Re: [sidr] Burstiness of BGP updates (was: WGLC: draft-ietf-sidr-bgpsec-reqs)

Jakob Heitz <> Tue, 15 November 2011 01:46 UTC

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From: Jakob Heitz <>
To: "George, Wes" <>, Randy Bush <>
Date: Mon, 14 Nov 2011 20:46:42 -0500
Thread-Topic: [sidr] Burstiness of BGP updates (was: WGLC: draft-ietf-sidr-bgpsec-reqs)
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Cc: "Sriram, Kotikalapudi" <>, sidr wg list <>
Subject: Re: [sidr] Burstiness of BGP updates (was: WGLC: draft-ietf-sidr-bgpsec-reqs)
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I can not believe that it will be 2X.

First case: A beacon will very rarely cause a different

Second case: There is actually a changed route being updated.
You will receive both a regular update and a signature.
Only one of those will casue a new bestpath in the great
majority of cases.

Basically, in the large majority of cases, a signature does not
change the bestpath.

Jakob Heitz.

> -----Original Message-----
> From: George, Wes []
> Sent: Monday, November 14, 2011 5:37 PM
> To: Jakob Heitz; Randy Bush
> Cc: Sriram, Kotikalapudi; sidr wg list
> Subject: RE: [sidr] Burstiness of BGP updates (was: WGLC: draft-
> ietf-sidr-bgpsec-reqs)
> > From: [] On
> Behalf
> > Of Jakob Heitz
> >
> > The difference is that today's updates all have the same urgency.
> > BGPSEC is not urgent. It doesn't matter if you don't receive a
> > signature for a few minutes.
> > An UNREACH is not signed.
> [WEG] I don't totally agree with this characterization. If the
> BGPSec info triggers a recalculation of bestpath from what was
> chosen when the unsigned update came through, this has the potential
> to drive 2x the work, essentially take 2x longer for convergence,
> plus push another round of updates to downstream neighbors, another
> reprogram of the FIB, etc. Seems to me by the time we've gained any
> benefit of saving updates for later because the box is busy, we've
> triggered a far worse potential death spiral on a busy box.
> Processing a few additional updates is rather pale in comparison to
> having to consistently recalculate a non-trivial percentage of the
> table when the box gets "busy."
> Similar to buffering and QoS, you can't get something for nothing
> here, and there are limits to where deferred processing can help to
> smooth out peaks vs. simply throwing more capacity at the problem,
> especially in the land of often underutilized multi-core systems.
> Wes George
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