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Versions: 00 01 02 03 04 05 06 07                                       
BIER WG                                                         Z. Zhang
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                           A. Przygienda
Expires: May 3, 2017                                    Juniper Networks
                                                        October 30, 2016


                             BIER in BABEL
                  draft-zhang-bier-babel-extensions-00

Abstract

   BIER introduces a novel architecture for multicast packet forwarding.
   It does not require a signalling protocol to explicitly build
   multicast distribution trees, nor does it require intermediate nodes
   to maintain any per-flow state.

   Babel defines a distance-vector routing protocol that operates in a
   robust and efficient fashion both in ordinary wired as well as in
   wireless mesh networks.  This document defines a way to carry BIER
   information in Babel.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 3, 2017.

Copyright Notice

   Copyright (c) 2016 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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Advertisement of BIER information . . . . . . . . . . . . . .   3
     3.1.  BIER BFR-prefix and BIER sub-TLV  . . . . . . . . . . . .   3
       3.1.1.  BIER sub-TLV  . . . . . . . . . . . . . . . . . . . .   3
     3.2.  BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . .   3
     3.3.  Optional BIER sub-domain BSL conversion sub-sub-TLV . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   [I-D.ietf-bier-architecture] introduces a novel architecture for
   multicast data packets forwarding.  It does not require a signalling
   protocol to explicitly build multicast distribution trees, nor does
   it require intermediate nodes to maintain any per-flow state.  All
   the necessary extensions to perform this functionality are
   abbreviated by the "BIER architecture" moniker.

   BIER information can be carried in OSPF and ISIS routing protocol as
   defined in [I-D.ietf-bier-isis-extensions] and
   [I-D.ietf-bier-ospf-bier-extensions] respectively.  The according
   tables for BIER forwarding purposes are built when OSPF/ISIS performs
   according calculations on the advertised information.

   [RFC6126] and [I-D.ietf-babel-rfc6126bis] define a distance-vector
   routing protocol under the name of "Babel".  Babel operates in a
   robust and efficient fashion both in ordinary wired as well as in
   wireless mesh networks.

2.  Terminology

   The terminology of this documents follows
   [I-D.ietf-bier-architecture], [RFC6126], [RFC7557] and
   [I-D.ietf-babel-rfc6126bis].






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3.  Advertisement of BIER information

3.1.  BIER BFR-prefix and BIER sub-TLV

   BFR-prefix and according information is carried in a Babel Update TLV
   per [RFC6126].  Several new sub-TLVs and sub-sub-TLVs are defined to
   convey further BIER information such as BFR-id, sub-domain-id and
   BSL.

3.1.1.  BIER sub-TLV

   The BIER sub-TLV format aligns exactly with the definition and
   restrictions in [I-D.ietf-bier-isis-extensions] and
   [I-D.ietf-bier-ospf-bier-extensions].  It is a sub-TLV of Babel
   update TLV.  The prefix MUST NOT be summarized and the according sub-
   TLV MUST be treated as optional and transitive.

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  sub-Type     |   Length      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Reserved    | subdomain-id  |   BFR-id                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                          Figure 1: BIER sub-TLV

   o  Type: as indicated in IANA section.

   o  Length: 1 octet

   o  Reserved: MUST be 0 on transmission, ignored on reception.  May be
      used in future versions. 8 bits.

   o  subdomain-id: Unique value identifying the BIER sub-domain. 1
      octet.

   o  BFR-id: A 2 octet field encoding the BFR-id, as documented in
      [I-D.ietf-bier-architecture].  If no BFR-id has been assigned this
      field is set to the invalid BFR-id.

3.2.  BIER MPLS Encapsulation sub-sub-TLV

   The BIER MPLS Encapsulation sub-sub-TLV can be carried by BIER sub-
   TLV.  The format and restrictions are aligned with
   [I-D.ietf-bier-isis-extensions] and
   [I-D.ietf-bier-ospf-bier-extensions].  This sub-sub-TLV carries the
   information for the BIER MPLS encapsulation including the label range
   for a specific BSL for a certain <MT,SD> pair.



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        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | sub-sub-Type  |   Length      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Lbl Range Size|BS Len |                    Label              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                  Figure 3: MPLS Encapsulation sub-sub-TLV

   o  Type: value of 1 indicating MPLS encapsulation.

   o  Length: 1 octet

   o  Local BitString Length (BS Len): Encoded bitstring length as per
      [I- D.draft-ietf-bier-mpls-encapsulation-05]. 4 bits.

   o  Label Range Size: Number of labels in the range used on
      encapsulation for this BIER sub-domain for this bitstring length,
      1 octet.

   o  Label: First label of the range, 20 bits.  The labels are as
      defined in [I-D.ietf-bier-mpls-encapsulation].

3.3.  Optional BIER sub-domain BSL conversion sub-sub-TLV

   This sub-sub-TLV is used to carry the BSL information.  Its
   definition and restrictions are aligned with
   [I-D.ietf-bier-isis-extensions].

         0                   1                   2                   3
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        | sub-sub-Type  |   Length      |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Figure 4: BSL conversion sub-sub-TLV

4.  Security Considerations

   TBD

5.  Acknowledgements

   The draft is aligned with the [I-D.ietf-bier-isis-extensions] and
   [I-D.ietf-bier-ospf-bier-extensions] as far as feasible.







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6.  Normative References

   [I-D.ietf-babel-rfc6126bis]
              Chroboczek, J., "The Babel Routing Protocol", draft-ietf-
              babel-rfc6126bis-00 (work in progress), August 2016.

   [I-D.ietf-bier-architecture]
              Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
              S. Aldrin, "Multicast using Bit Index Explicit
              Replication", draft-ietf-bier-architecture-05 (work in
              progress), October 2016.

   [I-D.ietf-bier-isis-extensions]
              Ginsberg, L., Przygienda, T., Aldrin, S., and Z. Zhang,
              "BIER support via ISIS", draft-ietf-bier-isis-
              extensions-03 (work in progress), September 2016.

   [I-D.ietf-bier-mpls-encapsulation]
              Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J.,
              Aldrin, S., and I. Meilik, "Encapsulation for Bit Index
              Explicit Replication in MPLS Networks", draft-ietf-bier-
              mpls-encapsulation-05 (work in progress), July 2016.

   [I-D.ietf-bier-ospf-bier-extensions]
              Psenak, P., Kumar, N., Wijnands, I., Dolganow, A.,
              Przygienda, T., Zhang, Z., and S. Aldrin, "OSPF Extensions
              for BIER", draft-ietf-bier-ospf-bier-extensions-04 (work
              in progress), September 2016.

   [I-D.pfister-bier-over-ipv6]
              Pfister, P. and I. Wijnands, "An IPv6 based BIER Routing
              Underlay", draft-pfister-bier-over-ipv6-00 (work in
              progress), September 2016.

   [RFC6126]  Chroboczek, J., "The Babel Routing Protocol", RFC 6126,
              DOI 10.17487/RFC6126, April 2011,
              <http://www.rfc-editor.org/info/rfc6126>.

   [RFC7557]  Chroboczek, J., "Extension Mechanism for the Babel Routing
              Protocol", RFC 7557, DOI 10.17487/RFC7557, May 2015,
              <http://www.rfc-editor.org/info/rfc7557>.

Authors' Addresses








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   Zheng(Sandy) Zhang
   ZTE Corporation
   No. 50 Software Ave, Yuhuatai Distinct
   Nanjing
   China

   Email: zhang.zheng@zte.com.cn


   Tony Przygienda
   Juniper Networks

   Email: prz@juniper.net






































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