Network Working Group T. Wu Internet-Draft J. Ge Intended status: Standards Track X. Ding Expires: 31 August 2024 H. Wang Huawei 28 February 2024 BGP AS_PATH Validation State Extended Community draft-wu-sidr-aspa-validation-signaling-00 Abstract This document defines a new BGP opaque extended community to carry the AS_PATH validation state based on Autonomous System Provider Authorization (ASPA) inside an autonomous system. Internal BGP (IBGP) speakers that receive this validation state can configure local policies that allow it to influence their decision process. 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. 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 31 August 2024. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. Wu, et al. Expires 31 August 2024 [Page 1] Internet-Draft RPKI ASPA Extended Community February 2024 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 2. Origin Validation State Extended Community . . . . . . . . . 2 3. Deployment Considerations . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction This document defines a new BGP opaque extended community to carry the AS_PATH validation state based on Autonomous System Provider Authorization (ASPA) inside an autonomous system. Internal IBGP speakers that receive this validation state can configure local policies that allow it to influence their decision process. 2. Origin Validation State Extended Community The origin validation state extended community is an opaque extended community [RFC4360] with the following encoding: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0x43 | 0x03 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |validationstate| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Wu, et al. Expires 31 August 2024 [Page 2] Internet-Draft RPKI ASPA Extended Community February 2024 The value of the high-order octet of the extended Type field is 0x43, which indicates it is non-transitive and opaque [RFC7153]. The value of the low-order octet of the extended Type field is 0x03 which is an unassigned sub-type of non-transitive opaque extended communities. The Reserved field MUST be set to 0 and ignored upon the receipt of this community. The last octet of the extended community is an unsigned integer that gives the AS_PATH's validation state [I-D.ietf-sidrops-aspa-verification]. It can assume the following values: +-------+-----------------------------+ | Value | Meaning | +-------+-----------------------------+ | 0 | Lookup result = "Valid" | | 1 | Lookup result = "Unknown" | | 2 | Lookup result = "Invalid" | +-------+-----------------------------+ Figure 2 If the router is configured to support the extensions defined in this document, it SHOULD attach the AS-PATH validation state extended community to BGP UPDATE messages sent to IBGP peers by mapping the computed validation state in the last octet of the extended community. Similarly, a receiving BGP speaker, in the absence of validation state set based on local data, SHOULD derive a validation state from the last octet of the extended community, if present. An implementation SHOULD NOT send more than one instance of the AS- PATH validation state extended community. However, if more than one instance is received, an implementation MUST disregard all instances other than the one with the numerically greatest validation state value. If the value received is greater than the largest specified value (2), the implementation MUST apply a strategy similar to attribute discard [RFC7606] by discarding the erroneous community and logging the error for further analysis. By default, implementations MUST drop the AS-PATH validation state extended community if received from an External BGP (EBGP) peer, without processing it further. Similarly, by default, an implementation SHOULD NOT send the community to EBGP peers. However, it SHOULD be possible to configure an implementation to send or accept the community when warranted. An example of a case where the community would reasonably be received from, or sent to, an EBGP peer is when two adjacent ASes are under control of the same administration. Wu, et al. Expires 31 August 2024 [Page 3] Internet-Draft RPKI ASPA Extended Community February 2024 3. Deployment Considerations In deployment scenarios in which not all the speakers in an autonomous system are upgraded to support the extensions defined in this document, it is necessary to define policies that match on the AS-PATH validation extended community and set another BGP attribute that influences selection of the best path in the same way that an implementation of this extension would. 4. IANA Considerations The value 0x03 in the "Non-Transitive Opaque Extended Community Sub- Types" registry is unassigned by IANA. This value can be used as "BGP AS-PATH Validation State Extended Community". 5. Security Considerations Security considerations such as those described in [RFC4272] continue to apply. Since this document introduces an extended community that will generally be used to affect route selection, the analysis in Section 4.5 ("Falsification") of [RFC4593] is relevant. These issues are neither new, nor unique to the origin validation extended community. This document describes a scheme where router A outsources validation to some router B. If this scheme is used, the participating routers should have the appropriate trust relationship -- B should trust A either because they are under the same administrative control. The security properties of the propagation path between the two routers should also be considered. See [RFC7454] Section 5.1 for advice regarding protection of the propagation path. 6. References 6.1. 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 6.2. Informative References Wu, et al. Expires 31 August 2024 [Page 4] Internet-Draft RPKI ASPA Extended Community February 2024 [I-D.ietf-sidrops-aspa-verification] Azimov, A., Bogomazov, E., Bush, R., Patel, K., Snijders, J., and K. Sriram, "BGP AS_PATH Verification Based on Autonomous System Provider Authorization (ASPA) Objects", Work in Progress, Internet-Draft, draft-ietf-sidrops-aspa- verification-16, 29 August 2023, . [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC 4272, DOI 10.17487/RFC4272, January 2006, . [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, February 2006, . [RFC4593] Barbir, A., Murphy, S., and Y. Yang, "Generic Threats to Routing Protocols", RFC 4593, DOI 10.17487/RFC4593, October 2006, . [RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP Extended Communities", RFC 7153, DOI 10.17487/RFC7153, March 2014, . [RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, February 2015, . [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K. Patel, "Revised Error Handling for BGP UPDATE Messages", RFC 7606, DOI 10.17487/RFC7606, August 2015, . Authors' Addresses Tianhao Wu Huawei Email: wutianhao10@huawei.com Jun Ge Huawei Email: jack.gejun@huawei.com Xiangfeng Ding Huawei Wu, et al. Expires 31 August 2024 [Page 5] Internet-Draft RPKI ASPA Extended Community February 2024 Email: dingxiangfeng@huawei.com Haibo Wang Huawei Email: rainsword.wang@huawei.com Wu, et al. Expires 31 August 2024 [Page 6]