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BGP Extension For L3VPN Performance Monitoring
draft-fan-bess-pm-bgp-02

Document Type Active Internet-Draft (individual)
Authors Jiajia Fan , Zhenbin Li , Shunwan Zhuang
Last updated 2024-03-03
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draft-fan-bess-pm-bgp-02
Network Working Group                                             J. Fan
Internet-Draft                                                     Z. Li
Intended status: Standards Track                               S. Zhuang
Expires: 4 September 2024                                         Huawei
                                                            3 March 2024

             BGP Extension For L3VPN Performance Monitoring
                        draft-fan-bess-pm-bgp-02

Abstract

   This document describes a new VT address family in BGP to exchange
   information required for apply performance monitoring in MPLS/BGP
   VPN, as described in [I-D.dong-l3vpn-pm-framework].

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].

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 4 September 2024.

Copyright Notice

   Copyright (c) 2024 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

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   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminologies . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The New VT Sub Address Family . . . . . . . . . . . . . . . .   3
     3.1.  VT Sub Address Family . . . . . . . . . . . . . . . . . .   3
     3.2.  VT NLRI . . . . . . . . . . . . . . . . . . . . . . . . .   4
       3.2.1.  VT VPN-membership A-D Route . . . . . . . . . . . . .   5
       3.2.2.  VT Labeled Route  . . . . . . . . . . . . . . . . . .   5
   4.  Operations  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  VRF-to-VRF VPN Membership Auto Discovery  . . . . . . . .   6
     4.2.  VRF-to-VRF Labeled Route Exchange . . . . . . . . . . . .   7
       4.2.1.  VT Labeled Route Update . . . . . . . . . . . . . . .   7
       4.2.2.  VT Labeled Route Withdrawal . . . . . . . . . . . . .   7
     4.3.  VRF-to-VRF Labeled Route Application  . . . . . . . . . .   8
   5.  VT Route Selection Consideration  . . . . . . . . . . . . . .   8
   6.  Deployment Consideration  . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     10.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   This document describes the BGP encodings and procedures for
   exchanging the information elements required by applying traffic
   performance monitoring in MPLS/BGP VPN, as specified
   in[I-D.dong-l3vpn-pm-framework].

   Current BGP Labeled VPN Route exchange procedure combines VRF VPN-
   membership Auto-Discovery and L3VPN Label allocation together.  While
   applying PM for L3VPN needs BGP extended to support VPN membership
   Auto-Discovery and L3VPN Label allocation in a VRF-to-VRF manner.  To
   achieve this, a new Sub address family, called VRF-to-VRF Tunnel(VT)
   Subsequent Address Family, is introduced.

   This document defines two kinds of routes for VT NLRI:

   VPN-Membership A-D Route: for the use of doing VRF VPN membership
   auto-discovery in VRF-to-VRF manner

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   VT Labeled Route: for the use of allocating VT Label from Local VRF
   to Remote VRF to setup VRF-to-VRF Tunnel between the pair of VRFs.

2.  Terminologies

   This document uses the terminologies defined in [RFC4026]:

   *  ERT: Export Route Target

   *  IRT: Import Route Target

   *  PE: Provider Edge

   *  RD: Route Distinguisher

   *  VRF: Virtual Routing and Forwarding

   *  VT: VRF-to-VRF Tunnel

3.  The New VT Sub Address Family

   The BGP Multiprotocol Extensions [RFC4760] allow BGP to carry routes
   from multiple "address families".  In this document a new Subsequent
   Address Family is introduced, called "VT Sub Address Family".

3.1.  VT Sub Address Family

   VT Address Family uses AFI 1/2 to present IPv4/IPv6 Address Family
   and a specific VT_SAFI(TBD) to present VT Subsequent Address Family.

   VT MP_REACH_NLRI and MP_UNREACH_NLRI are formatted as described in
   [RFC4760]

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   +---------------------------------------------------+
   | Address Family Identifier (2 octets): 1/2         |
   +---------------------------------------------------+
   | Subsequent AFI (1 octet): VT_SAFI (TBD)           |
   +---------------------------------------------------+
   | Length of Next Hop (1 octet): 4                   |
   +---------------------------------------------------+
   | Next Hop: IPv4 Address                            |
   +---------------------------------------------------+
   | Reserved (1 octet)                                |
   +---------------------------------------------------+
   | BGP VT NLRI (Variable)                            |
   +---------------------------------------------------+
               Figure 1 VT MP_REACH_NLRI
   +---------------------------------------------------+
   | Address Family Identifier (2 octets): 1/2         |
   +---------------------------------------------------+
   | Subsequent AFI (1 octet): VT_SAFI (TBD)           |
   +---------------------------------------------------+
   | BGP VT NLRI (Variable)                            |
   +---------------------------------------------------+
               Figure 2 VT MP_UNREACH_NLRI

3.2.  VT NLRI

   BGP VT NLRI has format as depicted in following diagram:

   +---------------------------------------------------+
   | Route Type (1 octet)                              |
   +---------------------------------------------------+
   | Length (1 octet)                                  |
   +---------------------------------------------------+
   | Route Type Specific (Variable)                    |
   +---------------------------------------------------+
               Figure 3 IPv4 VT-Family NLRI

   Route Type indicates type of route under VT SAFI.

   Type 1: VT VPN membership A-D Route

   Type 2: VT Labeled Route

   Length defines Route Type specific routes length in octets

   Route Type specific route information field, encoded according to
   Route Type definition.

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3.2.1.  VT VPN-membership A-D Route

   VT VPN membership A-D Route, concisely named as VT A-D Route
   hereafter, is utilized for VRF-to-VRF VPN Membership Auto-Discovery
   between PEs.

   Its format is defined as following diagram:

   +--------------------------------------------------+
   | RD (8 octets)                                    |
   +--------------------------------------------------+
   | Local Router's IP Address                        |
   +--------------------------------------------------+
           Figure 4 VT VPN Membership A-D Route

   a) RD: RD of one VRF on advertising PE, encoded as described in
   [RFC4364].

   b) Local Router's IP Address: Advertising PE's IPv4/IPv6 address <RD,
   Local Router's IP Address> is defined as Prefix of VT A-D Route.

3.2.2.  VT Labeled Route

   VT Labeled Route is utilized for VRF-To-VRF Label(s) allocation and
   advertisement, its format is defined as following diagram.

   +---------------------------------------------------+
   | Local RD (8 octets)                               |
   +---------------------------------------------------+
   | Local Router's IP Address                         |
   +---------------------------------------------------+
   | Remote VRF's RD (8 octets)                        |
   +---------------------------------------------------+
   | Remote Router's IP Address                        |
   +---------------------------------------------------+
   | Label (3 octets)                                  |
   +---------------------------------------------------+
            Figure 5 VT Labeled Route Format

   a) Local RD: Route Distinguisher value of one VRF on advertising PE,
   encoded as described in [RFC4364].

   b) Local Router's IP Address: Advertising PE's IPv4/IPv6 address.

   c) Remote VRF's RD: Route Distinguisher value of Remote VRF encoded
   as described in [RFC4364].

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   d) Remote Router's IP Address: Remote PE's IPv4/IPv6 address.

   e) Label: The Label field carries one or more labels that corresponds
   to the stack of labels [RFC3032].  Each label is encoded as 3 octets,
   where the high-order 20 bits contain the label value, and the low-
   order bit contains "Bottom of Stack" as defined in [RFC3032].

   <Local RD, Local Router's IP Address, Remote VRF's RD, Remote
   Router's IP Address> which indicates a pair of VRFs is defined as the
   Prefix of VT Labeled Route.

4.  Operations

4.1.  VRF-to-VRF VPN Membership Auto Discovery

   For every PE, it needs to process all its VRF configured and generate
   one VT A-D Route for each VRF respectively.

   RD field MUST be filled with the VRF's RD value.

   Local Router's IP Address field MUST filled with the Advertising
   Router's IP address.

   The VT A-D Route MUST carry all IRTs of the VRF in BGP Update's Ext-
   Community Path Attribute, route importing request of one VRF is
   described by its corresponding VT A-D route.  In contrast VPN Labeled
   Routes carry ERTs in BGP Update's Ext-Community Path Attribute.

   If a VRF is created, then its corresponding VT A-D Route MUST be
   generated and advertised.

   If the VRF whose VT A-D Route has been advertised is deleted, then
   the VT A-D Route Withdrawal message MUST be generated and advertised.

   If IRT of the VRF whose VT A-D Route has been advertised is changed,
   then a VT A-D Route Update with same Prefix and latest IRTs MUST be
   advertised.

   When receiving PE receives VT A-D Route, VPN relationship matching
   MUST be checked between IRTs in VT A-D Route and ERTs of each Local
   VRF, this process is called VRF-to-VRF VPN membership Auto Discovery.

   Either finding one VRF-to-VRF VPN membership newly formed or
   released, receiving PE MUST proceed to the VT Labeled Route
   processing described in next section.

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4.2.  VRF-to-VRF Labeled Route Exchange

4.2.1.  VT Labeled Route Update

   If Receiving PE finds one new VRF-to-VRF VPN membership formed, it
   MUST allocate one VT MPLS Label for the VRF-to-VRF VPN membership and
   the label is advertised to the Remote VRF by VT Labeled Route.

   Local RD MUST filled with RD value of the Local VRF which is found
   belong to the same VPN with Remote VRF.

   Local Router's IP Address Must filled with the advertising PE's IPv4/
   IPv6 address.

   Remote VRF's RD MUST filled with RD value of the Remote VRF which
   belongs to a same VPN with the Local VRF.

   Remote Router's IP Address: Remote PE's IPv4/IPv6 address.

   Label: MUST be filled with one or more MPLS Labels allocated by
   advertising PE for the pair of VRFs.

   Only both sides of a pair of VRFs learnt each other's VT Labeled
   Route advertisement, the VRF-to-VRF tunnel between the pair of VRFs
   is considered setup.

4.2.2.  VT Labeled Route Withdrawal

   If receiving PE finds one existing VRF-to-VRF VPN membership released
   then it MUST send out the VT Labeled Route Withdrawal message, then
   release the MPLS Label(s) allocated.

   Local RD MUST be filled with RD value of the Local VRF.

   Local Router's IP Address MUST be filled with the advertising PE's
   IPv4/IPv6 address.

   Remote VRF's RD MUST be filled with RD value of the Remote VRF.

   Remote Router's IP Address: MUST be filled with Remote PE's IPv4/IPv6
   address.

   Label: MUST be filled with ZERO or the MPLS Labels value allocated
   for the VT Labeled Route.

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4.3.  VRF-to-VRF Labeled Route Application

   To achieve the goal of converting normal L3VPN MP2P forwarding model
   into P2P model which is required in [I-D.zheng-l3vpn-pm-analysis],
   after VPNv4 routes received, Receiving PE MUST apply VT Labels when
   downloading VPNv4 Route into Data Plan which is in detail described
   in [I-D.dong-l3vpn-pm-framework].

   Between a pair of PEs both support VT capability, It COULD be an
   implementation option that VPNv4 Routes from a remote VRF WOULD NOT
   be downloaded into a Local VRF's Forwarding Plan until a VT Labeled
   route received from same Remote VRF for the Local VRF.

   If VT Labeled Route withdrawal message is received, receiving PE MUST
   delete VT Labels from Forwarding Plane and VPNv4 Routes MUST be kept
   on Forwarding Plane with original VPNv4 Label as inner Label.

5.  VT Route Selection Consideration

   When receiving and processing VT A-D Route, the BGP best route
   selection procedure described in [RFC4271] MUST be followed.

   When receiving and processing VT Labeled Route, the BGP best route
   selection procedure described in [RFC4271] COULD be followed.

   Especially VT Labeled Route MUST be advertised ONLY to the BGP peer
   from which the best VT A-D route is received, the VT A-D route
   contains the Remote VRF's RD and Remote PE's IP address.

   If a Peer receives VT A-D or VT Labeled Route originated from itself,
   the route MUST be ignored.

6.  Deployment Consideration

   This document currently supports deploying VT SAFI in following two
   manners:

   a) Inner-AS L3VPN with Full-mesh IBGP sessions or Router Reflectors.

   b)Inter-AS L3VPN with Option A(VRF-to-VRF)[RFC4364].

   How to support Inter-AS L3VPN Option B(MP-EBGP) and Option-C
   [RFC4364] will be described in this draft's future version.

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7.  IANA Considerations

   A new SAFI value to present VT Subsequent Address Family is required
   and to be allocated by IANA.

8.  Security Considerations

   This extension to BGP does not change the underlying security issues.

9.  Acknowledgements

   TBD.

10.  References

10.1.  Normative References

   [I-D.dong-l3vpn-pm-framework]
              Dong, J., Li, Z., and B. Parise, "A Framework for L3VPN
              Performance Monitoring", Work in Progress, Internet-Draft,
              draft-dong-l3vpn-pm-framework-03, 27 October 2014,
              <https://datatracker.ietf.org/doc/html/draft-dong-l3vpn-
              pm-framework-03>.

   [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>.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
              <https://www.rfc-editor.org/info/rfc3032>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <https://www.rfc-editor.org/info/rfc4364>.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <https://www.rfc-editor.org/info/rfc4760>.

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10.2.  Informative References

   [I-D.zheng-l3vpn-pm-analysis]
              Zheng, L., Li, Z., Aldrin, S., and B. Parise, "Performance
              Monitoring Analysis for L3VPN", Work in Progress,
              Internet-Draft, draft-zheng-l3vpn-pm-analysis-03, 3 July
              2014, <https://datatracker.ietf.org/doc/html/draft-zheng-
              l3vpn-pm-analysis-03>.

Authors' Addresses

   Jiajia Fan
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China
   Email: fanjiajia@huawei.com

   Zhenbin Li
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China
   Email: lizhenbin@huawei.com

   Shunwan Zhuang
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China
   Email: zhuangshunwan@huawei.com

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