Group Policy ID BGP Extended Community
draft-wlin-bess-group-policy-id-extended-community-03

bess                                                              W. Lin
Internet-Draft                                          Juniper Networks
Intended status: Standards Track                                J. Drake
Expires: 22 April 2024                                        Individual
                                                                  D. Rao
                                                           Cisco Systems
                                                         20 October 2023

                 Group Policy ID BGP Extended Community
         draft-wlin-bess-group-policy-id-extended-community-03

Abstract

   Group Based Policy can be used to achieve micro or macro segmentation
   of user traffic.  For Group Based Policy, a Group Policy ID, also
   known as Group Policy Tag, is used to represent a logical group that
   shares the same policy and access privilege.  This specification
   defines a new BGP extended community that can be used to propagate
   Group Policy ID through a BGP route advertisement in the control
   plane.  This is to facilitate policy enforcement at the ingress node
   when the optimization of network bandwidth is desired.

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 22 April 2024.

Copyright Notice

   Copyright (c) 2023 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.

Lin, et al.               Expires 22 April 2024                 [Page 1]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

   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 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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  NVO Use Case  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Interconnecting multiple EVPN VXLAN domains . . . . . . . . .   4
   5.  EVPN Interworking with IPVPN  . . . . . . . . . . . . . . . .   5
   6.  The Group Policy ID Extended Community  . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     10.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Terminology

   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
   BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   EVPN: Ethernet Virtual Private Networks, as per [RFC7432].

   GBP: Group Based Policy

   VXLAN: Virtual Extensible LAN

   NVO: Network Virtualization Overlay

   NVE: Network Virtualization Edge

   DCI: Data Center Interconnect

Lin, et al.               Expires 22 April 2024                 [Page 2]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

2.  Introduction

   In the virtualized overlay network where EVPN with VXLAN
   encapsulation is used as the overlay solution, without external
   management software or controller, the propagation of a Group Policy
   ID is done through the data plane.  The source Group Policy ID is
   encoded in the VXLAN header before the user traffic is sent to the
   VXLAN tunnel.  The encoding format of a Group Policy ID in the VXLAN
   header is specified in [I-D.smith-vxlan-group-policy].

   When the source Group Policy ID is propagated through the data plane
   to the remote VXLAN tunnel endpoint, the policy enforcement is
   carried out at the egress node based on both the source and
   destination Group Policy tags.  The policy rule for the source and
   destination Group Policy tags may result in the traffic being dropped
   at the remote VXLAN tunnel endpoint which is the egress node.  To
   send the traffic all the way from an ingress node and then drop it at
   an egress node is an inefficient use of the network bandwidth.

   To optimize the network bandwidth usage, it may be desirable to have
   policy enforcement done at the head-end of a VXLAN tunnel that is the
   ingress node for the user traffic.  To accomplish this, there is a
   need to communicate the destination Group Policy ID from the egress
   node to the ingress node.  This document defines a Group Policy ID
   BGP Extended Community that can be used in the control plane to
   achieve the propagation of Group Policy ID from an egress node to an
   ingress node.

3.  NVO Use Case

   In an EVPN VXLAN overlay network, a policy group tag may be assigned
   based on the MAC, IP, port, VLAN, etc, or a combination of the above.
   Similar to the MAC/IP addresses in the EVPN network, once the Policy
   Group ID is known for a local host/server/VM attached to an EVPN
   network, its Group Policy ID can be advertised to other Network
   Virtualization Edge devices in the control plane through the Group
   Policy ID extended community.  The scheme used for classification and
   allocation of Policy Group IDs used for GBP in an EVPN overlay
   network with VXLAN encapsulation is outside the scope of this
   document.

Lin, et al.               Expires 22 April 2024                 [Page 3]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

   Policy group tag propagation in the EVPN/BGP control plane can be
   applied to the EVPN type-2 MAC/IP route[RFC7432], EVPN type-3
   Ethernet Inclusive Multicast route [RFC7432] or EVPN type-5 IP host
   and prefix route [RFC9136].  If Policy Group ID is allocated for a
   MAC address, IP host or prefix address through the GBP classification
   scheme, EVPN can encode its Group Policy ID through the Group Policy
   ID extended community and advertise it alongside its corresponding
   EVPN route.

   For the flows that the ingress VXLAN tunnel endpoint has learned its
   destination group policy tag through EVPN/BGP control plane
   signaling, the policy enforcement can be thus carried out right at
   the ingress node.  Otherwise, policy enforcement can be carried out
   at the egress node.  If policy enforcement is carried out at the
   head-end VXLAN tunnel, the ingress node MUST set the GBP applied bit,
   the A-bit as it is specified in [I-D.smith-vxlan-group-policy], to 1
   in the VXLAN header before forwarding the traffic to the VXLAN
   tunnel.  Otherwise, the ingress node sets the A-bit to 0 in the VXLAN
   header.

4.  Interconnecting multiple EVPN VXLAN domains

   EVPN VXLAN based deployments may comprise of multiple EVPN networks,
   domains or sites.  In such cases, a VXLAN overlay may extend from an
   ingress node to an egress node across different domains; or it may be
   divided into multiple stitched overlay segments that are
   interconnected via DCI through gateway devices.

   In this document, we simply refer to each EVPN network or site as a
   EVPN domain or domain for short unless it is explicitly specified
   otherwise.

   From a control plane point of view, border GWs in each domain may
   learn routes of other domains either via direct peering sessions or
   via a set of external route reflectors.

   In such deployments, the allocation and management of Group Policy
   IDs may be done independently in different domains, and consequently
   the allocated values scoped to each domain.  Therefore, when a group
   policy tag is signaled with routes to a different domain, the tag
   needs to be translated to a value local to the receiving domain
   before it can be used in a group based policy at an ingress node in
   that domain.

   A domain may receive routes from multiple sender domains.  In order
   to facilitate simpler and flexible application of translation
   policies regardless of the deployed overlay design or control plane
   peering model, the advertised Policy ID may also carry with it a

Lin, et al.               Expires 22 April 2024                 [Page 4]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

   Scope, which identifies the allocation domain.  Any suitable BGP node
   in the route distribution path can then consistently translate a
   received Policy ID based on the scope.

   Scope assignment is done by the administrator or orchestration system
   managing the multi-domain deployment.  The exact mechanism is out of
   the purview of this document.

5.  EVPN Interworking with IPVPN

   In the EVPN interworking use case as it is specified in the
   [I-D.ietf-bess-evpn-ipvpn-interworking], two or more EVPN networks/
   domains are interconnected by a layer 3 IP-VPN network with VPN-IPv4/
   VPN-IPv6 BGP address families.  To support ingress policy
   enforcement, the Policy Group ID extended community needs to be
   propagated by the GW PEs sitting at the border of an EVPN domain and
   IP-VPN domain from one domain to another.

   For the Uniform-Propagation-Mode defined in the
   [I-D.ietf-bess-evpn-ipvpn-interworking], when propagating an EVPN IP
   prefix route across the domain boundary to IP-VPN network, the
   Gateway PE SHOULD propagate communities, extended communities and
   large communities except for all the EVPN extended communities.  The
   Policy Group ID extended community defined in this document is a new
   transitive Opaque Extend Community.  It is not subject to stripping
   at the GW PE when the Uniform-Propagation-Mode is used, and SHOULD be
   propagated.

6.  The Group Policy ID Extended Community

   The Group Policy ID BGP Extended Community is a new transitive Opaque
   Extended Community with a Type value of 0x03.  This extended
   community may be advertised along with an EVPN type-2 MAC/IP route,
   EVPN type-3 Ethernet Inclusive Multicast route, and EVPN type-5 IP
   prefix route.  This new Opaque Extended Community enables the EVPN
   route it is attached to propagate the Group Policy ID used for Group
   Based Policy in the control plane.

   When the "Uniformed-Propagation-Mode" is used under the EVPN and
   IPVPN interworking use case, the Group Policy ID extended community
   is carried over by the GW PE when a route for a given IP or IPv6
   prefix is propagated from one domain to another with a different
   address family.

Lin, et al.               Expires 22 April 2024                 [Page 5]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

    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=0x03   |   Sub-Type    |        Policy ID Scope        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Reserved           |    Group Policy ID            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Policy ID Scope: The Policy ID Scope field is 16-bit long, and is an
   optional field.

   Group Policy ID (GPI): The GPI field is 16-bit long and it encodes
   the value of a Group Policy ID.

   The reserved fields MUST be set to zero by the sender and ignored by
   the receiver.

   If the Policy ID Scope is not set, any EVPN VXLAN NVE node that
   receives a route with a Group Policy ID may use the received value as
   is.  If the Scope is set, a node that has the same locally configured
   Scope in the received route may use the received Policy ID value.  A
   node that has a different local Scope than in the received route may
   need to translate the received Policy ID to a locally assigned value.

7.  IANA Considerations

   For the Group Policy ID extended community defined in this document,
   IANA has allocated the following codepoint in the Sub-type registry
   of Type 0x03 Transitive Opaque Extended Community.

    Sub-Type     Name                                  Reference

    0x17         Group Policy ID Extended Community    [this document]

8.  Security Considerations

   All the security considerations for BGP extended communities can be
   applied there.  Attackers may alter the value carried in a BGP
   extended community.  In this case, the Group Policy ID carried in the
   Group Policy ID field can be altered by attackers, which could lead
   to the wrong policy rule being enforced on the user traffic.

9.  Acknowledgements

   The authors would like to thank Jeffrey Zhang, Jeff Haas for their
   careful review and valuable feedbacks.

Lin, et al.               Expires 22 April 2024                 [Page 6]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

   We also would like to thank Prasad Miriyala and Selvakumar Sivaraj
   for their contributions.

10.  References

10.1.  Normative References

   [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>.

   [RFC7432]  Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
              Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
              Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
              2015, <https://www.rfc-editor.org/info/rfc7432>.

   [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>.

   [RFC9136]  Rabadan, J., Ed., Henderickx, W., Drake, J., Lin, W., and
              A. Sajassi, "IP Prefix Advertisement in Ethernet VPN
              (EVPN)", RFC 9136, DOI 10.17487/RFC9136, October 2021,
              <https://www.rfc-editor.org/info/rfc9136>.

10.2.  Informative References

   [I-D.ietf-bess-evpn-ipvpn-interworking]
              Rabadan, J., Sajassi, A., Rosen, E. C., Drake, J., Lin,
              W., Uttaro, J., and A. Simpson, "EVPN Interworking with
              IPVPN", Work in Progress, Internet-Draft, draft-ietf-bess-
              evpn-ipvpn-interworking-09, 9 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bess-
              evpn-ipvpn-interworking-09>.

   [I-D.smith-vxlan-group-policy]
              Smith, M. and L. Kreeger, "VXLAN Group Policy Option",
              Work in Progress, Internet-Draft, draft-smith-vxlan-group-
              policy-05, 22 October 2018,
              <https://datatracker.ietf.org/doc/html/draft-smith-vxlan-
              group-policy-05>.

Authors' Addresses

   Wen Lin
   Juniper Networks
   Email: wlin@juniper.net

Lin, et al.               Expires 22 April 2024                 [Page 7]
Internet-Draft   Group Policy ID BGP Extended Community     October 2023

   John Drake
   Individual
   Email: je_drake@yahoo.com

   Dhananjaya Rao
   Cisco Systems
   Email: dhrao@cisco.com

Lin, et al.               Expires 22 April 2024                 [Page 8]