Re: [Idr] 1 Week last call on changes to: draft-ietf-idr-bgp-ls-segment-routing-ext-17.txt [3/25/2021 to 4/1/2021]

["Ketan Talaulikar (ketant)" <[e-mail]>]

Hello All,



A minor point (IMHO worth clarification) related to this draft-ietf-idr-bgp-ls-segment-routing-ext has come to my notice out of the ongoing AD-review and discussion [1] for the draft-ietf-lsr-isis-srv6-extensions.



This is related to the Prefix Attribute Flags TLV : https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-ls-segment-routing-ext-17#section-2.3.2



Currently the draft says that for IS-IS they are derived from the IPv4/IPv6 Extended Reachability Attribute Flags sub-TLV as specified in https://datatracker.ietf.org/doc/html/rfc7794#section-2.1



What we missed (though it is described in RFC7794 sec 2.1), is that for the X-flag, the value needs to be picked from the IS-IS TLVs 236 and 237.



The proposed changes are in sec 2.3.2 as follows:



<OLD/>

      *  IS-IS flags correspond to the IPv4/IPv6 Extended Reachability

         Attribute Flags defined in section 2.1 of [RFC7794]<https://datatracker.ietf.org/doc/html/rfc7794#section-2.1>

</OLD>



<NEW/>

      *  IS-IS flags correspond to the IPv4/IPv6 Extended Reachability

         Attribute Flags defined in section 2.1 of [RFC7794]. Note: for

         the prefix reachability advertisement via IS-IS TLVs 236

         [RFC5308] and 237 [RFC5120], the value of the X-flag to be set

         in the BGP-LS TLV is determined from the fixed format of those

         IS-IS TLVs instead of the IS-IS IPv4/IPv6 Extended Reachability

         Attributes Flags sub-TLV.

</NEW>



I wanted to check with WG/chairs/AD if this is something that we ought to fix/update at this stage in the draft.



Thanks,

Ketan



[1] https://mailarchive.ietf.org/arch/msg/lsr/HAtgICjP4qB23LKfbyZQigDeQSo/





-----Original Message-----
From: Idr <[e-mail]> On Behalf Of Susan Hares
Sent: 25 March 2021 20:07
To: [e-mail]
Subject: [Idr] 1 Week last call on changes to: draft-ietf-idr-bgp-ls-segment-routing-ext-17.txt [3/25/2021 to 4/1/2021]



IDR:



This is a 1 Week WG call for comments the changes to draft-ietf-bgp-ls-segment-routing-ext-17.txt.



https://tools.ietf.org/html/draft-ietf-idr-bgp-ls-segment-routing-ext-17



The comments on this document are only for the changes from -16 to -17.txt



Ketan summarized the changes in his early message with



"This update to the BGP-LS SR draft (that was sitting in the RFC-editor Q due to misref) was required to the recent changes in the

https://datatracker.ietf.org/doc/html/draft-ietf-lsr-ospf-prefix-originator-

09 that was the missing reference as part of the AD review.



It updates the references to the Source Router Identifier TLV for OSPF and introduces a new TLV for the Source OSPF Router-ID TLV to cover the new TLV introduced by draft-ietf-lsr-ospf-prefix-originator."



It is a fine summary of the changes.



Please send comments if you are concerned about the changes.



Unless comments are heard, the intent is to allow the RFC editor to publish based on the -17.txt version.



Cheers, Susan Hares





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