Re: CVS commit: src/sys/net

[mlelstv%serpens.de@localhost (Michael van Elst)]

mouse%Rodents-Montreal.ORG@localhost (Mouse) writes:

>>> Maybe "network interface" is not the right abstraction for bridges
>>> to be instances of, then?  (Though, at least in my experience,
>>> NetBSD's "bridge" interfaces are more like switches than bridges.)
>> A switch is a bridge with more than two ports.

>Then what is my 8-port 10Mb hub?  Switch, bridge, neither?

Neither, it's a repeater.

Repeater / Hub -> Layer 1. Incoming signal from one port at a time
is send out (after some amplification / regeneration) to all other
ports. Single collision domain.

Bridge / Switch -> Layer 2. Packets (or often just a few bits to reduce
latency) are buffered and transmitted to other ports, a forwarding
database is used to prune destinations. Separates multiple collision
domains.

The terms Hub and Switch came up when the devices got more than two ports,
but functionally these are not different from the earlier terms.

There are hybrid devices. I have a thingie that has some 10Mbit and some
100 Mbit ports. Technically it's two repeaters with a two port bridge
in between. Since repeaters work on layer 1, they cannot translate
different speeds. A bridge can.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."