Operational management of Loop Free Alternates
draft-ietf-rtgwg-lfa-manageability-04

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Document Type Active Internet-Draft (rtgwg WG)
Last updated 2014-11-12 (latest revision 2014-08-11)
Replaces draft-litkowski-rtgwg-lfa-manageability
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Routing Area Working Group                                  S. Litkowski
Internet-Draft                                               B. Decraene
Intended status: Standards Track                                  Orange
Expires: February 12, 2015                                   C. Filsfils
                                                                 K. Raza
                                                           Cisco Systems
                                                            M. Horneffer
                                                        Deutsche Telekom
                                                               P. Sarkar
                                                        Juniper Networks
                                                         August 11, 2014

             Operational management of Loop Free Alternates
                 draft-ietf-rtgwg-lfa-manageability-04

Abstract

   Loop Free Alternates (LFA), as defined in RFC 5286 is an IP Fast
   ReRoute (IP FRR) mechanism enabling traffic protection for IP traffic
   (and MPLS LDP traffic by extension).  Following first deployment
   experiences, this document provides operational feedback on LFA,
   highlights some limitations, and proposes a set of refinements to
   address those limitations.  It also proposes required management
   specifications.

   This proposal is also applicable to remote LFA solution.

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].

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

Litkowski, et al.       Expires February 12, 2015               [Page 1]
Internet-Draft              LFA manageability                August 2014

   This Internet-Draft will expire on February 12, 2015.

Copyright Notice

   Copyright (c) 2014 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Operational issues with default LFA tie breakers  . . . . . .   3
     2.1.  Case 1: Edge router protecting core failures  . . . . . .   3
     2.2.  Case 2: Edge router choosen to protect core failures
           while core LFA exists . . . . . . . . . . . . . . . . . .   5
     2.3.  Case 3: suboptimal core alternate choice  . . . . . . . .   5
     2.4.  Case 4: ISIS overload bit on LFA computing node . . . . .   6
   3.  Need for coverage monitoring  . . . . . . . . . . . . . . . .   7
   4.  Need for LFA activation granularity . . . . . . . . . . . . .   8
   5.  Configuration requirements  . . . . . . . . . . . . . . . . .   8
     5.1.  LFA enabling/disabling scope  . . . . . . . . . . . . . .   8
     5.2.  Policy based LFA selection  . . . . . . . . . . . . . . .   9
       5.2.1.  Connected vs remote alternates  . . . . . . . . . . .   9
       5.2.2.  Mandatory criteria  . . . . . . . . . . . . . . . . .  10
       5.2.3.  Enhanced criteria . . . . . . . . . . . . . . . . . .  10
       5.2.4.  Retrieving alternate path attributes  . . . . . . . .  11
       5.2.5.  ECMP LFAs . . . . . . . . . . . . . . . . . . . . . .  12
       5.2.6.  SRLG  . . . . . . . . . . . . . . . . . . . . . . . .  13
       5.2.7.  Link coloring . . . . . . . . . . . . . . . . . . . .  14
       5.2.8.  Bandwidth . . . . . . . . . . . . . . . . . . . . . .  15
       5.2.9.  Alternate preference  . . . . . . . . . . . . . . . .  16
   6.  Operational aspects . . . . . . . . . . . . . . . . . . . . .  17
     6.1.  ISIS overload bit on LFA computing node . . . . . . . . .  17
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