Re: [spring] WG adoption call - draft-hu-spring-segment-routing-proxy-forwarding

[[e-mail]]

[speaking as WG contributor]

Hi authors, all

I have some comments specific to the binding SID aspect.


§2
"   For a binding segment of a possible failed node, the node advertises
   the information about the binding segment, including the binding SID
   and the list of SIDs associated with the binding SID, to its direct
   neighbors only.  Note that the information is not advertised in the
   network domain. »

§3.2.2

   "For supporting binding SID proxy forwarding, a new IS-IS TLV, called

   Binding Segment TLV, is defined.  It contains a binding SID and a

   list of segments (SIDs).  This TLV may be advertised in IS-IS Hello

   (IIH) PDUs, LSPs, or in Circuit Scoped Link State PDUs (CS-LSP)

   [RFC7356<https://datatracker.ietf.org/doc/html/rfc7356>]. »



>From an IS-IS standpoint, it seems to me that:

-    Advertising it in the LSP PDU would flood the information in the whole area/level, hence does not match the goal stated in §2

-    Advertising it in the Hello PDU is not a reliable way to sync information (except if duplicated in all hello which implies others issues such as lack of space) and adding the reliability seem like a major change to IS-IS

In all cases, as already raised by Stéphane, this is a subject for the LSR WG.




More importantly, the binding SIDs are probably coming from "somewhere" such as configuration, PCE, BGP, BGP-LS... Why not using the exact same signaling to duplicate it on the neighbors? (this may probably require some extensions for some protocols but a priori light ones and would not impact the IGP with information which may not belong to the IGP.)

Thanks,
Regards,
--Bruno



Orange Restricted
From: spring <[e-mail]> On Behalf Of [e-mail]
Sent: Thursday, January 13, 2022 11:19 AM
To: SPRING WG <[e-mail]>
Subject: [spring] WG adoption call - draft-hu-spring-segment-routing-proxy-forwarding

Dear WG,

This message starts a 2 week WG adoption call, ending 27/01/2022, for draft-hu-spring-segment-routing-proxy-forwarding
https://datatracker.ietf.org/doc/draft-hu-spring-segment-routing-proxy-forwarding/

After review of the document please indicate support (or not) for WG adoption of the document to the mailing list.

Please also provide comments/reasons for your support (or lack thereof) as this is a stronger way to indicate your (non) support as this is not a vote.

If you are willing to work on or review the document, please state this explicitly. This gives the chairs an indication of the energy level of people in the working group willing to work on the document.

Thanks!
Bruno, Jim, Joel

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