TC keeps dropping off the network - any idea what's happened to it?

[ascender]

Recently my TC has started to drop off the network. It'll disappear from Finder and the Airport Utility can't find it. Only way to recover it is with a power cycle. Up until recently its been working well.

Obviously as I'm relying on this thing for my backups, its a bit worrying, so I was just wondering if anyone else has had similar problems?

Thanks.