-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Todd Flinders
Sent: Friday, January 26, 2001 12:20 PM
To: [EMAIL PROTECTED]
Subject: Re: [newbie] Networking question...
"The switch is far better than a hub. I see no reason
to purchase a hub. The hub would share the bandwidth
among all the ports. So if you have 100mb 5-port hub,
each port gets 20mb."
While your intent is very good, this statement is incorrect and misleading
to newbies.
I recently had to explain this very misconception to another newbie on this
list who had been told the same by an overzealous sales person...
Yes a hub "shares" it's bandwidth among it's ports, but it doesn't do it as
you describe.
ANY connected device is free to "grab" the LAN at full bandwidth. Collision
avoidance and detection comes into play, as another device must listen for
traffic on the LAN before attempting to utilize it. The device wanting to
enter into the fray, must "back off" if it "hears" a transmission already in
progress on the LAN.
The end result is that -NOT- that "each port gets 20mb". Rather transmission
time is divided among all the connected and active devices.
Thus if a device is not transmitting, it does not use up bandwidth.
Since on a 5 port LAN it is unlikely that saturation will occur for any
length of time, a switch, while nice, remains overkill.
Should all 5 workstations decide to stream an entire CD-ROM to another
machine, then indeed the difference between a switch and hub would be
apparent.
But then again on a 5 port LAN, even with a switch, you'll probably be
waiting on the recipient devices anyway, giving you somewhat similar
performance...
I.E. if three machines are sending to one device, at least two will be
waiting at any time, even with a switch...
-JMS
