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BIER WG                                                       Quan Xiong
Internet-Draft                                               Greg Mirsky
Intended status: Standards Track                              Fangwei Hu
Expires: September 2, 2019                               ZTE Corporation
                                                               Chang Liu
                                                            China Unicom
                                                           March 1, 2019


                                BIER BFD
                        draft-hu-bier-bfd-03.txt

Abstract

   Point to multipoint (P2MP) BFD is designed to verify multipoint
   connectivity.  This document specifies the application of P2MP BFD in
   BIER network.

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
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   This Internet-Draft will expire on September 2, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  BIER BFD Encapsulation  . . . . . . . . . . . . . . . . . . .   3
   4.  Bootstrapping BIER BFD  . . . . . . . . . . . . . . . . . . .   3
     4.1.  BIER OAM Ping Bootstrap . . . . . . . . . . . . . . . . .   3
     4.2.  IGP protocol Bootstrap  . . . . . . . . . . . . . . . . .   4
       4.2.1.  IS-IS extension for BIER BFD  . . . . . . . . . . . .   4
       4.2.2.  OSPF extension for BIER BFD . . . . . . . . . . . . .   5
   5.  Discriminators and Packet Demultiplexing  . . . . . . . . . .   5
   6.  Active Tail in BIER BFD . . . . . . . . . . . . . . . . . . .   5
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   6
     10.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Bit Index Explicit Replication (BIER) [RFC8279] provides optimal
   forwarding of multicast data packets through a multicast domain.  It
   does so without requiring any explicit tree-building protocol and
   without requiring intermediate nodes to maintain any per-flow state.
   BIER resilience use cases are described in
   [I-D.xiong-bier-resilience] including End-to-End 1+1 and 1:1
   Protection and the failure detection mechanisms MAY use P2MP BFD and
   P2MP active tail detection method respectively.

   [I-D.ietf-bfd-multipoint] defines a method of using Bidirectional
   Forwarding Detection(BFD) to monitor and detect unicast failures
   between the sender (head) and one or more receivers (tails) in
   multipoint or multicast networks.
   [I-D.ietf-bfd-multipoint-active-tail] describes active tail
   extensions to the BFD protocol for multipoint networks.

   This document describes the procedures for using such mode of BFD
   protocol to verify multipoint or multicast connectivity between a
   multipoint sender (the "head", Bit-Forwarding Ingress Routers(BFIRs))
   and a set of one or more multipoint receivers (the"tails", Bit-
   Forwarding Egress Routers(BFERs)).  The BIER BFD only supports the



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   unidirectional multicast.  This document defines the use of P2MP BFD
   as per [I-D.ietf-bfd-multipoint], and active tail as per
   [I-D.ietf-bfd-multipoint-active-tail] for BIER-specific domain.

2.  Conventions used in this document

2.1.  Terminology

   This document uses the acronyms defined in [RFC8279] along with the
   following:

   BFD: Bidirectional Forwarding Detection.

   OAM: Operations, Administration, and Maintenance.

   P2MP: Point to Multi-Point.

2.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  BIER BFD Encapsulation

   BIER BFD encapsulation uses the BIER OAM packet format defined in
   [I-D.ietf-bier-ping].  The value of the Msg Type field MUST be set to
   BIER BFD (TBD1 by IANA ).  BFD Control packet, defined in Section 4
   [RFC5880] immediately follows the BIER OAM header.

4.  Bootstrapping BIER BFD

4.1.  BIER OAM Ping Bootstrap

   The BIER OAM ping could be used for BIER BFD bootstrap.  The BFIR
   sends the BIER OAM ping Echo request messages carring a BFD
   discriminator TLV which immediately follows the Target SI-Bitstring
   TLV (section 3.3.2 [I-D.ietf-bier-ping]) which MUST be included to
   carry the set of BFER information (Sub-domain-id, Set ID, BS Len,
   Bitstring) for the purpose of session establishment.

   The BFD discriminator TLV is a new TLV for BIER OAM TLV with the type
   (TBD2 by IANA) and the length of 4.  The value contains the 4-byte
   local discriminator generated by BFIR for this session.





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4.2.  IGP protocol Bootstrap

   An alternative option to bootstrap the BIER BFD is to advertise the
   BFD information IGP protocol in control plane.  This document defines
   a new BIER BFD Sub-TLV carried in IS-IS and OSPF capaibility to
   advertise My Discriminator for BFIR.

4.2.1.  IS-IS extension for BIER BFD

   The new BIER BFD Sub-TLV is carried in the ISIS router capaiblity
   TLV.  The format is as follows.


       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    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      My Discriminator                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     RESERVED          |            BIFT-id                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                 BitString  (first 32 bits)                    ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                                                               ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                 BitString  (last 32 bits)                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 1: BIER BFD Sub-TLV for IS-IS extension


   Type : TBD3 by IANA.

   Length : Length of the BIER BFD Sub-TLV for IS-IS extension, in
   bytes.

   My Discriminator : A unique, nonzero discriminator value generated by
   BFIR for each multipoint path.

   The BitString field carries the set of BFR-IDs of BFER(s) that the
   BFIR expects to establish BIER BFD session.

   The BIFT-id represents a particular Bit Index Forwarding Table (BIFT)
   as per [RFC8279].






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4.2.2.  OSPF extension for BIER BFD

   The new BIER BFD Sub-TLV is carried in the Router Information Link
   State Advertisement (LSA).  The format is as follows.


       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            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        My Discriminator                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     RESERVED          |            BIFT-id                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                 BitString  (first 32 bits)                    ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                                                               ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                 BitString  (last 32 bits)                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 2: BIER BFD Sub-TLV for OSPF extension


   Type : TBD4 by IANA.

   Length : Length of the BIER BFD Sub-TLV for OSPF extension, in bytes.

   Other fields in BIER BFD Sub-TLV is the same with section 4.2.1.

5.  Discriminators and Packet Demultiplexing

   The tail(BFER) demultiplexes incoming BFD packets based on a
   combination of the source address and My discriminator as specified
   in [I-D.ietf-bfd-multipoint].  The source address is BFIR-id and BIER
   MPLS Label (MPLS network) or BFIR-id and BIFT-id (Non-MPLS network)
   for BIER BFD.

6.  Active Tail in BIER BFD

   [I-D.ietf-bfd-multipoint-active-tail] defined an extension for
   Multipoint BFD, which allows tails to notify the head of the lack of
   multipoint connectivity.  For BIER BFD in active tail mode, the BFIR
   may learn the state and connectivity of the BFERs.  As per
   [I-D.ietf-bfd-multipoint-active-tail], the BFIR can send the Poll
   sequence messages in combination with the unicast BFD over the
   monitored BFERs.



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7.  Security Considerations

   For BIER OAM packet procssing security considerations, see
   [I-D.ietf-bier-ping].

   For general multipoint BFD security considerations, see
   [I-D.ietf-bfd-multipoint].

   No additional security issues are raised in this document beyond
   those that exist in the referenced BFD documents.

8.  Acknowledgements

   Authors would like to thank the comments and suggestions from Jeffrey
   (Zhaohui) Zhang, Donald Eastlake 3rd.

9.  IANA Considerations

   IANA is requested to assign new type from the BIER OAM Message Type
   registry as follows:

        +--------+-----------------------------+------------------+
        | Value  | Description                 |    Reference     |
        +--------+-----------------------------+------------------+
        |  TBD1  | BIER BFD                    | [this document]  |
        |  TBD2  | BFD discriminator TLV       | [this document]  |
        |  TBD3  | BIER BFD Sub-TLV for IS-IS  | [this document]  |
        |  TBD4  | BIER BFD Sub-TLV for OSPF   | [this document]  |
        +--------+-----------------------------+------------------+

                                  Table 1

10.  References

10.1.  Normative References

   [I-D.ietf-bfd-multipoint]
              Katz, D., Ward, D., Networks, J., and G. Mirsky, "BFD for
              Multipoint Networks", draft-ietf-bfd-multipoint-19 (work
              in progress), December 2018.

   [I-D.ietf-bier-ping]
              Kumar, N., Pignataro, C., Akiya, N., Zheng, L., Chen, M.,
              and G. Mirsky, "BIER Ping and Trace", draft-ietf-bier-
              ping-04 (work in progress), October 2018.






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   [I-D.xiong-bier-resilience]
              Xiong, Q., hu, f., and G. Mirsky, "The Resilience for
              BIER", draft-xiong-bier-resilience-01 (work in progress),
              October 2018.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
              <https://www.rfc-editor.org/info/rfc5880>.

   [RFC6213]  Hopps, C. and L. Ginsberg, "IS-IS BFD-Enabled TLV",
              RFC 6213, DOI 10.17487/RFC6213, April 2011,
              <https://www.rfc-editor.org/info/rfc6213>.

   [RFC6328]  Eastlake 3rd, D., "IANA Considerations for Network Layer
              Protocol Identifiers", BCP 164, RFC 6328,
              DOI 10.17487/RFC6328, July 2011,
              <https://www.rfc-editor.org/info/rfc6328>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [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>.

10.2.  Informative References

   [I-D.ietf-bfd-multipoint-active-tail]
              Katz, D., Ward, D., Networks, J., and G. Mirsky, "BFD
              Multipoint Active Tails.", draft-ietf-bfd-multipoint-
              active-tail-10 (work in progress), November 2018.

   [ISO9577]  ISO/IEC TR 9577:1999,, "International Organization for
              Standardization "Information technology -
              Telecommunications and Information exchange between
              systems - Protocol identification in the network layer"",
              1999.






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Authors' Addresses

   Quan Xiong
   ZTE Corporation
   No.6 Huashi Park Rd
   Wuhan, Hubei  430223
   China

   Phone: +86 27 83531060
   Email: xiong.quan@zte.com.cn


   Greg Mirsky
   ZTE Corporation
   USA

   Email: gregimirsky@gmail.com


   Fangwei Hu
   ZTE Corporation
   No.889 Bibo Rd
   Shanghai  201203
   China

   Phone: +86 21 68896273
   Email: hu.fangwei@zte.com.cn


   Chang Liu
   China Unicom
   No.9 Shouti Nanlu
   Beijing   100048
   China

   Phone: +86-010-68799999-7294
   Email: liuc131@chinaunicom.cn














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