Here is a snippet from the blog. There is a patch from Intel and a test method to see if your switch is effected in the full blog posting:
Let me elaborate on that for a second. When I say bring down an ethernet controller I mean BRING DOWN an ethernet controller. The system and ethernet interfaces would appear fine and then after a random amount of traffic the interface would report a hardware error (lost communication with PHY) and lose link. Literally the link lights on the switch and interface would go out. It was dead.
Nothing but a power cycle would bring it back. Attempting to reload the kernel module or reboot the machine would result in a PCI scan error. The interface was dead until the machine was physically powered down and powered back on. In many cases, for our customers, this meant a truck roll.
While debugging with this very patient reseller I started stopping the packet captures as soon as the interface dropped. Eventually I caught on to a pattern: the last packet out of the interface was always a 100 Trying provisional response, and it was always a specific length. Not only that, I ended up tracing this (Asterisk) response to a specific phone manufacturers INVITE.