On Thu, Jan 15, 2026 at 11:27 AM Bill Gage <[email protected]> wrote: > > Please excuse my ignorance, but ... modern Ethernet switches have MAC > address table sizes on the order of hundreds of thousands of entries. > Building a local switched (not routed) network using a hierarchy of > Ethernet switches appears to be a common practice.
Hi Bill, Larger networks, like in hyperscalers, are more likely to be L3 switched than spanning tree. There is also a know problem with Ethernet that it lacks a hop limit. > > So what problem does SUNH solve? 1. It reduces the size of the network layer header to reduce on-the-wire overhead 2. A smaller address simplifies switching and address lookups Tom > > /bill > > On 2026-01-09 5:53 p.m., Tom Herbert wrote: > > On Fri, Jan 9, 2026 at 2:03 PM dave seddon <[email protected]> wrote: > >> > >> > >> Now that the context is established, explain why 16 bits were chosen > >> for the source/destination address. I guess, but it's not in the > >> document; You were considering the number of hosts in the domain. > > > > The numbers being thrown around for scale-up networks seem to be a > > couple of thousand nodes at most. 16 bits nicely rounds to the power > > of two and allows plenty of space to scale to reasonably large GPU > > clusters. Also, for scale-up we anticipate pretty flat networks with > > may two or three hops at most (justifies smaller Hop Limits in the > > protocol). > > > > > > _______________________________________________ > Int-area mailing list -- [email protected] > To unsubscribe send an email to [email protected] _______________________________________________ Int-area mailing list -- [email protected] To unsubscribe send an email to [email protected]
