Network Working Group S. Bryant
Internet-Draft S. Previdi
Intended status: Informational Cisco Systems
Expires: November 25, 2013 M. Shand
Individual Contributor
May 24, 2013
A Framework for IP and MPLS Fast Reroute Using Not-via Addresses
draft-ietf-rtgwg-ipfrr-notvia-addresses-11
Abstract
This document presents an illustrative framework for providing fast
reroute in an IP or MPLS network through encapsulation and forwarding
to "not-via" addresses. The general approach described uses a single
level of encapsulation and could be used to protect unicast,
multicast, and LDP traffic against link, router, and shared risk
group failure, regardless of network topology and metrics.
The mechanisms presented in this document are purely illustrative of
the general approach and do not constitute a protocol specification.
The document represents a snapshot of the work of the Routing Area
Working Group at the time of publication and is published as a
document of record. Further work is needed before implementation or
deployment.
Requirements Language
The key words "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 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Bryant, et al. Expires November 25, 2013 [Page 1]
Internet-Draft IPFRR using Not-via Addresses May 2013
This Internet-Draft will expire on November 25, 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
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Table of Contents
1. The Purpose of this Document . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Overview of Not-via Repairs . . . . . . . . . . . . . . . . . 4
3.1. Use of Equal Cost Multi-Path . . . . . . . . . . . . . . 5
3.2. Use of LFA repairs . . . . . . . . . . . . . . . . . . . 5
4. Not-via Repair Path Computation . . . . . . . . . . . . . . . 6
4.1. Computing not-via repairs in distance and path vector
routing protocols . . . . . . . . . . . . . . . . . . . . 7
5. Operation of Repairs . . . . . . . . . . . . . . . . . . . . 7
5.1. Node Failure . . . . . . . . . . . . . . . . . . . . . . 7
5.2. Link Failure . . . . . . . . . . . . . . . . . . . . . . 8
5.2.1. Loop Prevention Under Node Failure . . . . . . . . . 8
5.3. Multi-homed Prefixes . . . . . . . . . . . . . . . . . . 8
5.4. Installation of Repair Paths . . . . . . . . . . . . . . 10
6. Compound Failures . . . . . . . . . . . . . . . . . . . . . . 11
6.1. Shared Risk Link Groups . . . . . . . . . . . . . . . . . 11
6.2. Local Area Networks . . . . . . . . . . . . . . . . . . . 16
6.2.1. Simple LAN Repair . . . . . . . . . . . . . . . . . . 16
6.2.2. LAN Component Repair . . . . . . . . . . . . . . . . 17
6.2.3. LAN Repair Using Diagnostics . . . . . . . . . . . . 18
6.3. Multiple Independent Failures . . . . . . . . . . . . . . 18
6.3.1. Looping Repairs . . . . . . . . . . . . . . . . . . . 19
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