Early Review of draft-ietf-idr-bgp-ct-srv6-03
review-ietf-idr-bgp-ct-srv6-03-opsdir-early-nainar-2024-03-27-00
Request | Review of | draft-ietf-idr-bgp-ct-srv6 |
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Requested revision | No specific revision (document currently at 05) | |
Type | Early Review | |
Team | Ops Directorate (opsdir) | |
Deadline | 2024-03-28 | |
Requested | 2024-03-12 | |
Requested by | Susan Hares | |
Authors | Kaliraj Vairavakkalai , Natrajan Venkataraman | |
I-D last updated | 2024-03-27 | |
Completed reviews |
Rtgdir Early review of -03
by Jonathan Hardwick
(diff)
Opsdir Early review of -03 by Nagendra Kumar Nainar (diff) Tsvart Early review of -03 by Dr. Joseph D. Touch (diff) |
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Comments |
RTG-DIR: Jon Hardwick worked on the draft-ietf-idr-bgp-ct-18 review. The draft-ietf-idr-bgp-ct-srv6-04 draft has been split from the draft-ietf-idr-bgp-ct draft. It may be useful to have Jon if he feels comfortable with the SRv6 review. OPS-DIR - Bo Wu did the review in July on drsaft-ietf-idr-bgp-ct-18. The draft-ietf-idr-bgp-ct-srv6-04 has been split from the draft-ietf-idr-bgp-ct draft. It may be useful for him to do the review of this draft. SEC-DIR—Intent (Color) could have security issues in this draft. Intent tracks service data (customer data) and places it over service quality tunnels. In one view, it is just more layering. In an alternate view, the color exposes some abstract qualities of the network. My understanding is that some people have questions SRv6 security. It would be good to provide feedback that differentiates between the general security and the additional issues this draft presents. TSV-DIR - Please look at this draft from the viewpoint of having intent (color) aware customer traffic forwarded over a VPN overlay (tunnels) that forwarded over a set of intent (color) aware underlay of tunnels. Please consider the problems with tunnels in your review of this text. |
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Assignment | Reviewer | Nagendra Kumar Nainar |
State | Completed | |
Request | Early review on draft-ietf-idr-bgp-ct-srv6 by Ops Directorate Assigned | |
Posted at | https://mailarchive.ietf.org/arch/msg/ops-dir/9OeIs5Quj2sNKL2nbNwrnOEtBVY | |
Reviewed revision | 03 (document currently at 05) | |
Result | Has issues | |
Completed | 2024-03-27 |
review-ietf-idr-bgp-ct-srv6-03-opsdir-early-nainar-2024-03-27-00
Hi, I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts per guidelines in RFC5706. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. Overall Summary: This draft is a experimental track proposing the relevant mechanisms to apply "Intent Driven Service Mapping" for SRv6 dataplane along with the relevant extensions. Based on my reading (version-03), there are a few gaps that needs to be clarified or addressed from the operational aspects. I am marking it as "Has issues" to get some clarification on the below: A BGP CT node that does not support MPLS forwarding advertises the special label 3 (Implicit NULL) in the [RFC8277] MPLS Label field. The Implicit NULL label carried in BGP CT route indicates to receiving node that it should not impose any BGP CT label for this route. Thus a pure SRv6 node carries Implicit NULL in the MPLS Label field in RFC8277 BGP CT NLRI. <Nagendra> The above appears to be a bit misleading. What if a node supports MPLS forwarding but is not enabled or if the node is connected to MPLS domain and SRv6 domain?. I think that the intention of the above statement is to instruct the receiver to use SRv6 encap. So I think it is better to rephrase the above based on the encapsulation intent (SRv6 vs MPLS vs etc) instead of mentioning it based on the protocol support. The BGP Classful Transport route update for SRv6 MUST include an attribute containing SRv6 SID information, with Transposition scheme disabled. <Nagendra> The being a normative MUST statement, I think it is better to clarify more about what "attribute" are we referring here. The MUST is for including "an attribute" or to to "disable the transposition scheme" or both?. I think it is better to clarify the same - Something like "...SRv6 MUST include BGP Prefix-SID attribute with SRv6 Service SUb-TLV and MUST disable the transposition scheme". The BGP Prefix-SID attribute as specified in [RFC9252] is used to carry this information correctly. <Nagendra> I think RFC8669 defines BGP prefix-SID attribute and RFC9252 introduces SRv6 Service TLVs for Prefix-SID attribute. If the [RFC9252] Prefix-SID attribute also contains a "SRv6 SID Structure Sub-Sub-TLV", <Nagendra> The above comment is applicable for this one as well. If the [RFC9252] Prefix-SID attribute also contains a "SRv6 SID Structure Sub-Sub-TLV", the Transposition Length is set to 0 and Transposition Offset is set to 0. <Nagendra> Based on the normative MUST statement defined in Section 4, I believe the above should be "MUST set the Transposition Length to 0"?. Or is it not mandatory here? A Next hop Resolution Scheme similar to that of BGP CT [BGP-CT] is used on IPv6 Unicast family to resolve “Colorful Prefix” locator routes that carry a mapping community to intent-aware paths in each domain. <Nagendra> By "mapping community", are you referring to the "color extended community" defined in draft-ietf-idr-cpr or the mapping community in Section 5.1 of draft-ietf-idr-bgp-ct? If a BGP speaker considers a received BGP CT route invalid for some reason, but is able to successfully parse the NLRI and attributes, Treat-as-withdraw approach from [RFC7606] is used <Nagendra> I think section 6 should refer section 7 of RFC9252 for additional error handling related to SRv6 service SUb-TLVs included in the BGP-Prefix SID attribute. Thanks, Nagendra