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New Member

Switches and hops

We have recently reconfigured our Ethernet network form a 3Com switched evironment where we would have switch to switch daisy chained from closet to closet to datacenter. We would average 4 to 8 hops from start to finish for just about every connection we made. We now have an environment where we jump no more than 4 hops to reach the destination. My problem is we do a file extraction from our IBM mainframe to a workstation. The extraction is a 400mb file and before we reconfigured our network the extraction was taking about 10-20 minutes. Since then it is taking 4 or more hours. Here is the existing path= Desktop(100mb, full) -->4006swtch (1gb full) --> 6513swtch (100mb full)--> 7200rtr (98mb)--> MF (via escon chnl). I have placed a Linksys 10/100 hub between the desktop and the 4006 switch and now the file extraction is back to normal. I am lost as to how adding a hop would increase the performance of this extraction. As a side note, we have seen nothing but increased performance from all of our other applications. This is the only one that has been affected.


Re: Switches and hops

Have you ensured that your duplex settings on the 4006 match that of your desk top?

Don't trust autonegotiation. Check it on the Cat to ensure.

A duplex mismatch might be causing some performance issues for you.

Hope this helps,


New Member

Re: Switches and hops

I did have a duplex mismatch between our 6513 core switch and our 7200 router that our mainframe is connected to. I have corrected this which has resolved some of the performance loss.

Thanks for the help.


Re: Switches and hops

You might have some compatibility issues with the NIC on the workstation and the Cat4000-

Did you enable portfast and make sure that you are not receiving any kinds of errors on the ports due to speed /duplex mismatch.

Try with hard cording the speed and duplex both on the switch and workstation and also on the try with auto on both.

Here is the link that will help you more with your troubleshooting.

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