Internet DRAFT - draft-wu-sidr-aspa-validation-signaling
draft-wu-sidr-aspa-validation-signaling
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.
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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.
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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
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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
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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.
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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,
<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>.
6.2. Informative References
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[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,
<https://datatracker.ietf.org/doc/html/draft-ietf-sidrops-
aspa-verification-16>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/info/rfc4272>.
[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>.
[RFC4593] Barbir, A., Murphy, S., and Y. Yang, "Generic Threats to
Routing Protocols", RFC 4593, DOI 10.17487/RFC4593,
October 2006, <https://www.rfc-editor.org/info/rfc4593>.
[RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP
Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
March 2014, <https://www.rfc-editor.org/info/rfc7153>.
[RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
February 2015, <https://www.rfc-editor.org/info/rfc7454>.
[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,
<https://www.rfc-editor.org/info/rfc7606>.
Authors' Addresses
Tianhao Wu
Huawei
Email: wutianhao10@huawei.com
Jun Ge
Huawei
Email: jack.gejun@huawei.com
Xiangfeng Ding
Huawei
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Email: dingxiangfeng@huawei.com
Haibo Wang
Huawei
Email: rainsword.wang@huawei.com
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