Hi Sasha: This document does not introduce the status of each VPN into the IGP; instead, it introduces the status of VPN protection groups. For a pair of PEs, regardless of how many multi-homed VPNs there are, only one Mirror SID will be advertised. Therefore, this will not cause scalability issues for the IGP
Thanks Zhibo From: Alexander Vainshtein [mailto:[email protected]] Sent: Wednesday, November 5, 2025 7:53 PM To: [email protected] Cc: rtgwg <[email protected]>; [email protected] Subject: [Lsr] Scalability issues in draft-ietf-rtgwg-srv6-egress-protection? Hi all, I have looked up the -20 revision of the draft<https://datatracker.ietf.org/doc/html/draft-ietf-rtgwg-srv6-egress-protection-20>, and I see that it explicitly mentions (e.g., in Section 3.1.1 in Section ) protection for SRv6 "service" SIDs as defined in RFC 9252. It I my understanding that the information about protection provided for such SIDs is distributed within the IGP domain by an appropriate link-state IGP (IS-IS or OSPF) – at least, no other way of distributing such relationships to the potential PLR is not defined in the draft. From my POV this raises a serious scalability concern about the proposed solution, since, potentially, a huge amount of information would be flooded by IGP to all the nodes in the IGP domain. This consideration is not relevant about "topological" SIDs since these are part of the topology natively learned and advertised by any link-state IGP. In particular, IGP convergence times may be seriously affected due to the need to redistribute this information. But "service" SIDs are normally distributed only to the PEs that participate in the service, and their number may exceed the number of links and nodes in the given IGP domain by an order of magnitude. For comparison, RFC 8679<https://www.rfc-editor.org/rfc/rfc8679.html> explicitly requires a session of the service label distribution protocol between the PLR and the protected egress PE, and RFC 8104<https://www.rfc-editor.org/rfc/rfc8679.html#RFC8104> describes in detail how (targeted) LDP can be used to distribute this information in the case of PW-based services. Hopefully these notes will be useful. Regards, Sasha Disclaimer This e-mail together with any attachments may contain information of Ribbon Communications Inc. and its Affiliates that is confidential and/or proprietary for the sole use of the intended recipient. Any review, disclosure, reliance or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please notify the sender immediately and then delete all copies, including any attachments.
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