Network Working Group R. Ogier
Request for Comments: 5614 SRI International
Category: Experimental P. Spagnolo
Boeing
August 2009
Mobile Ad Hoc Network (MANET) Extension of OSPF
Using Connected Dominating Set (CDS) Flooding
Abstract
This document specifies an extension of OSPFv3 to support mobile ad
hoc networks (MANETs). The extension, called OSPF-MDR, is designed
as a new OSPF interface type for MANETs. OSPF-MDR is based on the
selection of a subset of MANET routers, consisting of MANET
Designated Routers (MDRs) and Backup MDRs. The MDRs form a connected
dominating set (CDS), and the MDRs and Backup MDRs together form a
biconnected CDS for robustness. This CDS is exploited in two ways.
First, to reduce flooding overhead, an optimized flooding procedure
is used in which only (Backup) MDRs flood new link state
advertisements (LSAs) back out the receiving interface; reliable
flooding is ensured by retransmitting LSAs along adjacencies.
Second, adjacencies are formed only between (Backup) MDRs and a
subset of their neighbors, allowing for much better scaling in dense
networks. The CDS is constructed using 2-hop neighbor information
provided in a Hello protocol extension. The Hello protocol is
further optimized by allowing differential Hellos that report only
changes in neighbor states. Options are specified for originating
router-LSAs that provide full or partial topology information,
allowing overhead to be reduced by advertising less topology
information.
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.
Ogier & Spagnolo Experimental [Page 1]RFC 5614 MANET Extension of OSPF August 2009Copyright Notice
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Table of Contents
1. Introduction ....................................................4
1.1. Terminology ................................................5
2. Overview ........................................................7
2.1. Selection of MDRs, BMDRs, Parents, and Adjacencies .........8
2.2. Flooding Procedure .........................................9
2.3. Link State Acknowledgments ................................10
2.4. Routable Neighbors ........................................10
2.5. Partial and Full Topology LSAs ............................11
2.6. Hello Protocol ............................................12
3. Interface and Neighbor Data Structures .........................12
3.1. Changes to Interface Data Structure .......................12
3.2. New Configurable Interface Parameters .....................13
3.3. Changes to Neighbor Data Structure ........................15
4. Hello Protocol .................................................17
4.1. Sending Hello Packets .....................................17
4.2. Receiving Hello Packets ...................................20
4.3. Neighbor Acceptance Condition .............................24
5. MDR Selection Algorithm ........................................25
5.1. Phase 1: Creating the Neighbor Connectivity Matrix ........27
5.2. Phase 2: MDR Selection ....................................27
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