Hi Reshad, Thank you for reviewing it and the feedback. Agreed, we can include the reference to RFC7881.
In terms of the bug found by Claude, I can see why it produced that conclusion. There’s a bug in the explanation text that makes it describe S-BFD terminates on the downstream node, indicating the junction node, which is not intended, thus the example is misleading. I’ll modify that text to clarify it (and reconfirm with Claude =) ). I also believe we should refine the example further since the Junction SID on node F is not required, which will help with the clarity. Will make the update on next iteration. Thanks again! Andrew From: Reshad Rahman <[email protected]> Date: Thursday, July 23, 2026 at 11:32 PM To: Andrew Stone (Nokia) <[email protected]>; SPRING WG <[email protected]> Cc: BFD WG <[email protected]> Subject: Comments on draft-stone-spring-mpte-sr CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information. <Cross-posting to BFD> Hi Andrew, authors, I had concern that this document may violate S-BFD spec but upon checking RFC7880 section 7.2.1, it seems that there is no issue. BTW I think RFC7881 should also be in the reference list. I had my colleague Claude do a quick check and Claude believes there's an issue. I am too tired to verify this right now, but I am sending it just in case I forget. Regards, Reshad. Section 7.3.2 recommends that each egress SID list of each Junction Segment run "its own S-BFD session to the next downstream node." In the Appendix A example, Junction Segment C has SID List 2 [Adj-SID-CF, BSID-F]. The implied S-BFD session would be initiated from C and is supposed to verify reachability to F. But that's not what happens. When an S-BFD packet (per RFC 7881 / RFC 9612) is forwarded along [Adj-SID-CF, BSID-F]: 1. C pushes the full label stack and forwards to F via the adjacency SID. 2. F receives the packet with BSID-F on top. F processes BSID-F as a Binding SID — it swaps BSID-F for its own Junction Segment SID list [Adj-SID-FH] and forwards to H. 3. The S-BFD packet terminates at H (the DAG egress), not at F.
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