Re: [lisp] [Last-Call] Tsvart last call review of draft-ietf-lisp-pubsub-10

[[e-mail]]

Re-,

Fully agree that dedicating a small fraction of resources (not only links capacity but also CPU) is a good advice, but I don't think we can use any normative language for this. I tweaked the proposed text as follows:

NEW:
   As a reminder, the initial transmission and retransmission of Map-
   Notify messages by a Map-Server follow the procedure specified in
   Section 5.7 of [RFC9301].  Some state changes may trigger an overload
   that would impact, e.g., the outbound capacity of a Map-Server.  A
   similar problem may be experienced when a large number of state were
   simultaneously updated.  To prevent such phenomena, Map-Servers
   SHOULD be configured with policies to control the maximum number of
   subscriptions and also the pace of Map-Notify messages.  For example,
   the Map-Server may be instructed to limit the resources dedicated
   to handling unsolicited Map-Notify messages to a small fraction
   (e.g., less than 10%) of its overall processing and forwarding
   capacity.  The exact details to characterize such policies are
   deployment and implementation specific.  Likewise, this document does
   not specify which notifications take precedence when these policies
   are enforced.

Hope this is better.

Cheers,
Med

De : Magnus Westerlund <[e-mail]>
Envoyé : vendredi 27 janvier 2023 17:21
À : BOUCADAIR Mohamed INNOV/NET <[e-mail]>; [e-mail]
Cc : [e-mail]; [e-mail]; [e-mail]
Objet : Re: [Last-Call] Tsvart last call review of draft-ietf-lisp-pubsub-10

Hi,

That is a good start. The general problem for this type of problem is that one can reasonably calculate a pacing schedule based on target bit-rate at the outgoing interface. What one doesn't know is if what path the various message takes and if that is part of a traffic load causing congestion. The Map-Server will get some indication on potential congestion issue if it has to retransmit many messages as they aren't acked. I would think the most general thing I would say is to recommend that the pacing target a bit-rate that is no more than a small fraction of the expected bandwidth of the links to the xTRs.

That is likely preventing enough issues that there is no point in doing more advanced solution. But that is me assuming that the control plane will mostly run over links with Gbps+ capacity and that one configure this to not burst above like 1-5% of the link capacity one will not have any issues. But if there is more limited capacity or larger deployments maybe the completion time become an issue for each update.

Cheers

Magnus

From: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Date: Friday, 27 January 2023 at 15:53
To: Magnus Westerlund <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Subject: RE: [Last-Call] Tsvart last call review of draft-ietf-lisp-pubsub-10
Re-,

Thanks Magnus for clarifying.

I suggest to add the following in Section 6:

NEW:
   As a reminder, the initial transmission and retransmission of Map-
   Notify messages by a Map-Server follow the procedure specified in
   Section 5.7 of [RFC9301].  Some state changes may trigger an overload
   that would impact, e.g., the outbound capacity of a Map-Server.  A
   similar problem may be experienced when a large number of state were
   simultaneously updated.  To prevent such phenomena, Map-Servers
   SHOULD be configured with policies to control the maximum number of
   subscriptions and also the pace of Map-Notify messages.  The exact
   details to characterize such policies are deployment and
   implementation specific.  Likewise, this document does not specify
   which notifications take precedence when these policies are enforced.

Do we need to say more without going too much into implementation territory?

Cheers,
Med

De : Magnus Westerlund <[e-mail]<mailto:[e-mail]>>
Envoyé : vendredi 27 janvier 2023 11:39
À : BOUCADAIR Mohamed INNOV/NET <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Cc : [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
Objet : Re: [Last-Call] Tsvart last call review of draft-ietf-lisp-pubsub-10

Hi Med,

Overall, the spec leverages the mechanisms in both RFC9301 and RFC9303. I don't know if you checked those when performing your review.

MW: Yes, I looked at those, and as you cite some of it I can explain why I think this isn't sufficient for this specification.

> -----Message d'origine-----
> De : last-call <[e-mail]<mailto:[e-mail]>> De la part de Magnus
> Westerlund via Datatracker
> Envoyé : mardi 24 janvier 2023 14:20
> À : [e-mail]<mailto:[e-mail]>
> Cc : [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>;
> [e-mail]<mailto:[e-mail]>
> Objet : [Last-Call] Tsvart last call review of draft-ietf-lisp-
> pubsub-10
>
> Reviewer: Magnus Westerlund
> Review result: Not Ready
>
> This document has been reviewed as part of the transport area
> review team's ongoing effort to review key IETF documents. These
> comments were written primarily for the transport area directors,
> but are copied to the document's authors and WG to allow them to
> address any issues raised and also to the IETF discussion list for
> information.
>
> When done at the time of IETF Last Call, the authors should
> consider this review as part of the last-call comments they
> receive. Please always CC [e-mail]<mailto:[e-mail]> if you reply to or
> forward this review.
>
> My review comments are:
>
>
> C.      When a Map-Notify is to be sent there are no discussion in
> regards to
> congestion control of the transmission of the Map-Notify.


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