Telechat Review of draft-ietf-mpls-mna-ps-hdr-13
review-ietf-mpls-mna-ps-hdr-13-intdir-telechat-lemon-2026-08-02-00
| Request | Review of | draft-ietf-mpls-mna-ps-hdr |
|---|---|---|
| Requested revision | No specific revision (document currently at 19) | |
| Type | Telechat Review | |
| Team | Internet Area Directorate (intdir) | |
| Deadline | 2026-08-02 | |
| Requested | 2026-07-13 | |
| Requested by | Éric Vyncke | |
| Authors | Jaganbabu Rajamanickam , Rakesh Gandhi , Royi Zigler , Jie Dong , Jisu Bhattacharya | |
| I-D last updated | 2026-08-06 (Latest revision 2026-08-06) | |
| Completed reviews |
Rtgdir Early review of -06
by Loa Andersson
(diff)
Rtgdir Early review of -07 by Matthew Bocci (diff) Genart IETF Last Call review of -08 by Roni Even (diff) Opsdir IETF Last Call review of -08 by Chongfeng Xie (diff) Secdir IETF Last Call review of -08 by Yoav Nir (diff) Intdir Telechat review of -13 by Ted Lemon (diff) |
|
| Comments |
As MNA is vaguely the MPLS equivalent of SRv6 network programming and MPLS sits somewhere between layer-2 and layer-3, a INT review will be useful. Thanks. |
|
| Assignment | Reviewer | Ted Lemon |
| State | Completed | |
| Request | Telechat review on draft-ietf-mpls-mna-ps-hdr by Internet Area Directorate Assigned | |
| Posted at | https://mailarchive.ietf.org/arch/msg/int-dir/QFh8ISALzlpXtYGa264Cb-Qkbkk | |
| Reviewed revision | 13 (document currently at 19) | |
| Result | Ready w/issues | |
| Completed | 2026-08-02 |
review-ietf-mpls-mna-ps-hdr-13-intdir-telechat-lemon-2026-08-02-00
This is an intdir review of draft-ietf-mpls-mna-ps-hdr-13. This review is not coming from a place of knowledge of how MPLS works, so I'll briefly explain my understanding of what this document does: it extends the MPLS Network Action (MNA) header by providing a way to include additional data _after_ the rest of the MPLS headers so that the fast-path-readable headers come first in cases where the post-stack headers would, if included inline, potentially push some MPLS labels out of the readable label depth of the header. Because the point (again, as I understand it) of MPLS is to do label-based routing and avoid routing on the IP header, and because this is essentially an OAM extension to MPLS (again, as I understand it) this document should not have any new implications for the IP layer or layer two, with one exception: the size of the MPLS header can be increased through the use of this mechanism, so in principle it is possible that this could lead to a packet that fit in the MTU of the MPLS path to no longer fit. The document addresses this case by requiring that the node adding the PSMH header must not increase the size of the packet above the path MTU. However, the mechanism for discovering the path MTU described in RFC 3032 relies on ICMP too-big messages, so this is a bit circular, particularly if the packet to which the MNA post-stack header is being added is not an IP packet. Given that the post-stack header can in principle be fairly large, this feels like something that ought to be addressed explicitly, even if in current practice it's simply not an issue (as a non-expert I obviously have no clue whether or not this is the case). I'm marking the document "ready with issues" on this basis. This is not an assertion that there is a problem—it's just that I can't confirm from my reading whether or not there is a problem, so it feels worth mentioning. Aside from this the document makes sense and appears useful.