I have an Intel X540-T1 NIC installed in one of our servers that is exhibiting the problem outlined in the FreeBSD problem report kern/183390. The link to the problem report is as follows....
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/183390&cat= kern/183390: [ixgbe] 10gigabit networking problems
We are using the latest available version of the driver (2.5.15). I'm wondering when a newer version of the FreeBSD driver for this NIC will be released that resolves the issue described in the previously mentioned problem report. Basically, the NIC stops responding after moderate to heavy traffic load and the only way to solve the problem is to bring the interface down and then back up. I look forward to any suggestions about this issue. And hope Intel will take a good look at the problem and release a new version of the driver that solves it. Thank you.