Encapsulation for Bit Index Explicit Replication (BIER) in MPLS and Non-MPLS Networks
RFC 8296

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Internet Engineering Task Force (IETF)                 IJ. Wijnands, Ed.
Request for Comments: 8296                           Cisco Systems, Inc.
Category: Experimental                                     E. Rosen, Ed.
ISSN: 2070-1721                                   Juniper Networks, Inc.
                                                             A. Dolganow
                                                                   Nokia
                                                             J. Tantsura
                                                              Individual
                                                               S. Aldrin
                                                            Google, Inc.
                                                               I. Meilik
                                                                Broadcom
                                                            January 2018

        Encapsulation for Bit Index Explicit Replication (BIER)
                     in MPLS and Non-MPLS Networks

Abstract

   Bit Index Explicit Replication (BIER) is an architecture that
   provides optimal multicast forwarding through a "multicast domain",
   without requiring intermediate routers to maintain any per-flow state
   or to engage in an explicit tree-building protocol.  When a multicast
   data packet enters the domain, the ingress router determines the set
   of egress routers to which the packet needs to be sent.  The ingress
   router then encapsulates the packet in a BIER header.  The BIER
   header contains a bit string in which each bit represents exactly one
   egress router in the domain; to forward the packet to a given set of
   egress routers, the bits corresponding to those routers are set in
   the BIER header.  The details of the encapsulation depend on the type
   of network used to realize the multicast domain.  This document
   specifies a BIER encapsulation that can be used in an MPLS network
   or, with slight differences, in a non-MPLS network.

Wijnands, et al.              Experimental                      [Page 1]
RFC 8296                 BIER MPLS Encapsulation            January 2018

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8296.

Copyright 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
   (https://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
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Wijnands, et al.              Experimental                      [Page 2]
RFC 8296                 BIER MPLS Encapsulation            January 2018

Table of Contents

   1. Introduction ....................................................3
   2. BIER Header .....................................................5
      2.1. In MPLS Networks ...........................................5
           2.1.1. Encapsulation Initial Four Octets ...................5
                  2.1.1.1. The BIER-MPLS Label ........................5
                  2.1.1.2. Other Fields of the Initial Four Octets ....8
           2.1.2. Remainder of Encapsulation ..........................9
           2.1.3. Further Encapsulating a BIER Packet ................12
      2.2. In Non-MPLS Networks ......................................13
           2.2.1. Encapsulation Initial Four Octets ..................13
                  2.2.1.1. The BIFT-id ...............................13
                  2.2.1.2. Other Fields of the Initial Four Octets ...13
           2.2.2. Remainder of Encapsulation .........................14
           2.2.3. Further Encapsulating a BIER Packet ................15
   3. Imposing and Processing the BIER Encapsulation .................16