Remote-LFA Node Protection and Manageability
draft-ietf-rtgwg-rlfa-node-protection-12

The information below is for an old version of the document
Document Type Active Internet-Draft (rtgwg WG)
Authors Pushpasis Sarkar  , Shraddha Hegde  , Chris Bowers  , Hannes Gredler  , Stephane Litkowski 
Last updated 2017-01-20
Replaces draft-psarkar-rtgwg-rlfa-node-protection
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Routing Area Working Group                                P. Sarkar, Ed.
Internet-Draft                                    Individual Contributor
Intended status: Standards Track                                S. Hegde
Expires: July 24, 2017                                         C. Bowers
                                                  Juniper Networks, Inc.
                                                              H. Gredler
                                                           RtBrick, Inc.
                                                            S. Litkowski
                                                                  Orange
                                                        January 20, 2017

              Remote-LFA Node Protection and Manageability
                draft-ietf-rtgwg-rlfa-node-protection-12

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 utilized 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

   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
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   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

Sarkar, et al.            Expires July 24, 2017                 [Page 1]
Internet-Draft   R-LFA Node-Protection and Manageability    January 2017

   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 July 24, 2017.

Copyright Notice

   Copyright (c) 2017 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Node Protection with Remote-LFA . . . . . . . . . . . . . . .   4
     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 . . . . . . . . . . . . . . . . . . . . . . .   7
       2.2.4.  Link-Protecting PQ Space  . . . . . . . . . . . . . .   7
       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  . . . . . . . .   8
         2.2.6.3.  Q-Space . . . . . . . . . . . . . . . . . . . . .   9
     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.  Computing Node-Protecting R-LFA Paths for
               Destinations with ECMP primary nexthop nodes  . . . .  13
       2.3.4.  Limiting extra computational overhead . . . . . . . .  17
   3.  Manageability of Remote-LFA Alternate Paths . . . . . . . . .  18
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