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Re: [pim] Q on the congestion awareness of routing protocols

Dino Farinacci <farinacci@gmail.com> Mon, 05 December 2022 20:40 UTC

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Subject: Re: [pim] Q on the congestion awareness of routing protocols
From: Dino Farinacci <farinacci@gmail.com>
In-Reply-To: <CAEeTejJ3yS2fARZNchumfkNyc0cnFfVSW7VdtBaGzhJQ9KmpBg@mail.gmail.com>
Date: Mon, 05 Dec 2022 12:40:38 -0800
Cc: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>, bier@ietf.org, routing-discussion@ietf.org, tsv-area@ietf.org, pim@ietf.org
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To: Jon Crowcroft <Jon.Crowcroft@cl.cam.ac.uk>
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> I would use multipath quic rather than tcp. And for bier CTL, we want a fine hoppy protocol like PGMcc

Just one point about TCP vs multicast. You *can* get more paralellism from multicast where TCP from one central point (like a iBGP route reflector) will cause serialization delays. One could argue you get this with multicast by just moving the problem to the router that is replicating packets across an internal-crossbar switch or fabric. But you can imagine this is done by orders of magnitude less serializtion time.

And your Sally reference to SRM is a really simple way to understand the concepts and how they *could* be applied to routing protocols. In the 90s, at cisco, we looked at replacing the iBGP mesh (read: mess) with SRM, or SRM-like mechanisms. It was pre-PGM days.

Dino

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