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New Member

Speed and duplex mismatch

We have been experiencing some real problems with speed and duplex issues with the Catalyst 6500s. It seems to occur regardless of IOS or CatOS. Specifically RealTek cards. The realteks exhibit the following behavior - when set to auto and the switch is set to auto. There seems to be extremely slow connectivity. Also when the switch is set to 100 full and the card is set to 100 full the speed is slow. As an aside diagnostics show the connection to be 100 half. When the switch is set to 10 half and the card is set to 10 half it works pretty well.

Any ideas or suggestions? Have others experienced this problem. I am interested if others have experienced this issue and how others deal with the speed duplex issues between switch and NIC cards. Thanks.

8 REPLIES
Bronze

Re: Speed and duplex mismatch

New Member

Re: Speed and duplex mismatch

Thanks for the link. I have looked at that before but it was helpful to go back through again as this problem has been lingering for quite some time. How do others handle this issue? Do you auto on the switch and NIC or do you hard code? Any other advice is always appreciated. Thanks again. David

Purple

Re: Speed and duplex mismatch

Sounds as though the nic card isn't really being set as auto if the switch is saying the connect is 100/half as this is the default if it can't auto the duplex .

Are you seeing a lot errors on the port when it is slow ? If the problem is still there after hardcoding the switch and nic to 100/full then try a different make card if you have one available to you . Can't say I have of too man y people having problems when hardcoding the port and the nic , auto negotiate can be shakey at times though not as bad as it used to be .

New Member

Re: Speed and duplex mismatch

As you would suspect I am seeing quite a few collisions due to the fact that the switch is set to 100 full and the card decides that it wants to be 100 half (even when hard coded to 100 full). I also see runts (again pointing to a card problem?) I have tried to explain to people that it is most likely a card problem (as the problem does not exist with Intel Pro 100) but seems that others are convinced it must be a switch/config problem. I am just looking for more ammo to back up my assertion but don't really know what evidence would convince people. Thanks. David

Re: Speed and duplex mismatch

Couple things.....first, do you have any hubs on this link? that could explain the duplex wanting to go to half. Also, is the wiring CAT 5 or could it be CAT 3, that could explain the speed issue. Have you replaced the NIC or updated any drivers for the NIC? I have had to hard code the speed and duplex for many things and have found that if it is possible to hard code, it is a safe bet. As for it being a configuration issue...there are only 2 ways the port and be configured to.....Auto or hard code the speed and duplex.

Hope this helps.

Burleyman

New Member

Re: Speed and duplex mismatch

Thanks for the reply. The cabling is actually Cat6. There are no hubs in the picture. We have updated drivers with little success. I am not actually that concerned about auto not working correctly as I can envision problems with auto on the driver side. The weird thing is when both sides are hard coded 100 full and the NIC side reports 100 half. I am pretty sure it is a NIC problem but of course the people who would necessarily have to fix the problem would rather it be a switch problem Thanks again.

New Member

Re: Speed and duplex mismatch

Did you ever come up with a solution to your problem? I have a customer experiencing problems with a number of RealTek NICs built on to the motherboard.

Thanks.

New Member

Re: Speed and duplex mismatch

The solution turned about to be a BIOS/Power Management issue on the PC. The PC's were also using RealTek NICs. Make sure to turn off all of the Power Management features in the OS and the BIOS - also check with the manufacturer as the BIOS has to be set in a certain configuration which ours were not. Good luck.

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