Full Duplex Collisions???

[wrwiii122]

OK Im really confused. I thought you couldnt have collisions with a full duplex port but yet my switches are showing collisions even though they are set to full. Also I was told that some applications will not run right if the network cards are set to full duplex. Has anyone ever run into this?

[Richard Burts]

William

Part of the definition of full duplex is that the collision detection mechanism is disabled on a full duplex port/interface. So I believe it is impossible to have collisions on a port that is configured as full duplex - other than the possible result of some bug in the code.

Is it possible that the interface counters recorded collisions at some point in the past when the port was half duplex?

I have not run into any situation where an application would not run on a port set to full duplex. And I wonder how the application would know. One of the advantages of the layered model is that the upper layers are insulated from dependencies on what happens at lower layers. How would an application know whether the port was half duplex or full duplex?

HTH

Rick

[wrwiii122]

I will look into the collisions some more.

As far as the application go it is from Open Systems International. I was having a disagreement with a coworker about the network. He blamed the application error on the collisions on the ports and I disagreed and said fine lets go full duplex(they are servers) but OSI said they have seen issues with the program when it is run in full duplex. Sounded a little weird to me too because the OSI model should have been followed when designing the program and it shouldnt know. hmmmmm maybe Ill just do it and see what happens, I can always put it back.

Thanks Rick ( as usual a good, quick response)

[Richard Burts]

William

Thanks for the favorable comment.

If OSI says that they have seen issues with their program when it is run in full duplex, do you have the ability to send them questions/ask for support? If so, perhaps you can ask them for some details about the supposed problem when the application runs on a port that is full duplex?

HTH

Rick