ProLiant Servers (ML,DL,SL)
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ProLiant connection problems

Ben Page
Occasional Visitor

ProLiant connection problems

I have a problem that I can't understand. I was hoping you might be able to advise or suggest someone to speak with me on the problem.
We have several servers that have recently have begun to establish their ethernet connections at 100/Half rather than 100/FULL. Both the NIC and the switch are 'hard coded' to use 100/FULL but the connection ultimately succeeds at 100/Half. It is my understanding that when 100/FULL is specified at either end, negotiation between the switch and NIC is suspended and the connection is simply established. My question is this: "What conditions may exist between the NIC and the switch that would cause the session to be negotiated down to 100/Half?"
This situation is occurring on a variety of server platforms (G1 to G3) and Operating Systems and often not repeating on any particular server. For that reason I feel that we are seeing something more sinister than a back level NIC driver or faulty hardware. We have in fact found that rebooting the server (warm boot, not POR) will usually correct the connection to 100/FULL. We have tried an OS level software reset on the NIC (from the Control Panel applet) and logically dropping the connection from the switch but neither action corrects the connection. We have even gone as far as removing the interface cable to see if the NIC would came back to 100/FULL when reconnected. The problem becomes visible when the switch begins to accumulate 'collisions'. As you can imagine, I'm getting kind of desperate to find an explanation for this behavior.
Do you have any idea what may be happening here? Can you point me to any source that could help me diagnose the problem more completely?
I would really appreciate your response. Thanks in advance.

Paul D Sowards
Ashland Inc
Frequent Advisor

Re: ProLiant connection problems

Your ethernet card is configured to full duplex and starts to communicate in FD mode. As soon as it starts doing that a huge amount of collisions appear, so it turns itself back to HD. If your card generates collisions in FD mode, that means somewhere on your collision domain an ethernet card is talking HD. Have a look at your switch and see what that one is set to. Try setting one of the two sides (switch or server) to auto negotiate. What kind of cable (and how long) are you using? Try using a crossover cable and connect two affected server straight to each other. what is the result? maybe something's wrong with your switch