Ballot for draft-ietf-isis-segment-routing-msd
Yes
No Objection
Note: This ballot was opened for revision 15 and is now closed.
Thank you for a well written, clear and easy to understand document. Also thanks to Zitao Wang for the OpsDir review ( https://mailarchive.ietf.org/arch/msg/ops-dir/GT5r_8_OukxlqMb1NFdsbNysJIw ) While reviewing it I found some minor nits - these are not blocking comments, but please consider addressing them to make the document even better: 1: Section 1: " Path Computation Element Protocol (PCEP) SR extensions" I think this would read better as "The Path Computation ..." (Hey! I did say they were nits :-)) 2: Section 2. Node MSD Advertisement "Type: 23 (allocated by IANA via the early assignment process)" Comment: Thank you for mentioning here that this is an early allocation - it makes it much easier on the reviewer than flipping to the back of the document to check, flipping forward, etc.! 3: Section 3. Link MSD Advertisement "MSD values may be learned via a hardware API or may be provisioned." I don't quite get what a "hardware API" is -- perhaps "an API which talks directly to the hardware"? Or just drop API (or hardware)? 4: Section 6. IANA Considerations "Per TLV information where Link MSD sub-TLV can be part of: TLV 22 23 25 141 222 223 --- -------------------- yyyyyy Figure 5: TLVs where LINK MSD Sub-TLV can be present" I understand what this is trying to say, but I don't think it does a very good job of doing so. Perhaps remove the figure and just say "The LINK MSD Sub-TLV can be in TLVs 22, 23, 25,141, 222 or 223" or similar....
Sorry for the re-send; I forgot to add the following paragraph: I'm not sure I followed correctly some discussion around the rtgdir review, specifically the meaning of the indicated MSD value for SR-enabled vs. non-SR-enabled networks. In particular, I still don't really understand why it's okay to use the same codepoint (value 1 as assigned here) for the max SID depth in SR-enabled networks and for the max label depth in non-SR MPLS networks. Why couldn't they just be separate MSD Type codepoints? The shepherd writeup is silent about the WG's discussion of the IPR disclosure (but the corresponding ospf draft says this sort of thing is typical for LSR drafts). Section 3 The link MSD sub-TLV is defined for TLVs 22, 23, 25, 141, 222, and 223 to carry the MSD of the interface associated with the link. MSD Please add the appropriate qualifier (IS-IS?) before the list of TLV numbers. MSD-Value is a number in the range of 0-255. For all MSD-Types, 0 represents lack of the ability to support SID stack of any depth; any other value represents that of the link. It's unclear that there's a referent for "that of the link" to attach to. That is, is it better to say "represents the maximum SID depth supported by the link" (or similar)? Section 6 As discussed in the secdir review, this section needs to include guidance to the Experts to check that the meaning of the absence of an MSD type is specified. Given the text in draft-ietf-ospf-segment-routing-msd that attempts to place a similar requirement on future MSD types (but for OSPF vs. IS-IS usage thereof), hopefully this guidance can be phrased in an appropriately general fashion so as to apply to all places where the registered MSD value would be used. Section 7 Advertisement of the additional information defined in this document that is false, e.g., an MSD that is incorrect, may result in a path computation failing, having a service unavailable, or calculation of a path that cannot be supported by the head-end (the node performing the imposition). In the analogous OSPF document we split out the case of a value that is too small and a value that is too large, to describe the different consequences. I would also suggest rewording to something like "calculation by the head-end of a path that cannot be supported" to avoid the mis-parsing "(calculation of a path) (that cannot be supported by the head-end)".