Resource Public Key Infrastructure (RPKI) Origin Validation for BGP Export
Internet Initiative Japan & Arrcus
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randy@psg.com
ietf@rewvolk.de
Cisco
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jheitz@cisco.com
routing
security
RPKI
A BGP speaker may perform Resource Public Key Infrastructure (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 use the 'effective origin AS' of the processed
route, which may specifically be altered by the commonly available
knobs, such as removing private ASes, confederation handling, and
other modifications of the origin AS. This document updates RFC 6811.
Introduction
This document does not change the protocol or semantics of , BGP prefix origin validation. It highlights an
important use case of origin validation in external BGP (eBGP) egress policies,
explaining specifics of correct implementation in this context.
The term 'effective origin AS' as used in this document refers to
the Route Origin Autonomous System Number (ASN) 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 validating
BGP speaker MUST apply Route Origin Validation policy semantics (see
and )
after applying any egress configuration and policy.
This effective origin AS of the announcement might be affected by
removal of private ASes, confederation ,
migration , etc. Any AS_PATH modifications
resulting in effective origin AS change MUST be taken into
account.
This document updates by clarifying that
implementations must use the effective origin AS to determine the
Origin Validation state when applying egress policy.
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
when, and only when, they appear in all capitals, as shown here.
Suggested Reading
It is assumed that the reader understands BGP , the RPKI ,
Route Origin Authorizations (ROAs) , RPKI-based Prefix Validation , and Origin Validation
Clarifications .
Egress Processing
BGP implementations supporting RPKI-based origin validation MUST
provide the same policy configuration primitives for decisions based
on the 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 ASes, 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
-- i.e., better support for the robustness principle.
Operational Considerations
Configurations may have a complex policy where the effective
origin AS may not be easily determined before the outbound policies
have been run. It SHOULD be possible to specify a selective origin
validation policy to be applied after 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.
Security Considerations
This document does not create security considerations beyond
those of and . By
facilitating more correct validation, it attempts to improve BGP
reliability.
IANA Considerations
This document has no IANA actions.
References
Normative References
Informative References
Acknowledgments
Thanks to reviews and comments from , ,
, ,
,
, ,
, and .