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Slow access through new 3750

AFAIT asked
Last Modified: 2008-01-09
I have an ISP switch onsite (its a Cisco 2924M) that I have no physical or telnet access to.  Port 1 on the ISP switch goes to the Internet.  Port 2 on the ISP switch goes to my core 2950 (uplinked to another 2950) with all of my servers and users on it.  Port 3 on the ISP switch goes to a brand new 3750 (stacked to another 3750) which is soon going to be my new core.  I would like to eventually move all of the servers off of the 2950s and over to the 3750s, then decomission the 2950s.  The problem is when I move users or servers over to the 3750s, everything becomes extremely slow.  I realize that there are a lot of variables here, so I am just wondering if I could get some suggestions on places to start looking.  Any suggestions of things I have not tried will be rewarded with points.  As you can probably guess, I am relatively new to switching and routing so any help you could offer would be greatly appreciated.
Thank you in advance.  
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Les MooreSr. Systems Engineer
Top Expert 2008

I would say look for a duplex mismatch between the 3750 and the ISP switch
Are you using the 3750 stack at layer 3 or just as a L2 switch? Do you have routing enabled on the switch?


I did originally have a duplex mismatch and that was fixed actually.  It was still slow.  At first I tried the 3750s without ip routing enabled.  It was slow.  I have since turned it on since I want to eventually have some vlans and hopefully do some QoS stuff.  It is slow again.  Could it be something about the priority of the new switches maybe?  
Thank you so much for your help.
Sr. Systems Engineer
Top Expert 2008
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Ping times are just fine actually.  I did not try a traceroute acutally - I will try that.  There is not potential for an ip conflict.  I guess I am not 100% sure about a loop...I dont know much about that stuff.  I can say that there are no cables connecting the 2950s and the 3750s...and there is only one cable going from the ISP switch to the 2950....and there is only one cable going from the ISP switch to the 3750.
Thank you again for your help.  If you have any other suggestions in the meantime, I would love to hear them.


Just to add a bit more...just applications are slow...slow logins too...pings are fine.  Its very weird.
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