Network Working Group                                          W. Cheng
Internet Draft                                             China Mobile
Intended status: Informational                                    D. Li
Expires: February 29, 2026                          Tsinghua University
                                                                 C. Lin
                                                   New H3C Technologies
                                                                 S. Yue
                                                           China Mobile
                                                        August 20, 2025

            Intra-domain Source Address Validation (SAVNET) OAM
                  draft-cheng-savnet-intra-domain-oam-02


Abstract

   This document is a framework for how Source Address Validation
   (SAVNET) can be applied to operations and maintenance procedures for
   Intra-domain network.  The document is structured to outline how
   Operations and Management (OAM) functionality can be used to assist
   in fault, configuration, accounting, performance, and security
   management, commonly known by the acronym FCAPS.

Status of this Memo

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   This Internet-Draft will expire on February 20, 2026.

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   publication of this document. Please review these documents
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Table of Contents


   1. Introduction...................................................2
      1.1. Requirements Language.....................................3
   2. Terminology....................................................3
   3. Fault Management...............................................4
      3.1. Fault Detection...........................................4
      3.2. Fault Isolation...........................................4
   4. Operational and Manageability Considerations...................5
      4.1. OAM Configuration.........................................5
         4.1.1. Base Parameters......................................5
         4.1.2. Static SAV Parameters................................6
         4.1.3. IGP SAV Parameters...................................6
         4.1.4. BGP SAV Parameters...................................6
      4.2. OAM Notifications.........................................6
   5. Accounting.....................................................7
      5.1. Requirements..............................................7
      5.2. Location of Accounting....................................7
   6. Performance Management.........................................7
   7. Security Management............................................8
   8. Security Considerations........................................8
   9. References.....................................................9
      9.1. Normative References......................................9
      9.2. Informative References....................................9
   Authors' Addresses...............................................10

1. Introduction

   The purpose of intra-domain SAV is to prevent outgoing data packets
   from an intra-domain subnet (e.g., a host network or a customer
   network) from forging source addresses of other intra-domain subnets
   or other ASes, and to prevent incoming data packets from external
   ASes from forging source addresses of the local AS. To achieve this,
   intra-domain SAV should focus on SAV on host-facing routers,
   customer-facing routers, and AS border routers (see [I-D.ietf-
   savnet-intra-domain-architecture]). Specifically, host-facing or
   customer-facing routers should block data packets from the connected
   host or customer network that contain a spoofed source IP address
   not belonging to that network. AS border routers should block data


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   packets from other ASes that contain a spoofed source IP address
   belonging to the local AS.

   However, existing intra-domain SAV solutions (e.g., BCP38 [RFC2827]
   and BCP84 [RFC3704]) have issues like high operational overhead or
   inaccurate validation (see [I-D.ietf-savnet-intra-domain-problem-
   statement]). ACL-based ingress filtering requires manual operations
   to configure and update the SAV rules, while uRPF-based solutions
   might improperly block legitimate data packets in scenarios of
   routing asymmetry. To address these issues and guide the design of
   new intra-domain SAV solutions, [I-D.ietf-savnet-intra-domain-
   architecture] proposes the architecture of intra-domain SAVNET and
   introduces the use of SAV-specific information in intra-domain
   networks.

   Following the intra-domain SAVNET architecture, [I-D. draft-cheng-
   savnet-intra-domain-sav-igp] and [I-D. draft-cheng-savnet-intra-
   domain-sav-bgp] propose an intra-domain SAV solution. Based on these
   intra-domain SAV solutions, this document provides a framework and
   requirements for Intra-domain SAVNET Operations, Administration, and
   Maintenance (OAM). The approach of this document is to outline the
   functionality, potential mechanisms to provide the functions, and
   the required applicability of intra-domain OAM functions.

1.1. 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. Terminology

    SAV Rule: The rule in a router that describes the mapping
    relationship between a source address (prefix) and the valid
    incoming interface(s).  It is used by a router to make SAV decisions
    and is inferred from the SAV Information Base.

    Host-facing Router: An intra-domain router of an AS which is
    connected to an intra-domain host network (i.e., a layer-2 network).
    Customer-facing Router: An intra-domain router of an AS which is
    connected to an intra-domain customer network running the routing
    protocol (i.e., a layer-3 network).





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3. Fault Management

3.1. Fault Detection

    - Real-time Monitoring

      Network Monitoring Systems: Use protocols like SNMP, NetFlow,
      sFlow, etc., to monitor network traffic and device status in real-
      time, quickly identifying anomalies through monitoring data.

      Log Analysis: Automated log collection and analysis to detect
      abnormal logs or device error messages.

      Performance Monitoring: Monitor network performance metrics (such
      as latency, packet loss rate, jitter, etc.) to identify potential
      issues.

    - Alert System

      Threshold Alerts: Set threshold values to automatically trigger
      alerts when performance metrics exceed preset ranges.

      Pattern Recognition: Detect abnormal traffic patterns or behaviors
      using machine learning and pattern recognition techniques.

    - Automated Diagnostic Tools

      Self-check Tools: Use built-in self-check tools to perform regular
      checks on SAVNET configurations to detect configuration errors or
      inconsistencies.

      Fault Diagnostic System: Utilize intelligent fault diagnostic
      systems to quickly identify and locate faults.

    - Routing Protocol Analysis

      IGP/BGP Status Monitoring: Monitor IGP/BGP protocol status changes
      to identify routing table anomalies.

      SAVNET Table Validation: Regularly validate SAV table entries to
      avoid faults caused by incorrect configurations.

3.2. Fault Isolation

    - Interface Level




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      Disable Interface: If the fault comes from a specific network
      interface, you can temporarily disable that interface to prevent
      the spread of abnormal traffic.

      Adjust Traffic Path: Modify the routing policy to reroute traffic
      around the faulty interface.

    - Routing Level

      Adjust Routing Table: Modify the IGP/BGP routing table to avoid
      routing traffic through the faulty node or path.

      Withdraw Route Advertisements: Withdraw route advertisements for
      the faulty path in BGP, preventing other routers from forwarding
      traffic to the fault path.

    - Device Level

      Isolate Faulty Device: Temporarily isolate the faulty device from
      the network and activate backup devices.

      Device Restart: If the fault is due to a temporary issue with the
      device, try restarting the device to restore it to normal
      operation.

4. Operational and Manageability Considerations

4.1. OAM Configuration

    Routers may be configured to enable intra-domain SAVNET functions
    via the device Command Line Interface (CLI) or through one of the
    defined management protocols, such as the Network Configuration
    Protocol (NETCONF) [RFC6241]. The following is a non-exhaustive list
    of configuration parameters that apply to Intra-domain SAVNET.

4.1.1. Base Parameters

    - Global Configuration

      Enable SAVNET function.

      SAV mode, SAV table capacity, SAV sources priority.

    - Interface Configuration

      Control for SAVNET (function enable/disable), SAV mode.



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4.1.2. Static SAV Parameters

    - Static SAV rules configuration in the SAV table.

      SAV entries: "Source prefix" and "Incoming interface," including
      IPv4 and IPv6 SAV rules.

    - Capacity of the SAV table and upper limitation of IPv4 or IPv6 SAV
      rules.

4.1.3. IGP SAV Parameters

    - Enable SAVNET function under address families in the IGP.

    - Enable the IGP to calculate SAVNET interfaces.

    - IGP control to advertise SAVNET source address filtering function.

    - IGP control to filter SAVNET table entry generation.

4.1.4. BGP SAV Parameters

    - Enable BGP prefix iteration function.

    - BGP control to advertise SAVNET source address filtering function.

    - BGP control to filter SAVNET table entry generation.

4.2. OAM Notifications

    Intra-domain SAVNET OAM mechanisms should trigger notifications to
    alert operators to certain conditions.  Such conditions include but
    are not limited to:

    -  Faults detected by proactive mechanisms.

    -  Reception of event-driven defect indications.

    -  Logged security incidents pertaining to the OAM Message Channel.

    -  Protocol errors (for example, as caused by misconfiguration).

    Notifications generated by OAM mechanisms may be via YANG, Syslog
    messages, or any other standard management protocol that supports
    asynchronous notifications.




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5. Accounting

5.1. Requirements

   For intra-domain SAVNET, the following statistical functionalities
   are required:

   - Interface-based Statistics: Collect statistics at the interface
      level for traffic where the source address fails the intra-domain
      source address validation. Record the five-tuple information of
      the flows.

   - Interface-based Statistics: Collect statistics at the interface
      level for traffic where the source address passes the intra-domain
      source address validation. Record the five-tuple information of
      the flows.

   - Interface-based Statistics: Collect statistics at the interface
      level for traffic where the source address is not found in the
      intra-domain SAVNET table. Record the five-tuple information of
      the flows.

   - Per Intra-domain SAVNET Table Entry Statistics: Collect statistics
      for each table entry on the number of passes and drops, recording
      the five-tuple information of the flows.

   - Global Statistics: Collect global statistics for intra-domain
      source address checks, including the number of passes, drops,
      lookups not found, and blacklist hits. This aids in overall
      operational management.

   - Blacklist Statistics: Collect statistics for traffic where the
      source address hits the blacklist. Record the five-tuple
      information of the flows.

5.2. Location of Accounting

   For host-facing or customer-facing routers, interface-level
   statistics should be monitored. For intra-domain boundary routers,
   blacklist statistics are the focus. Other table-based statistics and
   global statistics should be monitored on all intra-domain routers.

6. Performance Management

   Performance management allows the measurement of the information
   transfer characteristics of Intra-domain SAVNET, which can then be
   compared against an SLA. This falls into two categories: latency
   (including jitter as a variation in latency) and information loss.

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   Perform performance measurements for traffic from different sources:

   - Traffic coming from host-facing or customer-facing routers.

   - Traffic entering the intra-domain from outside the intra-domain.

   - Traffic leaving the intra-domain.

   - Traffic within the intra-domain.

   The goal is to monitor performance characteristics when the intra-
   domain SAVNET function is enabled. The network operator can extract
   performance monitoring metrics based on whether one-way or two-way
   performance monitoring functions are performed:

   - For one-way performance monitoring functions, the metrics will be
      available at the target router.

   - For two-way performance monitoring functions, all metrics will be
      available at the source router, while a subset will be available
      at the target router. Specifically, metrics for both the direction
      from source to target and from target to source will be available
      at the source router. Metrics for the direction from source to
      target will be available at the target router.

7. Security Management

   TBD

8. Security Considerations

   This document describes a framework for Intra-domain SAVNET
   Operations and Management.  It does not introduce any new security
   concerns.

   The security considerations described in

    [I-D.ietf-savnet-intra-domain-problem-statement] and

    [I-D.ietf-savnet-intra-domain-architecture] also applies to this
    document.







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9. References

9.1. Normative References

    [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-
             03, 13 February 2024,
             <https://datatracker.ietf.org/doc/html/draft-ietf-savnet-
             intra-domain-problem-statement-03>.

    [I-D.ietf-savnet-intra-domain-architecture]Li, D., Wu, J., Qin, L.,
             Geng, N., and L. Chen, "Intra-domain Source Address
             Validation (SAVNET) Architecture",Work in Progress,
             Internet-Draft, draft-ietf-savnet-intra-domain-
             architecture-00, 12 April 2024,
             <https://datatracker.ietf.org/doc/html/draft-ietf-savnet-
             intra-domain-architecture-00>.

   [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>.

9.2. Informative References

   [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>.

   [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>.








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Authors' Addresses

   Weiqiang Cheng
   China Mobile
   China
   Email: chengweiqiang@chinamobile.com


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


   Changwang Lin
   New H3C Technologies
   China
   Email: linchangwang.04414@h3c.com

   Shengnan Yue
   China Mobile
   China
   yueshengnan@chinamobile.com
























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