Re: Distributed Router Fabrics

["Jakob Heitz \(jheitz\) via NANOG" <nanog () nanog org>]

Any-to-any connectivity is an O(x^2) (quadratic) problem.
When you build a fabric, you can add new pizza-boxes in a linear fashion as long as the existing boxes have spare ports 
to plug in the new boxes.
As soon as the spare ports run out, the quadratic hits.
Then the choices are either:

  *   Reduce any-to-any bandwidth to recover spare ports.
  *   Replace all the boxes by larger ones.
  *   Add a tier. Adds hops and increases convergence.

Kind Regards,
Jakob

-----Original Message-----
Date: Fri, 20 Dec 2024 10:06:36 -0600 (CST)
From: Mike Hammett <nanog () ics-il net>

I've noticed that the whitebox hardware vendors are pushing distributed router fabrics, where you can keep buying pizza 
boxes and hooking them into a larger and larger fabric. Obviously, at some point, buying a big chassis makes more 
sense. Does it make sense building up to that point? What are your thoughts on that direction?