [4],
           then the message SHOULD be fragmented.

   An OLSRv2 is considered for forwarding according to
           Section 4.4.

4.3  Message Considered for Processing

   If a message may be fragmented by dividing is considered for processing, the address blocks
   plus following TLVs among its fragments.  It MAY be necessary to use
   more address blocks than might otherwise tasks MUST
   be chosen without
   fragmentation.  Each message fragment may carry any number of these
   address blocks plus following TLVs.

   All message TLVs MUST be included identically in each fragment.

   All TLVs pertaining to performed:

   1.  If an address block MUST be included entry exists in the same
   fragment as Processed Set where:

       *  P_type == the address block.

   When transmitting fragmented content, each message containing a
   fragment MUST include a message TLV of type Content Sequence Number.
   The value of this Content Sequence Number TLV is a 16 type, or 0 if bit field
   uniquely identifying the "version" 2 of the content message
          semantics octet (in the message header) is clear, AND;

       *  P_addr == the originator address of the message.  If message, AND;

       *  P_seq_number == the content does not have an inherent sequence number or version
   number, the value of the Content Sequence Number TLV SHOULD message.

       then the message MUST NOT be set to processed.

   2.  Otherwise:

       1.  Create an entry in the Processed Set with:

           +  P_type = the message sequence number type, or 0 if bit 2 of the message containing
              semantics octet (in the first
   fragment.

   A message containing a fragment MUST include a message TLV of type
   Fragmentation.  The value of this Fragmentation TLV header) is a 16 bit field
   consisting clear;

           +  P_addr = originator address of two 8 bit sub-fields describing the message;

           +  P_seq_number = sequence number of
   fragments, and the fragment number (counting from zero). message;

           +  P_time = current time + P_HOLD_TIME.

       2.  If the same content with the same Content Sequence Number is sent
   more than once by message does not contain a node, the content MUST be fragmented and
   transmitted identically each time message TLV of type
           Fragment (or if it is sent.

4.  Packet Processing does and Message Forwarding

   Upon receiving a basic packet, a node examines each of the "message
   headers".  If the "message type" indicated number of fragments
           is known to the node, one) then process the message is
   processed locally fully according to its type.

       3.  Otherwise:

           1.  If the specifications for that message
   type -- forwarding of known messages is considered part of the
   message processing.  Otherwise, "wholly or partially self-contained" as
               indicated by its Fragment TLV then process the current
               message is treated as "unknown",
   and is only evaluated for forwarding.

4.1  Processing and Forwarding Repositories

   The following data-structures are employed in order far as possible according to ensure that a
   message is processed at most once and is forwarded at most once per
   interface of a node, and that fragmented content is treated
   correctly.

4.1.1  Received Message its type;

           2.  If the Fragment Set

   Each node maintains, for each OLSRv2 interface it possesses, a set of
   signatures of includes any messages received over that interface:

      (R_addr, R_seq_number, R_time)

   where:

   R_addr is with the same
               originator address of the received message;

   R_seq_number is the message and content sequence number of the received message;

   R_time specifies as the time at which this record expires
               current message, and *MUST* be
      removed.

   In a node, this is denoted either the "Received Message Set".

4.1.2  Processed Set

   Each node maintains same fragment number or a set
               different number of messages, which have been processed by fragments, then remove these messages
               are from the node:

      (P_addr, P_seq_number, P_time)

   where:

   P_addr is Fragment Set;

           3.  If the originator address Fragment Set includes messages containing all the
               remaining fragments of the received message;
   P_seq_number is same overall message as the
               current message sequence (i.e. if the number of messages in the received message;

   P_time specifies the time at which this record expires and *MUST* be
      removed.

   In a node, this is denoted the "Processed Set".

4.1.3  Forwarded
               Fragment Set

   Each node maintains a set of messages, which have been retransmitted/
   forwarded by the node:

      (F_addr, F_seq_number, F_time)

   where:

   F_addr is with the same originator address of the received message;

   F_seq_number is the message and content
               sequence number of as the received message;

   F_time specifies current message is equal to the time at which this record expires
               current message's number of fragments, less one) then all
               of these messages are removed from the Fragment Set and *MUST* be
      removed.

   In a node, this
               processed according to their type (taking account of any
               previous processing if any or all were wholly or
               partially self-contained);

           4.  Otherwise, the current message is denoted added to the "Forwarded Set".

4.1.4  Relay Fragment
               Set

   A node maintains with a set FG_time of FG_HOLD_TIME (possibly replacing an
               identical and previous received instance of neighbor interfaces, in the form same
               fragment of "relay
   tuples", the same content).

4.4  Message Considered for which it Forwarding

   If a message is to relay flooded messages:

      (RS_if_addr, Rs_if_time)

   where:

   RS_if_addr considered for forwarding then if it is either of a
   message type defined in this document, or of an unknown message type
   it MUST use the address following algorithm.  A message type not defined in
   this document may specify the use of this, or another algorithm.
   (Such an other algorithm MAY use the neighbor interface, Received Set for which a node the receiving
   interface, it SHOULD relay flooded messages;

   RS_if_time specifies use the time at which this record expires and *MUST*
      be removed.

   In Forwarded Set similarly to the following
   algorithm.)

   If a node, message is considered for forwarding according to this
   algorithm, the following tasks MUST be performed:

   1.  If there is denoted no symmetric link in the "Relay Set".

4.2  Fragment Link Set

   A node stores messages containing fragmented content in form of
   "fragment tuples" until all fragments are received between the
       receiving interface and the messages
   can be processed:

           (F_message, F_time)

   where:

   F_message is sending interface (as indicated by
       the message source interface of the IP datagram containing a fragment;

   F_time specifies the time at which this record expires and message)
       then the message MUST be
      removed.

   In a node, this is denoted the "Fragment Set".

4.3  Actions when Receiving an OLSRv2-Packet

   Upon receiving a basic packet, a node MUST perform the following
   task:

   1.  If the packet contains no messages (i.e., the Packet Length is
       less than or equal to the size of the packet header), the packet
       MUST silently be discarded.

   2.  Otherwise, each encapsulated message is treated according to
       Section 4.4.

4.4  Actions when Receiving  Otherwise:

       1.  If an OLSRv2-Message

   A node MUST perform entry exists in the following tasks for a received OLSRv2-
   message:

      If Received Set for the receiving
           interface, where:

           +  RX_type == the message TTL <= 0 type, or 0 if the Originator Address bit 2 of the message is an interface address of the receiving node, then
              semantics octet (in the message MUST silently be dropped.

      If an entry exists in the received set for the receiving
      interface, where:

      *  R_addr header) is clear, AND;

           +  RX_addr == the originator address of the received message,
              AND;

      *  R_seq_number

           +  RX_seq_number == the sequence number of the received
              message.

           then the message MUST be discarded silently discarded.

       2.  Otherwise:

           1.  Create an entry in the Received Set for the receiving
               interface with:

          +  R_addr

               -  RX_type = the message type, or 0 if bit 2 of the
                  message semantics octet (in the message header) is
                  clear;

               -  RX_addr = originator address of the received message;

          +  R_seq_number

               -  RX_seq_number = sequence number of the received message;

          +  R_time

               -  RX_time = current time + R_HOLD_TIME. RX_HOLD_TIME.

           2.  If an entry exists in the message type is known to Forwarded Set where:

               -  FW_type == the receiving node, then:

          1. message type, or 0 if bit 2 of the
                  message contains a semantics octet (in the message TLV of type Fragment:

              1.  if header) is
                  clear;

               -  FW_addr == the Fragment Set contains all remaining fragments
                  necessary to reconstitute originator address of the content, received
                  message, AND;

               -  FW_seq_number == the messages
                  containing these fragments MUST be removed from sequence number of the
                  fragment set and received
                  message.

               then the message MUST be considered
                  for processing according to Section 4.5;

              2.  otherwise, silently discarded.

           3.  Otherwise if an entry exists in the message is added to the Fragment Set
                  with a F_time of XXXX (possibly replacing an identical
                  and previous received instance of the same fragment of
                  the same content).

          2.  Otherwise, if the message does not contain a message TLV
              of type Fragment,the message is considered for processing
              according to Section 4.5;

          Otherwise, if Relay Set, where
               RY_if_addr == source address of the message type is unknown to the receiving
          node, (as indicated
               by the message is considered for forwarding according to
          Section 4.6.

   Notice that known message types are not automatically considered for
   forwarding.  Forwarding of known message types MUST be specified as a
   property of processing source interface of that message type.

4.5  Message Considered for Processing

   If a message is considered for processing, the following tasks MUST
   be performed: IP datagram containing the
               message):

               1.  If  Create an entry exists in the Processed Forwarded Set where:

       *  P_addr == the originator address of the received message, AND;

       *  P_seq_number == with:

                   o  FW_type = the sequence number message type, or 0 if bit 2 of the received message.

       the
                      message MUST be discarded.

   2.  Otherwise:

       1.  Create an entry in semantics octet (in the Processed Set with:

           +  P_addr message header) is
                      clear;

                   o  FW_addr = originator address of the received message;

           +  P_seq_number

                   o  FW_seq_number = sequence number of the received message;

           +  P_time

                   o  FW_time = current time + P_HOLD_TIME. FW_HOLD_TIME.

               2.  Process  The message locally, according to header is modified as follows:

                   o  Decrement the specification for message TTL by 1;

                   o  Increment the received message type. hop count by 1;
               3.  If a  Transmit the message on all OLSRv2 interfaces of a known message type is to be forwarded, the
           algorithm in Section 4.6 MAY be performed.  All forwardable
           messages defined
                   node.

   Messages are retransmitted in this specification (TC, MA) do use the
           algorithm in format specified by [4] with the
   All-OLSRv2-Multicast address (see Section 4.6.

4.6  Message Considered for Forwarding

   If a message 17.1) as destination IP
   address.

5.  Information Repositories

   The purpose of OLSRv2 is considered for forwarding, to determine the following tasks MUST Routing Set, which may be performed:

   1.  If an entry exists in the Forwarded Set where:

       *  F_addr == the originator address of the received message, AND;

       *  F_seq_number == the sequence
   used to update IP's Routing Table, providing "next hop" routing
   information for IP datagrams.  In order to accomplish this, OLSRv2
   maintains a number of protocol sets, the received message.

       then information repository of
   the message MUST be discarded

   2.  Otherwise:

       1.  If an entry exists in protocol.  These sets are updated, directly or indirectly, by the Relay Set, where:

           +  RS_if_addr == message source address
   exchange of the received
              message

           2.  Create an entry messages between nodes in the Forwarded Set with:

               -  F_addr = originator address of network.  In turn the received message;

               -  F_seq_number = sequence number
   contents of the received
                  message;

               -  F_time = current time + F_HOLD_TIME.

           3.  The message header is modified as follows:

               -  decrement the message TTL by 1;

               -  increment the message hop count these messages are largely determined by 1;

           4.  If the message TTL > 0:

               -  Transmit the message on all OLSRv2 interfaces of the
                  node

5.  Information Repositories

   The signaling contents of OLSRv2 populates
   a set part of the information repositories,
   specified in this section.

5.1  Local Link the Neighbourhood Information Base

   The local link information base stores
   Base, which contains information about links
   between local interfaces the 1- and interfaces on adjacent nodes.

5.1.1  Link Set

   A node records a set 2- hop
   neighbourhoods of "Link Tuples":

     (L_local_iface_addr, L_neighbor_iface_addr,
      L_SYM_time, L_ASYM_time, L_willingness, L_time).

   where:

   L_local_iface_addr is the interface address node.  The remaining part of the local node;

   L_neighbor_iface_addr is information
   repository, the interface address of Topology Information Base (including the neighbor node ;

   L_SYM_time is Routing Set)
   contains information about the time until network which the link is considered symmetric;

   L_ASYM_time is not constrained to
   the time node's neighbourhood.  The Topology Information Base is updated
   by the OLSRv2 messages defined in this document, it is not used to
   define their contents.  The process of information exchange which
   leads to the population of the Neighbourhood Information Base and the
   Topology Information Base is started using only the node's own OLSRv2
   interface addresses and host and network associated addresses.  These
   are not affected by the exchange of the OLSRv2 messages defined in
   this document.

5.1  Neighborhood Information Base

   The neighborhood information base stores information about links
   between local interfaces and interfaces on adjacent nodes.

5.1.1  Link Set

   A node records a set of "Link Tuples":

     (L_local_iface_addr, L_neighbor_iface_addr,
      L_SYM_time, L_ASYM_time, L_willingness, L_time).

   where:

   L_local_iface_addr is the interface address of the local node;

   L_neighbor_iface_addr is the interface address of the neighbor node;

   L_SYM_time is the time until which the link is considered symmetric;

   L_ASYM_time is the time until which the neighbor interface is
      considered heard;
   L_willingness is the nodes willingness to be selected as MPR;

   L_time specifies when this record expires and *MUST* be removed.

              +-------------+-------------+--------------+
              | L_SYM_time  | L_ASYM_time | L_STATUS     |
              +-------------+-------------+--------------+
              | Expired     | Expired     | LOST         |
              |             |             |              |
              | Not Expired | Expired     | SYMMETRIC    |
              |             |             |              |
              | Not Expired | Not Expired | SYMMETRIC    |
              |             |             |              |
              | Expired     | Not Expired | ASYMMETRIC   |
              +-------------+-------------+--------------+

                                  Table 1

   The status of the link, denoted L_STATUS, can be derived based on the
   fields L_SYM_time and L_ASYM_time as defined in Table 1.

   In a node, the set of Link Tuples are is denoted the "Link Set".

5.1.2  2-hop  2-Hop Neighbor Set

   A node records a set of "2-hop tuples"

    (N_local_iface_addr, N_neighbor_iface_addr, N_2hop_iface_addr, N_time) "2-Hop Neighbor Tuples"

    (N2_local_iface_addr, N2_neighbor_iface_addr, N2_2hop_iface_addr, N2_time)

   describing symmetric links between its neighbors and the symmetric
   2-hop neighborhood.

   N_local_iface_addr

   N2_local_iface_addr is the address of the local interface over which
      the information was received;

   N_neighbor_iface_addr

   N2_neighbor_iface_addr is the interface address of a neighbor;

   N_2hop_iface_addr

   N2_2hop_iface_addr is the interface address of a 2-hop neighbor with
      a symmetric link to the node with interface address
      N_neighbor_iface_addr;

   N2_time specifies the time at which the tuple expires and *MUST* be
      removed.

   In a node, the set of 2-hop tuples are 2-Hop Neighbor Tuples is denoted the "2-hop "2-Hop
   Neighbor Set".

5.1.3  Neighborhood Address Association Set

   A node maintains, for each 1-hop and 2-hop neighbor with multiple
   addresses participating in the OLSRv2 network, a "Neighborhood
   Address Association Tuple", representing that "these n addresses belong
   to the same node".

       (I_neighbor_addr_list, I_time)

   I_neighbor_iface_addr_list

       (NA_neighbor_addr_list, NA_time)

   NA_neighbor_iface_addr_list is the list of interface addresses of the
      1-hop or 2-hop neighbor node;

   I_time

   NA_time specifies the time at which the tuple expires and *MUST* be
      removed.

   In a node, the set of Neighborhood Address Association Tuples is
   denoted the "Neighborhood Address Association Set".

5.1.4  MPR Set

   A node maintains a set of neighbors which are selected as MPR. MPRs.
   Their interface addresses are listed in the MPR Set.

5.1.5  MPR Selector Set

   A node maintains, for each interface of an 1-hop neighbor which has
   selected it as MPR, an "MPR Selector Tuple", representing the an
   interface of the neighbor node which have selected it as an MPR.

       (MS_neighbor_if_addr, MS_time)

   MS_neighbor_if_addr specifies the interface address of a 1-hop
      neighbor, which has selected the node as MPR;

   MS_time specifies the time at which the tuple expires and *MUST* be
      removed.

   Notice that if a MPR selector node has multiple interface addresses,
   the MPR Selector Set will contain one tuple for each interface
   address of the MPR selector.

5.1.6  Advertised Neighbor Set

   A node maintains a set of neighbor interface addresses, which are to
   be advertised through TC messages:

           (A_neighbor_iface_addr)
   For this set, an Advertised Neighbor Set Sequence Number (ASSN) is
   maintained.  Each time the Advertised Neighbor Set is updated, the
   ASSN MUST be incremented.

5.2  Topology Information Base

   Each node in the network maintains topology information

   The Topology Information Base stores topological information
   describing the network beyond the nodes neighborhood (i.e. beyond the
   Neighborhood Information Base of the node).

5.2.1  Topology Set

   Each node in the network maintains topology information about the
   network.

   For each destination in the network, at least one "Topology Tuple"

       (T_dest_iface_addr, T_last_iface_addr, T_seq, T_time)

   is recorded.

   T_dest_iface_addr is the interface address of a node, which may be
      reached in one hop from the node with the interface address
      T_last_iface_addr;

   T_last_iface_addr is, conversely, the last hop towards
      T_dest_iface_addr.  Typically, T_last_iface_addr is a MPR of
      T_dest_iface_addr;

   T_seq is a sequence number, and

   T_time specifies the time at which this tuple expires and *MUST* be
      removed.

   In a node, the set of Topology Tuples are denoted the "Topology Set".

6.  OLSRv2 Control Messages

   OLSRv2 employs two different message types for exchanging protocol
   information.  Those are HELLO messages, which are locally scoped, and
   TC messages, which are globally scoped.

6.1  HELLO Messages

   HELLO messages are,

5.2.2  Attached Network Set

   Each node in OLSRv2, exchanged  between neighbor nodes the network maintains information about attached
   networks.

   For each attached network, at least one "Attached Network Tuple"

       (AN_net_addr, AN_prefix_lenght, AN_gw_addr, AN_seq_no, AN_time)

   is recorded.

   AN_net_addr is the network address (prefix) of a network, which may
      be reached via the node with the purpose OLSRv2 interface address
      AN_gw_addr;

   AN_prefix_length is the length of populating the local link information base:

   o  Link Sensing: detecting new and lost adjacent interfaces and
      performing bidirectionality check prefix of links;

   o  2-hop Neighbor Discovery: detecting the 2-hop symmetric
      neighborhood network address
      AN_net_addr;

   AN_gw_addr is the address of a node;

   o  MPR Signaling: signal MPR selection to neighbor nodes and detect
      selection an OLSRv2 interface of MPRs

   HELLO messages are exchanged between neighbor nodes only, i.e. they
   are never forwarded by any node.

6.2  TC Messages

   TC messages are, in OLSRv2, transmitted a node which can
      act as gateway to the entire network with identified by the purpose of populating AD_net_addr/
      AD_prefix_length;

   AN_seq_no is a sequence number, and;

   AN_time specifies the topology information base:

   o time at which this tuple expires and *MUST* be
      removed.

   In a node, the set of Topology Discovery: ensure that information is present in each Tuples are denoted the "Topology Set".

5.2.3  Routing Set

   A node records a set of "Routing Tuples":

      (R_dest_iface_addr, R_next_iface_addr, R_dist, R_iface_addr)

   describing all destinations the next hop and (at least) a sufficient
      subset distance of links in order the path to provide least-hop paths to all
      destinations.

   TC messages are exchanged within each destination
   in the entire network, i.e. they are
   forwarded according to network for which a route is known.

   R_dest_iface_addr is the specification in section Section 4.6.

6.3  MA Messages

   MA messages are, in OLSRv2, transmitted by nodes with more than one interface address participating in of the OLSRv2 network with destination node;

   R_next_iface_addr is the purpose interface address of
   populating the Neighborhood Address Association Set (NAAS).

   MA messages are exchanged within "next hop" on the 2-hop neighborhood
      path towards R_dest_iface_addr;

   R_dist is the number of hops on the
   originator - i.e. are transmitted with a TTL=2 and are forwarded
   according path to R_dest_iface_addr;

   R_iface_addr is the specification in section Section 4.6.

7.  Populating address of the MPR Set

   Each node MUST select, from among its one-hop neighbors, local interface over which a subset of
   nodes as MPR.  This subset
      packet MUST be selected such that sent to reach R_next_iface_addr.

   In a message
   transmitted by the node, and retransmitted by all its MPR nodes, will
   be received by all nodes 2 hops away.

   Each node selects its MPR Set individually, utilizing the set of Routing Tuples is denoted the "Routing Set".

6.  OLSRv2 Control Message Structures

   Nodes using OLSRv2 exchange information
   in then neighbor set.  Initially, through messages.  One or
   more messages sent by a node will have an empty neighbor-
   set, thus, initially at the MPR set is empty.  A node SHOULD recalculate
   its MPR set when same time are combined into a change is detected to
   packet.  These messages may have originated at the neighbor set sending node, or 2-hop
   neighbor set.

   More specifically, a
   have originated at another node MUST calculate MPRs per interface, and forwarded by the
   union of sending node.
   Messages with different originators may be combined in the MPR sets of each interface make up the MPR set for the
   node.

   MPRs same
   packet.

   The packet and message format used by OLSRv2 is defined in [4].
   However this specification contains some options which are not used to flood control messages from a node into the network
   while reducing
   by OLSRv2.  In particular (using the number of retransmissions that will occur syntactical elements defined in a
   region.  Thus,
   the concept of MPR is an optimization of packet format specification):

   o  All OLSRv2 packets include a classical
   flooding mechanism.  While it is <packet-header>.

   o  All OLSRv2 messages, not essential that the MPR set is
   minimal, it is essential that limited to those defined in this
      document, include a full <msg-header> and hence have bits 0 and 1
      of <msg-semantics> cleared.

   o  All OLSRv2 message defined in this document have all strict 2-hop neighbors can remaining
      bits of <msg-semantics> cleared.

   Other options defined in [4] may be
   reached through the selected MPR nodes.  A node MUST select an MPR
   set such that freely used, in particular any strict 2-hop neighbor is covered by at least one
   MPR node.  A node
   values of <tlv-semantics> consistent with its specification.  An
   implementation of OLSRv2 MAY select additional MPRs beyond take full advantage of the minimum set.
   Keeping features of
   the MPR set small ensures that message specification in [4] allowing decisions relating to
   whether a message should be forwarded and/or processed to be taken
   parsing only the overhead message header (plus, if a message is to be
   processed but may be fragmented, only the first octets of the message
   body).

   OLSRv2 is kept
   at a minimum. messages are sent using UDP, see Appendix A contains an example heuristic for selecting MPRs.

8.  Populating the Advertised Neighbor Set C.

   The Advertised Neighbor Set contains remainder of this section defines, within the set framework of neighbor addresses,
   to which a node advertises links through TC messages. [4],
   message types and TLVs specific to OLSRv2.

6.1  General OLSRv2 Message TLVs

   This set
   SHOULD at least contain document specifies two message TLVs, which can be applied to any
   OLSRv2 control message, VALIDITY_TIME and INTERVAL_TIME, detailed in
   this section.

6.1.1  VALIDITY_TIME TLV

   All OLSRv2 messages specified in this specification MUST include a
   VALIDITY_TIME TLV, specifying for how long a node may, upon receiving
   a message, consider the addresses message content to be valid.  The validity
   time of the MPR Selector Set (i.e.
   all addresses, associated with a MPR selector through the
   Neighborhood Adverticed Address Set).  This set message MAY contain
   additional neighbor addresses.

   Each time an address is removed from the Advertised Neighbor Set, the
   ASSN MUST be incremented.  When an address is added specified to depend on the Advertised
   Neighbor Set, distance from the
   originator (i.e. the <hop-count> field in the ASSN SHOULD be incremented.

9.  HELLO Message Generation

   An OLSRv2 HELLO message is composed header as described
   defined in Section 3.2: [4]).  Thus, the VALIDITY_TIME TLV contains a
   set sequence of message TLVs, describing general properties
   pairs (time, hop-limit) in increasing hop-limit order, followed by a
   default value.

   Thus, an instance of a VALIDITY_TIME TLV could have the message and following
   value:

     <t_1><hl_1><t_2><hl_2> ... <t_i><hl_i> ....  <t_n><hl_n><t_default>

   Which would mean that the node emitting message, carrying this VALIDITY_TIME TLV,
   would have the HELLO, and a set of address blocks (with
   associated TLV sets), describing following validity times:

   o  <t_1> in the links and their associated
   properties.

   OLSRv2 HELLO messages are generated and transmitted per interface,
   i.e. different HELLO messages are generated and transmitted per
   OLSRv2 interface of a node.

   OLSRv2 HELLO messages are generated and transmitted periodically,
   with a default interval between two consecutive HELLO emissions on
   the same interface of HELLO_INTERVAL.

   This section specifies from 0 (exclusive) to <hl_1> (inclusive)
      hops away from the requirements, which HELLO message
   generation MUST fulfill.  An example algorithm is proposed originator;

   o  <t_i> in
   Appendix B.1.

9.1  HELLO Message: Message TLVs

   For each OLSRv2 interface a node MUST generate a HELLO message.  In
   that HELLO message, a node MAY include a the interval from <hl_(i-1)> (exclusive) to <hl_i>
      (inclusive) hops away from the originator; and

   o  <t_default> in the interval from <hl_n> (exclusive) to 255>
      (inclusive) hops away from the originator.

   The VALIDITY_TIME message TLV as specified specification is given in Table 2.

 +-------------+-------------------------------------+---------------+
 |

   VALIDITY_TIME message TLV specification overview

   +----------------+--------+-------------------+---------------------+
   |      Name      |  Type  | TLV Value       Length      | Default Value               |
 +-------------+-------------------------------------+---------------+
   +----------------+--------+-------------------+---------------------+
   | Willingness  VALIDITY_TIME |   TBD  |  (2*n+1) * 8 bits | {<time><hoplimit>}* | willingness to be selected as MPR.
   | WILL_DEFAULT                |
 +-------------+-------------------------------------+---------------+        |                   | <t_default>         |
   +----------------+--------+-------------------+---------------------+

                                  Table 2

   If a node does not advertise a Willingness TLV in HELLO messages,

   where <n> is the
   node MUST be assumed to have a willingness number of WILL_DEFAULT.

9.2  HELLO Message: Address Blocks (time, hop_limit) pairs in the TLV, and Address TLVs

   For each
   where <time> and <t_default> are represented as specified in section
   Section 16.

6.1.2  INTERVAL_TIME TLV

   OLSRv2 interface a node MUST generate messages of a HELLO given type MAY include an INTERVAL_TIME message with
   address blocks and address TLVs according to Table 3.

   +---------------------------+---------------------------------------+
   | The set of neighbor       | TLV (Type = Value)                    |
   | interfaces which are....  |                                       |
   +---------------------------+---------------------------------------+
   | HEARD over
   TLV, specifying the interface  | (Link Status=HEARD);                  |
   | over interval at which the HELLO is   | (Interface=TransmittingInterface)     |
   | messages of this type are being transmitted         |                                       |
   |                           |                                       |
   | SYMMETRIC over the        | (Link Status=SYMMETRIC);              |
   | interface over which
   generated by the  | (Interface=TransmittingInterface)     |
   | HELLO originator node.

   The INTERVAL_TIME message TLV specification is being            |                                       | given in Table 3.

   INTERVAL_TIME TLV specification overview

   +----------------+--------+-------------------+---------------------+
   | transmitted      Name      |  Type  |       Length      | Value               |
   +----------------+--------+-------------------+---------------------+
   |  INTERVAL_TIME | LOST over the interface   TBD  | (Link Status=LOST);       8 bits      | <time>              | over which the HELLO
   +----------------+--------+-------------------+---------------------+

                                  Table 3

   where <time> is   | (Interface=TransmittingInterface)     |
   | being transmitted         |                                       |
   |                           |                                       |
   | SYMMETRIC over ANY        | (Link Status=SYMMETRIC);              |
   | interface of the node     | (Interface=Other)                     |
   | other than the interface  |                                       |
   | over which time between two successive emissions of messages
   of the HELLO is   |                                       |
   | being transmitted         |                                       |
   |                           |                                       |
   | selected type, represented as MPR for the   | (Link Status=SYMMETRIC);              |
   | interface over which the  | (Interface=TransmittingInterface);    |
   | HELLO is transmitted      | (MPR Selection=True)                  |
   +---------------------------+---------------------------------------+

                                  Table 3

10.  HELLO Message Processing

   Upon receiving specified in section Section 16.

6.2  Local Interface Blocks

   The first address block, plus following TLV block in a HELLO message, or TC
   message is known as a node will update its local link
   information base according to the specification given Local Interface Block.  A Local Interface Block
   is not distinguished in this
   section.

   For any way other than by being the purpose of this section, please notice first address
   block in the following:

   o message.

   A Local Interface Block contains the "validity time" addresses of a message is calculated from the Vtime
      field all of the message header as specified in Section 17;

   o  the "originator address" refers to the address, contained in the
      "originator address" field
   interfaces of the originating node that support OLSRv2 message header specified
      in Section 3.1;

   o  a HELLO message MUST neither be forwarded nor be recorded and
   participate in the
      duplicate set;

   o  the address blocks considered exclude MANET, using the originator address
      block, unless explicitly specified;

   o standard <address-block> syntax
   from [4].  In a HELLO TC message this is valid when, for each address listed sufficient; in a HELLO message,
   those addresses, if any, which correspond to interfaces other than
   that on which the
      address blocks:

      *  the address HELLO message is associated with at least one sent must have a corresponding
   OTHER_IF TLV.  In this case (only) this OTHER_IF TLV with Type=Link
         Status, AND

      *  the SHALL NOT have a
   <value> field.

   Note that a Local Interface Block may include more than one address is associated with at least
   for each interface, and hence in a HELLO message may contain more
   than one address without an OTHER_IF TLV.

6.3  HELLO Messages

   A HELLO message MUST contain:

   o  a message TLV VALIDITY_TIME Section 6.1.1

   o  one or more address blocks with
         Type=Interface, AND

      *  all the associated address block TLVs with identical type, that the

   The first (mandatory) address block is
         associated with, have identical values (e.g.
         Interface=TransmittingInterface is not compatible with
         Interface=Other for instance), AND

      *  if the a Local Interface Block, as
   specified in Section 6.2.  Other (optional) address is associated with one blocks contain
   1-hop neighbors' interface addresses.

   A HELLO message MAY optionally contain:

   o  a message TLV "MPR Selection=True",
         then it MUST be associated also with one INTERVAL_TIME as specified in Section 6.1.2

   o  a message TLV "Link
         Status=SYMMETRIC".

      Invalid WILLINGNESS, as specified in Section 6.3.1

6.3.1  HELLO messages are not processed.

10.1  Populating the Link Set

   Upon receiving Message: Message TLVs

   In a HELLO message, a node SHOULD update its Link Set
   with the information contained in the HELLO.  Thus, for each address,
   listed MAY include a message TLV as specified in the HELLO
   Table 4.

   VALIDITY_TIME message address blocks (see Section 6):

   1.  if there exists no link tuple with

       *  L_neighbor_iface_addr == Source Address TLV specification overview

   +----------------+--------+-------------------+---------------------+
   |      Name      |  Type  |       Length      | Value               |
   +----------------+--------+-------------------+---------------------+
   |   WILLINGNESS  |   TBD  |       8 bits      | <The node's         |
   |                |        |                   | willingness to be   |
   |                |        |                   | selected as MPR>    |
   +----------------+--------+-------------------+---------------------+

                                  Table 4

   A node's willingness to be selected as MPR ranges from WILL_NEVER
   (indicating that a new tuple node MUST NOT be selected as MPR by any node) to
   WILL_ALWAYS (indicating that a node MUST always be selected as MPR.

   If a node does not advertise a Willingness TLV in HELLO messages, the
   node MUST be assumed to have a willingness of WILL_DEFAULT.

6.3.2  HELLO Message: Address Blocks TLVs

   HELLO message address block TLV specification overview

   +----------------+--------+-------------------+---------------------+
   |      Name      |  Type  |       Length      | Value               |
   +----------------+--------+-------------------+---------------------+
   |   LINK_STATUS  |   TBD  |       8 bits      | One of HEARD,       |
   |                |        |                   | SYMMETRIC, LOST.    |
   |                |        |                   |                     |
   |       MPR      |   TBD  |       0 bits      | No value, i.e.      |
   |                |        |                   | novalue bit (see    |
   |                |        |                   | [4]) set            |
   |                |        |                   |                     |
   |    OTHER_IF    |   TBD  |    0 or 8 bits    | In a Local          |
   |                |        |                   | Interface Block     |
   |                |        |                   | none, otherwise     |
   |                |        |                   | either of SYMMETRIC |
   |                |        |                   | or LOST             |
   +----------------+--------+-------------------+---------------------+

                                  Table 5

6.4  TC Messages

   A TC message MUST contain:

   o  a message TLV VALIDITY_TIME Section 6.1.1

   o  a message TLV CONTENT_SEQUENCE_NUMBER [4]

   o  one or more address blocks with associated address block TLVs.

   The first (mandatory) address block is a Local Interface Block, as
   specified in Section 6.2.  Other (optional) address blocks contain
   1-hop neighbors' interface addresses and/or host or network addresses
   for which this node may act as a gateway.  In the latter case they
   may use PREFIX_LENGTH TLV(s) as specified in [4].

   A TC message MAY optionally contain:

   o  a message TLV INTERVAL_TIME as specified in Section 6.1.2

7.  HELLO Message Generation

   An OLSRv2 HELLO message is composed of a set of message TLVs,
   describing general properties of the message and the node emitting
   the HELLO, and a set of address blocks (with associated TLV sets),
   describing the links and their associated properties.

   OLSRv2 HELLO messages are generated and transmitted per interface,
   i.e. different HELLO messages are generated and transmitted per
   OLSRv2 interface of a node.

   OLSRv2 HELLO messages are generated and transmitted periodically,
   with a default interval between two consecutive HELLO emissions on
   the same interface of HELLO_INTERVAL.

   This section specifies the requirements, which HELLO message
   generation MUST fulfill.  An example algorithm is proposed in
   Appendix B.1.

   For each OLSRv2 interface a node MUST generate a HELLO message with a
   Local Interface Block as the first address block, as specified in
   Section 6.2, followed by address blocks and address TLVs according to
   Table 6.

   +---------------------------+---------------------------------------+
   | The set of neighbor       | TLV(s) (Type = Value)                 |
   | interfaces which are ...  |                                       |
   +---------------------------+---------------------------------------+
   | HEARD, but not SYMMETRIC  | LINK_STATUS=HEARD                     |
   | over the interface over   |                                       |
   | which the HELLO message   |                                       |
   | is being transmitted      |                                       |
   |                           |                                       |
   | SYMMETRIC over the        | LINK_STATUS=SYMMETRIC                 |
   | interface over which the  |                                       |
   | HELLO message is being    |                                       |
   | transmitted               |                                       |
   |                           |                                       |
   | LOST over the interface   | LINK_STATUS=LOST                      |
   | over which the HELLO      |                                       |
   | message is being          |                                       |
   | transmitted               |                                       |
   |                           |                                       |
   | Not SYMMETRIC over the    | OTHER_IF=SYMMETRIC                    |
   | interface over which the  |                                       |
   | HELLO message is being    |                                       |
   | transmitted, but          |                                       |
   | SYMMETRIC over one or     |                                       |
   | more other interfaces of  |                                       |
   | the node                  |                                       |
   |                           |                                       |
   | Not SYMMETRIC over any    | OTHER_IF=LOST                         |
   | interface or LOST over    |                                       |
   | the interface over which  |                                       |
   | the HELLO message is      |                                       |
   | being transmitted, but    |                                       |
   | previously reported as    |                                       |
   | OTHER_IF=SYMMETRIC and    |                                       |
   | still HEARD or LOST over  |                                       |
   | one or more interfaces of |                                       |
   | the node other than the   |                                       |
   | interface over which the  |                                       |
   | HELLO message is being    |                                       |
   | transmitted               |                                       |
   |                           |                                       |
   | Selected as MPR for the   | MPR                                   |
   | interface over which the  |                                       |
   | HELLO message is          |                                       |
   | transmitted               |                                       |
   +---------------------------+---------------------------------------+

                                  Table 6

   In order that an address can be reported as OTHER_IF=LOST by a node
   with more than one interface participating in the MANET, such a node
   MAY maintain an Other Interface Set of addresses for each interface.
   The Other Interface Set for an interface is updated when a HELLO
   message is to be transmitted over that interface, and used to
   determine which addresses are reported as OTHER_IF=LOST in that
   message.  The Other Interface Set of addresses is updated and used as
   follows:

   1.  Each address that the HELLO message is to include with a
       corresponding TLV with Type=LINK_STATUS and Value=SYMMETRIC is
       removed from the set.

   2.  Each address that the HELLO message is to include with a
       corresponding TLV with Type=OTHER_IF and Value=SYMMETRIC is added
       to the set if not already present.

   3.  Each other address in the set (not included in the HELLO message
       with a corresponding TLV with Type=OTHER_IF and Value=SYMMETRIC)

       1.  Is removed if the HELLO message is to include it with a
           corresponding TLV with Type=LINK_STATUS and Value=LOST.

       2.  Is removed if it is not HEARD or LOST over an interface other
           than the interface over which the HELLO message is to be
           transmitted.

       3.  Otherwise is included in the HELLO message with a TLV with
           Type=OTHER_IF and Value=LOST.  (Note that the address may
           also have a corresponding TLV with Type=LINK_STATUS and
           Value=HEARD if appropriate.)

7.1  HELLO Message: Transmission

   Messages are retransmitted in the packet/message format specified by
   [4] with the All-OLSRv2-Multicast address as destination IP address
   and with a TTL=1.

8.  HELLO Message Processing

   Upon receiving a HELLO message, a node will update its local link
   information base according to the specification given in this
   section.

   For the purpose of this section, please notice the following:

   o  the "validity time" of a message is calculated from the VALIDITY-
      TIME TLV of the message as specified in Section 6.1.1;

   o  the "Source Address" is the source address as indicated by the
      source interface of the IP datagram containing the message;

   o  a HELLO message MUST neither be forwarded nor be recorded in the
      Processing and Forwarding Repositories;

   o  the address blocks considered exclude the Local Interface Block,
      unless explicitly specified;

   o  a HELLO message is only valid when, for each address listed in the
      address blocks:

      *  the address is associated with a TLV with Type=Link Status OR a
         TLV with Type=Other Interface Status OR both, the latter either
         when the TLV with Type=Link Status has Value=HEARD, or when the
         the TLV with Type=Link Status has Value=LOST and the TLV with
         Type=Other Interface Status has Value=SYMMETRIC, AND

      *  if the address is associated with a TLV with Type=MPR, then it
         MUST also be associated with a TLV with Type=Link Status and
         Value=SYMMETRIC.

      Invalid HELLO messages are not processed.

8.1  Populating the Link Set

   Upon receiving a HELLO message, a node SHOULD update its Link Set
   with the information contained in the HELLO.  Thus, for the Local
   Interface Block (see Section 6.2) the Neighbor Address Association
   Set is updated as specified by Section 13.  For each address, listed
   in the subsequent HELLO message address blocks (see Section 6):

   1.  if there exists no link tuple with:

       *  L_neighbor_iface_addr == Source Address
       a new tuple is created with

       *  L_neighbor_iface_addr = Source Address;

       *  L_local_iface_addr    = Address of the interface which
          received the HELLO message;

       *  L_SYM_time            = current time - 1 (expired);

       *  L_time                = current time + validity time.

   2.  The tuple (existing or new) with L_neighbor_iface_addr == Source
       Address is then modified as follows:

       1.  if the node finds the address of the interface, which
           received the HELLO message, in one of the address blocks
           included in message, then the tuple is modified as follows:

           1.  if the occurrence of L_local_iface_addr in the HELLO
               message is:

               -  associated with a TLV with (Type == "LINK_STATUS",
                  Value == LOST)

               then

               -  L_SYM_time = current time - 1 (i.e., expired)

           2.  else if the occurrence of L_local_iface_addr in the HELLO
               message:

               -  is associated with:

                  o  a TLV with (Type == "LINK_STATUS", Value ==
                     SYMMETRIC);

                  OR;

                  o  a TLV with (Type == "LINK_STATUS", Value == HEARD);

               then

               -  L_SYM_time = current time + validity time,

               -  L_time     = L_SYM_time + L_HOLD_TIME.

       2.  L_ASYM_time = current time + validity time;

       3.  L_time = max(L_time, L_ASYM_time)

   3.  Additionally, the willingness field is updated as follows:

          If a TLV with Type=="WILLINGNESS" is present in the message
          TLVs, then:

          +  L_willingness = Value of the TLV

          otherwise:

          +  L_willingness = WILL_DEFAULT

   The rule for setting L_time is the following: a link losing its
   symmetry SHOULD still be advertised in HELLOs (with the remaining
   status as defined by Table 1) during at least the duration of the
   "validity time".  This  allows neighbors to detect the link breakage.
   Thus, the Local Link Set must maintain information, also about LOST
   links, until the link would otherwise expire.

8.2  Populating the 2-Hop Neighbor Set

   Upon receiving a HELLO message from a symmetric neighbor interface, a
   node SHOULD update its 2-hop Neighbor Set.

   If the Source Address is the L_local_iface_addr from a link tuple
   included in the Link Set with L_STATUS equal to SYMMETRIC (in other
   words: if the Source Address is a symmetric neighbor interface) then
   the 2-hop Neighbor Set SHOULD be updated as follows:

   1.  for each address (henceforth: 2-hop neighbor address), listed in
       the HELLO message:

       1.  if the 2-hop neighbor address is an interface address of the
           receiving node silently discard the 2-hop neighbor address
           (in other words: a node is not its own 2-hop neighbor).

       2.  else if the 2-hop neighbor address has a TLV with:

           +  (Type=LINK_STATUS, Value == SYMMETRIC); OR

           +  (Type=OTHER_IF, Value=SYMMETRIC);

           a 2-hop tuple is created with

       *  L_neighbor_iface_addr = Source Address;

       *  L_local_iface_addr with:

           +  N2_local_iface_addr    = Address address of the interface over
              which
          received the HELLO message was received;

           +  N2_neighbor_iface_addr = source address of the message;

       *  L_SYM_time

           +  N2_2hop_iface_addr     = current time - 1 (expired);

       *  L_time 2-hop neighbor address;

           +  N2_time                = current time + validity time.

   2.  The

           This tuple (existing or new) may replace an older similar tuple with the same
           N2_local_iface_addr, N2_neighbor_iface_addr and
           N2_2hop_iface_addr values.

       3.  else if the 2-hop neighbor address has a TLV with:

       *  L_neighbor_iface_addr

           +  (Type == Source Address

       is LINK_STATUS, Value == LOST); OR

           +  (Type == OTHER_IF, Value == LOST),

           then modified as follows:

       2.  if the node finds any 2-hop tuple with:

           +  N2_local_iface_addr equal to the address of the interface, interface
              over which
           received the HELLO message was received; AND

           +  N2_neighbor_iface_addr equal to the source address of the
              message; AND

           +  and N2_2hop_iface_addr equal to the 2-hop neighbour
              address

           MUST be deleted.

8.3  Populating the MPR Selector Set

   Upon receiving a HELLO message, in if a node finds one of its own
   interface addresses, listed with an MPR TLV (indicating that the
   originator node has selected one of the receiving node's interfaces
   as MPR), the MPR Selector Set SHOULD be updated as follows:

   For each address blocks
           included in message, the Local Interface Block of the received
   message:

   1.  If there exists no MPR Selector tuple with:

       *  MS_if_addr   == that address

       then the a new tuple is created with:

       *  MS_if_addr   =  that address

   2.  The tuple (new or otherwise) with:

       *  MS_if_addr   == that address

       is then modified as follows:

           1.  if the occurrence

       *  MS_time       =  current time + validity time.

   MPR Selector tuples are removed upon expiration of L_local_iface_addr MS_time, or upon
   link breakage as described in the HELLO
               message is associated with a TLV with Type="Link Status"
               and value=LOST, Section 8.4.

8.4  Neighborhood and it 2-Hop Neighborhood Changes

   A change in the neighborhood is also associated with an TLV
               with Type="Interface" and Value="TransmittingInterface"
               then

               - detected when:

   o  Link Loss: the L_SYM_time = current field of a link tuple expires (either
      due to time - 1 (i.e., expired)

           2.  else if the occurrence out, or as a result of L_local_iface_addr processing a TLV (Type ==
      LINK_STATUS, Value == LOST)).

   o  Link Acquisition: a new link tuple is inserted in the HELLO
               message is associated Link Set
      with a TLV with Type="Link Status"
               and value=SYMMETRIC non expired L_SYM_time or HEARD, and it is also associated
               with an TLV a tuple with Type="Interface" and
               Value="TransmittingInterface" then

               - expired L_SYM_time = current time + validity time,

               -  L_time     =
      is modified so that L_SYM_time + NEIGHB_HOLD_TIME.

       3.  L_ASYM_time = current time + validity time;

       4.  L_time = max(L_time, L_ASYM_time)
   3.  Additionally, the willingness field becomes non-expired.  This is updated
      considered as follows:

          If a TLV with Type="Willingness" is present in the message
          TLVs, then

          +  L_willingness = Value of the TLV

          otherwise:

          +  L_willingness = WILL_DEFAULT

   The rule for setting L_time is the following: a link losing its
   symmetry SHOULD still be advertised in HELLOs (with the remaining
   status as defined by Table 1) during at least the duration of the
   "validity time".  This  allows neighbors to detect the acquisition if there was previously no such
      link breakage.

10.2  Populating the 2-Hop tuple.

   o  Neighbor Set

   Upon receiving a HELLO message from Loss: all links to a symmetric neighbor interface, a node SHOULD update its have have been lost.

   A change in the 2-hop neighborhood is detected when a 2-Hop Neighbor Set.

   If the Originator Address
   Tuple expires or is deleted according to section Section 8.2.

   The following processing occurs when changes in the L_local_iface_addr from a neighborhood or
   the 2-hop neighborhood are detected:

   o  In case of link tuple
   included in loss, all 2-Hop Neighbor Tuples with

      *  N2_local_iface_addr == interface address of the Link Set node where the
         link was lost

      *  N2_neighbor_iface_addr == interface address of the neighbor

      MUST be deleted.

   o  In case of neighbor loss, all MPR Selector tuples associated with L_STATUS equal to SYMMETRIC (in other
   words: if
      that neighbor are deleted.  More precisely:

      *  all MPR selector tuples with MS_iface_addr == interface address
         of the Originator Address is a symmetric neighbor interface)
   then MUST be deleted, along with any interface
         addresses associated in the 2-hop Neighbor Address Association Set.

   o  The MPR Set SHOULD MUST be updated as follows:

   1.  for each address (henceforth: 2-hop neighbor address), listed re-calculated when a link acquisition or loss
      is detected, or when a change in the 2-hop neighborhood is
      detected.

   o  An additional HELLO message with a Link Status TLV equal to SYMMETRIC:

       1.  if MAY be sent when the 2-hop neighbor address is an address of MPR Set or the receiving
           node:

              silently discard
      neighborhood changes.

   Additionally, proper update of the 2-hop neighbor address.

           (in other words: sets describing local topology
   should be made when a node is not its own 2-hop neighbor).

       2.  Otherwise, Neighbor Association Address Tuple has a 2-hop tuple is created with:

           +  N_local_iface_addr    = address list
   of the interface over addresses which is modified.

9.  TC Message Generation

   TC messages are, in OLSRv2, transmitted with the HELLO message was received;

           +  N_neighbor_iface_addr = Originator Address purpose of
   populating the message;

           +  N_2hop_iface_addr     = 2-hop neighbor address;

           +  N_time                = current time + validity time.

           This tuple may replace an older similar tuple with same
           N_local_iface_addr, N_neighbor_iface_addr and
           N_2hop_iface_addr values.

10.3  Populating Topology Set, the Relay Attached Network Set

   Upon receiving a HELLO message, if a and the
   Neighborhood Address Association Set:

   o  Topology Discovery: ensure that information is present in each
      node finds one describing all destinations and a sufficient subset of its own
   interface addresses, listed with an MPR TLV (indicating links
      in order to provide least-hop paths to all destinations.

   o  Multiple Interface Declaration: ensure that nodes, up to two hops
      away from the
   originator node has selected one originator, are aware of the receiving nodes interfaces as
   MPR), the  Relay Set SHOULD be updated as follows:

   For each address in interface configuration
      of the originator address block:

   1.  If there exists no Relay tuple with:

       *  RS_if_addr   == that address

       then node.

   Thus, nodes with a new tuple is created with:

       *  RS_if_addr   =  that address

   2.  The tuple (new non-empty Advertised Neighbor Set, or otherwise) with

       *  RS_if_addr   == that address

       is then modified as follows:

       *  RS_time       =  current time + validity time.

   Relay tuples which are removed upon expiration
   specifically reporting an empty Advertised Neighbor Set (for a period
   of RS_time, T_HOLD_TIME following reporting a non-empty Advertised Neighbor
   Set) or upon link
   breakage as described in Section 10.4.

10.4  Neighborhood with more than one interface which supports OLSRv2 and 2-hop Neighborhood Changes

   A change
   participates in the neighborhood is detected when:

   o MANET, MUST generate TC messages, according to
   the following:

   1.  The L_SYM_time field node includes, in its first address block of the TC message,
       a link tuple expires.  This is considered Local Interface Block as a link loss.

   o  A new link tuple is inserted specified in Section 6.2

   2.  If the Link node has a non-empty Advertised Neighbor Set with or is
       specifically reporting an empty Advertised Neighbor Set, or it
       has a non expired
      L_SYM_time one or more attached non-OLSRv2 networks, to which it
       wishes to advertise routes to the network, it furthermore:

       1.  includes a tuple message TLV (Type = CONTENT_SEQ_NUMBER TLV, Value
           = the Advertised Neighbor Set Sequence Number);

       2.  includes address blocks, containing its Advertised Neighbor
           Set (if non-empty);

       3.  includes address blocks and PREFIX_LENGTH TLVs, describing
           attached non-OLSRv2 networks;

       4.  sets the TTL of the message to the network diameter.

   3.  Otherwise, the node:

       1.  sets the TTL of the message to 2.

   OLSRv2 TC messages are generated and transmitted periodically, with expired L_SYM_time is modified so that
      L_SYM_time becomes non-expired.  This is considered as a link
      appearance if there was previously no such link tuple.

   A change
   default interval between two consecutive TC emissions by the same
   node of TC_INTERVAL.

9.1  TC Message: Transmission

   Messages are retransmitted in the 2-hop neighborhood is detected when a 2-hop neighbor
   tuple expires or packet/message format specified by
   [4] with the All-OLSRv2-Multicast address as destination IP address
   and is deleted forwarded according to the specification in section
   Section 10.2.

   The following processing occurs when changes 4.4.  If fragmentation is necessary, a FRAGMENTATION TLV MUST
   be included, and each fragment SHOULD be flagged as partially or
   wholly self contained as specified in [4].

10.  TC Message Processing

   Upon receiving a TC message, a node MUST update its topology
   information base according to the neighborhood or specification given in this
   section.

   For the 2-hop neighborhood are detected:

   o  In case of link loss, all 2-hop tuples with

      *  N_local_iface_addr == interface address purpose of this section, note the node where following:

   o  the
         link was lost

      *  N_neighbor_iface_addr == interface address "validity time" of a message is calculated from the neighbor

      MUST be deleted.
      VALIDITY_TIME message TLV according to the specification in
      Section 16;

   o  In case of neighbor interface loss, if there exists no link left  the "originator address" refers to this neighbor node, all MPR selector tuples associated with
      that neighbor are deleted.  More precisely:

      *  If there exists an entry the address, contained in the neighbor address iface
         association set where

         +  I_neighbor_iface_addr_list includes
      "originator address" field of the OLSRv2 message header specified
      in [4];

   o  the
            N_neighbor_iface_addr ASSN of the lost link tuple

         AND such has there exists a link tuple such has

         +  L_neighbor_iface_addr node, originating the TC message, is one recovered as
      the value of the addresses CONTENT_SEQ_NO message TLV in
            I_neighbor_iface_addr_list

         then a link to the neighbor interface was lost, but the
         neighbor node itself is still TC message, if
      any.

10.1  Checking Freshness & Validity of a neighbor (with another link), TC message

   In order to be able to ensure that only valid and the mpr selector set fresh information
   is not changed,

      *  otherwise, recorded in the neighbor Topology Set, each node is lost, and all MPR selector
         tuples with MS_iface_addr == interface address of maintains an ASSN History
   Set, recording the neighbor
         MUST be deleted, along with any interface address associated highest ASSN received from each node in the neighbor address iface association set.

   o  The MPR set MUST be re-calculated when a link appearance or loss
      is detected, or when a change
   network, in the 2-hop neighborhood is
      detected.

   o  An additional HELLO message MAY be sent when form of a "ASSN History Tuples":

       (AS_Address, AS_seq, AS_time)

   AS_Address is the MPR set changes.

   Additionally, proper update originator address of a received TC message;

   AS_seq is the sets describing local topology
   should be made when highest received ASSN seen in a neighbor association address TC message from
      AS_Address;

   AS_time is the time at which this tuple has expires and MUST be removed.

   Upon receiving a list
   of addresses which is modified.

11. TC Message Generation

   An OLSRv2 message, a node MUST check if the TC message is composed
   fresh and valid as described in  Section 3.2: a set
   of message TLVs, describing general properties of follows:

   1.  If the TC message has more than one address block (i.e. not just
       a Local Interface Block) and does not contain a message-TLV of
       type CONTENT_SEQ_NO. then the
   node emitting message MUST be discarded;

   2.  otherwise, if the TC, and ASSN History Set contains a set tuple where:

       *  AS_Address == Originator Address of address blocks (with associated
   TLV sets), describing the links and their associated properties.

   OLSRv2 TC messages are generated and transmitted per node, i.e. message; AND
       *  AS_seq > the ASSN recovered from the
   same TC messages are generated and transmitted on all OLSRv2
   interfaces of a node.

   OLSRv2 message,

       then the TC messages are generated and transmitted periodically, with message MUST be discarded;

   3.  otherwise a
   default interval between two consecutive tuple is inserted in the ASSN History Set with:

       *  AS_Address = Originator Address in the message;

       *  AS_seq = The ASSN, extracted from the message;

       *  AS_time = current time + AS_HOLD_TIME.

       possibly replacing an existing tuple with the same AS_Address.

10.2  Updating the Topology Set

   A node SHOULD update its Topology Set as follows:

   1.  For each address, LocAddr, from the Local Interface Block in the
       TC emissions by message:

       1.  For each advertised neighbor address, listed in an address
           block other than the Local Interface Block in the same
   node of TC_INTERVAL.

11.1 TC Message: Message TLVs

   Each OLSRv2 node, selected as MPR (i.e. a node with message,
           which does NOT have an associated PREFIX_LENGTH TLV:

           1.  if there exists a non-empty MPR
   Selector Set) MUST generate TC messages with message TLVs according
   to the following table:

   +----------------------+----------------------+---------------------+
   | TLV Type             | TLV Value            | Default Value       |
   +----------------------+----------------------+---------------------+
   | Content Seq. no      | <the current value   | N/A                 |
   |                      | of tuple in the ASSN of Topology Set where:

               T_dest_iface_addr == advertised neighbor address; AND

               T_last_iface_addr == LocAddr.

               then the   |                     |
   |                      | node>                |                     |
   +----------------------+----------------------+---------------------+

                                  Table 4

11.2  TC Message: Address Blocks and Address TLVs

   Each OLSRv2 node, selected tuple is updated as MPR (i.e. a node with follows:

               T_time = current time + validity time

               T_seq = ASSN

           2.  Otherwise, a non-empty MPR
   Selector Set) new topology tuple is created with:

               T_dest_iface_addr = advertised neighbor address, AND

               T_last_iface_addr = LocAddr; AND

               T_seq = ASSN.

10.3  Purging Old Entries from the Topology Set

   Old entries from the Topology Set MUST generate be purged as follows:

   1.  For each address, LocAddr, from the Local Interface Block in the
       TC messages with address blocks and
   address TLVs according to message:

       1.  all tuples in the following table:

   +---------------------------------+---------------------------------+
   | Addresses                       | TLVs                            |
   +---------------------------------+---------------------------------+
   | The set of neighbor interfaces, |                                 |
   | which have selected Topology Set where:

           T_last_iface_addr == LocAddr AND

           T_seq < ASSN

           MUST be removed.

10.4  Updating the Attached Networks Set

   A node SHOULD update its Attached Networks Set as |                                 |
   | MPR                             |                                 |
   +---------------------------------+---------------------------------+

                                  Table 5

12. follows:

   1.  For each address, LocAddr, from the Local Interface Block in the
       TC Message Processing

   Upon receiving a message:

       1.  For each advertised neighbor address, listed in an address
           block other than the Local Interface Block in the TC message,
           which does have an associated PREFIX_LENGTH TLV:

           1.  if there exists a node will update its topology
   information base according to the specification given tuple in this
   section.

   For the purpose of this section, please notice Attached Networks Set
               where:

               AN_net_addr == advertised neighbor address; AND

               AN_prefix_length == the following:

   o prefix length as recoveredf from
                  the "validity time" of PREFIX_LENGTH TLV; AND

               AN_gw_addr == LocAddr.

               then the tuple is updated as follows:

               AN_time = current time + validity time

               AN_seq = ASSN

           2.  Otherwise, a message new topology tuple is calculated created with:

               AN_net_addr == advertised neighbor address; AND

               AN_prefix_length == the prefix length as recoveredf from
                  the Vtime
      field of PREFIX_LENGTH TLV; AND

               AN_gw_addr == LocAddr.

               AN_time = current time + validity time

               AN_seq = ASSN

10.5  Purging Old Entries from the Attached Network Set

   TBD

10.6  Processing Unfragmented TC Messages

   If an unfragmented TC message, i.e. a TC message header without a
   FRAGMENTATION message TLV, is received, it MUST be processed as specified in Section 17;

   o
   follows:

   1.  Verify freshness and validity of the "originator address" refers to TC message (see
       Section 10.1).  If the address, contained in message is not discarded, then continue;

   2.  Update the
      "originator address" field of Topology Set (see Section 10.2);

   3.  Purge old entries from the OLSRv2 message header specified
      in Topology Set (see Section 3.1;

   o 10.3);

   4.  Update the ASSN of Attached Networks Set (see Section 10.4;

   5.  Purge old entries from the node, originating Attached Networks Set (see
       Section 10.5);

   6.  Update the Neighborhood Address Association Set (see Section 13).

10.7  Processing Partially or Wholly Self-Contained Fragmented TC message,
      Messagess

   If a TC message contains a FRAGMENTATION message TLV which indicates
   that the fragment is recovered as a partially or wholly self-contained message,
   then the value following processing SHOULD be carried out immediately upon
   receipt of each received fragment (if not then it MUST be carried out
   for each fragment once all fragments have been received):

   1.  Verify freshness and validity of the Content Seq. no message TLV in the TC message;

   Upon receiving a TC message, a node SHOULD update its topology set as
   follows:

   1. message (see
       Section 10.1).  If the sender interface (NB: not originator) address of this message is not in discarded, then continue;
   2.  Update the symmetric 1-hop neighborhood of this node, Topology Set (see Section 10.2);

   3.  Update the message Neighborhood Address Association Set (see Section 13).

   4.  Update the Attached Networks Set (see Section 10.4;

   Once all fragments have been received, the following processing MUST
   be discarded; carried out once:

   1.  Purge old entries from the Topology Set (see Section 10.3);

   2.  otherwise, if  Purge old entries from the TC message does not contain Attached Networks Set (see
       Section 10.5);

11.  Populating the MPR Set

   Each node MUST select, from among its one-hop neighbors, a message-TLV subset of
       type Content Seq. no., the
   nodes as MPRs.  This subset MUST be selected such that a message SHOULD
   transmitted by the node, and retransmitted by all its MPR nodes, will
   be discarded;

   3.  otherwise, if there exist some tuple in received by all nodes 2 hops away.

   Each node selects its MPR Set individually, utilizing the topology set where:

       T_last_iface_addr == originator address information
   in the message AND

       T_seq > ASSN;

       then Link Set, 2-Hop Neighbor Set and Neighborhood Address
   Association Set. Initially these sets will be empty, as will be the TC message
   MPR Set. A node SHOULD be discarded.

   4.  The topology set recalculate its MPR Set when a relevant change
   is then updated in two steps:

       1.  any topology tuple where:

           T_last_iface_addr == originator address in made to the message AND

           T_seq < ASSN

           SHOULD be removed.

       2.  For Link Set, 2-Hop Neighbor Set or Neighborhood Address
   Association Set.

   More specifically, a node MUST calculate MPRs per interface, the
   union of the MPR Sets of each address, listed in interface make up the TC message:

           1.  if there exists MPR Set for the
   node.

   MPRs are used to flood control messages from a tuple in node into the topology set where:

               T_dest_iface_addr == advertised neighbor address, AND

               T_last_iface_addr == originator address;

               then network
   while reducing the tuple is updated as follows:

               T_time = current time + validity time.

               (Note number of retransmissions that necessarily: T_seq == ASSN).

           2.  Otherwise, will occur in a new topology tuple
   region.  Thus, the concept of MPR is created with:

               T_dest_iface_addr == advertised an optimization of a classical
   flooding mechanism.  While it is not essential that the MPR Set is
   minimal, it is essential that all strict 2-hop neighbors can be
   reached through the selected MPR nodes.  A node MUST select an MPR
   Set such that any strict 2-hop neighbor main address,
                  AND

               T_last_iface_addr == originator address in is covered by at least one
   MPR node.  A node MAY select additional MPRs beyond the message
                  AND

               T_seq == ASSN;

13.  MA Message Generation

   An minimum set.
   Keeping the MPR Set small ensures that the overhead of OLSRv2 MA message is composed as described in Section 3.2: kept
   at a set minimum.

   Appendix A contains an example heuristic for selecting MPRs.

12.  Populating Derived Sets

   The Relay Set and the Advertised Neighbor Set of message TLVs, describing general properties OLSRv2 are denoted
   derived sets, since updates to these sets are not directly a function
   of the message and exchanges, but rather are derived from updates to other
   sets, in particular the
   node emitting MPR Selector Set.

12.1  Populating the Relay Set

   The Relay Set contains the MA, and a set of address blocks (with associated
   TLV sets).  These address blocks MUST list all addresses of the node neighbor addresses, for which are participating in a
   node is supposed to relay broadcast traffic.  This set SHOULD at
   least contain the OLSRv2 network.  Other addresses of the node MPR Selector set (i.e. all
   addresses, associated with a MPR selector through the Neighborhood
   Address Association Set).  This set MAY also be included.

   An OLSRv2 MA message describes contain additional neighbor
   addresses.

12.2  Populating the Advertised Neighbor Set

   The Advertised Neighbor Set contains the set of neighbor addresses, associated
   to which a
   given node.  Nodes with a single address SHOULD NOT generate MA node advertises links through TC messages.  Nodes with multiple addresses, participating in the OLSRv2
   network  This set
   SHOULD generate MA messages.

   OLSRv2 MA messages are generated and transmitted per node, i.e. at least contain the
   same MA messages are generated and transmitted on all OLSRv2
   interfaces addresses of a node.

   OLSRv2 TC messages are generated and transmitted periodically, the MPR Selector Set (i.e.
   all addresses, associated with a
   default interval between two consecutive MA emissions by MPR selector through the same
   node of TC_INTERVAL.

14.  MA Message Processing

   Upon receiving a MA message
   Neighborhood Address Association Set).  This set MAY contain
   additional neighbor addresses.

   Each time an address is removed from the node Advertised Neighbor Set, the
   ASSN MUST be incremented.  When an address is added to the Advertised
   Neighbor Set, the ASSN MUST be incremented.

13.  Populating the Neighborhood Address Association Set

   All OLSRv2 messages containing a Local Interface Block (including
   HELLO and TC messages) SHOULD be used to update its the Neighborhood
   Address Association Set as follows:

   1.  All neighborhood address association tuples where

       *  I_neighbor_addr_list contains at least one address which  If there is a Neighborhood Address Association Tuple, any of
       whose addresses are in the Local Interface Block being processed,
       then discard that tuple.

   2.  A tuple is
          listed in added to the received MA message,

       SHOULD be removed, and a new neighborhood address association
       tuple SHOULD be created with: Neighborhood Address Association Set,
       where:

       *  I_neighbor_addr_list  NA_neighbor_addr_list = list of all addresses contained in from the
          received MA message; Local Interface
          Block;

       *  I_time  NA_time = current time + validity time.

15. NA_HOLD_TIME.

14.  Routing Table Calculation

   A node records a set of "routing tuples":

      (R_dest_iface_addr, R_next_iface_addr, R_dist, R_iface_addr)

   describing the next hop and distance of the path to each destination
   in the network for which a route is known.

   R_dest_iface_addr is the interface address of the destination node;

   R_next_iface_addr is the interface address of the "next hop" on the
      path towards R_dest_iface_addr;

   R_dist is the number of hops on the path to R_dest_iface_addr;

   R_iface_addr is the address of the local interface over which a
      packet MUST be sent to reach R_next_iface_addr.

   In a node, the set of routing tuples is denoted the "routing set".

   The routing set Routing Set is updated when a change (an entry appearing/
   disappearing) is detected in:

   o  the link set, Link Set,

   o  the neighbor address association set, Neighbor Address Association Set,

   o  the 2-hop neighbor set, Neighbor Set,

   o  the topology set, Topology Set,

   Updates to the routing set Routing Set does not generate or trigger any messages
   to be transmitted.  The state of the routing set Routing Set SHOULD, however, be
   reflected in the IP routing table by adding and removing entries from
   the routing table as appropriate.

   To construct the routing set Routing Set of node X, a shortest path algorithm is
   run on the directed graph containing the arcs X -> Y where Y is any
   symmetric neighbor of X (with Link Type equal to SYM), the arcs Y ->
   Z where Y is a neighbor node with willingness different of WILL_NEVER
   and there exists an entry in the 2-hop Neighbor set Set with Y as
   N_neighbor_iface_addr
   N2_neighbor_iface_addr and Z as N_2hop_iface_addr, N2_2hop_iface_addr, and the arcs U ->
   V, where there exists an entry in the topology set Topology Set with V as
   T_dest_iface_addr and U as T_last_iface_addr.  The graph is
   complemented with the arcs W0 -> W1 where W0 and W1 are two addresses
   of interfaces of a same neighbor (in a neighbor address association
   tuple).

   The following procedure is given as an example for (re-)calculating
   the routing set Routing Set (with a breadth-first algorithm):

   1.  All the tuples from the routing set Routing Set are removed.

   2.  The new routing tuples are added starting with the symmetric
       neighbors (h=1) as the destinations.  Thus, for each tuple in the
       link set
       Link Set where:

       *  L_STATUS           =           == SYMMETRIC (L_STATUS is calculated as
          indicated in Table 1)

       a new routing tuple is recorded in the routing set Routing Set with:

       *  R_dest_iface_addr  = L_neighbor_iface_addr, of the link tuple;

       *  R_next_iface_addr  = L_neighbor_iface_addr, of the link tuple;
       *  R_dist             = 1;

       *  R_iface_addr       = L_local_iface_addr of the link tuple.

   3.  for each neighbor address association tuple, for which two
       addresses A1 and A2 exist in I_neighbor_iface_addr_list where:

       *  there exists a routing tuple with:

          +  R_dest_iface_addr = == A1

       *  there is no routing tuple with:

          +  R_dest_iface_addr = == A2

       then a tuple in the routing set Routing Set is created with:

       *  R_dest_iface_addr = A2;

       *  R_next_iface_addr = R_next_iface_addr of the route tuple of
          A1;

       *  R_dist            = R_dist of the route tuple of A1 (e.g. 1);

       *  R_iface_addr      = R_iface_addr of the route tuple of A1.

   4.  for each symmetric strict 2-hop neighbor where the
       N_neighbor_iface_addr
       N2_neighbor_iface_addr has a willingness different from
       WILL_NEVER a tuple in the routing set Routing Set is created with:

       *  R_dest_iface_addr = N_2hop_iface_addr N2_2hop_iface_addr of the 2-hop neighbor;

       *  R_next_iface_addr = the R_next_iface_addr of the route tuple
          with:

          +  R_dest_iface_addr == N_neighbor_iface_addr N2_neighbor_iface_addr of the 2-hop
             tuple;

       *  R_dist            = 2;

       *  R_iface_addr      = the R_iface_addr of the route tuple with:

          +  R_dest_iface_addr == N_neighbor_iface_addr N2_neighbor_iface_addr of the 2-hop
             tuple;

   5.  The new route tuples for the destination nodes h+1 hops away are
       recorded in the routing table.  The following procedure MUST be
       executed for each value of h, starting with h=2 and incrementing
       by 1 for each iteration.  The execution will stop if no new tuple
       is recorded in an iteration.

       1.  For each topology tuple in the topology set, Topology Set, if its
           T_dest_iface_addr does not correspond to R_dest_iface_addr of
           any route tuple in the routing set Routing Set AND its T_last_iface_addr
           corresponds to R_dest_iface_addr of a route tuple whose
           R_dist is equal to h, then a new route tuple MUST be recorded
           in the routing set Routing Set (if it does not already exist) where:

           +  R_dest_iface_addr = T_dest_iface_addr;

           +  R_next_iface_addr = R_next_iface_addr of the route tuple
              where:

              -  R_dest_iface_addr == T_last_iface_addr

           +  R_dist           = h+1; and

           +  R_iface_addr     = R_iface_addr of the route tuple where:

              -  R_dest_iface_addr == T_last_iface_addr.

       2.  Several topology tuples may be used to select a next hop
           R_next_iface_addr for reaching the node R_dest_iface_addr.
           When h=1, h==1, ties should be broken such that nodes with highest
           willingness and MPR selectors are preferred as next hop.

16.

15.  Proposed Values for Constants

   This section list the values for the constants used in the
   description of the protocol.

16.1  Message Types

   o  HELLOv2 = 5

   o  TCv2 = 6

16.2

15.1  Message Intervals

   o  HELLO_INTERVAL        = 2 seconds

   o  REFRESH_INTERVAL      = 2 seconds

   o  TC_INTERVAL           = 5 seconds

16.3

15.2  Holding Times

   o  NEIGHB_HOLD_TIME  L_HOLD_TIME           = 3 x HELLO_INTERVAL

   o  N2_HOLD_TIME          = 3 x REFRESH_INTERVAL

   o  TOP_HOLD_TIME  NA_HOLD_TIME          = 3 x TC_INTERVAL

   o  T_HOLD_TIME           = 3 x TC_INTERVAL

   o  RX_HOLD_TIME          = 30 seconds

   o  FW_HOLD_TIME          = 30 seconds

   o  P_HOLD_TIME           = 3 x TC_INTERVAL 30 seconds

   o  DUP_HOLD_TIME  FG_HOLD_TIME          = 30 seconds

16.4

15.3  Willingness

   o  WILL_NEVER            = 0

   o  WILL_LOW              = 1

   o  WILL_DEFAULT          = 3

   o  WILL_HIGH             = 6

   o  WILL_ALWAYS           = 7

17.

15.4  Time

   o  C                 = 0.0625 seconds (1/16 second)

16.  Representing Time

   In HELLO messages,

   OLSRv2 specifies several TLVs, where time, in seconds, is to be
   represented via an 8 bit field.

   Of these 8 bits, the 4 highest four bits of the value of the TLV with
   Type="Htime" (see Appendix D.2.1) represent the mantissa (a) and
   the four lowest bits represent the exponent (b), yielding that the HELLO interval
   is expressed thus: C*(1+a/16)*2^b [in seconds]

   Similarily, the validity time is represented by its mantissa (four
   highest bits of Vtime field) and by its exponent (four lowest bits of
   Vtime field).  In other words: that:

   o  validity  time = C*(1+a/16)* 2^b  [in seconds]

   where a is the integer represented by the four highest bits of Vtime the
   time field and b the integer represented by the four lowest bits of Vtime
   the time field.  The proposed value of the scaling factor C is
   specified in Section 16

18. 15.  All nodes in the network MUST use the same
   value of C.

17.  IANA Considerations

   OLSRv2 defines a TLV "Type" field for message TLVs and address block
   TLVs respectively.  Two new registries MUST

17.1  Multicast Addresses

   A well-known multicast address, All-OLSRv2-Multicast, must be created for values
   registered and defined for both IPv6 and IPv4.  The addressing scope
   is link-local, i.e. this TLV type field, with initial assignments as specified address is similar to the all nodes/routers
   multicast address of IPv6 in Table 6
   and that it targets all OLSRv2 capable nodes
   adjacent to the originator of an IP datagram.

17.2  Message Types

   OLSRv2 defines two message types, which must be allocated from the
   "Assigned Message Types" repository of [4]

   +--------------------+--------+-------------------------------------+
   |      Mnemonic      |  Value | Description                         |
   +--------------------+--------+-------------------------------------+
   |       HELLOv2      |   TBD  | Local Signaling                     |
   |                    |        |                                     |
   |        TCv2        |   TBD  | Global Signaling                    |
   +--------------------+--------+-------------------------------------+

                                  Table 7

   Assigned message

17.3  TLV Types

   OLSRv2 defines three Message TLV types, which must be allocated from
   the "Assigned message TLV Types" repository of [4]

   +--------------------+--------+-------------------------------------+
   |      Mnemonic      |  Value | Description                         |
   +--------------------+--------+-------------------------------------+
   |    Fragmentation    VALIDITY_TIME   |   TBD  | The time (in seconds) from receipt  |
   |                    |    0        | Specifies behavior in case of the message during which the     |
   |                    |        | information contained in a message  |
   |                    |        | is to be valid                      |
   |                    |        | content fragmentation                                     |
   |    INTERVAL_TIME   |   TBD  | The time (in seconds) between two   |
   |  Content Sequence                    |    1        | A sequence number, associated with successive transmissions of         |
   |       Number                    |        | the content messages of the message a given type            |
   |                    |        |                                     |
   |     Willingness     WILLINGNESS    |    2   TBD  | Specifies a nodes node's willingness [0-7]      |
   |                    |        | [0-7] to act as a relay and to parttake      |
   |                    |        | partake in network formation        |
   +--------------------+--------+-------------------------------------+
                                  Table 6

   Assigned 8

   OLSRv2 defines three Address Block TLV types, which must be allocated
   from the "Assigned address block TLV Types Types" repository of [4]

   +--------------------+--------+-------------------------------------+
   |      Mnemonic      |  Value | Description                         |
   +--------------------+--------+-------------------------------------+
   |     Link Status      OTHER_IF      |    0   TBD  | Specifies that an address is        |
   |                    |        | associated to an interface other    |
   |                    |        | than the one where the message is   |
   |                    |        | transmitted, and may specify its    |
   |                    |        | status (verified bidirectional or   |
   |                    |        | lost)                               |
   |                    |        |                                     |
   |     LINK_STATUS    |   TBD  | Specifies a given link's status     |
   |                    |        | (asymmetric, verified               |
   |                    |        | bidirectional, lost)                |
   |                    |        |                                     |
   |         MPR        |    1   TBD  | Specifies that a given address is   |
   |                    |        | selected as MPR                     |
   +--------------------+--------+-------------------------------------+

                                  Table 7

   OLSRv2 message types MUST be assigned from the 9

18.  References

   [1]  Clausen, T., "The Optimized Link State Routing Protocol",
        RFC 3626, October 2003.

   [2]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", RFC 2119, BCP 14, March 1997.

   [3]  Atkins, D., Stallings, W., and P. Zimmermann, "PGP Message
        Exchange Formats", RFC 1991, August 1996.

   [4]  Clausen, T., Dean, J., and C. Dearlove, "Generalized MANET
        Packet/Message Format", Work In
        Progress draft-ietf-manet-packetbb-00.txt, February 2006.

   [5]  ETSI, "ETSI STC-RES10 Committee.  Radio equipment and systems:
        HIPERLAN type 1, functional specifications ETS 300-652",
        June 1996.

   [6]  Jacquet, P., Minet, P., Muhlethaler, P., and N. Rivierre,
        "Increasing reliability in cable free radio LANs: Low level
        forwarding in HIPERLAN.", 1996.

   [7]  Qayuum, A., Viennot, L., and A. Laouiti, "Multipoint relaying:
        An efficient technique for flooding in mobile wireless
        networks.", 2001.

Authors' Addresses

   Thomas Heide Clausen
   LIX, Ecole Polytechnique, France

   Phone: +33 6 6058 9349
   Email: T.Clausen@computer.org
   URI:   http://www.lix.polytechnique.fr/Labo/Thomas.Clausen/

   Christopher M. Dearlove
   BAE Systems Advanced Technology Centre

   Phone: +44 1245 242194
   Email: chris.dearlove@baesystems.com

   The OLSRv2 repository
   (HELLOv2, TCv2) Design Team
   MANET Working Group

Appendix A.  Example Heuristic for Calculating MPRs

   The following specifies a proposed heuristic for selection of MPRs.

   In graph theory terms, MPR computation is a "set cover" problem,
   which is a difficult optimization problem, but for which an easy and
   efficient heuristics exist: the so-called "Greedy Heuristic", a
   variant of which is described here.  In simple terms, MPR computation
   constructs an MPR Set that enables a node to reach any 2-hop
   interfaces through relaying by one relaying through an MPR node.

   There are several peripheral issues that the algorithm need to
   address.  The first one is that some nodes have some willingness
   WILL_NEVER.  The second one is that some nodes may have several
   interfaces.

   The algorithm hence need to be precised in the following way:

   o  All neighbor nodes with willingness equal to WILL_NEVER MUST
      ignored in the following algorithm: they are not considered as
      neighbors (hence not used as MPR), MPRs), nor as 2-hop neighbors (hence
      no attempt to cover them is made).

   o  Because link sensing is performed by interface, the local network
      topology, is best described in terms of links: hence the algorithm
      is considering neighbor interfaces, and 2-hop neighbor interfaces
      (and their addresses).  Additionally, asymmetric links are
      ignored.  This is reflected in the definitions below.

   o  MPR computation is performed on each interface of the node: on
      each interface I, the node MUST select some neighbor interface, interfaces,
      so that all 2-hop interfaces are reached.

   >From

   From now on, MPR calculation will be described for one interface I on
   the node, and the following terminology will be used in describing
   the heuristics:

   neighbor interface (of I) - An interface of a neighbor to which there
      exist a symmetrical link on interface I.

   N  - the set of such neighbor interfaces

   2-hop neighbor interface (of I) An interface of a symmetric strict
      2-hop neighbor and which can be reached from a neighbor interface
      for I.

   N2 - the set of such 2-hop neighbor interfaces

   D(y): - the degree of a 1-hop neighbor interface y (where y is a
      member of N), is defined as the number of symmetric neighbor
      interfaces of node y which are in N2

   MPR set Set - the set of the neighbor interfaces selected as MPR. MPRs.

   The proposed heuristic selects iteratively some interfaces from N as
   MPR
   MPRs in order to cover 2-hop neighbor interfaces from N2, as follows:

   1.  Start with an MPR set Set made of all members of N with N_willingness
       equal to WILL_ALWAYS

   2.  Calculate D(y), where y is a member of N, for all interfaces in
       N.

   3.  Add to the MPR set Set those interfaces in N, which are the *only*
       nodes to provide reachability to an interface in N2.  For
       example, if interface B in N2 can be reached only through a
       symmetric link to interface A in N, then add interface B to the
       MPR set. Set. Remove the interfaces from N2 which are now covered by a
       interface in the MPR set. Set.

   4.  While there exist interfaces in N2 which are not covered by at
       least one interface in the MPR set: Set:

       1.  For each interface in N, calculate the reachability, i.e.,
           the number of interfaces in N2 which are not yet covered by
           at least one node in the MPR set, Set, and which are reachable
           through this neighbor interface;

       2.  Select as a an MPR the interface with highest N_willingness
           among the interfaces in N with non-zero reachability.  In
           case of multiple choice select the interface which provides
           reachability to the maximum number of interfaces in N2.  In
           case of multiple interfaces providing the same amount of
           reachability, select the interface as MPR whose D(y) is
           greater.  Remove the interfaces from N2 which are now covered
           by an interface in the MPR set. Set.

   Other algorithms, as well as improvements over this algorithm, are
   possible.  For example:

   o  Some 2-hop neighbors may have several interfaces.  The described
      algorithm attempts to reach every such interface of the nodes.
      However, whenever information that several 2-hop interfaces are,
      in fact, interfaces of the same 2-hop neighbor, is available, it
      can be used: only one of the interfaces of the 2-hop neighbor
      needs to be covered.  This information is provided in the
      Neighborhood Address Association Set.

   o  Assume that in a multiple-interface multiple interface scenario there exists more
      than one link between nodes 'a' and 'b'.  If node 'a' has selected
      node 'b' as MPR for one of its interfaces, then node 'b' can be
      selected as MPR with minimal performance loss by any other
      interfaces on node 'a'.

   o  In a multiple interface scenario MPRs are selected for each
      interface of the selecting node, providing full coverage of all
      2-hop nodes accessible through that interface.  The overall MPR
      Set is then the union of these sets.  These sets do not however
      have to be selected independently, if a node is selected as an MPR
      for one interface it may be automatically added to the MPR
      selection for other interfaces.

Appendix B.  Example Algorithms for Generating Control Traffic

   The proposed generation of the control messages proceeds in four
   steps.  HELLO messages, like messages and TC messages consist both essentially in consist of a
   list of advertised addresses of neighbors (some part of the
   topology).

   Hence, a first step is to collect the set of relevant of addresses which
   are to be advertised.  Because there are a number of TLVs which can
   be associated to with each address (including mandatory ones), this
   steps step
   results into in a list of addresses, each associated with a certain number
   of TLVs.

   Thus, the

   The second step is then to regroup the addresses which share exactly
   the same TLVs (same Type and same Value), into an address block which
   will be associated with a list of TLVs.

   The third step is to pack the message header and message TLVs into a
   string
   sequence of octets.

   The fourth step consists in of packing every address block obtained in
   the second step: step by finding the longest common prefix of the addresses
   in the address block (the head), then, packing the list of the tail tails
   of the addresses into a string sequence of octets, followed by the TLVs of
   the address block.

   This generation method can be used for TC generation and HELLO
   generation: in each case, all what need to be specified is the
   message headers, message TLVs, and the list of each address with its
   associated TLVs.

   The message headers are identical to RFC 3626, and should be filled
   in the same way.  The orginator address block Local Interface Block MUST include all of the participating
   interface addresses of the node (including the one of chosen for as the
   node's originator address and included in the message header) header).

Appendix B.1  Example Algorithm for Generating HELLO messages

   This section proposes an algorithm for generating HELLOs HELLO messages.
   Periodically, on every each interface I, the node generates a HELLO message different on each
   specific to that interface, as follows:

   1.  First, the list of the links of the interface is collected.  It
       is the list of the link tuples Link Tuples where:

       *  L_local_iface_addr == address of the interface

       Each corresponding address L_neighbor_iface_addr is then
       advertized
       advertised with the following TLVs:

       *  Type="Link Status",  Type="LINK-STATUS", Value=L_STATUS, the status of the link
          (see Section 5.1.1) 5.1.1);

       *  Type="Interface" Value="TransmittingInterface"  Type="OTHER_IF", if and only if as specified in Section 7);

       *  Type="MPR Selection", Value="True",  Type="MPR", if and only of the address L_neighbor_iface_addr
          is one an interface address in the MPR set. Set.

   2.  Second, if the node has several interfaces, more than one interface, for each address
       which was not previously advertised, advertised and for which there exists a
       link tuple
       Link Tuple on another interface where:

       *  L_local_iface_addr is different from address of the interface
          I
          I; AND

       *  L_STATUS == SYMMETRIC

       the corresponding address L_neighbor_iface_addr is advertized advertised
       with the following TLVs: TLV:

       *  Type="Link Status", Value=L_STATUS, status of  Type="OTHER_IF", Value=SYMMETRIC.

   3.  Third, if the link (see node has more than one interface, for each
       interface address which is to be reported as LOST as specified in
       Section 5.1.1) 7) the interface address is advertised with the following
       TLV:

       *  Type="Interface" Value="Other"

   3.  Type="OTHER_IF", Value=LOST.

   4.  Then a HELLO message is generated using the previous method, with
       the proper specified headers and TLVs:

       *  a message TLV with Type="Htime" Type="VALIDITY_TIME" and Value=encoding of the
          HELLO generation interval, is
          L_HOLD_TIME, SHALL be added

       *  a message TLV with Type="Willingness" Type="INTERVAL_TIME" and Value=the
          willingness of the node.  If a node has a willingness Value=encoding of
          WILL_DEFAULT, a node
          HELLO_INTERVAL, SHOULD NOT include be added

       *  a message TLV with
          type="Willingness";

       * Type="WILLINGNESS" and Value=the
          willingness of the message header including Vtime, which MUST node.  This SHOULD NOT be set to a
          value higher than included if this generation interval, typically 3 times
          the generation interval, to allow for message losses.
          value is WILL_DEFAULT, it SHALL be included otherwise.

Appendix B.2  Example Algorithm for Generating TC messages

   Periodically, the node generates TC messages, broadcast on all the
   interfaces of the node, as follows:

   1.  Each A_iface_addr in the Advertised Neighbor set, will Set, SHALL be
       included in the TC message.

   2.  The TC message is generated using the previous method with the proper headers, and including (except
       where the Advertised Neighbor Set is empty and the mandatory TC message is
       not specifically reporting this, see Section 9) including the
       message TLV,
       Type="ASSN" Type="CONTENT_SEQUENCE_NUMBER", Value=the current value of the
       ASSN of the node.

Appendix C.  Protocol and Port Number

   Packets in OLSRv2 are communicated using UDP.  Port 698 has been
   assigned by IANA for exclusive usage by the OLSR (v1 and v2)
   protocol.

Appendix D.  OLSRv2  Packet and Message Layout

   This section specifies the translation from the abstract descriptions
   of OLSRv2 control signals, employed in the protocol specification,
   and the bit-layout in the control-frames actually exchanged between
   the nodes.

Appendix D.1  General OLSR Packet Format

   The basic layout of any packet in OLSRv2 is as follows (omitting IP
   and UDP headers):

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Packet Length         |    Packet Sequence Number     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Message Type |     Vtime     |         Message Size          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Originator Address                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Time To Live |   Hop Count   |    Message Sequence Number    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Number of Msg TLVs      |    Number of Address Blocks   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Msg TLV   |   Msg TLV   |                                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+                                   +
      |                                                               |
      :                             ...                               :
      |                                                               |
      +                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   |   Msg TLV   |           Padding           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |          Originator Address Block: Addr Block 1               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                       Addr Block 2                            |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      :                                                               :
      |                                                               |
               (etc.)

   The generic packet format defined in RFC3626 encapsulates messages,
   similarly to OLSRv1.  OLSRv2 messages are defined as new message
   types.  These messages contain packets employed in the same header as OLSRv1 messages,
   with address blocks protocol specification, and TLVs, as described below. the bit-layout
   packets actually exchanged between the nodes.

Appendix D.1.1  Message TLVs D.1  OLSRv2 Packet Format

   The TLV format (Type-Length-Value) basic layout of an OLSRv2 packet is used to introduce information as described in a flexible way.  A message TLV associates some information
   (depending on [4].  However
   the type) following points should be noted.

   OLSRv2 uses only packets with a packet header.  Thus all OLSRv2
   packets have the node/address that originated the
   message. following layout.

      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 0 0 0 0 0 0 0|   Reserved    |     Type    Packet Sequence Number     |  Length

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |

     |                            Message                            |

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                                 +

     :                                    Value                              ...                              :

     |                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Appendix D.1.2  Address Block

   An address block is a way of representing addresses, as well as
   information associated

     |                                                               |

     |                            Message                            |

     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   All reserved bits are also unset (zero).

   OLSRv2 uses only packets with addresses, in a compact and flexible way.
   The proposed format of an address block is as follows: complete message header.  Thus all
   OLSRv2 messages have the following layout.

      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

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |  # addresses  |  Addr. length | Head length  Message Type |      #TLV Resv  |U|N|0|0|         Message Size          |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                                                               |
      :                             Head                              :
      |                      Originator Address                       |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |       Tail      |       Tail      |                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                           +
      |                                                               |
      :                              ...                              :
      |                                                               |
      +                                             +-+-+-+-+-+-+-+-+-+  Time To Live |   Hop Count   |       Tail    Message Sequence Number    |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Addr. Block TLV | Addr. Block TLV |                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                           +
      |                                                               |
      :                             ...                               :                                                               |

     |                    Message Body +                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Padding                     | Addr. Block TLV

     |           Padding                                                               |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   # addresses - The number of addresses in the address block

   Addr. length - The length, in bits, of an individual address.  For
      IPv4 addresses, this field MUST be set to 32 For IPv6 addresses,
      this field MUST be set to 128

   Prefix length - The length of

   In standard OLSRv2 messages (HELLO and TC) the common prefix of U and N bits are also
   unset(zero).  In all OLSRv2 messages the addresses
      in the address block. 0 <= Prefix length < Addr. length A prefix
      length of 0 indicates, that the prefix field (following) is
      absent.

   #TLV - reserved bits marked Resv
   above are also unset (zero).

   The number layouts of TLV's in the message body, address block.

   Prefix The longest sequence of bits block, TLV block and TLV are
   as in [4], allowing all options.  Standard (HELLO and TC) messages
   contain a first address block which is common among contains local interface
   addresses, all other address blocks contain information specific to
   the
      addresses, included in message type.  Except by being first, the local interface address block.  This field
   block is not distinguished in any way.

   An example HELLO message, using IPv4 (four octet) addresses is as
   follows.  The overall message length is 56 octets (it does not need
   padding).  The message has a TTL of 1 and a
      fixed length, hop count of 0, as specified in the field "prefix length"

   Host sent
   by its originator.

   The host fields specifies the unique part message has a message TLV block with content length 12 octets
   containing three message TLVs.  These TLVs represent message validity
   time, message interval time and willingness.  Each uses a TLV with
   semantics value 4, indicating no start and stop indexes are included,
   and each has a value length of all the addresses,
      included in the 1 octet.

   The first address block.  Indeed, letting + denote the
      concatenation operator, the expression prefix+host will yield block contains a
      unique address. single local interface address,
   with head length 4; thus although 1 tail is indicated, no tail octets
   are included.  This field os address block has no TLVs (TLV block content
   length 0 octets).

   The second, and last, address block reports 4 neighbour interface
   addresses, with address head length 3 octets.  The following TLV
   block (content length 11 octets) includes two TLVs.

   The first of these TLVs reports the link status of all four
   neighbours in a fixed length = "Addr. length"
      - "Prefix length"
   TLV A TLV carries single multivalue TLV, the information, associated to one, or a set of, first two addresses in are
   HEARD, the classic type-length-value format.  This format is
      explicitly given below.

   Padding A variable-length field last two addresses are SYMMETRIC.  The TLV semantics value
   of all-zero's, 12 indicates, in addition to achieve 32-bit
      alignment of the packet.

   Note that this is a multivalue TLV, that
   no alignments start index and stop index are attempted -- included, since values for all alignments happen in the
   address block listed above.

Appendix D.1.3  Address Block
   addresses are included.  The TLV

   Again, the value length of 4 octets indicates
   one octet per value per address.

   The second of these TLV format (Type-Length-Value) indicates that the last address (start index
   3, stop index 3) is used to introduce
   information in a flexible way inside Address Blocks.  An Address
   Block an MPR.  This TLV associates some information with some address(s) listed in
   the has no value, or value length,
   fields, as indicated by its semantics octet being equal to 1.

      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

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |     HELLO     |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                      Originator Address Block.                       |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0|    Message Sequence Number    |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| VALIDITY-TIME |0 0 0 0 0 1 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|     Value     | INTERVAL-TIME |0 0 0 0 0 1 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|     Value     |  WILLINGNESS  |0 0 0 0 0 1                   2                   3 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|     Value     |0 0 0 0 0 1 2 3 4 5 6 7 8 9 0 0|     Head      |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                  Head (cont)                  |0 0 0 0 0 0 0 1|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 2 3 4 5 6 7 8 9 1|     Head      |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |          Head (cont)          |0 0 0 0 0 1 2 3 4 5 6 7 8 9 0 0|     Tail      |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |     Tail      |     Tail      |     Tail      |0 0 0 0 0 0 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 1 0 1 1|  LINK-STATUS  |0 0 0 0 1 1 0 0|0 0 0 0 0 1 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |     Type     HEARD     |  Index Start     HEARD     |   Index Stop   SYMMETRIC   |     Length   SYMMETRIC   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |    Value        ...
      +-+-+-+-+-+-+-+-+

   Type This field specifies the type of the TLV.

   Addr Start This field specifies to which address      MPR      |0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 1|0 0 0 0 0 0 1 1|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   An example TC message, using IPv4 (four octet) addresses, is as
   follows.  The overall message length is 67 octets, the final octet is
   padding.

   The message has a message TLV applies: the
      addresses listed between Index Start and Index Stop.

   Addr Stop This field specifies block with content length 13 octets
   containing three TLVs.  The first TLV is a content sequence number
   TLV used to which address carry the TLV applies: 2 octet ANSN.  The semantics value is 4
   indicating that no index fields are included.  The other two TLVs are
   validity and interval times as for the HELLO message above.

   The message has three address blocks.  The first address block
   contains 3 local interface addresses listed between Index Start and Index Stop.

   Length This field specifies the (with common head length of the data contained in
      "Value"

   Value This field is 2
   octets) and has a field of the TLV block with content length specified in Length, which
      contains data -- information, which is to be interpreted according
      to the specification by 4 octets containing a
   single TLV with semantics value 1, indicating that the "Type" TLV has no
   value field, and in the context given
      by or length thereof.  This TLV indicates that the "addr#" second
   and "Offset" fields.

Appendix D.2  Layout of OLSRv2 Specified Messages

   The message format specified for OLSRv2 allows a great deal of
   flexibility in how control messages are organized.  For example,
   while it is possible to represent a sequence third of these addresses as an
   address-block, it is also possible -- although possibly less optimal
   -- (indexes 1 to represent 2) are for other
   interfaces than the same sequence as individual addresses in an
   OLSRv2 control message.

   This section will, therefore, give an example of how OLSRv2 HELLO and
   TC messages typically can be be generated.  It is, however, important
   to keep in mind that this section presents one possible instance of
   HELLO and on which this TC messages.

Appendix D.2.1  Layout of HELLO Messages

   HELLO TLVs

 +-------------+---------------+------------+-------------------------+
 | Type        | Scope         | Importance | Description             |
 +-------------+---------------+------------+-------------------------+
 | Status      | Address Block | MUST       | SYM, ASYM, LOST         |
 |             |               |            |                         |
 | MPR         | Address Block | MUST       | Nodes selected as MPR   |
 |             |               |            |                         |
 | Willingness | Message       | MAY        | Willingness information |
 |             |               |            |                         |
 | Htime       | Message       | MUST       | Htime information       |
 +-------------+---------------+------------+-------------------------+

                                  Table 8

Appendix D.2.2  Layout message is transmitted.

   The other two address blocks contain neighbour interface addresses,
   with head lengths 2 and 4 respectively.  The first of TC messages

   TC TLVs

  +------+-------+------------+-------------------------------------+
  | Type | Scope | Importance | Description                         |
  +------+-------+------------+-------------------------------------+
  | ASSN | Msg   | MUST       | Advertised Neighbor Sequence Number |
  +------+-------+------------+-------------------------------------+

                                  Table 9 these, with 3
   addresses, has an empty TLV block (content length 0 octets).  The
   second, which contains 1 address, has a TLV block (content length 4
   octets) with a single TLV (semantics value 4 indicating no indexes
   needed) indicating that this is a network address with the given
   prefix length (itself with length 1 octet).

      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

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |      TC Msg  Type |     Vtime     |         Message Size          |       |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Originator Address                       |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Time To to Live  |   Hop Count   |    Message Sequence Number    |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1| CONT_SEQ_NUM  |0 0 0 0 0 1 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 1 0|         Value (ASSN)          |    Number of Msg TLVs   (1)   |  Number of Address Blocks (1) VALIDITY_TIME |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1|     Value     |                   ANSN (Message TLV) INTERVAL_TIME |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |# addresses(17)|Addr lgth (32) |Prefx lgth (28)|    #TLV  (2)

     |0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1|     Value     |0 0 0 0 0 0 1 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |             Head              |0 0 0 0 0 0 1 1|     Tail      |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                        IP Prefix  Tail (cont)  |             Tail              |     Tail      |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Host1  Tail (cont)  |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|   OTHER_IF    |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Host2             Head              |0 0 0 0 0 0 1 1|     Tail      | Host3

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Host4  Tail (cont)  | Host5             Tail              | Host6     Tail      | Host7

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Host8  Tail (cont)  |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|0 0 0 0 0 1 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     | Host9                             Head                              |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| PREFIX-LENGTH | Host10| Host11| Host12| Host13| Host14| Host15| Host16| Host17|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    Same Node (Addr. Block TLV)                |

     |0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 1|Value (Length) |0 0 0 0 0 0 0 0|

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Appendix E.  Node Configuration

   OLSRv2 does not make any assumption about node addresses, other than
   that each node is assumed to have at least one a unique and routable
   IP address. address for each interface that it has which participates in the
   MANET.

   When applicable, a recommended way of connecting an OLSR OLSRv2 network to
   an existing IP routing domain is to assign an IP prefix (under the
   authority of the nodes/gateways connecting the MANET with the routing
   domain) exclusively to the OLSR OLSRv2 area, and to configure the gateways
   statically to advertise routes to that IP sequence to nodes in the
   existing routing domain.

Appendix E.1  IPv6 Specific Considerations

   In the case of IPv6, a node's routable IP address can either be a
   global address, or a manet-local address (as described in
   draft-wakikawa-manet-ipv6).  Typically an OLSRv2 may have several
   addresses, for example: a link-local address and a routable address.
   However the link-local address is only valid within the 1-hop
   neighborhood.  It may be used to resolve neighbor state with the
   Neighbor Discovery Protocol, but routes to link-local addresses MUST
   NOT be advertized and MUST NOT be inserted in routing tables.  Only
   routable addresses are stored in routing tables, and a routable
   address MUST be used for the originator address in HELLO messages and
   in TC messages.

   OLSRv2 uses a specific flooding address (ff02::3) called the All-
   OLSRv2-Multicast address.  This address is similar to all nodes/
   routers multicast address in IPv6 specification  (i.e. ff02::1 or
   ff02::2).  The difference is that All-OLSRv2-Multicast specifies that
   intended receivers are OLSRv2 nodes.  Since the All-OLSRv2-Multicast
   address is a link-local address, the message sent to the multicast
   address can not reach further than 1 hop.  Each OLSRv2 node MUST
   process flooding packets and possibly re-flood the packets to the
   same destination (ff02::3), if they are designated forwarders.  Note
   that although ff02::3 is a link-local address, each flooded message
   MUST be transmitted with a routable address as originator address. to nodes in the
   existing routing domain.

Appendix F.  Security Considerations

   Currently, OLSR OLSRv2 does not specify any special security measures.  As
   a proactive routing protocol, OLSR OLSRv2 makes a target for various
   attacks.  The various possible vulnerabilities are discussed in this
   section.

Appendix F.1  Confidentiality

   Being a proactive protocol, OLSR OLSRv2 periodically diffuses topological
   information.  Hence, if used in an unprotected wireless network, the
   network topology is revealed to anyone who listens to OLSR OLSRv2 control
   messages.

   In situations where the confidentiality of the network topology is of
   importance, regular cryptographic techniques techniques, such as exchange of OLSR
   OLSRv2 control traffic messages encrypted by PGP [9] [3] or encrypted by
   some shared secret key key, can be applied to ensure that control traffic
   can be read and interpreted by only those authorized to do so.

Appendix F.2  Integrity

   In OLSR, OLSRv2, each node is injecting topological information into the
   network through transmitting HELLO messages and, for some nodes, TC
   messages.  If some nodes for some reason, malicious or malfunction,
   inject invalid control traffic, network integrity may be compromised.
   Therefore, message authentication is recommended.

   Different such situations may occur, for instance:

   1.  a node generates TC messages, advertising links to non-neighbor
       nodes;

   2.  a node generates TC messages, pretending to be another node;

   3.  a node generates HELLO messages, advertising non-neighbor nodes;

   4.  a node generates HELLO messages, pretending to be another node;

   5.  a node forwards altered control messages;

   6.  a node does not broadcast forward control messages;

   7.  a node does not select multipoint relays correctly;

   8.  a node forwards broadcast control messages unaltered, but does
       not forward unicast data traffic;
   9.  a node "replays" previously recorded control traffic from another
       node.

   Authentication of the originator node for control messages (for
   situation
   situations 2, 4 and 5) and on the individual links announced in the
   control messages (for situation situations 1 and 3) may be used as a
   countermeasure.  However to prevent nodes from repeating old (and
   correctly authenticated) information (situation 9) temporal
   information is required, allowing a node to positively identify such
   delayed messages.

   In general, digital signatures and other required security
   information may be transmitted as a separate OLSRv2 message type,
   thereby allowing that "secured" and "unsecured" nodes can coexist in
   the same network, if desired, or signatures and security information
   may be transmitted within the OLSRv2 HELLO and TC messages, using the
   TLV mechanism.

   Specifically, the authenticity of entire OLSRv2 control messages can
   be established through employing IPsec authentication headers,
   whereas authenticity of individual links (situation (situations 1 and 3) require
   additional security information to be distributed.

   An important consideration is, that all control messages in OLSR OLSRv2
   are transmitted either to all nodes in the neighborhood (HELLO
   messages) or broadcast to all nodes in the network (e.g., TC (TC messages).

   For example, a control message in OLSRv2 is always a point-to-
   multipoint transmission.  It is therefore important that the
   authentication mechanism employed permits that any receiving node can
   validate the authenticity of a message.  As an analogy, given a block
   of text, signed by a PGP private key, then anyone with the
   corresponding public key can verify the authenticity of the text.

Appendix F.3  Interaction with External Routing Domains

   OLSRv2 does, through the use of TC messages, provide a basic
   mechanism for injecting external routing information to the OLSRv2
   domain.  Section XXX  Appendix E also specifies that routing information can be
   extracted from the topology table or the routing table of OLSR OLSRv2 and,
   potentially, injected into an external domain if the routing protocol
   governing that domain permits.

   Other than as described in the section XXX, Appendix E, when operating nodes,
   connecting OLSRv2 to an external routing domain, care MUST be taken
   not to allow potentially insecure and un-trustworthy untrustworthy information to be
   injected from the OLSRv2 domain to external routing domains.  Care
   MUST be taken to validate the correctness of information prior to it
   being injected as to avoid polluting routing tables with invalid
   information.

   A recommended way of extending connectivity from an existing routing
   domain to an OLSRv2 routed MANET is to assign an IP prefix (under the
   authority of the nodes/gateways connecting the MANET with the exiting
   routing domain) exclusively to the OLSRv2 MANET area, and to
   configure the gateways statically to advertise routes to that IP
   sequence to nodes in the existing routing domain.

Appendix F.4  Node Identity

   OLSR

   OLSRv2 does not make any assumption about node addresses, other than
   that each node is assumed to have at least one a unique and routable
   IP address. address for each interface that it has which participates in the
   MANET.

Appendix G.  Flow and Congestion Control

   TBD

Appendix H.  Sequence Numbers

   Sequence numbers are used in OLSR with the purpose of discarding
   "old" information, i.e., messages received out of order.  However
   with a limited number of bits for representing sequence numbers,
   wrap-around (that the sequence number is incremented from the maximum
   possible value to zero) will occur.  To prevent this from interfering
   with the operation of OLSRv2, the following MUST be observed.

   The term MAXVALUE designates in the following the largest possible
   value for a sequence number.

   The sequence number S1 is said to be "greater than" the sequence
   number S2 if:

   o  S1 > S2 AND S1 - S2 <= MAXVALUE/2 OR

   o  S2 > S1 AND S2 - S1 > MAXVALUE/2

   Thus when comparing two messages, it is possible - even in the
   presence of wrap-around - to determine which message contains the
   most recent information.

Appendix I.  References

   o  [1]   P. Jacquet, P. Minet, P. Muhlethaler, N. Rivierre.
      Increasing reliability in cable free radio LANs: Low level
      forwarding in HIPERLAN.  Wireless Personal Communications, 1996.

   o  [2]   A. Qayyum, L. Viennot, A. Laouiti.  Multipoint relaying: An
      efficient technique for flooding in mobile wireless networks. 35th
      Annual Hawaii International Conference on System Sciences
      (HICSS'2001).

   o  [3]   ETSI STC-RES10 Committee.  Radio equipment and systems:
      HIPERLAN type 1, functional specifications ETS 300-652, ETSI, June
      1996.

   o  [4]  P. Jacquet and L. Viennot, Overhead in Mobile Ad-hoc Network
      Protocols, INRIA research report RR-3965, 2000.

   o  [5] Bradner, S., "Key words for use in RFCs to Indicate
      Requirement Levels", BCP 14, RFC 2119, March 1997.

   o  [6]   T. Clausen, G. Hansen, L. Christensen and G. Behrmann.  The
      Optimized Link State Routing Protocol, Evaluation through
      Experiments and Simulation.  IEEE Symposium on "Wireless Personal
      Mobile Communications", September 2001.

   o  [7]   T. Clausen, P. Jacquet, A. Laouiti, P. Muhlethaler, A.
      Qayyum and L. Viennot.  Optimized Link State Routing Protocol.
      IEEE INMIC Pakistan 2001. [8]   Narten, T. and H. Alvestrand,
      "Guidelines for Writing an IANA Considerations Section in RFCs",
      BCP 26, RFC 2434, October 1998.

   o  [9]   Atkins, D., Stallings, W. and P. Zimmermann, "PGP Message
      Exchange Formats", RFC 1991, August 1996.

   o  [10]  P. Jacquet, A. Laouiti, P. Minet, L. Viennot, "Performance
      analysis of OLSR multipoint relay flooding in two ad hoc wireless
      network models", INRIA research report RR-4260, 2001.

   o  [11] T. Clausen (ed), P. Jacquet (ed), "The Optimized Link State
      Routing Protocol", RFC3626, October 2003

Appendix J.  Contributors

   This specification is the result of the joint efforts of the
   following contributers -- listed alphabetically.

   o  Cedric Adjih, INRIA, France, <Cedric.Adjih@inria.fr>

   o  Emmanuel Baccelli, INRIA, Hitachi Labs Europe, France,
      <Emmanuel.Baccelli@inria.fr>

   o  Thomas Heide Clausen, PCRI, France<T.Clausen@computer.org>

   o  Justin Dean, NRL, USA<jdean@itd.nrl.navy.mil>

   o  Christopher Dearlove, BAE Systems, UK,
      <Chris.Dearlove@baesystems.com>

   o  Satoh Hiroki, Hitachi SDL, Japan, <h-satoh@sdl.hitachi.co.jp>

   o  Philippe Jacquet, INRIA, France, <Philippe.Jacquet@inria.fr>

   o  Monden Kazuya, Hitachi SDL, Japan, <monden@sdl.hitachi.co.jp>

   o  Kenichi Mase, University, Japan, <mase@ie.niigata-u.ac.jp>

   o  Ryuji Wakikawa, KEIO University, Japan, <ryuji@sfc.wide.ad.jp>

Appendix K. J.  Acknowledgements

   The authors would like to acknowledge the team behind OLSRv1,
   specified in RFC3626, including Paul Muhlethaler, Anis Laouiti, Pascale Minet, Laurent
   Viennot (all at INRIA, France), and Amir Qayuum (Center for Advanced
   Research in Engineering) for their contributions.

   The authors would like to gratefully acknowledge the following people
   for intense technical discussions, early reviews and comments on the
   specification and its components: Kenichi Mase (Niigata University),
   Li Li (CRC), Louise Lamont (CRC), Joe Macker (NRL), Alan Cullen (BAE
   Systems), Philippe Jacquet (INRIA), Khaldoun Al Agha (LRI), Richard
   Ogier (?), Song-Yean Cho (Samsung Software Center), Shubhranshu Singh
   (Samsung AIT) and the entire IETF MANET working group.

Author's Address

   Thomas Heide Clausen
   LIX, Ecole Polytechnique, France

   Phone: +33 6 6058 9349
   Email: T.Clausen@computer.org
   URI:   http://www.lix.polytechnique.fr/Labo/Thomas.Clausen/

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