Re: [Idr] WG LC for draft-ietf-idr-bgp-prefix-sid-17.txt (2/23 to 3/9/2018)

["John G. Scudder" <[e-mail]>]

Hi All,

I went back and reviewed the diffs and list traffic around the latest revision, and I have one small concern. In addition to the large normative change of removing the IPv6 SID, which was well reviewed, and some editorial improvements, there's one more normative change I didn't see flagged to the list for review:

-16:
  If multiple different prefixes are received with the same label
  index, either all or all but one of the different prefixes MUST have
  their BGP Prefix-SID attribute considered as "conflicting".  If one
  of the different prefixes is considered "acceptable", it is
  RECOMMENDED that the first prefix using the label index is selected.

-17:
  If multiple different prefixes are received with the same label
  index, all of the different prefixes MUST have their BGP Prefix-SID
  attribute considered as "conflicting".

I see the mailing list discussion, mainly between Robert and Acee, that must have led to this change. I don't see discussion of the change itself. One can argue that everyone had the opportunity to look at the rfcdiff, but nonetheless I'm not fully convinced that in the case of this change, "silence gives [informed] consent" (a.k.a. "unanimous tacit approval") -- it's just a few lines and unless you're looking for it, you might easily breeze by it if reviewing quickly.

I don't want to drag this out interminably but I do want to make sure the group is aware of this change, before returning the document to Alvaro for advancement. I'll also make sure we mention it during the IDR meeting tomorrow. 

Thanks,

--John

> On Mar 9, 2018, at 1:48 PM, Acee Lindem (acee) <[e-mail]> wrote:
> 
> Hi Sue, Alvaro, IDR WG,
>  
> The WG last group on the changes to the BGP Prefix-SID draft has completed with unanimous tacit approval from IDR WG. Can we go ahead and advance it? I believe we were going to send it directly the IESG w/o a second IETF last call. 
> Thanks,
> Acee
>  
> From: Idr <[e-mail]> on behalf of Susan Hares <[e-mail]>
> Date: Friday, February 23, 2018 at 6:09 PM
> To: IDR List <[e-mail]>
> Cc: "[e-mail]" <[e-mail]>
> Subject: [Idr] WG LC for draft-ietf-idr-bgp-prefix-sid-17.txt (2/23 to 3/9/2018)
>  
>   <>
> This begins a 2 week IDR WG last call on changes to the BGP Prefix SID draft.
>  
> The changes are removal of the IPv6 SID TLV/SRv6 data plane and error/conflict handling modifications to section 4. The reasons for removing the IPv6 SID TLV were explained in https://mailarchive.ietf.org/arch/msg/idr/3YE8hDCj0ky0NPFoLrTHV2AAEJ8 <https://urldefense.proofpoint.com/v2/url?u=https-3A__mailarchive.ietf.org_arch_msg_idr_3YE8hDCj0ky0NPFoLrTHV2AAEJ8&d=DwMGaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=hLt5iDJpw7ukqICc0hoT7A&m=WGUfpxYrh9724KMU8rPD4r0IXQC68R_5FBGmzx2OsSw&s=TcIfwaxEmg2iAtMCMAnUWweAfo1uL6t9zvnofDuFurE&e=>. The error/conflict handling changes were made based on fruitful  review comments and discussions very late in the process.
>  
> Just to refresh your memory, this draft has return from the IESG to the WG.  It is the intent of the WG chairs if IDR WG reaches consensus on this version to immediately send it back the IESG for publication.
>  
> Susan Hares