This is for embedded system, kernel 3.0.35-cm-fx6-4,

fs is using ubuntu.

since this is embedded system, there's no GUI, you can just view message outputs from console.
(BUT we do have 2 login sessions, 1 is for GUI, don't ask me why, someone else did it)

The problem is we use networkmanager to manager the 2 ethernet ports. Most of the time it's fine.

Once a while no network connection, and turned out to be networkmanager has died.

Pls note this could happen during weekends, no one is doing anything to the board, which has our application running.

Where should i get started on this pls ?

Not sure if related, but someone's board displays this,

** (process:31111): WARNING **: Could not initialize NMClient /org/freedesktop/NetworkManager: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Error: nmcli (0.9.4.0) and NetworkManager (unknown) versions don't match. Force execution using --nocheck, but the results are unpredictable.

actually "NetworkManager --version" shows 0.9.4.0 as well, lost ...