Retro networking / WAN communities

Paul Koning paulkoning at comcast.net
Tue Apr 12 12:44:19 CDT 2022



> On Apr 12, 2022, at 1:25 PM, Grant Taylor via cctalk <cctalk at classiccmp.org> wrote:
> 
> On 4/12/22 8:50 AM, Paul Koning via cctalk wrote:
>> A device that doesn't do address learning and floods unicast frames is not a bridge but rather a non-standard piece hardware.
> 
> I feel like a "hub" qualifies as "a device that doesn't do address learning and floods unicast frames".
> 
> To me, the fundamental difference between a hub and a switch / bridge is address learning.
> 
> I can't tell if your (quoted) statement is specific to /just/ bridges / switches or could include hubs.  Your first comment addresses bridges directly, thus meaning that your second non-targeted comment might target more.

In my experience, "hub" is a vague marketing term.  It might mean a backplane into which networking modules are plugged -- the DEChub-90 and DEChub-900 are examples.  It might mean a chassis accepting networking cards that offer repeater, bridging, or other services -- I think Chipcom and Cabletron used the term in that fashion.

Non-learning layer 2 packet switching devices to me are hypothetical beast, I never met one and I'm glad I didn't.  Building such a thing would be a silly thing to do in my view.  So no, I don't think I would call that a "hub" because all the "hubs" I ever ran into were something different entirely.

	paul



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