RPKI-based Validation with Prioritized Resource Data
draft-zhang-sidrops-prioritized-route-validation-00

sidrops                                                         J. Zhang
Internet-Draft                                   Zhongguancun Laboratory
Intended status: Informational                                     M. Xu
Expires: 22 April 2026                                            CERNET
                                                                 N. Geng
                                                                  Huawei
                                                                  C. Xie
                                                           China Telecom
                                                                 Y. Wang
                                                     Tsinghua University
                                                         19 October 2025

          RPKI-based Validation with Prioritized Resource Data
          draft-zhang-sidrops-prioritized-route-validation-00

Abstract

   RPKI ROAs and other digitally signed objects provide a practical
   solution to validate BGP routes for preventing route hijacks.  During
   ROV operations, validation data may be sourced not only from issued
   ROAs but also from other local sources.  These data sources can vary
   in terms of credibility, and ROV operations may therefore require
   different response actions for invalid or unknown routes.  This
   document takes ROV as an example to describe a flexible RPKI-based
   route validation using multi-priority data, and outlines relevant use
   cases, framework, and requirements for ROV operations that involve
   multi-priority data.

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   This Internet-Draft will expire on 22 April 2026.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Gap analysis  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Framework . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Requirements for Multi-Priority RPKI ROV  . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   RPKI Route Origin Authorizations (ROAs) and other digitally signed
   objects provide a practical solution to validate BGP routes for
   preventing route hijacks.  For example, Route Origin Validation (ROV)
   built on ROAs stands as a practical and effective approach to combat
   prefix origin hijacking.  In ROV operations, the validating data
   utilized is not limited to ROAs alone; it may also include various
   types of local data from other sources.  These additional data
   sources can exhibit varying levels of credibility, with some being
   highly reliable due to their authoritative origins and others being
   less credible due to potential inconsistencies or lack of
   verification.  Correspondingly, ROV operations need to be flexible
   enough to take different actions when dealing with invalid routes and
   unknown routes.  This document takes ROV as an example to describe a
   flexible RPKI-based route validation using multi-priority data, and
   elaborates the gap analysis, framework, and specify the key
   requirements for implementing ROV with multi-priority data in current
   RPKI infrastructure.

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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.  Gap analysis

   RPKI-based Route Origin Validation (ROV) fundamentally relies on
   Route Origin Authorization (ROA) data.  However, it is recognized
   that ROA deployment has the following deployment issues: incomplete
   coverage of routes in the global routing table, the existence of ROAs
   with erroneous registrations, and the common practice where network
   operators locally filter certain Validated ROA Payload (VRP) data or
   supplement it with external sources (e.g., data inferred through
   machine learning).  Technologies like SLURM (Simplified Local
   Internet Number Resource Management) can be used to apply such local
   modifications.

   Due to such mixed data sources, the credibility of the data varies to
   different degrees and is no longer uniform.  Accordingly, network
   operators require the ability to apply different actions to
   validation results based on the credibility of the underlying data.
   This approach offers benefits such as the following use case: an ISP
   (Internet Service Provider) might supplement RPKI ROAs with data
   derived from its own operational experience, but assign a lower
   credibility to this supplementary data.  In this scenario, when a
   route is validated as "invalid" by RPKI ROAs, the router can discard
   the route; if a route is validated as "invalid" by supplementary data
   with medium credibility, the router can be configured to trigger an
   alert.

   However, current RPKI technology does not support such operations.
   Regardless of the source of the validation data, the same type of
   validation result triggers the same operation.  This fails to meet
   the need for customized processing of different scenarios in network
   operations.  This document describes a RPKI validation framework and
   requirements with multi-priority data to make RPKI-based validation
   processing more flexible and operable.

3.  Framework

   This document proposes a framework shown as the following figure.  It
   sopports RPKI-based validation with prioritized resource data.

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                   +-----------------+
                   | RP/Cache server |
                   | +-------------+ |
                   | | prioritized | |<-----RPKI data
                   | | resource    | |<-----AI data
                   | | data        | |<-----Locally
                   | +-------------+ |      imported data
                   +-----------------+
                     /             \
                    / RTR PDUs with \
                   / priority levels \
                  /                   \
    +-----------\/-----+        +------\/----------+
    |      Router      |        |      Router      |
    |+----------------+|        |+----------------+|
    ||route validation||        ||route validation||
    ||with prioritized||        ||with prioritized||
    ||resource data   ||        ||resource data   ||
    |+----------------+|        |+----------------+|
    +------------------+        +------------------+

   The RP/Cache server collects and manages resouce data (e.g., ROA/
   other digitally signed objects, like ASPA) which are from different
   sources such as RPKI repository, AI inference, and local import.  The
   data from different sources will be set to different priorities.  The
   RP/Cache server needs to decide how to merge these data from
   different sources.

   The data will be syncronized from the RP/Cache server to routers
   through tools like RTR.  Routers will do BGP route validation with
   priorities being taken into consideration.  Particularly, the
   validaiton output for a route can be Valid, Unknown, or Invalid-
   _level_. A route validated as invalid will be marked with Invalid as
   well as a credibility level of the validation result.  For example,
   "Invalid-_1_" means the validation result of invalid is derived based
   on the source data with the priority of _1_ and thus has a
   credibility level of _1_.

   Network operators can do configurations on routers to taken different
   policies on the invalid routes with different credibility levels.
   For example, suppose there are two ROA records on a router: 1) the
   prefix of 192.0.1.0/24 is authorized to AS 65001, which has a high
   priority of _1_ and 2) the prefix of 192.0.2/24 is authorized to AS
   65002, which has a relatively low priority of _2_. For the route with
   the prefix of 192.0.1.0/24 and the origin of AS 65003, the validation
   result will be invalid-_1_. Operators can configure the router to
   discard the route because the validation result is with a high
   credibility level.  For the route with the prefix of 192.0.2.0/24 and

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   the origin of AS 65003, the validation result will be invalid-_2_.
   Operators can choose to set a lower priority for this route to
   influence the route selection outcome.  This is because the
   validation result is with a relatively low credibility level and
   adopting a conservative handling policy to the route may be safer.

   The proposed framework brings two main benefits:

   *  Enhancing BGP route handling after route validation.  When the
      resource data are from multiple data sources with different levels
      of credibility, operators can implement customized priority
      settings to the resource data and apply different handling
      policies.

   *  Improving early deployment benefits and promoting the deployment
      of RPKI-based routing validation techniques.  When the
      registration rate of RPKI data is not high, operators can
      supplement data with techniques like AI while still being able to
      take "discarding" action on invalid routes with high credibility
      levels.

4.  Requirements for Multi-Priority RPKI ROV

   This section outlines the requirements for extending the RPKI
   architecture to support the processing and propagation of RPKI data
   with multiple priority levels.  These requirements are necessary to
   enable differentiated handling of routing validation results based on
   their perceived credibility, such as those derived from authoritative
   sources (e.g., RPKI ROAs) versus inferred or supplemental sources
   (e.g., AI-inferred data).

   1.  Priority Setting.  Implementations processing RPKI data on local
       cache (e.g., Relying Party software) SHOULD support the
       assignment of a priority level to each validated RPKI object.
       The priority MAY be configurable based on the data source (e.g.,
       RPKIsigned, locally imported, or AI-inferred).  The priority
       value SHOULD be represented in a standardized format to ensure
       interoperability.

   2.  Multi-Priority Data Merge.  Implementations SHOULD merge data
       from multiple sources according to a defined algorithm.  This
       algorithm SHOULD specify how to handle conflicts, including rules
       for merging data of the same priority and for superseding lower-
       priority data with higher-priority data.

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   3.  SLURM Support for Priority Marking.  The SLURM mechanism SHOULD
       be extended to allow local exceptions and additions to include a
       priority attribute.  This enables network operators to override
       or supplement RPKI data with local policies that reflect
       differentiated credibility.

   4.  RTR Support for Priority Marking.  The RPKI-to-Router (RTR)
       protocol MUST be extended to convey the priority of the
       validation data it delivers.  This enables routers to apply
       appropriate local policy based on the credibility of the origin.
       To provide flexibility in deployment, two implementation models
       MAY be supported.  Network operators SHOULD choose which
       implementation to deploy based on their specific operational
       preferences and infrastructure:

       4.1.  One single local cache server transmits data of multiple
       priority levels.  The protocol SHOULD be extended to include a
       new field within its Protocol Data Units (PDUs) to explicitly
       carry the priority level for each payload data item.  This model
       allows a router to maintain a single, simple transport session
       with one cache server while receiving a mixed-priority data set.

       4.2.  A router establishes transport sessions with multiple local
       cache servers, where each server is designated to provide data
       for a specific priority level (e.g., a primary server provides
       high-priority RPKI-validated data, and a secondary server
       provides low-priority supplemental data).  The protocol itself
       remains unchanged, as the priority is derived from the
       configuration of the router-to-server association.

   5.  BGP route validation (e.g., ROV, ASPA, etc.) with Priority
       Awareness.  BGP route validation processes SHOULD be enhanced to
       support a multi-priority data model.  The validation process
       SHOULD annotate the resulting validation state (Valid, Invalid)
       with an indication of the priority level, which identifies the
       priority tier of the data that was used to reach that conclusion.
       For example, an "Invalid" result derived from a local override
       (high-priority) MUST be distinguishable from an "Invalid" result
       derived from inferred data (low-priority).  This annotated
       validation state SHOULD then be used to inform subsequent routing
       policy actions.  Implementations SHOULD provide flexible policy
       mechanisms that allow network operators to define actions (e.g.,
       reject, depreference, warn, accept) based on both the validation
       state (e.g., Invalid) and its associated assurance level (e.g.,
       High or Low).

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   6.  Router Handling of Priority-Based Invalid Routes.  BGP speakers
       SHOULD support configurable policies to handle invalid routes
       based on the priority of the validation data.  For example,
       routes invalidated by high-priority data MAY be deprioritized or
       discarded, while those invalidated by low-priority data MAY be
       retained with a warning.

   7.  BMP Support for Priority in Validation Reports.  The BGP
       Monitoring Protocol (BMP) SHOULD be extended to include priority
       information in reports of BGP route validation results.  This
       enables network operators to monitor and analyze routing
       decisions based on data credibility.

5.  Security Considerations

   This document defines a framework for handling RPKI data with
   multiple levels of priority (assurance), which introduces new
   considerations beyond those of the base RPKI system [RFC6480].

   Amplification of RPKI Repository Failures: If a high-priority source
   (e.g., a primary RTR cache) becomes stale or unavailable, the system
   may fall back to low-priority data.  This could lead to a mass re-
   evaluation of routes from a 'Unknown' state to a 'Valid' or 'Invalid'
   state based on less credible information, potentially causing
   widespread routing churn.  Implementations should include mechanisms
   to detect such scenarios and allow operators to define appropriate
   fallback behaviors.

6.  IANA Considerations

   This document has no IANA action.

7.  References

7.1.  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>.

   [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>.

7.2.  Informative References

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   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
              February 2012, <https://www.rfc-editor.org/info/rfc6480>.

Authors' Addresses

   Jia Zhang
   Zhongguancun Laboratory
   Beijing
   China
   Email: zhangj@zgclab.edu.cn

   Mingwei Xu
   CERNET
   Beijing
   China
   Email: xmw@cernet.edu.cn

   Nan Geng
   Huawei
   Beijing
   China
   Email: gengnan@huawei.com

   Chongfeng Xie
   China Telecom
   Beijing
   China
   Email: xiechf@chinatelecom.cn

   Yangyang Wang
   Tsinghua University
   Beijing
   China
   Email: wangyy@cernet.edu.cn

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