Hi guys

I'm currently getting a bottleneck at the link back to our server. We have about 5 switches and 150 machines all coming into one cab, but then everything's running through a 1Gb link back to the switch near the server. Short of upgrading everything I'm thinking about installing new Gb switches at either end and just running 3 new cables between the cabs, which in theory should then give a 4Gb connection between the bottleneck cab and the server switch.

Am I correct in thinking this or does anyone else have ay other suggestions? This is the problem when bits have been bolted on year after year, trying to get all these daisy-chained switches to run efficiently.

Someone else has suggested installing a Gig switch in the bottlenecked cab to plug all the other switches into, but I don't get how this will halp as even with them all on a Gig link, they'll still all be going down one 1Gb line to the server :S

Any thoughts appreciated

Cheers :)

server<>backbone switch<>all other switches

This is the proper design with everything going into the backbone switch.

You should avoid cascading switches beyond this design.

To accomplish this you would run a gig line from EACH cabinet switch to the switch the server is connected to.

I would also recommend only managed switches [you don't mention that] and doing adapter teaming at the server. This is where you combine two nics into one trunk to the backbone switch. It takes a managed switch that supports one of the adapter teaming protocols and nics like IBM or HP that can be teamed by the manufacturers adapter software.

This design will give the server a 2gig pipe to the backbone and a gig pipe from the backbone to every switch.

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Thanks for that. The network originally followed that rule but over time other bits have been added and corners have been cut to avoid spending money (it's cheaper in the short term to link new switches to the nearest cab instead of the server cab). It's a high school so geographical layout isn't ideal. I'll have to ask them how much money they want to spend :)

They are all 3com managed switches btw, although I think the infrastructure needs a fiar bit of work before tweaking settings on the network hardware. They're currently installing a third server for load balancing so 1Gb to each should be fine if we can sort out the bottlenecks at the far end of the site.

Thanks for your help :)

What model 3Com switches are they?

They may or may not be capable of MLT (multi link trunking) and SMLT (split MLT). I know we have two or three 4400's that have GBIC's in them, but only offer 100 Mbps to the desktop (phasing them out very soon) and they aren't MLT/SMLT capable.

When talking to the powers that be about budget, you might want to point out that it's better to spend the money up front and build for longevity and growth than to cheap out and end up spending more money in the long run doing workarounds and bottlenecking your network.