[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00

BIER Workgroup                                                H. Bidgoli
Internet Draft                                               J. Kotalwar
Intended status: Standard Track                                    Nokia
                                                                 Z.Zhang
                                                        Juniper Networks
                                                            Eddie Leyton
                                                                  Vrizon
                                                        Mankamana Mishra
                                                            I. Wijanands
                                                      Cisco System, Inc.


Expires: January 7, 2020                                    July 6, 2019


                   M-LDP Signaling Through BIER Core
               draft-hb-bier-mldp-signaling-over-bier-00

Abstract

   Bit Index Explicit Replication (BIER) is an architecture that
   provides multicast forwarding through a "BIER domain" without
   requiring intermediate routers to maintain multicast related per-flow
   state.  Neither does BIER require an explicit tree-building protocol
   for its operation.  A multicast data packet enters a BIER domain at a
   "Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at
   one or more "Bit-Forwarding Egress Routers" (BFERs).  The BFIR router
   adds a BIER header to the packet.  Such header contains a bit-string
   in which each bit represents exactly one BFER to forward the packet
   to.  The set of BFERs to which the multicast packet needs to be
   forwarded is expressed by the according set of bits switched on in
   BIER packet header.

   This document describes the procedure needed for mLDP tunnels to be
   signaled over and stitched through a BIER core, allowing LDP routers
   to run traditional Multipoint LDP services through a BIER core.


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), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.




Bidgoli, et al.         Expires January 7, 2020                 [Page 1]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


   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." The list
   of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on October 8, 2017.

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
   (http://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  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2. Conventions used in this document . . . . . . . . . . . . . . .  3
     2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . .  3
   3. mLDP Signaling Through BIER domain  . . . . . . . . . . . . . .  4
     3.1. Ingress BBR procedure . . . . . . . . . . . . . . . . . . .  5
       3.1.1. Automatic tLDP session creation . . . . . . . . . . . .  5
     3.2. EBBR procedure method . . . . . . . . . . . . . . . . . . .  6
   4. Datapath Forwarding . . . . . . . . . . . . . . . . . . . . . .  6
     4.1. Datapath traffic flow . . . . . . . . . . . . . . . . . . .  6
   5. Recursive FEC . . . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
   7. Security Considerations . . . . . . . . . . . . . . . . . . . .  7
   8. References  . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     8.1. Normative References  . . . . . . . . . . . . . . . . . . .  7
     8.2. Informative References  . . . . . . . . . . . . . . . . . .  7
   7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . .  7
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  7




Bidgoli, et al.         Expires January 7, 2020                 [Page 2]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


1. Introduction

   Some operators that are using mLDP P2MP LSPs for their multicast
   transport would like to deploy BIER technology in some segment of
   their network. This draft explains a method to signal mLDP services
   and stitch it to a BIER domain, with minimal disruption and
   operational impact to the mLDP domain.

2. Conventions used in this document

   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].

2.1. Definitions

   Some of the terminology specified in [I-D.draft-ietf-bier-
   architecture-05] is replicated here and extended by necessary
   definitions:

   BIER:

          Bit Index Explicit Replication (The overall architecture of
          forwarding multicast using a Bit Position).

   BFR:

          Bit Forwarding Router (A router that participates in Bit Index
          Multipoint Forwarding).  A BFR is identified by a unique BFR-
          prefix in a BIER domain.

   BFIR:

          Bit Forwarding Ingress Router (The ingress border router that
          inserts the Bit Map into the packet).  Each BFIR must have a
          valid BFR-id assigned. BFIR is term used for dataplain packet
          forwarding.

   BFER:

          Bit Forwarding Egress Router.  A router that participates in
          Bit Index Forwarding as leaf.  Each BFER must be a BFR.  Each
          BFER must have a valid BFR-id assigned. BFIR is term used for
          dataplain packet forwarding.

   BBR:

          BIER Boundary router. The router between the LDP domain and



Bidgoli, et al.         Expires January 7, 2020                 [Page 3]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


          BIER domain.

   IBBR:

          Ingress BIER Boundary Router. The ingress router from
          signaling point of view. It maintains mLDP adjacency toward
          the LDP domain and determines if the mLDP FEC needs to be
          signaled across the BIER domain via targeted ldp.

   EBBR:

          Egress BIER Boundary Router. The egress router in BIER domain
          from signaling point of view. It terminates the targeted ldp
          signaling through BIER domain. It also keeps track of all
          IBBRs that are part of this p2mp tree

   BFT:

          Bit Forwarding Tree used to reach all BFERs in a domain.

   BIFT:

          Bit Index Forwarding Table.

   BIER sub-domain:

          A further distinction within a BIER domain identified by its
          unique sub-domain identifier.  A BIER sub-domain can support
          multiple BitString Lengths.



   BFR-id:

          An optional, unique identifier for a BFR within a BIER sub-
          domain.


3. mLDP Signaling Through BIER domain












Bidgoli, et al.         Expires January 7, 2020                 [Page 4]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


                        bbr                   bbr
        |---LDP Domain--|-----BIER domain-----|---LDP domain--|
   S--( A )-----------( B ) ---- ( C ) ---- ( D )-----------( E )--h


                       ebbr                  ibbr
    Sig  <----MLDP------|<----targeted LDP----|<---MLDP------
   (new)

                      bfir                  bfer
          ------------->|--------BIER-------->|------------->  Datapatah
                                                            (new)

                     Figure 1: bier boundary router

   As per figure 1, point-to-multipoint and multipoint-to-multipoint
   LSPs established via mLDP [RFC6388] can be signaled through a bier
   domain via targeted LDP sessions. This procedure is explained in
   [RFC7060] (Using LDP Multipoint Extension on Targeted LDP Sessions).

   This documents provides some details and defines some needed
   procedures.


3.1. Ingress BBR procedure

   The Ingress BBR (IBBR) is connected to the mLDP on one side and a
   bier domain on the other side. To connect the LDP domains via BIER
   domain IBBR needs to be a establish targeted LDP session with EBBR
   closest to the root of the P2mp or mp2mp LSP. To do so IBBR will
   follow procedures in [RFC7060] in particular the section "6. targeted
   mLDP with Multicast Tunneling".

   The target LDP session can be established manually via configuration
   or via automated mechanism.


3.1.1. Automatic tLDP session creation

   A tLDP session can be generated automatically from every IBBR to EBBR
   when a mLDP FEC arrives on the IBBR. The Root node address in the
   mLDP FEC can be used to find the EBBR. To identify the EBBR same
   procedures as [RFC7060} section 2.1 can be used or the procedures as
   explained in the [draft-ietf-bier-pim-signaling] appendix A. After
   fining the IBBR the tLDP session can be initiated from the IBBR to
   EBBR.





Bidgoli, et al.         Expires January 7, 2020                 [Page 5]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


3.2. EBBR procedure method

   The Egress BBR (EBBR) is connected to the mLDP domain which the root
   of the P2MP or MP2MP LSP resides on. The EBBR should accept the tLDP
   session and assign a upstream assigned label for arriving FEC.

   The EBBR should follow the [RFC7060] procedures with following
   modifications:

   - The label assigned by EBBR cannot be Implicit Null. This is to
   ensure that identity of each p2mp and/or mp2mp tunnel in BIER domain
   is uniquely distinguished.

   - The label can be assigned from a domain-wide Common Block (DCB) [I-
   D.zzhang-bess-mvpn-evpn-aggregation-label], as well as upstream
   assigned.

   - The Interface ID TLV [RFC6389]includes a new BIER sub-domain sub-
   tlv (type TBD)

   With same token the EBBR should track all the arriving FECs and the
   IBBRs that are generating these FECs. EBBR will use this information
   to build the bier header for each set of common FEC arriving from the
   IBBRs.


4. Datapath Forwarding

4.1. Datapath traffic flow

   On BFIR when the MPLS label for P2MP/MP2MP LSP arrives a lookup in
   ILM table is done and the label is swapped with tLDP upstream
   assigned label. The BFIR will note all the BFERs that are interested
   in specific p2mp/mp2mp LSP (as per section 3.2). BFIR will put the
   corresponding BIER header with bit index set for all IBBRs interested
   in this P2MP LSP. BFIR will set the  BIERHeader.Proto = MPLS and will
   forward the BIER packet into BIER domain.

   In the BIER domain normal BIER forwarding procedure will be done, as
   per [RFC 8279]

   The IBBRs will receive the BIER packet, will look at the protocol of
   BIER header (MPLS). BFER will remove the BIER header and will do a
   lookup in the ILM table for the upstream assigned label and perform
   its corresponding action.

   It should be noted that these procedures are valid if BFIR is the
   ILER and/or BFER is the ELER as per [RFC 7060]



Bidgoli, et al.         Expires January 7, 2020                 [Page 6]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


5. Recursive FEC

   The above procedures also will work with a mLDP recursive FEC. The
   root used to determine the EBBR is the outer root of the FEC. The
   entire recursive FEC needs to be preserve when it is forwarded via
   tLDP and the label request.

6.  IANA Considerations

   This document contains no actions for IANA.

7. Security Considerations

   TBD

8. References

8.1. Normative References

   [BIER_ARCH] Wijnands, IJ., Rosen, E., Dolganow, A., Przygienda, T.,
   and S. Aldrin, "Multicast using Bit Index Explicit Replication",
   internet-draft draft-ietf-bier-architecture-08, October 2016.

8.2. Informative References

   [BIER_MVPN] Rosen, E., Ed., Sivakumar, M., Wijnands, IJ., Aldrin, S.,
   Dolganow, A., and T. Przygienda, "Multicast VPN Using Bier",
   internet-draft draft-ietf-bier-mvpn-08, January 2017.

   [ISIS_BIER_EXTENSIONS] Ginsberg, L., Przygienda, T., Aldrin, S., and
   Z. Zhang, "BIER Support via ISIS", internet-draft draft-ietf-bier-
   isis-extensions-06.txt, March 2017.

   [OSPF_BIER_EXTENSIONS] Psenak, P., Kumar, N., Wijnands, IJ.,
   Dolganow, A., Przygienda, T., Zhang, Z., and S. Aldrin, "OSPF
   Extensions for Bit Index Explicit Replication", internet-draft draft-
   ietf-ospf-bier-extensions-09.txt, March 2017.

7. Acknowledgments <Add any acknowledgements>

Authors' Addresses

   Hooman Bidgoli (editor)
   Nokia
   600 March Rd.
   Ottawa, Ontario K2K 2E6
   Canada




Bidgoli, et al.         Expires January 7, 2020                 [Page 7]


Internet-Draft      MLDP Signaling Through BIER Core        July 6, 2019


   Email: hooman.bidgoli@nokia.com

   Jayant Kotalwar
   Nokia
   380 N Bernardo Ave,
   Mountain View, CA 94043
   US

   Email: jayant.kotalwar@nokia.com

   Zhaohui Zhang
   Juniper Networks

   EMail: zzhang@juniper.net


   IJsbrand Wijnands
   Cisco Systems

   EMail: ice@cisco.com

   Eddie Leyton
   Vrizon

   Email: Edward.leyton@verizonwireless.com

   Mankamana Mishra
   Cisco System
   821 alder drive
   Milpitas California
   USA

   Email: mankamis@cisco.com


















Bidgoli, et al.         Expires January 7, 2020                 [Page 8]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/