Topology Dissemination Based on Reverse-Path Forwarding (TBRPF)
RFC 3684

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 11

Network Working Group                                           R. Ogier
Request for Comments: 3684                             SRI International
Category: Experimental                                        F. Templin
                                                                   Nokia
                                                                M. Lewis
                                                       SRI International
                                                           February 2004

    Topology Dissemination Based on Reverse-Path Forwarding (TBRPF)

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 (2004).  All Rights Reserved.

Abstract

   Topology Dissemination Based on Reverse-Path Forwarding (TBRPF) is a
   proactive, link-state routing protocol designed for mobile ad-hoc
   networks, which provides hop-by-hop routing along shortest paths to
   each destination.  Each node running TBRPF computes a source tree
   (providing paths to all reachable nodes) based on partial topology
   information stored in its topology table, using a modification of
   Dijkstra's algorithm.  To minimize overhead, each node reports only
   *part* of its source tree to neighbors.  TBRPF uses a combination of
   periodic and differential updates to keep all neighbors informed of
   the reported part of its source tree.  Each node also has the option
   to report additional topology information (up to the full topology),
   to provide improved robustness in highly mobile networks.  TBRPF
   performs neighbor discovery using "differential" HELLO messages which
   report only *changes* in the status of neighbors.  This results in
   HELLO messages that are much smaller than those of other link-state
   routing protocols such as OSPF.

Ogier, et al.                 Experimental                      [Page 1]
RFC 3684                         TBRPF                     February 2004

Table of Contents

   1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements. . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Applicability Section . . . . . . . . . . . . . . . . . . . .   5
   5.  TBRPF Overview. . . . . . . . . . . . . . . . . . . . . . . .   6
       5.1.   Overview of Neighbor Discovery . . . . . . . . . . . .   6
       5.2.   Overview of the Routing Module. .. . . . . . . . . . .   8
   6.  TBRPF Packets . . . . . . . . . . . . . . . . . . . . . . . .  10
       6.1.   TBRPF Packet Header. . . . . . . . . . . . . . . . . .  10
       6.2.   TBRPF Packet Body. . . . . . . . . . . . . . . . . . .  11
              6.2.1.  Padding Options (TYPE = 0 thru 1). . . . . . .  12
              6.2.2.  Messages (TYPE = 2 thru 10). . . . . . . . . .  13
   7.  TBRPF Neighbor Discovery. . . . . . . . . . . . . . . . . . .  13
       7.1.   HELLO Message Format . . . . . . . . . . . . . . . . .  13
       7.2.   Neighbor Table . . . . . . . . . . . . . . . . . . . .  14
       7.3.   Sending HELLO Messages . . . . . . . . . . . . . . . .  15
       7.4.   Processing a Received HELLO Message. . . . . . . . . .  16
       7.5.   Expiration of Timer nbr_life . . . . . . . . . . . . .  18
       7.6.   Link-Layer Failure Notification. . . . . . . . . . . .  18
       7.7.   Optional Link Metrics. . . . . . . . . . . . . . . . .  18
       7.8.   Configurable Parameters. . . . . . . . . . . . . . . .  19
   8.  TBRPF Routing Module. . . . . . . . . . . . . . . . . . . . .  19
       8.1.   Conceptual Data Structures . . . . . . . . . . . . . .  19
       8.2.   TOPOLOGY UPDATE Message Format . . . . . . . . . . . .  21
       8.3.   Interface, Host, and Network Prefix Association
              Message Formats. . . . . . . . . . . . . . . . . . . .  23
       8.4.   TBRPF Routing Operation. . . . . . . . . . . . . . . .  24
              8.4.1.  Periodic Processing. . . . . . . . . . . . . .  24
              8.4.2.  Updating the Source Tree and Topology
                      Graph. . . . . . . . . . . . . . . . . . . . .  25
              8.4.3.  Updating the Routing Table . . . . . . . . . .  26
              8.4.4.  Updating the Reported Node Set . . . . . . . .  27
              8.4.5.  Generating Periodic Updates. . . . . . . . . .  29
              8.4.6.  Generating Differential Updates. . . . . . . .  29
              8.4.7.  Processing Topology Updates. . . . . . . . . .  30
              8.4.8.  Expiring Topology Information. . . . . . . . .  32
              8.4.9.  Optional Reporting of Redundant Topology
                      Information. . . . . . . . . . . . . . . . . .  32
              8.4.10. Local Topology Changes . . . . . . . . . . . .  33