Traffic Engineering for Bit Index Explicit Replication (BIER-TE)
draft-ietf-bier-te-arch-03

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Last updated 2019-09-20 (latest revision 2019-07-08)
Replaces draft-eckert-bier-te-arch
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Network Working Group                                     T. Eckert, Ed.
Internet-Draft                                                    Huawei
Intended status: Standards Track                              G. Cauchie
Expires: January 9, 2020                                Bouygues Telecom
                                                                M. Menth
                                                 University of Tuebingen
                                                            July 8, 2019

    Traffic Engineering for Bit Index Explicit Replication (BIER-TE)
                       draft-ietf-bier-te-arch-03

Abstract

   This memo introduces per-packet stateless strict and loose path
   engineered replication and forwarding for Bit Index Explicit
   Replication packets ([RFC8279]).  This is called BIER-TE.

   BIER-TE leverages the BIER architecture ([RFC8279]) and extends it
   with a new semantic for bits in the bitstring.  BIER-TE can leverage
   BIER forwarding engines with little or no changes.

   In BIER, the BitPositions (BP) of the packets bitstring indicate BIER
   Forwarding Egress Routers (BFER), and hop-by-hop forwarding uses a
   Routing Underlay such as an IGP.

   In BIER-TE, BitPositions indicate adjacencies.  The BIFT of each BFR
   are only populated with BPs that are adjacent to the BFR in the BIER-
   TE topology.  The BIER-TE topology can consist of layer 2 or remote
   (route) adjacencies.  The BFR then replicates and forwards BIER
   packets to those adjacencies.  This results in the aforementioned
   strict and loose path forwarding.

   BIER-TE can co-exist with BIER forwarding in the same domain, for
   example by using seperate sub-domains.  In the absence of routed
   adjacencies, BIER-TE does not require a BIER routing underlay, and
   can then be operated without requiring an IGP routing protocol.

   BIER-TE operates without explicit in-network tree-building and
   carries the multicast distribution tree in the packet header.  It can
   therefore be a good fit to support multicast path steering in Segment
   Routing (SR) networks.

Status of This Memo

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

Eckert, et al.           Expires January 9, 2020                [Page 1]
Internet-Draft                BIER-TE ARCH                     July 2019

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Copyright Notice

   Copyright (c) 2019 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Basic Examples  . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  BIER-TE Topology and adjacencies  . . . . . . . . . . . .   7
     1.3.  Comparison with BIER  . . . . . . . . . . . . . . . . . .   8
     1.4.  Requirements Language . . . . . . . . . . . . . . . . . .   8
   2.  Layering  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     2.1.  The Multicast Flow Overlay  . . . . . . . . . . . . . . .   9
     2.2.  The BIER-TE Controller Host . . . . . . . . . . . . . . .   9
       2.2.1.  Assignment of BitPositions to adjacencies of the
               network topology  . . . . . . . . . . . . . . . . . .  10
       2.2.2.  Changes in the network topology . . . . . . . . . . .  10
       2.2.3.  Set up per-multicast flow BIER-TE state . . . . . . .  10
       2.2.4.  Link/Node Failures and Recovery . . . . . . . . . . .  10
     2.3.  The BIER-TE Forwarding Layer  . . . . . . . . . . . . . .  11
     2.4.  The Routing Underlay  . . . . . . . . . . . . . . . . . .  11
   3.  BIER-TE Forwarding  . . . . . . . . . . . . . . . . . . . . .  11
     3.1.  The Bit Index Forwarding Table (BIFT) . . . . . . . . . .  11
     3.2.  Adjacency Types . . . . . . . . . . . . . . . . . . . . .  12
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