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Community Member

3750G-24TS port connecting problems.

We recently setup this switch to enable gigabit networking, but have had to set all ports to speed 100 after repetitive failures to negotiate connecting ports. On the connecting ports, the machines negotiate a link, then drop the link, negotiate a link, then drop the link, etc. This has happened on several different connecting ports. Is there anything that is misconfigured on the switch that may cause this occur? We have tried manually setting speeds on both the switch and the connecting port and are still unable to establish a connection other than 100mb/s. Please advise.

5 REPLIES
Community Member

Re: 3750G-24TS port connecting problems.

Try to use the "speed nonegotiate" command on the gigabit ports. Maybe this will help you.

Community Member

Re: 3750G-24TS port connecting problems.

That is not a valid command on our gigabitethernet interfaces. Do you mean "no speed negotiate"?

Community Member

Re: 3750G-24TS port connecting problems.

That command does not work on our gigabitethernet interfaces. Do you mean "no speed negotiate"?

Community Member

Re: 3750G-24TS port connecting problems.

The command speed nonegotiate is used within the 4500 Catalyst Switch running IOS Version 12.1(19).

The no speed negotiate command should have the same effect. What OS is running on your switch? So, you may try the no speed negotiate command... ...maybe it helps!(?)

Community Member

Re: 3750G-24TS port connecting problems.

We recently also installed a 3750 that had the same problem. Unfortunately I am not aware of IEEE standards regarding autonegotiation, so these problems arise when different manufacturers try to autonegotiate. I was using my 3750 specifically to connect IBM servers with Gig NICs to my network. I had the same dropping issue until I changed both the port AND the server NIC to 1000Mbps and FULL duplex. The default for the ports is half duplex at 10/100Mbps. When I did this, the port would go orange for the 30 seconds to establish the connections, then be steady green and the link at the server was stable. Hope that helps.

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