Switch Design Question

[jfwebber]

Currently I have end-users on two floors. On the first floor I have 3 3Com SS3300 and two SSII Dual speed hubs. The switches are connect via a matrix module and the hubs connect to a switch via a cross-over.

On the second floor I have three SS4400 connected via a matrix module.

The two switch stacks are connect via fiber.

It is all one large VLAN, one subnet, and STP is not enabled.

The network is somewhat slow and Im sure the switch design has a bit to due with it. Any suggestions that may possibly improve speed would be appreciated.

Thanks. Jim Webber
Network Administrator MCSE CNA

 

[TimRegester]

When you say 'somewhat slow' what do you mean?

Is it your client to server response that is slow?

Have you tested end to end throughput and found it to be lacking, if so, how did you test?

If you have one flat VLAN and one subnet and a maximum of 192 hosts are you sure you have no problem with broadcast levels? Are you using multicast without the network being set up properly to work with this?

As for the Switch design the 3300 and the 4400s are all non-blocking wirespeed switches the design of the switches is unlikely to be the problem, it may be due to your network design. Given the switches you have I wonder if the servers are all plugged into the 4400s or the 3300s with the DS Hubs on the edge.

In short, you need real evidence before blaming the switches. You need to test throughput in a controlled way you need to eliminate issues like the host or server operating system or hardware, once you have narrowed down the suspects you will probably be able to enlighten us more as to the true nature of the issues you have.

I once worked on a network where the Server manager was constantly whinging about the network being slow and blaming the hubs and switches. I responded with "it's not the comms" and had the evidence to prove it. In all but one case a server patch or a server upgrade fixed it, something as daft as the nic on a server being set to the wrong speed and duplex mode can cause a slow network.

A good start maybe to run 3Com Network Supervisor and see what you get.