A survey on BGP MRAI timer values in practice

Thu Jun 10 15:12:08 UTC 2021

My question at this point is, what slow global convergence?  When I (or any of my downstreams) adjusts a prefix, I nearly always see global propagation in well under 60 seconds.  Among networks where I can check, at least.
I understand it could be technically possible to see near-instantaneous global convergence in more like <5sec, but... on a global scale, neither I nor my customers care about the difference between 5s and 60s.  Do other people need <60s propagation?
-Adam
________________________________
From: NANOG <nanog-bounces+athompson=merlin.mb.ca at nanog.org> on behalf of Mark Tinka <mark at tinka.africa>
Sent: June 10, 2021 02:36
To: nanog at nanog.org <nanog at nanog.org>
Subject: Re: A survey on BGP MRAI timer values in practice

On 6/10/21 08:26, Saku Ytti wrote:

> I don't understand the question, but the way I read the question it
> may be unanswerable even if I did understand it. As the reader would
> self-define negligible and well acceptable and answer yes/no based on
> the definition they used, which might be different to the definition
> writer intended.

It's possible we've become accustom to a slow, global BGP, due to a
perception of fragility (and complexity), which favours stability over
speed.

I suppose the size of the current BGP and the nature of the FSM it lends
itself to does some to account for those perceptions.

At a per-ISP level, it is not impossible to speed up (i)BGP convergence.
On a global scale, taking the least common denominator to allow for all
manner of network we don't know about, allowing the ship a wide turn in
BGP waters, at least on a perceptive level, seems like an unsigned
social agreement amongst autonomous systems.

Ultimately, I feel we aren't talking enough about this, and hopefully,
this thread gets us to that point.

Mark.
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