IDR Working Group                                                W. Wang
Internet-Draft                                                   A. Wang
Intended status: Standards Track                           China Telecom
Expires: September 4, 2022                                       H. Wang
                                                     Huawei Technologies
                                                               G. Mishra
                                                            Verizon Inc.
                                                               S. Zhuang
                                                                 J. Dong
                                                     Huawei Technologies
                                                           March 3, 2022


      VPN Prefix Outbound Route Filter (VPN Prefix ORF) for BGP-4
                    draft-wang-idr-vpn-prefix-orf-02

Abstract

   This draft defines a new Outbound Route Filter (ORF) type, called the
   VPN Prefix ORF.  The described VPN Prefix ORF mechanism is applicable
   when the VPN routes from different VRFs are exchanged via one shared
   BGP session (e.g., routers in a single-domain connect via Route
   Reflector).

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 September 4, 2022.

Copyright Notice

   Copyright (c) 2022 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



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   (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 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Operation process of VPN Prefix ORF mechanism on sender . . .   4
     4.1.  Intra-domain Scenarios and Solutions  . . . . . . . . . .   5
       4.1.1.  Scenario-1 and Solution (Unique RD, One RT) . . . . .   5
       4.1.2.  Scenario-2 and Solution (Unique RD, Multiple RTs) . .   7
       4.1.3.  Scenario-3 and Solution (Universal RD)  . . . . . . .   8
   5.  Operation process of VPN Prefix ORF mechanism on receiver . .   8
   6.  Withdraw of VPN Prefix ORF entries  . . . . . . . . . . . . .   9
   7.  VPN Prefix ORF Encoding . . . . . . . . . . . . . . . . . . .   9
     7.1.  Source PE TLV . . . . . . . . . . . . . . . . . . . . . .  10
     7.2.  Route Target TLV  . . . . . . . . . . . . . . . . . . . .  11
   8.  Implementation Considerations . . . . . . . . . . . . . . . .  11
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   11. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .  12
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   [I-D.wang-idr-vpn-routes-control-analysis] analysis the scenarios and
   necessaries for VPN routes control in the shared BGP session.  This
   draft analyzes the existing solutions and their limitations for these
   scenarios, proposes the new VPN Prefix ORF solution to meet the
   requirements that described in section 8 of
   [I-D.wang-idr-vpn-routes-control-analysis].

   Now, there are several solutions can be used to alleviate these
   problem:

   o  Route Target Constraint (RTC) as defined in [RFC4684]

   o  Address Prefix ORF as defined in [RFC5292]

   o  CP-ORF mechanism as defined in [RFC7543]




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   o  PE-CE edge peer Maximum Prefix

   o  Configure the Maximum Prefix for each VRF on edge nodes

   However, there are limitations to existing solutions:

   1) Route Target Constraint

   RTC can only filter the VPN routes from the uninterested VRFs, if the
   "trashing routes" come from the interested VRF, filter on RTs will
   erase all prefixes from this VRF.

   2) Address Prefix ORF

   Using Address Prefix ORF to filter VPN routes need to pre-
   configuration, but it is impossible to know which prefix may cause
   overflow in advance.

   3) CP-ORF Mechanism

   [RFC7543] defines the Covering Prefixes ORF (CP-ORF).  A BGP speaker
   sends a CP-ORF to a peer in order to pull routes that cover a
   specified host address.  A prefix covers a host address if it can be
   used to forward traffic towards that host address.

   CP-ORF is applicable in Virtual Hub-and-Spoke[RFC7024] VPN and also
   the BGP/MPLS Ethernet VPN (EVPN) [RFC7432]networks, but its main aim
   is also to get the wanted VPN prefixes and can't be used to filter
   the overwhelmed VPN prefixes dynamically.

   4) PE-CE edge peer Maximum Prefix

   The BGP Maximum-Prefix feature is used to control how many prefixes
   can be received from a neighbor.  By default, this feature allows a
   router to bring down a peer when the number of received prefixes from
   that peer exceeds the configured Maximum-Prefix limit.  This feature
   is commonly used for external BGP peers.  If it is applied to
   internal BGP peers, for example the VPN scenarios, all the VPN routes
   from different VRFs will share the common fate, which is not
   desirable for the fining control of the VPN Prefixes advertisement.

   5) Configure the Maximum Prefix for each VRF on edge nodes

   When a VRF overflows, it stops the import of routes and log the extra
   VPN routes into its RIB.  However, PEs still need to parse the BGP
   updates.  These processes will cost CPU cycles and further burden the
   overflowing PE.




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   This draft defines a new ORF-type, called the VPN Prefix ORF.  This
   mechanism is event-driven and does not need to be pre-configured.
   When a VRF of a router overflows, the router will find out the VPN
   prefix (RD, RT, source PE, etc.) of offending VPN routes in this VRF,
   and send a VPN Prefix ORF to its BGP peer that carries the relevant
   information.  If a BGP speaker receives a VPN Prefix ORF entry from
   its BGP peer, it will filter the VPN routes it tends to send
   according to the entry.

   VPN Prefix ORF is applicable when the VPN routes from different VRFs
   are exchanged via one shared BGP session.

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 [RFC2119] .

3.  Terminology

   The following terms are defined in this draft:

   o  RD: Route Distinguisher, defined in [RFC4364]

   o  ORF: Outbound Route Filter, defined in [RFC5291]

   o  AFI: Address Family Identifier, defined in [RFC4760]

   o  SAFI: Subsequent Address Family Identifier, defined in [RFC4760]

   o  EVPN: BGP/MPLS Ethernet VPN, defined in [RFC7432]

   o  RR: Router Reflector, provides a simple solution to the problem of
      IBGP full mesh connection in large-scale IBGP implementation.

   o  VRF: Virtual Routing Forwarding, a virtual routing table based on
      VPN instance.

4.  Operation process of VPN Prefix ORF mechanism on sender

   The operation of VPN Prefix ORF mechanism on each device is
   independent, each of them makes a local judgement to determine
   whether it needs to send VPN Prefix ORF to its peers.  The operators
   need to make sure the algorithms in different devices consistent.  On
   PE, each VRF has a prefix limit, and routes associated with each <RD,
   source PE> tuple has a pre-configurated quota.





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   o  when routes associated with <RD, source PE> tuple past the quota
      but the prefix limit of VRF is not exceeded, PE should send
      warnings to the operator, and the VPN Prefix ORF mechanism should
      not be triggered.

   o  when routes associated with <RD, source PE> tuple past the quota
      and the prefix limit is exceeded and there is no other VRFs on
      offended PE need VPN routes with this RD, they should be dropped
      via VPN Prefix ORF mechanism.

   When the VPN Prefix ORF mechanism is triggered, the device must send
   an alarm information to network operators.

4.1.  Intra-domain Scenarios and Solutions

   For intra-AS VPN deployment, there are three scenarios:

   o  RD is allocated per VPN per PE, each VRF only import one RT(see
      Section 4.1.1).

   o  RD is allocated per VPN per PE.  Multiple RTs are associated with
      such VPN routes, and are imported into different VRFs in other
      devices(see Section 4.1.2).

   o  RD is allocated per VPN, each VRF imports one/multiple RTs(see
      Section 4.1.3).

   The following sections will describe solutions to the above scenarios
   in detail.

4.1.1.  Scenario-1 and Solution (Unique RD, One RT)

   In this scenario, RD is allocated per VPN per PE.  The offending VPN
   routes only carry one RT.  We assume the network topology is shown in
   Figure 1.
















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 +------------------------------------------------------------------------+
 |                                                                        |
 |                                                                        |
 |        +-------+                                       +-------+       |
 |        |  PE1  +----------------+    +-----------------+  PE4  |       |
 |        +-------+                |    |                 +-------+       |
 |     VPN1(RD11,RT1)              |    |              VPN2(RD12,RT2)     |
 |     VPN2(RD12,RT2)              |    |                                 |
 |                               +-+----+-+                               |
 |                               |   RR   |                               |
 |                               +-+----+-+                               |
 |                                 |    |                                 |
 |                                 |    |                                 |
 |        +-------+                |    |                 +-------+       |
 |        |  PE2  +----------------+    +-----------------+  PE3  |       |
 |        +-------+                                       +-------+       |
 |     VPN1(RD21,RT1)                                  VPN1(RD31,RT1)     |
 |     VPN2(RD22,RT2,RT1)                              VPN2(RD32,RT2)     |
 |                                                                        |
 |                                 AS 100                                 |
 |                                                                        |
 +------------------------------------------------------------------------+
                 Figure 1 Network Topology of Scenario-1

   When PE3 sends excessive VPN routes with RT1, while both PE1 and PE2
   import VPN routes with RT1, the process of offending VPN routes will
   influence performance of VRFs on PEs.  PEs and RR should have some
   mechanisms to identify and control the advertisement of offending VPN
   routes.

   On PE1, each VRF has a prefix limit, and each <RD, source PE> tuple
   imported into VRF has a quota.  When routes associated with <RD31,
   PE3> tuple past the quota but the prefix limit of VPN1 VRF is not
   exceeded, PE1 sends a warning message to the operator, and the VPN
   Prefix ORF mechanism should not be triggered.  After the prefix limit
   of VPN1 VRF is exceeded, due to there is no other VRFs on PE1 need
   the VPN routes with RT1, PE1 will generate a BGP ROUTE-REFRESH
   message contains a VPN Prefix ORF entry, and send to RR.  RR will
   withdraw and stop to advertise such offending VPN routes (RD31, RT1,
   source PE is PE3) to PE1.

   On PE2, both VPN1 VRF and VPN2 VRF import VPN routes with RT1.  If
   PE2 triggers VPN Prefix ORF mechanism when VPN1 VRF overflows, VPN2
   VRF cannot receive VPN routes with RT1 as well.  PE2 should not
   trigger the VPN Prefix ORF mechanism to RR (RD31, RT1, source PE is
   PE3) until all the VRFs that import RT1 on it overflow.





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4.1.2.  Scenario-2 and Solution (Unique RD, Multiple RTs)

   In this scenario, RD is allocated per VPN per PE.  Multiple RTs are
   associated with the offending VPN routes, and be imported into
   different VRFs in other devices.  We assume the network topology is
   shown in Figure 2.

 +------------------------------------------------------------------------+
 |                                                                        |
 |                                                                        |
 |        +-------+                                       +-------+       |
 |        |  PE1  +----------------+    +-----------------+  PE4  |       |
 |        +-------+                |    |                 +-------+       |
 |     VPN1(RD11,RT1)              |    |              VPN2(RD42,RT2)     |
 |     VPN2(RD12,RT2)              |    |                                 |
 |                               +-+----+-+                               |
 |                               |   RR   |                               |
 |                               +-+----+-+                               |
 |                                 |    |                                 |
 |                                 |    |                                 |
 |        +-------+                |    |                 +-------+       |
 |        |  PE2  +----------------+    +-----------------+  PE3  |       |
 |        +-------+                                       +-------+       |
 |     VPN1(RD21,RT1)                                  VPN1(RD31,RT1,RT2) |
 |                                                     VPN2(RD32,RT2)     |
 |                                                                        |
 |                                 AS 100                                 |
 |                                                                        |
 +------------------------------------------------------------------------+
                Figure 2 Network Topology of Scenario-2

   When PE3 sends excessive VPN routes with RT1 and RT2, while both PE1
   and PE2 import VPN routes with RT1, and PE1 also imports VPN routes
   with RT2.

   On PE1, when routes associated with <RD31, PE3> tuple past the quota
   but the prefix limit of VPN1 VRF is not exceeded, PE1 sends a warning
   to the operator.  After the prefix limit of VPN1 VRF is exceeded, due
   to there is no other VRFs on PE1 need the VPN routes with RT1, PE1
   will generate a BGP ROUTE-REFRESH message contains a VPN Prefix ORF
   entry, and send to RR.  RR will withdraw and stop to advertise such
   offending VPN routes to PE1.

   On PE2, due to there is only one VRF imports VPN routes with RT1.  If
   it overflows, it will trigger VPN Prefix ORF (RD31, RT1, comes from
   PE3) mechanisms.  RR will withdraw and stop to advertise such
   offending VPN routes to PE2.




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4.1.3.  Scenario-3 and Solution (Universal RD)

   In this scenario, RD is allocated per VPN.  One/Multiple RTs are
   associated with the offending VPN routes, and be imported into
   different VRFs in other devices.  We assume the network topology is
   shown in Figure 3.

 +------------------------------------------------------------------------+
 |                                                                        |
 |                                                                        |
 |        +-------+                                       +-------+       |
 |        |  PE1  +----------------+    +-----------------+  PE4  |       |
 |        +-------+                |    |                 +-------+       |
 |     VPN1(RD1,RT1)               |    |              VPN2(RD12,RT2)     |
 |     VPN2(RD12,RT2)              |    |                                 |
 |                               +-+----+-+                               |
 |                               |   RR   |                               |
 |                               +-+----+-+                               |
 |                                 |    |                                 |
 |                                 |    |                                 |
 |        +-------+                |    |                 +-------+       |
 |        |  PE2  +----------------+    +-----------------+  PE3  |       |
 |        +-------+                                       +-------+       |
 |     VPN1(RD1,RT1)                                   VPN1(RD1,RT1,RT2)  |
 |                                                     VPN2(RD32,RT2)     |
 |                                                                        |
 |                                 AS 100                                 |
 |                                                                        |
 +------------------------------------------------------------------------+
                  Figure 3 Network Topology of Scenario-3

   When PE3 sends excessive VPN routes with RD1 and attached RT1 and
   RT2, while both PE1 and PE2 import VPN routes with RT1, the process
   of offending VPN routes will influence performance of VRFs on PEs.

   When PE2 overflows and PE1 does not overflow.  PE2 triggers the VPN
   Prefix ORF message (RD1, RT1, comes from PE3).  Using Source PE and
   RD, RR will only withdraw and stop to advertise VPN routes (RD1, RT1)
   come from PE3 to PE2.  The communication between PE2 and PE1 for VPN1
   will not be influenced.

5.  Operation process of VPN Prefix ORF mechanism on receiver

   The receiver of VPN Prefix ORF entries may be a RR or PE.  As it
   receives the VPN Prefix ORF entries, it will check <AFI/SAFI, ORF-
   Type, Sequence, Route Distinguisher> to find if it already existed in
   its ORF-Policy table.  If not, the receiver will add the VPN Prefix
   ORF entries into its ORF-Policy table; otherwise, the receiver will



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   discard it.  Before the receiver send a VPN route, it will check its
   ORF-Policy table whether there is a related VPN Prefix ORF entry or
   not.  If not, the receiver will send this VPN route; otherwise, the
   receiver will stop sending that VPN route to its peer.

6.  Withdraw of VPN Prefix ORF entries

   When the VPN Prefix ORF mechanism is triggered, the alarm information
   will be generated and sent to the network operators.  Operators
   should manually configure the network to resume normal operation.
   Due to devices can record the VPN Prefix ORF entries sent by each
   VRF, operators can find the entries needs to be withdrawn, and
   trigger the withdraw process as described in [RFC5291] manually.
   After returning to normal, the device sends withdraw ORF entries to
   its peers who have previously received ORF entries.

7.  VPN Prefix ORF Encoding

   In this section, we defined a new ORF type called VPN Prefix Outbound
   Route Filter (VPN Prefix ORF).  The ORF entries are carried in the
   BGP ROUTE-REFRESH message as defined in [RFC5291].  A BGP ROUTE-
   REFRESH message can carry one or more ORF entries.  The ROUTE-REFRESH
   message which carries ORF entries contains the following fields:

   o  AFI (2 octets)

   o  SAFI (1 octet)

   o  When-to-refresh (1 octet): the value is IMMEDIATE or DEFER

   o  ORF Type (1 octet)

   o  Length of ORF entries (2 octets)

   A VPN Prefix ORF entry contains a common part and type-specific part.
   The common part is encoded as follows:

   o  Action (2 bits): the value is ADD, REMOVE or REMOVE-ALL

   o  Match (1 bit): the value is PERMIT or DENY

   o  Reserved (5 bits)

   VPN Prefix ORF also contains type-specific part.  The encoding of the
   type-specific part is shown in Figure 4.






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             +-----------------------------------------+
             |                                         |
             |      Route Distinguisher (8 octets)     |
             |                                         |
             +-----------------------------------------+
             |                                         |
             |        Optional TLVs (variable)         |
             |                                         |
             +-----------------------------------------+

               Figure 4: VPN Prefix ORF type-specific encoding

   o  Route Distinguisher: distinguish the different user routes.  The
      VPN Prefix ORF filters the VPN routes it tends to send based on
      Route Distinguisher.

   o  Optional TLVs: carry the potential additional information to give
      the extensibility of the VPN Prefix ORF mechanism.

   Note that if the Action component of an ORF entry specifies REMOVE-
   ALL, the ORF entry does not include the type-specific part.

   When the BGP ROUTE-REFRESH message carries VPN Prefix ORF entries, it
   must be set as follows:

   o  The ORF-Type MUST be set to VPN Prefix ORF.

   o  The AFI MUST be set to IPv4, IPv6, or Layer 2 VPN (L2VPN).

   o  If the AFI is set to IPv4 or IPv6, the SAFI MUST be set to MPLS-
      labeled VPN address.

   o  If the AFI is set to L2VPN, the SAFI MUST be set to BGP EVPN.

   o  The Match field MUST be set to DENY.

7.1.  Source PE TLV

   Source PE TLV is defined to identify the source of the VPN routes.
   Using source PE and RD to filter VPN routes together can achieve more
   refined route control.  The source PE TLV contains the following
   types:

   o  In single-domain or Option C cross-domain scenario, NEXT_HOP
      attribute is fixed during routing transmission, so it can be used
      as source address.

         Type = 1, Length = 4 octets, value = NEXT_HOP.



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         Type = 2, Length = 16 octets, value = NEXT_HOP.

   o  In Option B or Option AB cross-domain scenario, NEXT_HOP attribute
      may be changed by ASBRs and cannot be used as the source address.
      The originator can be traced by the Route Origin Community in BGP
      (as defined in Section&nbsp;5 of [RFC4360]).

         Type = 3, Length = 6 octets, value = the value field of Route
         Origin Community.

   In principle, when the device can extract Route Origin Community from
   the received packet, the value of Source PE TLV should be set to
   Route Origin Community; Otherwise, the value should be set to
   NEXT_HOP.

7.2.  Route Target TLV

   Route Target TLV is defined to identify the RT of the offending VPN
   routes.  RT and RD can be used together to filter VPN routes when the
   source VRF contains multiple RTs, and the VPN routes with different
   RTs may be assigned to different VRFs on the receiver.  The encoding
   of Route Target TLV is following:

      Type = 4, Length = 8*n (n is the number of RTs that the offending
      VPN routes attached) octets, value = the RT of the offending VPN
      routes.  If multiple RTs are included, there must be an exact
      match.

8.  Implementation Considerations

   Before originating an VPN Prefix ORF message, the device should
   compare the list of RD and RT(s) carried by VPN routes signaled for
   filtering and the RD and RT(s) imported by not affected VRF(s).  Once
   they have intersection, the VPN Prefix ORF message MUST NOT be
   originated.

   Since the motivation of VPN Prefix ORF mechanism is to filter the
   unwanted VPN routes, "Match" field of VPN Prefix ORF message MUST be
   set to "DENY".  The default behavior of the VPN Prefix ORF MUST be
   PERMIT-ALL.

9.  Security Considerations

   A BGP speaker will maintain the VPN Prefix ORF entries in an ORF-
   Policy table, this behavior consumes its memory and compute
   resources.  To avoid the excessive consumption of resources,
   [RFC5291] specifies that a BGP speaker can only accept ORF entries
   transmitted by its interested peers.



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10.  IANA Considerations

   This document defines a new Outbound Route Filter type - VPN Prefix
   Outbound Route Filter (VPN Prefix ORF).  The code point is from the
   "BGP Outbound Route Filtering (ORF) Types".  It is recommended to set
   the code point of VPN Prefix ORF to 66.

   This document also define a VPN Prefix ORF TLV type under "Border
   Gateway Protocol (BGP) Parameters", three TLV types are defined:

    +===========================+======+===========================+
    | Registry                  | Type |       Meaning             |
    +===========================+======+===========================+
    |IPv4 Source PE TLV         | 1    |IPv4 address for source PE.|
    +---------------------------+------+---------------------------+
    |IPv6 Source PE TLV         | 2    |IPv6 address for source PE.|
    +---------------------------+------+---------------------------+
    |ROC Source PE TLV          |      |Route Origin Community for |
    |                           | 3    |Source PE.                 |
    +---------------------------+------+---------------------------+
    |Route Target TLV           | 4    |Identify the RT of the     |
    |                           |      |offending VPN routes       |
    +---------------------------+------+---------------------------+

        Figure 5: IANA Allocation for newly defined TLVs

11.  Acknowledgement

   Thanks Robert Raszuk, Jim Uttaro, Jakob Heitz, Jeff Tantsura, Rajiv
   Asati, John E Drake, Gert Doering, Shuanglong Chen, Enke Chen and
   Srihari Sangli for their valuable comments on this draft.

12.  Normative References

   [I-D.ietf-bess-evpn-inter-subnet-forwarding]
              Sajassi, A., Salam, S., Thoria, S., Drake, J. E., and J.
              Rabadan, "Integrated Routing and Bridging in Ethernet VPN
              (EVPN)", draft-ietf-bess-evpn-inter-subnet-forwarding-15
              (work in progress), July 2021.

   [I-D.wang-idr-vpn-routes-control-analysis]
              Wang, A., Wang, W., Mishra, G. S., Wang, H., Zhuang, S.,
              and J. Dong, "Analysis of VPN Routes Control in Shared BGP
              Session", draft-wang-idr-vpn-routes-control-analysis-04
              (work in progress), September 2021.






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   [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>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <https://www.rfc-editor.org/info/rfc4360>.

   [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>.

   [RFC4684]  Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
              R., Patel, K., and J. Guichard, "Constrained Route
              Distribution for Border Gateway Protocol/MultiProtocol
              Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
              Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
              November 2006, <https://www.rfc-editor.org/info/rfc4684>.

   [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>.

   [RFC5291]  Chen, E. and Y. Rekhter, "Outbound Route Filtering
              Capability for BGP-4", RFC 5291, DOI 10.17487/RFC5291,
              August 2008, <https://www.rfc-editor.org/info/rfc5291>.

   [RFC5292]  Chen, E. and S. Sangli, "Address-Prefix-Based Outbound
              Route Filter for BGP-4", RFC 5292, DOI 10.17487/RFC5292,
              August 2008, <https://www.rfc-editor.org/info/rfc5292>.

   [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>.

   [RFC7543]  Jeng, H., Jalil, L., Bonica, R., Patel, K., and L. Yong,
              "Covering Prefixes Outbound Route Filter for BGP-4",
              RFC 7543, DOI 10.17487/RFC7543, May 2015,
              <https://www.rfc-editor.org/info/rfc7543>.

Authors' Addresses







Wang, et al.            Expires September 4, 2022              [Page 13]


Internet-Draft                   RD-ORF                       March 2022


   Wei Wang
   China Telecom
   Beiqijia Town, Changping District
   Beijing, Beijing  102209
   China

   Email: weiwang94@foxmail.com


   Aijun Wang
   China Telecom
   Beiqijia Town, Changping District
   Beijing, Beijing  102209
   China

   Email: wangaj3@chinatelecom.cn


   Haibo Wang
   Huawei Technologies
   Huawei Building, No.156 Beiqing Rd.
   Beijing, Beijing  100095
   China

   Email: rainsword.wang@huawei.com


   Gyan S. Mishra
   Verizon Inc.
   13101 Columbia Pike
   Silver Spring  MD 20904
   United States of America

   Phone: 301 502-1347
   Email: gyan.s.mishra@verizon.com


   Shunwan Zhuang
   Huawei Technologies
   Huawei Building, No.156 Beiqing Rd.
   Beijing, Beijing  100095
   China

   Email: zhuangshunwan@huawei.com







Wang, et al.            Expires September 4, 2022              [Page 14]


Internet-Draft                   RD-ORF                       March 2022


   Jie Dong
   Huawei Technologies
   Huawei Building, No.156 Beiqing Rd.
   Beijing, Beijing  100095
   China

   Email: jie.dong@huawei.com












































Wang, et al.            Expires September 4, 2022              [Page 15]