MPLS Working Group                                             G. Mirsky
Internet-Draft                                                 ZTE Corp.
Intended status: Standards Track                          April 21, 2017
Expires: October 23, 2017


     BFD for Multipoint Networks over Point-to-Multi-Point MPLS LSP
                     draft-mirsky-mpls-p2mp-bfd-00

Abstract

   This document describes procedures for using Bidirectional Forwarding
   Detection (BFD) for multipoint networks to detect data plane failures
   in Multiprotocol Label Switching (MPLS) point-to-multipoint (p2mp)
   Label Switched Paths (LSPs).  It also describes applicability of out-
   band solutions to bootstrap a BFD session in this environment.

Status of This Memo

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

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   This Internet-Draft will expire on October 23, 2017.

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   described in the Simplified BSD License.



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Table of Contents

   1.  Conventions used in this document . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Multipoint BFD Encapsulation  . . . . . . . . . . . . . . . .   3
     3.1.  IP Encapsulation of Multipoint BFD  . . . . . . . . . . .   3
     3.2.  Non-IP Encapsulation of Multipoint BFD  . . . . . . . . .   3
   4.  Bootstrapping Multipoint BFD  . . . . . . . . . . . . . . . .   4
     4.1.  LSP Ping  . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Control Plane . . . . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Source MEP ID IP Address Type . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Conventions used in this document

1.1.  Terminology

   MPLS: Multiprotocol Label Switching

   LSP: Label Switched Path

   BFD: Bidirectional Forwarding Detection

   p2mp: Point-to-Multipoint

   FEC: Forwarding Equivalence Class

   G-ACh: Generic Associated Channel

   ACH: Associated Channel Header

   GAL: G-ACh Label

1.2.  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 RFC 2119 [RFC2119].







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2.  Introduction

   [I-D.ietf-bfd-multipoint] defines a method of using Bidirectional
   Detection (BFD) [RFC5880] to monitor and detect unicast failures
   between the sender (head) and one or more receivers (tails) in
   multipoint or multicast networks.  This document describes procedures
   for using such mode of BFD protocol to detect data plane failures in
   Multiprotocol Label Switching (MPLS) point-to-multipoint (p2mp) Label
   Switched Paths (LSPs).  The document also describes applicability of
   out-band solutions to bootstrap a BFD session in this environment.

3.  Multipoint BFD Encapsulation

   [I-D.ietf-bfd-multipoint] defines the tail of multipoint BFD session
   demultiplexes received BFD control packet based not on Your
   Discriminator, as defined in [RFC5880], but using source IP address,
   My Discriminator and the identity of the multipoint tree which the
   Multipoint BFD Control packet was received from.  The identity of the
   multipoint tree MAY be provided by the p2mp MPLS LSP label in case of
   inclusive p-tree or upstream assigned label in case of aggregate
   p-tree.

3.1.  IP Encapsulation of Multipoint BFD

   IP/UDP encapsulation for multipoint BFD over p2mp MPLS LSP follows
   the same rules as defined in Section 7 [RFC5884] for BFD over p2p
   LSP:

      UDP destination port MUST be set to 3784;

      destination IP address MUST be from the 127/8 range for IPv4 and
      from the 0:0:0:0:0:FFFF:7F00/104 range for IPv6;

      if multiple alternative paths for the given p2mp LSP Forwarding
      Equivalence Class(FEC) exist, the MultipointHead SHOULD use
      Entropy Label [RFC6790] used for LSP Ping [RFC8029] to excercise
      that particular alternative path;

      or the MultipointHead MAY use, as destination IP address, the IP
      address discovered by LSP Ping traceroute [RFC8029] to exercise
      that particular alternate path.

3.2.  Non-IP Encapsulation of Multipoint BFD

   Non-IP encapsulation for multipoint BFD over p2mp MPLS LSP MUST use
   Generic Associated Channel (G-ACh) Label (GAL) [RFC5586] at the
   bottom of the label stack followed by Associated Channel Header
   (ACH).  Channel Type field in ACH MUST be set to BFD CV [RFC6428].



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   To provide identity of the MultipointHead for the particular
   multipoint BFD session this document defines new Source MEP ID type
   TBA1 Section 5.1 IP Address.  If the Legnth value is 4, then the
   Value field contains IPv4 address.  If the Length value is 16, then
   the Value field contains IPv6 address.  Any other value of the Length
   field MUST be considered as error and the BFD control packet MUST be
   discarded.

4.  Bootstrapping Multipoint BFD

4.1.  LSP Ping

   MaultipointHead MAY use LSP Ping [RFC8029] using in Target FEC TLV,
   as appropriate, sub-TLVs defined in Section 3.1 [RFC6425].

4.2.  Control Plane

   BGP-BFD Attribute [I-D.ietf-bess-mvpn-fast-failover] MAY be used to
   bootstrap multipoint BFD session on a tail.

5.  IANA Considerations

5.1.  Source MEP ID IP Address Type

   IANA is required to allocate value (TBD) for the Source Source MEP ID
   IP Address type from the "CC/CV MEP-ID TLV" registry which is under
   the "Pseudowire Associated Channel Types" registry.

                  +-------+-------------+---------------+
                  | Value | Description | Reference     |
                  +-------+-------------+---------------+
                  | TBA1  |  IP Address | This document |
                  +-------+-------------+---------------+

                Table 1: Source MEP ID IP Address TLV Type

6.  Security Considerations

   Thi document does not introduce new security aspects but inherits all
   security considerations from [RFC5880], [RFC5884], [RFC7726],
   [I-D.ietf-bfd-multipoint], [RFC8029], and [RFC6425].

7.  Acknowledgements








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8.  Normative References

   [I-D.ietf-bess-mvpn-fast-failover]
              Morin, T. and R. Kebler, "Multicast VPN fast upstream
              failover", draft-ietf-bess-mvpn-fast-failover-02 (work in
              progress), March 2017.

   [I-D.ietf-bfd-multipoint]
              Katz, D., Ward, D., and J. Networks, "BFD for Multipoint
              Networks", draft-ietf-bfd-multipoint-09 (work in
              progress), October 2016.

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

   [RFC5586]  Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
              "MPLS Generic Associated Channel", RFC 5586,
              DOI 10.17487/RFC5586, June 2009,
              <http://www.rfc-editor.org/info/rfc5586>.

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

   [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
              "Bidirectional Forwarding Detection (BFD) for MPLS Label
              Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884,
              June 2010, <http://www.rfc-editor.org/info/rfc5884>.

   [RFC6425]  Saxena, S., Ed., Swallow, G., Ali, Z., Farrel, A.,
              Yasukawa, S., and T. Nadeau, "Detecting Data-Plane
              Failures in Point-to-Multipoint MPLS - Extensions to LSP
              Ping", RFC 6425, DOI 10.17487/RFC6425, November 2011,
              <http://www.rfc-editor.org/info/rfc6425>.

   [RFC6428]  Allan, D., Ed., Swallow, G., Ed., and J. Drake, Ed.,
              "Proactive Connectivity Verification, Continuity Check,
              and Remote Defect Indication for the MPLS Transport
              Profile", RFC 6428, DOI 10.17487/RFC6428, November 2011,
              <http://www.rfc-editor.org/info/rfc6428>.

   [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
              L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
              RFC 6790, DOI 10.17487/RFC6790, November 2012,
              <http://www.rfc-editor.org/info/rfc6790>.




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   [RFC7726]  Govindan, V., Rajaraman, K., Mirsky, G., Akiya, N., and S.
              Aldrin, "Clarifying Procedures for Establishing BFD
              Sessions for MPLS Label Switched Paths (LSPs)", RFC 7726,
              DOI 10.17487/RFC7726, January 2016,
              <http://www.rfc-editor.org/info/rfc7726>.

   [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
              Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
              Switched (MPLS) Data-Plane Failures", RFC 8029,
              DOI 10.17487/RFC8029, March 2017,
              <http://www.rfc-editor.org/info/rfc8029>.

Author's Address

   Greg Mirsky
   ZTE Corp.

   Email: gregimirsky@gmail.com

































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