Re: [Idr] [spring] Error Handling for BGP-LS with Segment Routing

Alvaro Retana <> Wed, 19 December 2018 18:13 UTC

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From: Alvaro Retana <>
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Date: Wed, 19 Dec 2018 10:13:32 -0800
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To: Robert Raszuk <>
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Subject: Re: [Idr] [spring] Error Handling for BGP-LS with Segment Routing
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On December 18, 2018 at 6:23:19 PM, Robert Raszuk ( wrote:



What comes as #1 question to your points is a comparison of SR controller
with regular BGP RR.

I think it is safe to assume that error handling on SR controller would be
no more aggressive then on RRs. So if there is error the updates may be
dropped on the RRs itself, logged and proper NOC alarm generated.

IMO this is no different regardless if you use SR with BGP-LS or just plane
regular BGP routing.

In general, I agree that error handling should be the same regardless of
the type of BGP speaker (RR, controller, PE, whatever).

So unless your goal here is to point out the deficiency of BGP error
handling RFC I am not sure what is so specific to BGP-LS and SR.

No, the goal is not to point at any deficiency in the error handling RFC.
I just replied to Bruno saying: " I don’t want to rehash the discussion
from rfc7606 about the types of approached and whether there should be more
or not (or what those could be)…. I’m just pointing out that I think the
current approach is not the right one for all applications.”

When BGP-LS was defined, it was noted that the "information present in this
document carries purely application-level data that has no immediate
corresponding forwarding state impact.”  I think that SR has a direct
impact on the forwarding state of the network.  That is what is specific
about BGP-LS+SR.

To be clear, this thread is about using BGP-LS with applications that have
an impact on forwarding/route selection in the network, like SR (Bruno
pointed at lsvr and there may be others).  It is not about about the error
handling approaches (rfc7606) or BGP sessions in general…just that specific

Thanks for helping me clarify what I mean.  Hopefully this makes more
sense. ;-)