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Source Address Validation at Intra-domain Network Boundary Using BGP
draft-li-idr-savnet-intra-domain-bgp-00

Document Type Active Internet-Draft (individual)
Authors Dan Li , Shengnan Yue , Zhenbin Li , Lancheng Qin
Last updated 2025-10-20
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draft-li-idr-savnet-intra-domain-bgp-00
IDR                                                                D. Li
Internet-Draft                                       Tsinghua University
Intended status: Standards Track                                  S. Yue
Expires: 23 April 2026                                      China Mobile
                                                                   Z. Li
                                                     Huawei Technologies
                                                                  L. Qin
                                                 Zhongguancun Laboratory
                                                         20 October 2025

  Source Address Validation at Intra-domain Network Boundary Using BGP
                draft-li-idr-savnet-intra-domain-bgp-00

Abstract

   This document proposes a solution for Source Address Validation (SAV)
   at the intra-domain network boundary using BGP.  Routers at the
   boundary automatically generate accurate SAV rules by using routing
   information and SAV-specific information.  These rules construct a
   validation boundary which checks the validity of the source address
   of any data packets flowing into the intra-domain network.  This
   document also introduces BGP extensions for communicating SAV-
   specific information among routers at the boundary.

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 23 April 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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
   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
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  SAV Procedure at Edge Routers . . . . . . . . . . . . . . . .   3
   3.  SAV Procedure at Border routers . . . . . . . . . . . . . . .   6
   4.  BGP Extensions for Intra-domain SAVNET  . . . . . . . . . . .   6
     4.1.  BGP Protocol Relationship . . . . . . . . . . . . . . . .   6
     4.2.  Full-mesh IBGP Peering  . . . . . . . . . . . . . . . . .   6
     4.3.  BGP SAVNET Protocol Extension . . . . . . . . . . . . . .   7
       4.3.1.  BGP SAVNET SAFI . . . . . . . . . . . . . . . . . . .   7
       4.3.2.  BGP SAVNET NLRI . . . . . . . . . . . . . . . . . . .   7
       4.3.3.  SPA TLVs  . . . . . . . . . . . . . . . . . . . . . .   7
   5.  Decision Process with BGP SAVNET  . . . . . . . . . . . . . .   9
     5.1.  BGP SAVNET NLRI Selection . . . . . . . . . . . . . . . .   9
       5.1.1.  Self-Originated NLRI  . . . . . . . . . . . . . . . .   9
     5.2.  BGP Source Prefix Filtering . . . . . . . . . . . . . . .  10
   6.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  Process of BGP SAVNET NLRIs . . . . . . . . . . . . . . .  10
     6.2.  Process of BGP SAVNET SPA TLVs  . . . . . . . . . . . . .  10
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  11
   References  . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     Normative References  . . . . . . . . . . . . . . . . . . . . .  11
     Informative References  . . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   Source address validation (SAV) is essential for mitigating source
   address spoofing attacks ([RFC6959]) on the Internet.  The current
   operational intra-domain SAV mechanisms include Access List Control
   (ACL) [RFC2827] and unicast Reverse Path Forwarding [RFC3704].  Their
   technical problems are detailed in
   [I-D.ietf-savnet-intra-domain-problem-statement] and a new intra-
   domain SAV solution that can generate accurate SAV rules in an
   automatic way is needed.

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   This document proposes a solution for SAV at the intra-domain network
   boundary using BGP.  We refer to both edge routers and border routers
   as routers at the boundary of an intra-domain network.  Routers at
   the boundary automatically generate accurate SAV rules by using
   routing information and SAV-specific information.  These rules
   construct a validation boundary which checks the validity of the
   source address of any data packets flowing into the intra-domain
   network.  This document also introduces BGP extensions for
   communicating SAV-specific information among routers at the boundary.

1.1.  Terminology

   SAV Rule: The rule that describes the mapping relationship between a
   source address (prefix) and its valid incoming router interface(s).

   SAV-specific Information: The information specialized for SAV rule
   generation, which is exchanged among routers.

   Non-BGP Customer Network: A stub network connected to one or more
   routers of the AS for Internet connectivity.  It only originates
   traffic and does not participate in BGP routing exchanges with the
   AS.

   Edge Router: A router connected to hosts or non-BGP customer networks
   of the local AS.  It forwards traffic from hosts or non-BGP customer
   networks into the intra-domain network.

   Border Router: A router positioned at the boundary between the local
   AS and one or more external Autonomous Systems (ASes).  It runs EBGP
   and exchanges routing information with external peers.

1.2.  Requirements Language

   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
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  SAV Procedure at Edge Routers

   Edge routers will generate a prefix allowlist on interfaces facing a
   non-BGP customer network or a set of host, including only prefixes
   that can be used as the source address by the non-BGP customer
   network or the set of hosts.  For example, in Figure 1, the prefix
   allowlist on Intf. 1 should only include all the source prefixes of
   non-BGP customer network1, the prefix allowlist on Intf. 2 and Intf.
   3 should only include all the source prefixes of non-BGP customer

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   network2, and the prefix allowlist on Intf.4 should only include the
   network segment of the hosts.

   +-----------------------------------------+
   |               Other ASes                |
   +-----------------------------------------+
                 |      |
                 |      |
   +-------------|------|--------------------+
   | AS          |      |                    |
   |       Intf.5|      |Intf.6              |
   |           +-*------*-+                  |
   |           | Router 3 |                  |
   |           +----------+                  |
   |              /     \                    |
   |             /       \                   |
   |            /         \                  |
   |   +----------+     +----------+         |
   |   | Router 1 |     | Router 2 |         |
   |   +--#-----#-+     +-#-----#--+         |
   |Intf.1|Intf.2\ Intf.3/       \Intf.4     |
   |      |       \     /         \          |
   |      |        \   /           \         |
   |   Non-BGP    Non-BGP           Hosts    |
   |   Customer1  Customer2                  |
   +-----------------------------------------+

   Intf '#' enables prefix allowlist
   Intf '*' enables prefix blocklist

       Figure 1: An example of SAV at the boundary of an intra-domain
                                  network

   To construct a prefix allowlist on the specific interface, the edge
   router inspects its local Routing Information Base (RIB) and
   identifies destination prefixes that are reachable via that
   interface.  These prefixes should cover the complete source address
   space of the connected hosts, single-homed non-BGP customer networks,
   or multi-homed non-BGP customer networks with symmetric routing.

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   In asymmetric routing scenarios, these prefixes derived from the
   local RIB may fail to cover the complete source address space of
   multi-homed non-BGP customer networks.  For example, in Figure 1, the
   prefix that is reachable via Intf.2 may be part of the complete
   source address space of non-BGP customer network2 because the other
   part is only reachable via Intf.3.  One approach is to configure
   static routes with lower priority on the Intf.2 and Intf.3 of Router1
   to achieve symmetric routing, without influencing the Forwarding
   Information Base (FIB) . However, static configuration requires
   additional manual overhead.

   To address this limitation, the Source Prefix Advertisement (SPA)
   process [I-D.li-savnet-source-prefix-advertisement] is required to
   enable the construction of a more accurate and complete allowlist.
   During the SPA process, edge routers will announce these prefixes
   together with other SAV-specific information.  The SAV-specific
   information includes:

   *  Multi-homing Interface Group Type (MIIG-Type): It indicates the
      type of the interface that learns the prefix.  In general, there
      are two types of interfaces: single-homing interface (e.g., Intf.1
      and Intf.4 in Figure 1) and multi-homing interface (e.g., Intf.2
      and Intf.3 in Figure 1).

   *  Multi-homing Interface Group Tag (MIIG-Tag): It is to identify the
      non-BGP customer network of the prefix.  Prefixes belonging to the
      same non-BGP customer network MUST have the identical MIIG-Tag
      value.  Different non-BGP customer networks MUST have different
      MIIG-tag values.

   *  (Only) Source Flag: It indicates whether the prefix is an
      internal-use-only prefix.  By default, the flag is set because
      most prefixes are internal-use-only.  For prefixes which are also
      used to source traffic by other ASes, the flag should be unset.

   The detailed procedure for the prefix allowlist generation is as
   follows:

   1.  For each interface connecting a non-BGP customer network or a set
       of hosts, create a set of unique prefixes that are reachable via
       that interface by inspecting the local RIB.  Call it Set A.

   2.  Considering prefixes and SAV-specific information provided by
       other edge routers, create a set of unique prefixes that have the
       same MIIG-Type and MIIG-Tag as prefixes in Set A.  Call it Set B.

   3.  Form the union of Set A and Set B.  Apply the union set at the
       interface as a prefix allowlist.

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3.  SAV Procedure at Border routers

   Border routers aim to generate a prefix blocklist on interfaces
   facing an external AS, including prefixes that can be only used as
   the source address by the local AS (i.e., internal source addresses).
   For example, in Figure 1, the prefix blocklist on Intf. 5 and Intf. 6
   should include the prefixes of non-BGP customer network1, non-BGP
   customer network2, and hosts.

   The detailed procedure for the prefix blocklist generation is as
   follows:

   1.  Considering prefixes and SAV-specific information provided by
       edge routers, creat a set of unique prefixes with Source Flag
       being set.  Call it Set C.

   2.  Apply Set C at the interface facing an external AS as a prefix
       blocklist.

4.  BGP Extensions for Intra-domain SAVNET

4.1.  BGP Protocol Relationship

   The BGP extensions for SPA communication follow a backward compatible
   manner without impacting existing BGP functions.  New BGP SAVNET
   subsequent address families will be introduced under the IPv4 address
   family and the IPv6 address family, respectively.  The BGP UPDATE
   message (specifically the MP_REACH_NLRI and the MP_UNREACH_NLRI
   attributes) and the BGP Refresh message will be extended.  AFI and
   SAFI will be used for distinguishing the BGP SAVNET messages from
   other messages.

   A few existing path attributes such as Originator_ID and Clister_list
   or newly defined path attributes MAY be used for BGP SAVNET.
   Actually, most existing path attributes are not necessarily required
   for BGP SAVNET.  However, if the unnecessary path attributes are
   carried in BGP updates, they will be accepted, validated, and
   propagated consistent with the BGP protocol.

4.2.  Full-mesh IBGP Peering

   Edge or border routers enabling BGP SAVNET MUST establish full-mesh
   iBGP sessions either through direct iBGP sessions or route-
   reflectors.  SAVNET messages within an AS can be advertised through
   the full-mesh BGP SAVNET sessions.  The extensions of BGP messages
   for carrying SAVNET messages will be introduced in Section 4.3.

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4.3.  BGP SAVNET Protocol Extension

4.3.1.  BGP SAVNET SAFI

   To make good isolation with existing BGP services, this document
   defines BGP SAVNET SAFIs under the IPv4 address family and the IPv6
   address family, respectively.  The values require IANA registration
   as specified in Section 8.  Two BGP SAVNET speakers MUST establish a
   BGP SAVNET peer and MUST exchange the Multiprotocol Extensions
   Capability [RFC5492] to ensure that they are both capable of
   processing BGP SAVNET messages properly.

4.3.2.  BGP SAVNET NLRI

   The BGP SAVNET NLRI is used to transmit SPA messages (either IPv4 or
   IPv6).  The BGP SAVNET NLRI TLVs are carried in BGP UPDATE messages
   as (1) route advertisement carried within Multiprotocol Reachable
   NLRI (MP_REACH_NLRI) [RFC4760], and (2) route withdraw carried within
   Multiprotocol Unreachable NLRI (MP_UNREACH_NLRI).

   While encoding an MP_REACH_NLRI attribute containing BGP SAVNET NLRI
   TLVs, the "Length of Next Hop Network Address" field SHOULD be set to
   0 upon the sender.  The "Network Address of Next Hop" field SHOULD
   not be encoded upon the sender, because it has a 0 length and MUST be
   ignored upon the receiver.

4.3.3.  SPA TLVs

   The BGP SAVNET NLRI TLV each carries an SPA message including a
   source prefix and related information.  Therefore, the NLRI TLV is
   called SPA TLV.  This type of TLVs are used in SPA process within an
   AS.  The format is shown below:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | RouteType (1) |   Length (1)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Origin router-id (4)                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  MaskLen (1)  |        IP Prefix (variable)                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | MIIG-Type (1) | Flags (1)   |S|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         MIIG-Tag (4)                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 2: SPA TLV format

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   The meaning of these fields are as follows:

   *  RouteType (key): Type of the BGP SAVNET NLRI TLV, the value is 1
      for SPA TLV within an AS.

   *  Length: The length of the BGP SAVNET NLRI value, the RouteType and
      Length fields are excluded.

   *  Origin router-id (key): The router ID of the originating node of
      the source prefix in the deployment domain.

   *  MaskLen (key): The mask length in bits, which also indicates the
      valid bits of the IP Prefix field.

   *  IP Prefix (key): IP address.  The length ranges from 1 to 4 bytes
      for IPv4 and ranges from 1 to 16 bytes for IPv6.  Format is
      consistent with BGP IPv4/IPv6 unicast address.

   *  MIIG-Type (non-key): Multi-homing Ingress Interface Group Type.

      -  Type value 0: Unknown.  Indicates that this prefix does not
         come from any non-BGP customer networks or hosts.  It can be a
         local prefix or a local domain prefix.

      -  Type value 1: Single-homing interface.  Indicates that this
         prefix comes from a non-BGP customer network or a set of hosts
         that is single-homed to the local domain.

      -  Type value 2: Multi-homing interface.  Indicates that this
         prefix comes from a non-BGP customer network or a set of hosts
         that is multi-homed to the local domain, and is connected only
         to the local domain.

      -  Type value 3~255: Reserved for future use.

   *  Flags (non-key): Bitmap, indicating the attribute flag of the SPA
      prefix, currently taken:

      -  bit 0 (S bit) : Source Flag.  The value of 1 indicates that the
         SPA prefix is single-homing.  The value of 0 indicates that the
         SPA prefix is multi-homing.

   *  MIIG-Tag (non-key): Multi-homing Ingress Interface Group Tag. The
      value ranges from 1 to 0xFFFFFFFE.  The value 0 is invalid and the
      value 0xFFFFFFFF is reserved.

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5.  Decision Process with BGP SAVNET

   The Decision Process described in [RFC4271] works to determines a
   degree of preference among routes with the same prefix.  The Decision
   Process involves many BGP Path attributes, which are not necessary
   for BGP SAVNET SPA process, such as next-hop attributes and IGP-
   metric attributes.  Therefore, this document introduces a simplified
   Decision Process for SAVNET SAFI.

   The purpose of SPA is to maintain a uniform Source Prefix list, which
   is the mapping from original router-id to IP addresses, across all
   routers in the deploy domain.  To ensure this, it is RECOMMENDED that
   all routers deploy no ingress or egress route-policies for BGP
   SAVNET.

5.1.  BGP SAVNET NLRI Selection

   The Decision Process described in [RFC4271] no longer apply, and the
   Decision Process for BGP SAVNET NLRI are as follows:

   1.  The locally imported route is preferred over the route received
       from a peer.

   2.  The route received from a peer with the numerically larger
       originator is preferred.

   3.  The route received from a peer with the numerically larger Peer
       IP Address is preferred.

5.1.1.  Self-Originated NLRI

   BGP SAVNET NLRI with origin router-id matching the local router-id is
   considered self-originated.  All locally imported routes should be
   considered self-originated by default.

   Since the origin router-id is part of the NLRI key, it is very
   unlikely that a self-originated NLRI would be received from a peer.
   Unless a router-id conflict occurs due to incorrect configuration.
   In this case, the self-originated NLRI MUST be discarded upon the
   receiver, and appropriate error logging is RECOMMENDED.

   On the other hand, besides the route learn from peers, a BGP SAVNET
   speaker MUST NOT advertise NLRI which is not self-originated.

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5.2.  BGP Source Prefix Filtering

   In actual network deployment, operaters may need to specify whether
   some source prefixes requires filtering, and BGP community attributes
   can be used to identify the source prefixes that require filtration.

6.  Error Handling

6.1.  Process of BGP SAVNET NLRIs

   When a BGP SAVNET speaker receives a BGP Update containing a
   malformed MP_REACH_NLRI or MP_UNREACH_NLRI, it MUST ignore the
   received TLV and MUST NOT pass it to other BGP peers.  When
   discarding a malformed TLV, a BGP SAVNET speaker MAY log a specific
   error.

   If duplicate NLRIs exist in a MP_REACH_NLRI or MP_UNREACH_NLRI
   attribute, only the last one SHOULD be used.

6.2.  Process of BGP SAVNET SPA TLVs

   When a BGP SAVNET speaker receives an SPA TLV with an undefined type,
   it SHOULD be ignored or stored without parsing.

   When a BGP SAVNET speaker receives an SPA TLV with a 0 origin router-
   id, or the origin router-id is the same as the local router-id, it
   MUST be considered malformed.

   When a BGP SAVNET speaker receives an SPA TLV with an invalid MaskLen
   field, which is out of the range 1~32 for IPv4 and 1~128 for IPv6, it
   MUST be considered malformed.

   When a BGP SAVNET speaker receives an SPA TLV with an address field,
   whose length in bytes do not match with the remaining data, it MUST
   be considered malformed.

   When a BGP SAVNET speaker receives an SPA TLV with an unsupported
   MIIG-Type, it SHOULD be ignored or stored without parsing.

   When a BGP SAVNET speaker receives an SPA TLV with a MIIG-Type 0
   (Unknown), its MIIG-Tag MUST also be 0, vice versa.  Otherwise this
   SPA TLV MUST be considered malformed.

   When a BGP SAVNET speaker receives a malformed SPA TLV, it MUST
   ignore the received TLV and MUST NOT pass it to other BGP peers.
   When discarding a malformed TLV, a BGP SAVNET speaker MAY log a
   specific error.

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   When a BGP SAVNET speaker processes Flags in an SPA TLV, the defined
   bits MUST be processed and the undefined bits MUST be ignored.

7.  Security Considerations

   TBD.

8.  IANA Considerations

   The BGP SAVNET SAFIs under the IPv4 address family and the IPv6
   address family need to be allocated by IANA.

Acknowledgements

   TBD.

References

Normative References

   [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>.

   [RFC5492]  Scudder, J. and R. Chandra, "Capabilities Advertisement
              with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
              2009, <https://www.rfc-editor.org/info/rfc5492>.

   [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>.

   [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>.

Informative References

   [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>.

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   [RFC6959]  McPherson, D., Baker, F., and J. Halpern, "Source Address
              Validation Improvement (SAVI) Threat Scope", RFC 6959,
              DOI 10.17487/RFC6959, May 2013,
              <https://www.rfc-editor.org/info/rfc6959>.

   [RFC3704]  Baker, F. and P. Savola, "Ingress Filtering for Multihomed
              Networks", BCP 84, RFC 3704, DOI 10.17487/RFC3704, March
              2004, <https://www.rfc-editor.org/info/rfc3704>.

   [RFC2827]  Ferguson, P. and D. Senie, "Network Ingress Filtering:
              Defeating Denial of Service Attacks which employ IP Source
              Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
              May 2000, <https://www.rfc-editor.org/info/rfc2827>.

   [I-D.ietf-savnet-intra-domain-problem-statement]
              Li, D., Wu, J., Qin, L., Huang, M., and N. Geng, "Source
              Address Validation in Intra-domain Networks Gap Analysis,
              Problem Statement, and Requirements", Work in Progress,
              Internet-Draft, draft-ietf-savnet-intra-domain-problem-
              statement-19, 3 October 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-savnet-
              intra-domain-problem-statement-19>.

   [I-D.li-savnet-source-prefix-advertisement]
              Qin, L., Geng, N., and D. Li, "Source Prefix Advertisement
              for Intra-domain SAVNET", Work in Progress, Internet-
              Draft, draft-li-savnet-source-prefix-advertisement-05, 15
              October 2025, <https://datatracker.ietf.org/doc/html/
              draft-li-savnet-source-prefix-advertisement-05>.

Authors' Addresses

   Dan Li
   Tsinghua University
   Beijing
   China
   Email: tolidan@tsinghua.edu.cn

   Shengnan Yue
   China Mobile
   Beijing
   China
   Email: yueshengnan@chinamobile.com

Li, et al.                Expires 23 April 2026                [Page 12]
Internet-Draft  Source Address Validation at Intra-domai    October 2025

   Zhenbin Li
   Huawei Technologies
   Beijing
   China
   Email: lizhenbin@huawei.com

   Lancheng Qin
   Zhongguancun Laboratory
   Beijing
   China
   Email: qinlc@mail.zgclab.edu.cn

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