Barry A.Clark (MCP)
----- Original Message -----
From: Dave Gillett <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, January 16, 2000 11:01 PM
Subject: Re: [PCSOFT] Switch or network hub?



On 13 Jan 00, at 22:47, Dr. Jorge R. Fernández wrote:

> Hi,
>
> Does somebody know wich is the difference between a switch an a
> network hub?
>
> TIA,
>
> Jorge

  A simple, and almost accurate, way to think of them is to think of
a hub as a multi-port repeater and a switch as a multi-port bridge.
Recall that a repeater boosts and retransmits *everything*, while a
bridge passes only (a) broadcast packets and (b) packets whose
destination MAC address is reachable only by forwarding.

  A network which entirely relies on switches -- no hubs anywhere --
can avoid transmission collisions and so allow nodes to run in full-
duplex instead of half-duplex, effectively doubling the effective
bandwidth at each node (allbeit limited to 100% in each
direction...).  And -- up to the aturation capacity of the switch --
multiple conversations that don't have overlapping memberships can
run simultaneously at 100% of network speed.  [Note that this is
typical of true peer-to-peer networking, and less typical of server-
centric use.]
  The result is that if you have RJ-45 UTP wiring in your LAN, you
may be able to obtain a hefty performance boost simply by replacing
central hubs with switches, without having to upgrade every NIC in
the building from 10 Mbps to 100 Mbps.

David G

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