Re: Cisco 2950 Uplink problem

sschulz · ‎07-09-2003

We have installed a Cisco 2950 switch onto an existing network. The problem we have is that if we set the uplink port to 100MbFD the performance is impacted. This is not the first switch we have connected on this network but is the first one to cause us any problems. The IOS is 12.1(13)EA1.

Once the switch is set to Auto config, there are no performance problems and I need to know if anyone has had similar problems or can advise why this is an issue.

Thanks

milan.kulik · ‎07-09-2003

Hi,

what device is on the other end of the line?

Are you sure that it is also set to 100Mbps/Full when setting the 2950 uplink this way?

It is necessary to set both line ends the same way - either auto or 100Mb/Full.

If one end is 100Mb/Full and the other end is auto you are in trouble.

Regards,

Milan

sschulz · ‎07-09-2003

The other end is connected to a Cisco 3548xl. This was configured to 100MbFD as well. I checked that both ends were set to 100MbFD before installing the switch. It was only after I changed both ends to Auto that the problem was fixed.

milan.kulik · ‎07-09-2003

Strange....

Usually setting 100MbFD is recommended to fix autonegotiation problems.

Is the port 100MbFD after the autonegotiation or is it 10Mb or HD now?

If it is not 100MbFD, have you checked the cable - what is the cable length?

Regards,

Milan

sschulz · ‎07-09-2003

After Auto negotiation it reports that the link is auto negotiating at 100MbFD. The 2 switches are about 10 metres apart linked by a crossover cable. This cable was previously used in a Cisco 2924M without any problems.

bhaase · ‎07-09-2003

What kind of errors are you seeing on both interfaces?

mdoldan · ‎07-10-2003

Please provide the config of the 2950.

I have seen a number of problems with the 2950's most are caused by an issue with VTP. Several Cisco CCIE's have recommended making VTP transparent which has consistently solved the problem for me.