Disabling Ethernet Flow-Control at the Endpoint

Question

We have several issues with disconnects, freezing, web session resets, and other goofy things with applications that access resources over the internet. My biggest problem has been outlook using RCP over HTTPS (MS Outlook). I expect this because our internet connection is over loaded. Here is the kicker, the problem with Outlook happens even when bandwidth usage is low.

I was helping with troubleshooting another issue and happened to notice Flow-Control is disabled on the Ethernet ports for the switch (I know it is default, I just never really thought about it). Well most computers have it enabled by default. Just because I hadn't tried it before, I disabled Ethernet Flow-Control on my computer and now Outlook and my other internet accessible apps are working appropriately (no disconnects, resets, or session loss). I don’t want to test this change in other areas without having a little more information, so I have a couple of questions. Is this a fluke, if not why would this happen and does it mean that I need to increase my buffers? Anything else I may be missing?

I have ran perfmon in Windows 7 looking at the NIC and Packet Outbound and receive errors are generally pretty low if at all.

Answer 1

Is this a fluke?

Probably.

does it mean that I need to increase my buffers?

You disabled flow-control, so this would've made the problem worse if it were a buffer overflow issue. Error counters should tell you if there were any issues.

Flow Control is a negotiated function. If the switch has it "off" (send and receive), then the connected devices should disable it as well. Of course, this assumes your nics, drivers, and switches are braindamaged.