Use of OSPF-MDR in Single-Hop Broadcast Networks
RFC 7038
| Document | Type |
RFC - Experimental
(October 2013; No errata)
Updates RFC 5614
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | WG Document | |
| Document shepherd | Acee Lindem | ||
| Shepherd write-up | Show (last changed 2013-06-04) | ||
| IESG | IESG state | RFC 7038 (Experimental) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Stewart Bryant | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IC | ||
Internet Engineering Task Force (IETF) R. Ogier
Request for Comments: 7038 SRI International
Updates: 5614 October 2013
Category: Experimental
ISSN: 2070-1721
Use of OSPF-MDR in Single-Hop Broadcast Networks
Abstract
RFC 5614 (OSPF-MDR) extends OSPF to support mobile ad hoc networks
(MANETs) by specifying its operation on the new OSPF interface of
type MANET. This document describes the use of OSPF-MDR (MANET
Designated Router) in a single-hop broadcast network, which is a
special case of a MANET in which each router is a (one-hop) neighbor
of each other router. Unlike an OSPF broadcast interface, such an
interface can have a different cost associated with each neighbor.
The document includes configuration recommendations and simplified
mechanisms that can be used in single-hop broadcast networks.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This document is a product of the Internet Engineering
Task Force (IETF). It represents the consensus of the IETF
community. It has received public review and has been approved for
publication by the Internet Engineering Steering Group (IESG). Not
all documents approved by the IESG are a candidate for any level of
Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7038.
Ogier Experimental [Page 1]
RFC 7038 OSPF-MDR in Single-Hop Broadcast Networks October 2013
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
OSPF-MDR [RFC5614] specifies an extension of OSPF [RFC2328, RFC5340]
to support mobile ad hoc networks (MANETs) by specifying its
operation on the new OSPF interface of type MANET. OSPF-MDR
generalizes the Designated Router (DR) to a connected dominating set
(CDS) consisting of a typically small subset of routers called MANET
Designated Routers (MDRs). Similarly, the Backup Designated Router
(BDR) is generalized to a subset of routers called Backup MDRs
(BMDRs). MDRs achieve scalability in MANETs similar to the way DRs
achieve scalability in broadcast networks:
o MDRs have primary responsibility for flooding the Link State
Advertisements (LSAs). Backup MDRs provide backup flooding when
MDRs temporarily fail.
o MDRs allow the number of adjacencies to be dramatically reduced by
requiring adjacencies to be formed only between MDR/BMDR routers
and their neighbors.
In addition, OSPF-MDR has the following features:
o MDRs and BMDRs are elected based on information obtained from
modified Hello packets received from neighbors.
o If adjacency reduction is used (the default), adjacencies are
formed between MDRs so as to form a connected subgraph. An option
(AdjConnectivity = 2) allows for additional adjacencies to be
formed between MDRs/BMDRs to produce a biconnected subgraph.
o Each non-MDR router becomes adjacent with an MDR called its
Parent, and optionally (if AdjConnectivity = 2) becomes adjacent
with another MDR or BMDR called its Backup Parent.
Ogier Experimental [Page 2]
RFC 7038 OSPF-MDR in Single-Hop Broadcast Networks October 2013
o Each router advertises connections to its neighbor routers as
point-to-point links in its router-LSA. Network-LSAs are not
used.
o In addition to full-topology LSAs, partial-topology LSAs may be
used to reduce the size of router-LSAs. Such LSAs are formatted
as standard LSAs, but advertise links to only a subset of
neighbors.
o Optionally, differential Hellos can be used, which reduce overhead
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