Why would a hub work when a switch doesn't?

Why would a hub work when a switch doesn't?

We recently had a very strange problem. Two users share a 1gbps switch, and their network connection has been getting worse and worse (it does not disconnect, but has gotten REALLY slow, down to bytes/second). We tried three different known-good switches, with no luck, even with only one person plugged into the switch, and even when forced to 10mbps. The offices around theirs (all using 1gbps switches) have no problems.

Asked by: Guest | Views: 220

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Guest [Entry]

"To answer your question, the only times a hub works better then a switch is when you have bad hardware or incompatible hardware. The first is relatively easy to test, but incompatibilities can be difficult to find. I have run into switches that just don't like communicating with particular switches. Try switches that are different models and manufactures and see if that makes a difference. The duplex mode (Full or Half) used can also make a difference so make sure you try both communication methods.

In your situation, I would suggest you start from something called a ""working set"". That means you build a chain of devices that work, then swap out individual parts one at a time. To start, you need to identify the components in the chain. This is usually everything between the troubled computer and your network backbone. In this case, the components that could be having problems are as follows:

The office computers
The cable connecting to the ""switch/hub""
The ""switch/hub""
Cable connecting to wall
Patch from wall to building switch
Building switch

I would go into one of the other offices and plug swap a known good computer for a bad one. If it works fine, then change out the cables. If that works, swap out the switch in the room. If that works, swap the port used at the building level switch with the one used by the other office. If that all works, move all the currently working parts back into the ""bad"" office and try it again.

If it dies anywhere along that chain, then you should be able to figure out what it broken. Keep in mind that your building switch (device on other end of wall plate) could have a bad port and may be only to work with a hub.

Hope this helps"