Comment 12 for bug 833479

Long shot... Can you use another device with ping and tcpdump to determine whether the packet loss is during reception or transmission?

If it is only at reception then it might be that the 82577LM chipset is affected by the same issue as the 82579LM chipset reported in bug 870127. (Intel may be able to offer an answer here?)

Affected 82579LM users could use the following as a basis to workaround the issue:

Download the 1.5.1 e1000e drivers from http://sourceforge.net/projects/e1000/files/e1000e%20stable/1.5.1/
tar xvzf e1000e-1.5.1.tgz
cd e1000e-1.5.1/src
make # You will need to ensure that you have the kernel header files installed
rmmod e1000e # Remove current driver
insmod e1000e.ko
/etc/init.d/networking restart

A knowledgeable 82577LM user might determine this by modifying the patch at [1] (which is applied in 1.5.1 and later) to try the same technique with their chipset, presumably by replacing instances of I82579_LPI_CTRL_FORCE_PLL_LOCK_COUNT with I82577_LPI_CTRL_FORCE_PLL_LOCK_COUNT and I82579_LPI_CTRL with I82577_LPI_CTRL.

[1] http://patchwork.ozlabs.org/patch/109926/

Just a thought...