TRILL: Resilient Distribution Trees
draft-ietf-trill-resilient-trees-09

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INTERNET-DRAFT                                              Mingui Zhang
Intended Status: Proposed Standard                                Huawei
Updates: 6325                                         Tissa Senevirathne
                                                              Consultant
                                                    Janardhanan Pathangi
                                                                 Gigamon
                                                           Ayan Banerjee
                                                                   Cisco
                                                          Anoop Ghanwani
                                                                    DELL
Expires: July 23, 2018                                  January 19, 2018

                  TRILL: Resilient Distribution Trees
                draft-ietf-trill-resilient-trees-09.txt

Abstract

   The TRILL (Transparent Interconnection of Lots of Links) protocol
   provides multicast data forwarding based on IS-IS link state routing.
   Distribution trees are computed based on the link state information
   through Shortest Path First calculation. When a link on the
   distribution tree fails, a campus-wide re-convergence of this
   distribution tree will take place, which can be time consuming and
   may cause considerable disruption to the ongoing multicast service.

   This document specifies how to build backup distribution trees to
   protect links on the primary distribution tree. Since the backup
   distribution tree is built up ahead of the link failure, when a link
   on the primary distribution tree fails, the pre-installed backup
   forwarding table will be utilized to deliver multicast packets
   without waiting for the campus-wide re-convergence. This minimizes
   the service disruption. This document updates RFC 6325.

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
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   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
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   The list of current Internet-Drafts can be accessed at
 

Zhang, et al.            Expires July 23, 2018                  [Page 1]
INTERNET-DRAFT        Resilient Distribution Trees      January 19, 2018

   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

Copyright and License Notice

   Copyright (c) 2018 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  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1. Conventions used in this document . . . . . . . . . . . . .  5
     1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . .  5
   2. Usage of the Affinity Sub-TLV . . . . . . . . . . . . . . . . .  6
     2.1. Indicating Affinity Links . . . . . . . . . . . . . . . . .  6
     2.2. Distribution Tree Calculation with Affinity Links . . . . .  7
   3. Distribution Tree Calculation . . . . . . . . . . . . . . . . .  8
     3.1. Designating Roots for Backup Distribution Trees . . . . . .  8
     3.2. Backup DT Calculation with Affinity Links . . . . . . . . .  9
       3.2.1. The Algorithm for Choosing Affinity Links . . . . . . .  9
       3.2.2. Affinity Links Advertisement  . . . . . . . . . . . . . 10
   4. Resilient Distribution Trees Installation . . . . . . . . . . . 10
     4.1. Pruning the Backup Distribution Tree  . . . . . . . . . . . 11
     4.2. RPF Filters Preparation . . . . . . . . . . . . . . . . . . 12
   5. Protection Mechanisms with Resilient Distribution Trees . . . . 12
     5.1. Global 1:1 Protection . . . . . . . . . . . . . . . . . . . 13
     5.2. Global 1+1 Protection . . . . . . . . . . . . . . . . . . . 14
       5.2.1. Failure Detection . . . . . . . . . . . . . . . . . . . 14
       5.2.2. Traffic Forking and Merging . . . . . . . . . . . . . . 14