Speed Mismatch - Port channels

[veerappan]

A server is connected to the switch with two nic cards which are teamed together and on the switch side the interface are bundled as a port channel.

The speed/duplex setting on both the server and the switch are configured to auto. But the 1st nic card gets negotiated to 100mbps/full with the switch, whereas the second nic gets negotiated for 1000mbps/full.Causing the port channel 4 to be split to port channel 4 & 4A due to speed mismatch.

Have tried to set the speed /duplex to 1000mbps on server & switch side, but the port goes down and remains down.

Any suggestions!!!! Thanks in advance....

[Leo Laohoo]

But the 1st nic card gets negotiated to 100mbps/full

Can this NIC card actually do 1Gb?

If not, then force the switch port-channel ports to negotiate to 100 Mbps so you can get the etherchannel going.

[veerappan]

Thanks for the response..

Can this NIC card actually do 1Gb?

Yes this card is capable of 1000Mbps.

Moreover have 3 other servers in a similar setup which are all part of a MLB setup, so dont want to reduce the speed for this particular portchannel alone while the other three are running at 1000Mbps.

Any suggestions!!!!

[coleman.j]

Have you tested the wireing with "test cable diagnostics tdr int x/x" or an actual test device? 10/100 only requires 2 pairs.gigabit requires all four.

other than that this is the behavior I see when Window's or Freebsd is not using an interface.

[veerappan]

Have you tested the wireing with "test cable diagnostics tdr int x/x"

Can I run this on a live setup, will it impact the production envoirnment / cpu utilisation.?/

[sdheer]

hi,

The TDR detects a cable fault by sending a signal  through the cable and reading the signal that is reflected back to it.  All or part of the signal can be reflected back by any number of cable  defects or by the end of the cable itself.

TDR can test cables up to a maximum length of 115 meters.

---

Use TDR to determine if the cabling is at fault if you cannot establish a link.

this could be run on live network as well.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/catos/8.x/configuration/guide/connect.html#wp1038122

Regards,

Swati

[veerappan]

Thanks,

Will run the test and post the reults..

[hobbe]

I would setup the links to not use Auto, only gig.

if you can not do that then I would start with changing cable, what type is the cabeling ?  cat5e ? 6?  if at all possible use 6 or better.

If the problem persists I would look for disturbance sources, such as power cabeling going near the data cabeling.

if I would find any such sources then I would move them as far as possible from the cabeling.

if this does not work then I would start checking the drivers for the NIC on the server.

I have seen links go back and forth from gig (1000 full) to 100 full and back several times a day with the auto feature enabled.

This can happen due to the cabeling quality or that it is getting to much disturbance when it sends a lot of data or a powercable/elevator/magnetic disturbance near it.

Good luck

[veerappan]

Thanks Hobbe for your troubleshooting steps, have raised a change request will try them once approved.