Network Working Group                                            R. Bush
Internet-Draft                        Internet Initiative Japan & Arrcus
Updates: 6811 (if approved)                                      R. Volk
Intended status: Standards Track                        Deutsche Telekom
Expires: October 9, 10, 2020                                       J. Heitz
                                                                   Cisco
                                                           April 7, 8, 2020

               BGP RPKI-Based Origin Validation on Export
                    draft-ietf-sidrops-ov-egress-03
                    draft-ietf-sidrops-ov-egress-04

Abstract

   A BGP speaker may perform RPKI origin validation not only on routes
   received from BGP neighbors and routes that are redistributed from
   other routing protocols, but also on routes it sends to BGP
   neighbors.  For egress policy, it is important that the
   classification uses the 'effective origin AS' of the processed route,
   which may specifically be altered by the commonly available knobs
   such as removing private ASs, confederation handling, and other
   modifications of the origin AS.  This document updates [RFC6811].

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 October 9, 10, 2020.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Suggested Reading . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Egress Processing . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4   3
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document does not change the protocol or semantics of [RFC6811],
   BGP prefix origin validation.  It highlights an important use case of
   origin validation in eBGP egress policies, explaining specifics of
   correct implementation in this context.

   The term 'effective origin AS' as used in this document refers to the
   Autonomous System number which is used by [RFC6811] BGP Prefix
   Route Origin
   Validation.

   As ASN [RFC6811] of the UPDATE to be sent to neighboring
   BGP speakers.

   The effective origin AS of a BGP UPDATE is decided by configuration
   and outbound policy of the BGP speaker, a speaker.  A validating BGP speaker
   MUST apply Route Origin Validation policy semantics (see [RFC6811]
   Sec 2 and [RFC8481] Sec 4) against the origin Autonomous
   System number which will actually be used by subsequent [RFC6811] BGP
   Prefix Origin Validation. after applying any egress configuration
   and policy.

   This effective origin AS of the announcement might be affected by
   removal of private ASs, confederation [RFC5065], migration [RFC7705],
   etc.  Any AS_PATH modifications resulting in effective origin AS
   change MUST be taken into account.

   This document updates [RFC6811] by clarifying that implementations
   must use the effective origin AS to determine the Origin Validation
   state when applying egress policy.

2.  Suggested Reading

   It is assumed that the reader understands BGP, [RFC4271], the RPKI,
   [RFC6480], Route Origin Authorizations (ROAs), [RFC6482], RPKI-based
   Prefix Validation, [RFC6811], and Origin Validation Clarifications,
   [RFC8481].

3.  Egress Processing

   BGP implementations supporting RPKI-based origin validation MUST
   provide the same policy configuration primitives for decisions based
   on validation state available for use in ingress, redistribution, and
   egress policies.  When applied to egress policy, validation state
   MUST be determined using the effective origin AS of the route as it
   will (or would) be announced to the peer.  The effective origin AS
   may differ from that of the route in the RIB due to commonly
   available knobs such as: removal of private ASs, AS path
   manipulation, confederation handling, etc.

   Egress policy handling can provide more robust protection for
   outbound eBGP than relying solely on ingress (iBGP, eBGP, connected,
   static, etc.) redistribution being configured and working correctly -
   better support for the robustness principle.

4.  Operational Considerations

   Configurations may have complex policy where the final announced effective origin AS
   may not be easily predicted determined before the outbound policies have been
   run.  Therefore it  It SHOULD be possible to specify a selective origin validation
   policy which will run to be applied after all any existing non-validating outbound
   policies.

   An implementation SHOULD be able to list announcements that were not
   sent to a peer, e.g., because they were marked Invalid, as long as
   the router still has them in memory.

5.  Security Considerations

   This document does not create security considerations beyond those of
   [RFC6811] and [RFC8481].  By facilitating more correct validation, it
   attempts to improve BGP reliability.

6.  IANA Considerations

   This document has no IANA Considerations.

7.  Acknowledgments

   Thanks to reviews and comments from Linda Dunbar, Nick Hilliard,
   Benjamin Kaduk, Chris Morrow, Keyur Patel, Alvaro Retana, Alvaro
   Retana, Job Snijders, Robert Sparks, and Robert Wilton.

8.  References

8.1.  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,
              <http://www.rfc-editor.org/info/rfc2119>.

   [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,
              <http://www.rfc-editor.org/info/rfc4271>.

   [RFC5065]  Traina, P., McPherson, D., and J. Scudder, "Autonomous
              System Confederations for BGP", RFC 5065,
              DOI 10.17487/RFC5065, August 2007,
              <http://www.rfc-editor.org/info/rfc5065>.

   [RFC6482]  Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
              Origin Authorizations (ROAs)", RFC 6482,
              DOI 10.17487/RFC6482, February 2012,
              <http://www.rfc-editor.org/info/rfc6482>.

   [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", RFC 6811,
              DOI 10.17487/RFC6811, January 2013,
              <http://www.rfc-editor.org/info/rfc6811>.

   [RFC7705]  George, W. and S. Amante, "Autonomous System Migration
              Mechanisms and Their Effects on the BGP AS_PATH
              Attribute", RFC 7705, DOI 10.17487/RFC7705, November 2015,
              <http://www.rfc-editor.org/info/rfc7705>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <http://www.rfc-editor.org/info/rfc8174>.

   [RFC8481]  Bush, R., "Clarifications to BGP Origin Validation Based
              on Resource Public Key Infrastructure (RPKI)", RFC 8481,
              DOI 10.17487/RFC8481, September 2018,
              <https://www.rfc-editor.org/info/rfc8481>.

8.2.  Informative References

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

Authors' Addresses

   Randy Bush
   Internet Initiative Japan & Arrcus
   5147 Crystal Springs
   Bainbridge Island, Washington  98110
   US

   Email: randy@psg.com

   Ruediger Volk
   Deutsche Telekom

   Email: rv@nic.dtag.de

   Jakob Heitz
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: jheitz@cisco.com