Julie <[log in to unmask]> wrote:
> Hi folks,
>
> Could someone tell me the difference between and hub and a switching hub?
> My understanding is that a switching hub will allow a 100Mbps communication,
> regardless if all stations can receive this speed.  Alternatively a plain
> (?) hub will  restrict the network to the lowest speed which is connected to
> it.

You can think of it this way. A simple hub is like a party line. All ethernet
traffic on all the computers connected to the hub see the same data, even if it
is not destined for them. This is analogous to thin wire ethernet, where all
connected systems have to listen to the same cable. This means that before
transmitting, each system has to listen for other traffic, and wait until it is
not busy.

A switch acts like a cross point switch, being smart enough to recognize which
packets are targeted to which computers connected to it. It does this by
learning the ethernet address of each connected system, and decoding the
ethernet address of the destination of each packet. It routes that packet ONLY
to the computer it is destined to. This means that several systems can be
communicating simultaneously. Not only does this greatly improve bandwidth
(since it is like many pipes, instaed of one shared pipe), but it allows
different speed interfaces to be mixed without affecting other ports.

These days, switches aren't that much more expensive than hubs. I highly
recommend using switches unless your budget is severly constrained.


--
Russ Poffenberger               Engineering Specialist
Schlumberger Technologies ATE   DOMAIN: [log in to unmask]
1601 Technology Drive
San Jose, Ca. 95110             Voice: (408)437-5254  FAX: (408)437-5246

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