IS-IS Operational Enhancements for Network Maintenance Events
draft-ietf-isis-oper-enhance-02

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Document Type Active Internet-Draft (isis WG)
Authors Naiming Shen  , Tony Li  , Shane Amante  , Mikael Abrahamsson 
Last updated 2013-01-14
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IS-IS Working Group                                              N. Shen
Internet-Draft                                                     T. Li
Intended status: Informational                       Cisco Systems, Inc.
Expires: July 18, 2013                                         S. Amante
                                                  Level 3 Communications
                                                          M. Abrahamsson
                                                                   Tele2
                                                        January 14, 2013

     IS-IS Operational Enhancements for Network Maintenance Events
                    draft-ietf-isis-oper-enhance-02

Abstract

   This document describes an improved IS-IS neighbor management scheme
   which can be used to enhance operational experience in terms of
   convergence speed and finer control of neighbor cost over a LAN.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on July 18, 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

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Interface Shutdown Black Hole . . . . . . . . . . . . . . . 3
     1.2.  LAN of Last Resort  . . . . . . . . . . . . . . . . . . . . 3
     1.3.  Specification of Requirements . . . . . . . . . . . . . . . 3

   2.  Sending Hellos with Fast Exit Notification  . . . . . . . . . . 3

   3.  Pseudonodes with Non-zero Metrics . . . . . . . . . . . . . . . 4
     3.1.  Operational Considerations  . . . . . . . . . . . . . . . . 5

   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5

   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5

   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5

   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 6

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1.  Introduction

   The IS-IS [ISO 10589] routing protocol has been widely used in
   Internet Service Provider IP/MPLS networks.  Operational experience
   with the protocol, combined with ever increasing requirements for
   lossless operations have demonstrated some operational issues.  This
   document describes those issues and some mechanisms for dealing with
   those issues.  These mechanisms do involve implementation support,
   but do not require protocol changes.

1.1.  Interface Shutdown Black Hole

   One of these operationally problematic issues occurs when IS-IS is
   disabled on only one side of a link.  This can result in a
   significant delay before neighbor(s) on the other end of the same
   link notice this change.  In turn, this can result in several seconds
   during which traffic is blackholed, until the IS-IS neighbor(s) time
   out the adjacency and IS-IS reconverges.

1.2.  LAN of Last Resort

   Another issue stems from a situation when operators want to
   temporarily make an interface a "last resort" link for transit
   traffic.  This is a straightforward, though cumbersome, operation to
   perform on a point-to-point link.  Each device on the link is
   reconfigured to use very high metric.  This causes traffic to divert
   to other links in the network.  This same operation is more difficult
   on a multi-access LAN.  There, the operator would have to increase
   the metric on each and every interface attached to the LAN, requiring
   the reconfiguration of a number of systems.
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