tech-net: Re: bridges,switch

Subject: Re: bridges,switch
To: Erik E. Fair <fair@clock.org>
From: Andrew Gillham <gillhaa@ghost.whirlpool.com>
List: tech-net
Date: 04/19/1999 19:21:29

Erik E. Fair writes:
[...]
> bridge - packet store&forward device; can retransmit for a collision.
> "learning bridges" collect up station addresses on a per port basis, and do
> not forward packets involved in "local conversations" to other ports. These
> can be used to extend an Ethernet beyond its length limit (as can routers).
> 
> switch - same as a "learning bridge" (marketing-speak)
The only addendum I would have to this, is that typically bridges were
much slower.
How bridges are different than switches: (typically)
	* Performance (bridges are slower)
		Usually bridging was/is(?) done in software.
 Switching is almost always done in silicon.
		Switching is essentially "high speed bridging."
	* Scaleability (switches are bigger)
		Bridges were usually limited on interfaces.
		Switches typically have 10's of interfaces.
-Andrew
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