Hi Gunter, 

Thanks for the review. 

> On Dec 17, 2024, at 10:22 AM, Gunter van de Velde (Nokia) 
> <[email protected]> wrote:
> 
> # Gunter Van de Velde, RTG AD, comments for draft-ietf-lsr-ospf-admin-tags-22
> 
> # The referenced line numbers are derived from the idnits tool:
> https://author-tools.ietf.org/api/idnits?url=https://www.ietf.org/archive/id/draft-ietf-lsr-ospf-admin-tags-22.txt
> 
> # Many thanks for this write-up. The document is well written and was a 
> pleasure to read.
> 
> # idnits tool comes up clean
> 
> # Many thanks to Christian Hopps for the Shepherd write-up, Russ White for 
> the RTGDIR review and Qiufang Ma for the YANGDOCTORS review
> 
> #DETAILED COMMENTS
> #==================
> 
> 139      Type     A 16-bit field set to TBD.
> 
> GV> From readability, maybe call out that there is a:
> TBD1: "OSPF Extended Prefix TLV Sub-TLV" Registry
> TBD2: "OSPFv3 Extended-LSA Sub-TLV" Registry
> TBD3: "OSPFv3 SRv6 Locator LSA Sub-TLVs" Registry

I've added and updated the "IANA Considerations" although I'm not sure if it is 
more readable. 



> 
> 210   action.  Whether or not tag A precedes or succeeds tag B SHOULD NOT
> 211   change the meaning of the tag set.  The number of tags supported MAY
> 
> GV> the "tag set" wording may be unclear and confusing. Is it the "tag that 
> is set" or the "set of tags".
> What about:

I don't see it as confusing as the former would be "set tag" rather than "tag 
set". 

> 
> "
> Regardless of whether tag A precedes or follows tag B, the meaning of the tag 
> SHOULD NOT be affected.

I don't see this as confusing but I've replaced "tag set" with "tags". 




> "
> 
> 211   change the meaning of the tag set.  The number of tags supported MAY
> 212   limit the number of tags that are propagated.  When propagating
> 
> GV> I suspect that this is referencing to the number of tags on the ABR 
> and/or the router originating the prefix with its associated tags?
> Is this something that can be further accurately explained? What about:
> 
> "
> The number of supported tags on the router originating the prefix or on an 
> ABR MAY limit the number of tags that are ultimately propagated.

I've added ABR as that is what this statement pertains. 



> "
> 
> 217   For configured area ranges, NSSA ranges, and configured aggregation
> 218   of redistributed routes, tags from component routes SHOULD NOT be
> 219   propagated to the summary.  Implementations SHOULD provide a
> 220   mechanism to configure multiple tags for area ranges, NSSA ranges,
> 221   and redistributed route summaries.
> 
> GV> Why is this a SHOULD NOT instead of a MUST NOT? What breaks or causes 
> issues if tags would be propagated to a summary?

The fact that a summary could represent a single prefix or a 1000, make 
propagating tags unwieldy and hard to specify.
I don't think this needs to be a MUST NOT as summarization is a local matter. 



> 
> 226   these LSAs will all have different tags.  In this situation, the OSPF
> 227   router MUST associate the tags from one of the LSAs contributing a
> 228   path and, if the implementation supports multiple tags, MAY associate
> 229   tags from multiple contributing LSAs up to the maximum number of tags
> 230   supported.  It is RECOMMENDED that tags from LSAs are added to the
> 
> GV> It displays "multiple tags supported", however it is unclear by which 
> router this observation must be applied

I've clarified that this done by the ABR. 


> 
> 247   However, the default behavior SHOULD be to advertise or propagate the
> 248   lesser number of all the tags associated with the prefix or the
> 249   maximum number of tags supported by the implementation.
> 
> GV> I managed to get confused with what the "lesser number" exactly means? is 
> this the number of tags according to the policy? 

It applies to the number of tags advertised - no matter whether they are 
propagated or it done via policy.  


> 
> GV> Would it be allowed for ABRs to impose additional tags upon prefixes for 
> management reasons? Or can only the router that originates a specific prefix 
> set one or multiple tags

Yes - but we don't want to precisely specify this. I changed "filter" to 
"modify".


> 
> 251   Both the support of this specification and the number of tags
> 252   supported by OSPF routers within an OSPF routing domain will limit
> 253   the usefulness and deployment of applications utilizing tags.
> 
> GV> Is it expected that all routers in the routing domain support the same 
> number of tags?

I don't see how we could enforce this - it will depend on future requirements. 
The implementations that I'm familiar support 1 or 2 (one implementation) and I 
added the additional, aka, application tag in the one supporting 2. 


> 
> 742 9.  IANA Considerations
> 743
> 744   The following values should be allocated from the "OSPF Extended
> 745   Prefix TLV Sub-TLV" Registry [RFC7684]:
> 746
> 747   *  TBD - Administrative Tag Sub-TLV
> 748
> 749   The following values should be allocated from the "OSPFv3 Extended-
> 750   LSA Sub-TLV" Registry [RFC8362]:
> 751
> 752   *  TBD - Administrative Tag Sub-TLV
> 753
> 754   The following values should be allocated from the "OSPFv3 SRv6
> 755   Locator LSA Sub-TLVs" Registry [RFC9513]:
> 756
> 757   *  TBD - Administrative Tag Sub-TLV
> 
> GV> maybe call out that there are three TBDs (TBD1, TBD2 and TBD3) as seen 
> from section 2

Yup. Again - thanks of for the review.

Acee



> 
> Brgds,
> G/
> 
> 

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