400G forwarding - how does it work?

James Bensley jwbensley+nanog at gmail.com
Wed Jul 27 19:50:29 UTC 2022

On Tue, 26 Jul 2022 at 21:39, Lawrence Wobker <ljwobker at gmail.com> wrote:
> So if this pipeline can do 1.25 billion PPS and I want to be able to forward 10BPPS, I can build a chip that has 8 of these pipelines and get my performance target that way.  I could also build a "pipeline" that processes multiple packets per clock, if I have one that does 2 packets/clock then I only need 4 of said pipelines... and so on and so forth.

Thanks for the response Lawrence.

The Broadcom BCM16K KBP has a clock speed of 1.2Ghz, so I expect the
J2 to have something similar (as someone already mentioned, most chips
I've seen are in the 1-1.5Ghz range), so in this case "only" 2
pipelines would be needed to maintain the headline 2Bpps rate of the
J2, or even just 1 if they have managed to squeeze out two packets per
cycle through parallelisation within the pipeline.


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