Replace a hub with a switch?

[Jerry Gramling]

My network consists of a single switch connected to 12 hubs (TrendNet,
Linksys, Netgear) that each support between 12 and 24 nodes. Eleven of my
hubs are 10/100 Mbps, but I have one 10 Mbps hub left. Should I replace that
hub with a switch or a newer 10/100 hub? I do not currently have a bandwidth
problem, it is more for convenience. Could this degrade network performance?

[Joseph Moore [SysOp]]

Jerry Gramling:

> Should I replace that
> hub with a switch or a newer 10/100 hub? I do not currently have a bandwidth
> problem, it is more for convenience. Could this degrade network performance?
>

I doubt it would degrade performance - it might increase performance for the
workstations connected to it. If you want to replace it, go ahead :)

Joe Moore
Novell Support Connection Volunteer Sysop

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[Dave Lunn]

Jerry,

I would bet money on it degrading performance until/unless all speed/duplex
mismatches are resolved.

In a strictly hub based network it is normal to find NICs set to 10/half,
100/half/ and 100/full. You get away with it because the hubs will only
handle half and don't care about duplex setting at all. Speed for most
users doesn't produce a huge difference in their daily use between 100 and
10 because they simply don't use the network that heavily.

If you *have* NICs set to full in the segment you are going to change, there
is every probability you will in actuality see 1-1.5 MB/s which will be a
huge difference to the users and they *will* notice.

NICs with switches should first be set to AUTONEGOTIATE. The switch if
manageable should be set to AUTONEGOTIATE. If that setting fails, then back
off to 100/half, never full duplex. If you retain 10baseT NICs, they should
be set to 10/half.

I would make the change to a switch. I would also change all NICs on that
segment to 100baseT. I also would not be too surprised to find out that one
or more of your eleven "hubs" was actually a switch.

For what it's worth, I would also very seriously consider buying several
small switches to do this with so that you can break up what is a
substantial collision domain. Right now, everything downstream from the
switch is one huge collision domain with redundancy, or 12 collision domains
with no redundancy. Switches can provide redundant pathing to the server
and break up the collision domain(s) so that everyone gets access with less
competition. You will likely be able to make a noticeable improvement (for
all users) by adding a couple of NICs to the server and a few well placed
small switches to the network.
--
Dave Lunn
NSC SysOp
http://support-forums.novell.com