Remote-LFA Node Protection and Manageability
draft-ietf-rtgwg-rlfa-node-protection-06
Routing Area Working Group P. Sarkar, Ed.
Internet-Draft Individual Contributor
Intended status: Standards Track S. Hegde
Expires: April 11, 2017 C. Bowers
Juniper Networks, Inc.
H. Gredler
RtBrick Inc.
S. Litkowski
Orange
October 8, 2016
Remote-LFA Node Protection and Manageability
draft-ietf-rtgwg-rlfa-node-protection-06
Abstract
The loop-free alternates computed following the current Remote-LFA
specification guarantees only link-protection. The resulting Remote-
LFA nexthops (also called PQ-nodes), may not guarantee node-
protection for all destinations being protected by it.
This document describes procedures for determining if a given PQ-node
provides node-protection for a specific destination or not. The
document also shows how the same procedure can be utilised for
collection of complete characteristics for alternate paths.
Knowledge about the characteristics of all alternate path is
precursory to apply operator defined policy for eliminating paths not
fitting constraints.
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
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provisions of BCP 78 and BCP 79.
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and may be updated, replaced, or obsoleted by other documents at any
Sarkar, et al. Expires April 11, 2017 [Page 1]
Internet-Draft RLFA Node-Protection and Manageabilty October 2016
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 11, 2017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Node Protection with Remote-LFA . . . . . . . . . . . . . . . 3
2.1. The Problem . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Additional Definitions . . . . . . . . . . . . . . . . . 6
2.2.1. Link-Protecting Extended P-Space . . . . . . . . . . 6
2.2.2. Node-Protecting Extended P-Space . . . . . . . . . . 6
2.2.3. Q-Space . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.4. Link-Protecting PQ Space . . . . . . . . . . . . . . 6
2.2.5. Candidate Node-Protecting PQ Space . . . . . . . . . 7
2.2.6. Cost-Based Definitions . . . . . . . . . . . . . . . 7
2.2.6.1. Link-Protecting Extended P-Space . . . . . . . . 7
2.2.6.2. Node-Protecting Extended P-Space . . . . . . . . 7
2.2.6.3. Q-Space . . . . . . . . . . . . . . . . . . . . . 8
2.3. Computing Node-protecting R-LFA Path . . . . . . . . . . 9
2.3.1. Computing Candidate Node-protecting PQ-Nodes for
Primary nexthops . . . . . . . . . . . . . . . . . . 9
2.3.2. Computing node-protecting paths from PQ-nodes to
destinations . . . . . . . . . . . . . . . . . . . . 11
2.3.3. Limiting extra computational overhead . . . . . . . . 13
3. Manageabilty of Remote-LFA Alternate Paths . . . . . . . . . 14
3.1. The Problem . . . . . . . . . . . . . . . . . . . . . . . 14
3.2. The Solution . . . . . . . . . . . . . . . . . . . . . . 15
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
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