Closed suehares closed 1 month ago
An SR Policy MAY be enabled for the Drop-Upon-Invalid behavior. This would entail the following:
any steering of a service (PW), destination (BGP-VPN), flow, or packet on the related SR Policy is maintained with the action to drop all of this traffic.
The Drop-Upon-Invalid behavior has been deployed in use cases where the operator wants some PW to only be transported on a path with specific constraints. When these constraints are no longer met, the operator wants the PW traffic to be dropped. Specifically, the operator does not want the PW to be routed according to the IGP shortest path to the PW endpoint.
reason: RFC9256 gives a behavior for IGP, but not for BGP.
Technical comment: BGP passes a valid SR Policy Candidate Route, which is declared valid for BGP (NLRI and TEA) with specific behavior (I-Flag). The general concept of the I-Flag is given in RFC9256 in Section 8.2, but the above portion of Section 8.2 points only to IGP rather than the tunnel.
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closed merged into https://github.com/ietf-wg-idr/draft-ietf-idr-sr-policy-safi/issues/32
RTG-DIR Issue-17 Section 2.4.3 - I-Flag
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Jeffrey: I also have trouble understanding this "Drop Upon Invalid" behavior. I read rfc9256 but still can't put the two together.