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Optimized Link State Routing Protocol (OLSR)
RFC 3626

Document type: RFC - Experimental (October 2003; No errata)
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

IETF State: (None)
Consensus: Unknown
Document shepherd: No shepherd assigned

IESG State: RFC 3626 (Experimental)
Responsible AD: Alex Zinin
Send notices to: <macker@itd.nrl.navy.mil>, <corson@flarion.com>

Network Working Group                                    T. Clausen, Ed.
Request for Comments: 3626                               P. Jacquet, Ed.
Category: Experimental                           Project Hipercom, INRIA
                                                            October 2003

              Optimized Link State Routing Protocol (OLSR)

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes the Optimized Link State Routing (OLSR)
   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 concept used in the protocol is that
   of multipoint relays (MPRs).  MPRs are selected nodes which forward
   broadcast messages during the flooding process.  This technique
   substantially reduces the message overhead as compared to a classical
   flooding mechanism, where every node retransmits each message when it
   receives the first copy of the message.  In OLSR, link state
   information is generated only by nodes elected as MPRs.  Thus, a
   second optimization is achieved by minimizing the number of control
   messages flooded in the network.  As a third optimization, an MPR
   node may chose to report only links between itself and its MPR
   selectors.  Hence, as contrary to the classic link state algorithm,
   partial link state information is distributed in the network.  This
   information is then used for route calculation.  OLSR provides
   optimal routes (in terms of number of hops).  The protocol is
   particularly suitable for large and dense networks as the technique
   of MPRs works well in this context.

Clausen & Jacquet             Experimental                      [Page 1]
RFC 3626              Optimized Link State Routing          October 2003

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
       1.1. OLSR Terminology.  . . . . . . . . . . . . . . . . . . .   5
       1.2. Applicability. . . . . . . . . . . . . . . . . . . . . .   7
       1.3. Protocol Overview  . . . . . . . . . . . . . . . . . . .   8
       1.4. Multipoint Relays  . . . . . . . . . . . . . . . . . . .   9
   2.  Protocol Functioning  . . . . . . . . . . . . . . . . . . . .   9
       2.1. Core Functioning   . . . . . . . . . . . . . . . . . . .  10
       2.2. Auxiliary Functioning  . . . . . . . . . . . . . . . . .  12
   3.  Packet Format and Forwarding  . . . . . . . . . . . . . . . .  13
       3.1. Protocol and Port Number.  . . . . . . . . . . . . . . .  13
       3.2. Main Address   . . . . . . . . . . . . . . . . . . . . .  13
       3.3. Packet Format  . . . . . . . . . . . . . . . . . . . . .  14
            3.3.1. Packet Header . . . . . . . . . . . . . . . . . .  14
            3.3.2. Message Header  . . . . . . . . . . . . . . . . .  15
       3.4. Packet Processing and Message Flooding . . . . . . . . .  16
            3.4.1. Default Forwarding Algorithm. . . . . . . . . . .  18
            3.4.2. Considerations on Processing and Forwarding . . .  20
       3.5. Message Emission and Jitter. . . . . . . . . . . . . . .  21
   4.  Information Repositories  . . . . . . . . . . . . . . . . . .  22
       4.1. Multiple Interface Association Information Base  . . . .  22
       4.2. Link sensing: Local Link Information Base. . . . . . . .  22
            4.2.1. Link Set. . . . . . . . . . . . . . . . . . . . .  22
       4.3. Neighbor Detection: Neighborhood Information Base. . . .  23
            4.3.1. Neighbor Set. . . . . . . . . . . . . . . . . . .  23
            4.3.2. 2-hop Neighbor Set. . . . . . . . . . . . . . . .  23
            4.3.3. MPR Set . . . . . . . . . . . . . . . . . . . . .  23
            4.3.4. MPR Selector Set. . . . . . . . . . . . . . . . .  23
       4.4. Topology Information Base  . . . . . . . . . . . . . . .  24
   5.  Main Addresses and Multiple Interfaces  . . . . . . . . . . .  24
       5.1. MID Message Format . . . . . . . . . . . . . . . . . . .  25
       5.2. MID Message Generation . . . . . . . . . . . . . . . . .  25
       5.3. MID Message Forwarding . . . . . . . . . . . . . . . . .  26
       5.4. MID Message Processing . . . . . . . . . . . . . . . . .  26
       5.5. Resolving a Main Address from an Interface Address . . .  27
   6.  HELLO Message Format and Generation . . . . . . . . . . . . .  27
       6.1. HELLO Message Format . . . . . . . . . . . . . . . . . .  27
            6.1.1. Link Code as Link Type and Neighbor Type. . . . .  29

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