Document: draft-ietf-spring-dhc-distribute-srv6-locator-dhcp Title: Distribute SRv6 Locator by DHCP Reviewer: Adrian Farrel Review result: Has Issues
RTG Dir review in Working Group Last Call Reviewer: Adrian Farrel Review result: Has issues Hello, I have been selected as the Routing Directorate reviewer for this draft. The Routing Directorate seeks to review all routing or routing-related drafts as they pass through IETF last call and IESG review, and sometimes on special request. The purpose of the review is to provide assistance to the Routing ADs. For more information about the Routing Directorate, please see https://wiki.ietf.org/en/group/rtg/RtgDir This is an "early review" coinciding with working group last call. It would be helpful if you could consider them along with any other working group last call comments that you receive, and strive to resolve them through discussion or by updating the draft. Cheers, Adrian Document: draft-ietf-spring-dhc-distribute-srv6-locator-dhcp-09 Reviewer: Adrian Farrel Review Date: 2025-09-07 Intended Status: Standards Track = Summary: This document is easy enough to understand, and the protocol elements seem well defined, with error cases called out. I believe interoperable implementation would not be hard. However, there is one major issue of clarity (which is hopefully easy to resolve) and a number of minor issues/nits that would be nice to fix. = General: I trust this document has been reviewed by the DHC WG. If not, it would be worth sending them a heads-up. --- It seems to me that there is more background information than is needed. It is not necessary to explain how SRv6 works, because that is already covered in other documents. If you have time to edit down the Introduction, that would be nice - but it is not a critical issue. = Major: I think that the Introduction describes a problem, but then proposes DHCP to address a different problem. The problem you seem to describe is: A CPE that does not run an IGP cannot distribute or receive SRv6 locators. The solution provided seems to address the following problem: An SRv6 Segment Endpoint Node needs to determine its own SRv6 locator through some form of distribution or configuration. This is compounded by section 3 which basically says: - SR configuration at he CPE can be complex - Discovery by the BRAS of routes to CPEs cannot always be achieved using an IGP. The problem description in Section 3 seems much more accurate. Perhaps you can reflect it in the text in the Introduction. That said, I think that the material in Sections 4 and 5 only addresses the first of the two problems described in Section 3. Further, Figure 4 includes "Distribute Locator Route" but there is no description of this. Perhaps there is an assumption that the BRAS is the DHCP server or relay so that the routes are automagically learned, but there seems to be no statement of this, and so no consideration of what happens if the BRAS is just passing DHCP packets through unexamined. There is just a single sentence in 5.3 about routes and BRAS acting as DHCP server: If the BRAS device acts as a DHCPv6 server, the server also MUST delete the corresponding SRv6 locator route locally. While 5.4 has two sentences about the DHCP relay (without reference to the BRAS): The first DHCPv6 relay agent needs to record the SRv6 locator assigned by the DHCPv6 server, including SRv6 locator information, lifetime, etc. and generates SRv6 locator route locally. After receiving the DHCPv6 Release or Decline messages from the client, or the valid lifetime of SRv6 Locator prefix expires, the DHCPv6 relay agent MUST delete the SRv6 locator route locally. = Minor: You should review the text to check that all uses of lower case "must", "should", and "may" are really intended to be lower case and not use BCP 14 upper case. --- Section 6 Thanks for including this. It is helpful. It would be nice to clarify whether the implementations are client, relay, or server. = Nits: 4.2 has "IA SRv6 Locator Option" but 4.1 names the field as "IA_SRV6_LOCATOR-Options" And you need to decide between: - IA SRv6 Locator option - IA SRv6 Locator-option - IA SRv6 Locator Option This is particularly sensitive in the context of: More than one IA SRv6 Locator option can appear in a single IA_SRV6_LOCATOR option. _______________________________________________ spring mailing list -- [email protected] To unsubscribe send an email to [email protected]
