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BIER                                                            Z. Zhang
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                           A. Przygienda
Expires: January 9, 2020                          Juniper Networks, Inc.
                                                             I. Wijnands
                                                           Cisco Systems
                                                              H. Bidgoli
                                                                   Nokia
                                                              M. McBride
                                                               Futurewei
                                                            July 8, 2019


                         BIER in IPv6 (BIERin6)
                      draft-zhang-bier-bierin6-03

Abstract

   BIER is a new architecture for the forwarding of multicast data
   packets.  This document defines native IPv6 encapsulation for BIER
   hop-by-hop forwarding or BIERin6 for short.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119.

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 https://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 January 9, 2020.







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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
   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IPv6 Header . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  IPv6 Options Considerations . . . . . . . . . . . . . . .   3
   3.  BIER Header . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  IPv6 Encapsulation Advertisement  . . . . . . . . . . . . . .   4
     4.1.  Format  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Inter-area prefix redistribution  . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   BIER [RFC8279] is a new architecture for the forwarding of multicast
   data packets.  It provides optimal forwarding through a "multicast
   domain" and it does not necessarily precondition construction of a
   multicast distribution tree, nor does it require intermediate nodes
   to maintain any per-flow state.

   This document specifies non-MPLS BIER forwarding in an IPv6 [RFC8200]
   environment, refferred to as BIERin6, using non-MPLS BIER
   encapsulation specified in [RFC8296].

   MPLS BIER forwarding in IPv6 is outside the scope of this document.

   This document uses terminology defined in [RFC8279] and [RFC8296].




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   [RFC8296] defines the BIER encapsulation format in MPLS and non-MPLS
   environment.  In case of non-MPLS environment, a BIER packet is the
   payload of an "outer" encapsulation, which has a "next protocol"
   codepoint that is set to a value that means "non-MPLS BIER".

   That can be used as is in a pure IPv6 non-mpls environment.  Between
   two directly connected BFRs, a BIER header could directly follow link
   layer header, e.g., an Ethernet header (with the Ethertype set to
   0xAB37).  If a BFR needs to tunnel BIER packets to another BFR, e.g.
   per [RFC8279] Section 6.9, IPv6 encapsulation can be used, with the
   destination address being the downstream BFR and the Next Header
   field set to a to-be-assigned value for "non-MPLS BIER".

   The IPv6 encapsulation could be used even between two directly
   connected BFRs in the following two cases:

   o  An operator mandates all traffic to be carried in IPv6.

   o  A BFR does not have BIER support in its "fast forwarding path" and
      relies on "slow/software forwarding path", e.g. in environments
      like [RFC7368] where high throughput multicast forwarding
      performance is not critical.

2.  IPv6 Header

   Whenever IPv6 encapsulation is used for BIER forwarding, The Next
   Header field in the IPv6 Header (if there are no extension headers),
   or the Next Header field in the last extension header is set to TBD,
   indicating that the payload is a BIER packet.

   If the neighbor is directly connected, The destination address in
   IPv6 header SHOULD be the neighbor's link-local address on this
   router's outgoing interface, the source destination address SHOULD be
   this router's link-local address on the outgoing interface, and the
   IPv6 TTL MUST be set to 1.  Otherwise, the destination address SHOULD
   be the BIER prefix of the BFR neighbor, the source address SHOULD be
   this router's BIER prefix, and the TTL MUST be large enough to get
   the packet to the BFR neighbor.

   The Flow-ID in the IPv6 packet SHOULD be copied from the entropy
   field in the BIER encapsulation.

2.1.  IPv6 Options Considerations

   RFC 8200 section 4, defines the IPv6 extension headers.  Currently
   there are two defined extension headers, Hop-by-Hop and Destination
   options header, which can carry a variable number of options.  These
   extension headers are inserted by the source node.



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   For directly connected BIER routers, IPv6 Hop-by-Hop or Destination
   options are irrelevant and SHOULD NOT be inserted by BFIR on the
   BIERin6 packet.  In this case IPv6 header, Next Header field should
   be set to TBD.  Any IPv6 packet arriving on BFRs and BFERs, with
   multiple extension header where the last extension header has a Next
   Header field set to TBD, SHOULD be discard and the node should
   transmit an ICMP Parameter Problem message to the source of the
   packet (BFIR) with an ICMP code value of TBD10 ('invalid options for
   BIERin6').

   This also indicates that for disjoint BIER routers using IPv6
   encapsulation, there SHOULD NOT be any IPv6 Hop-by-Hop or Destination
   options be present in a BIERin6 packet.  In this case, if additional
   traffic engineering is required, IPv6 tunneling (i.e.  BIERin6 over
   SRv6) can be implemented.

3.  BIER Header

   The BIER header MUST be encoded per Section 2.2 of [RFC8296].

   The BIFT-id is either encoded per
   [I-D.ietf-bier-non-mpls-bift-encoding] or per advertised by BFRs, as
   specificed in [I-D.dhanaraj-bier-lsr-ethernet-extensions].

4.  IPv6 Encapsulation Advertisement

   When IPv6 encapsulation is not required between directly connected
   BFRs, no signaling in addition to that specified in
   [I-D.dhanaraj-bier-lsr-ethernet-extensions] is needed.

   Otherwise, a node that requires IPv6 encapsualtion MUST advertise the
   BIER IPv6 transportation sub-TLV/sub-sub-TLV according to local
   configuration or policy in the BIER domain to request other BFRs to
   always use IPv6 encapsulation.

   In presence of multiple encapsulation possibilities hop-by-hop it is
   a matter of local policy which encapsulation is imposed and the
   receiving router MUST accept all encapsulations that it advertised.

4.1.  Format

   The BIER IPv6 transportation is a new sub-TLV of BIER defined in OSPF
   [RFC8444], and a new sub-sub-TLV of BIER Info sub-TLV defined in ISIS
   [RFC8401].







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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
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |    Type       |   Length      |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  Type: For OSPF, value TBD1 (prefer 12) is used to indicate it is
      the IPv6 transportation sub-TLV.  For ISIS, value TBD2 (prefer 3)
      is used to indicate it is the IPv6 transportation sub-sub-TLV.

   o  Length: 0.

4.2.  Inter-area prefix redistribution

   When BFR-prefixes are advertised across IGP areas per
   [I-D.dhanaraj-bier-lsr-ethernet-extensions] or redistributed across
   protocol boundaries per [I-D.zwzw-bier-prefix-redistribute], the BIER
   IPv6 transportation sub-TLV or sub-sub-TLV MAY be re-advertised/re-
   distributed as well.

5.  IANA Considerations

   IANA is requested to assign a new "BIER" type for "Next Header" in
   the "Assigned Internet Protocol Numbers" registry.

   IANA is requested to assign a new "BIERin6" type for "invalid
   options" in the "ICMP code value" registry.

   IANA is requested to assign a new "BIER IPv6 transportation Sub-TLV"
   type in the "OSPFv2 Extended Prefix TLV Sub-TLVs" Registry.

   IANA is requested to set up a new "BIER IPv6 transportation Sub-sub-
   TLV" type in the "IS-IS BIER Info sub-TLV" Registry.

6.  Security Considerations

   General IPv6 and BIER security considerations apply.

7.  Acknowledgement

   The authors would like to thank Jeffrey Zhang for his review and
   valuable contributions.

8.  References







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8.1.  Normative References

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC8279]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
              Explicit Replication (BIER)", RFC 8279,
              DOI 10.17487/RFC8279, November 2017,
              <https://www.rfc-editor.org/info/rfc8279>.

   [RFC8296]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
              for Bit Index Explicit Replication (BIER) in MPLS and Non-
              MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
              2018, <https://www.rfc-editor.org/info/rfc8296>.

   [RFC8401]  Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z.
              Zhang, "Bit Index Explicit Replication (BIER) Support via
              IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018,
              <https://www.rfc-editor.org/info/rfc8401>.

   [RFC8444]  Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A.,
              Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2
              Extensions for Bit Index Explicit Replication (BIER)",
              RFC 8444, DOI 10.17487/RFC8444, November 2018,
              <https://www.rfc-editor.org/info/rfc8444>.

8.2.  Informative References

   [I-D.dhanaraj-bier-lsr-ethernet-extensions]
              Dhanaraj, S., Wijnands, I., Psenak, P., Zhang, Z., Yan,
              G., and J. Xie, "LSR Extensions for BIER over Ethernet",
              draft-dhanaraj-bier-lsr-ethernet-extensions-00 (work in
              progress), January 2019.

   [I-D.ietf-bier-bar-ipa]
              Zhang, Z., Przygienda, T., Dolganow, A., Bidgoli, H.,
              Wijnands, I., and A. Gulko, "BIER Underlay Path
              Calculation Algorithm and Constraints", draft-ietf-bier-
              bar-ipa-04 (work in progress), May 2019.

   [I-D.ietf-bier-idr-extensions]
              Xu, X., Chen, M., Patel, K., Wijnands, I., and T.
              Przygienda, "BGP Extensions for BIER", draft-ietf-bier-
              idr-extensions-06 (work in progress), January 2019.



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   [I-D.ietf-bier-non-mpls-bift-encoding]
              Wijnands, I., Xu, X., and H. Bidgoli, "An Optional
              Encoding of the BIFT-id Field in the non-MPLS BIER
              Encapsulation", draft-ietf-bier-non-mpls-bift-encoding-01
              (work in progress), October 2018.

   [I-D.zhang-bier-babel-extensions]
              Zhang, Z. and T. Przygienda, "BIER in BABEL", draft-zhang-
              bier-babel-extensions-01 (work in progress), June 2017.

   [I-D.zwzw-bier-prefix-redistribute]
              Zhang, Z., Bo, W., Zhang, Z., and I. Wijnands, "BIER
              Prefix Redistribute", draft-zwzw-bier-prefix-
              redistribute-02 (work in progress), March 2019.

   [RFC7368]  Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J.
              Weil, "IPv6 Home Networking Architecture Principles",
              RFC 7368, DOI 10.17487/RFC7368, October 2014,
              <https://www.rfc-editor.org/info/rfc7368>.

Authors' Addresses

   Zheng(Sandy) Zhang
   ZTE Corporation

   EMail: zzhang_ietf@hotmail.com


   Tony Przygienda
   Juniper Networks, Inc.

   EMail: prz@juniper.net


   IJsbrand Wijnands
   Cisco Systems

   EMail: ice@cisco.com


   Hooman Bidgoli
   Nokia

   EMail: hooman.bidgoli@nokia.com







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   Mike McBride
   Futurewei

   EMail: mmcbride@futurewei.com















































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