Performance drops with switch "upgrade"

Our office network is configured with a server running Windows Server 2003 Small Business Server and clients running Windows XP Pro. We are spread over 2 adjacent buildings and all are connected using category 5 and category 5e cabling and two 10/100 Mbit switches. Some of the newer clients have Gigabit NIC's.

Last week I had some trouble with one of the switches, so I replaced it with a spare that I keep on hand "just in case ", and ordered a new replacement. I figured that I would take this opportunity to upgrade part of the network with a gigabit switch. I thought that the CAD systems would benefit from the higher bandwidth.

Yesterday I installed the new switch, along with a gigabit NIC in the server. Now, after suffering through a day of very slow and frequently dropped connections, I have returned everything to the 10/100 switch, and performance has returned to what it was before the "upgrade ". Then I swapped a single client over to the gigabit switch, and saw the performance on that machine drop again; Returned it the the 10/100 switch and the performance went back up!

So now I am wondering if the result I am seeing is perhaps due to cabling problems, or something such, which could be causing garbled data when forced to the higher bandwidth connection? I tried running a single piece of category 5e cable from the gigabit switch to one of the clients, and it seemed to perform about the same as when connected to the 10/100 switch via the cable that runs up through the wall and across the ceiling. Yes, the existing cabling is very ad-hoc, and has been strung non-professionally as the network has evolved over the years.

I would appreciate any suggestions on how I should proceed with this. Right now I am thinking of sending the gigabit switch back and just putting in a new 10/100 switch.

Tom

 

When do you want me to start pulling your new cable?



Get a professional to test your cable segments.

Preferably with a Lantek 7G

http://www.datacomtools.com/catalog/lantek7.htm

 

Definitely sounds like you're trying to run a Ferrari over a dirty-track.

The faster the network, the more demands it puts on the network. Therefore, the standard of cabling needs to be better to run faster speeds as Scott points out.

I expect the problem will be the auto-negotiation. The gigabit switch will waste time trying to run at gigabit speeds before it drops down to 100Mb/s. If the switched is managed, you should be able to use it's web interface to force the connection speed to 100Mb/s on your problem connections.

You should find that some connections will be fine (for example into a nearby server), so you can leave them as auto-negotiate). This will allow you to get the best out of your current set up.

However, as Scott suggests: by far the best solution is to get your cabling sorted out - and that means getting a professional network cable installer in.

BTW - splendid picture.