I discovered recently that if you modern cable modem/router on your home network reboots itself (for maintenance, eg. an in-line update, etc) that you may lose the proper identity of your network. The Time machine could be happily trotting along, i. e. 'green light' and the modem is fine, but your home network is now renamed and none of your devices are on it....
At first I thought that the modem had re dubbed itself as the 'King of NAT' when it had rebooted--claiming that job from the Time Capsule, which is Also a 'router'. I had previously set it up for my TC to take point on the NAT job on my network.
I wasn't looking forward to having to re-configure the Motorolla Surfboard's settings to hand over that authority to the TC.
As it turns out, I didn't have to. Since the TC wasn't screaming 'double NAT', as it will when that is happening--with the 'blinking amber light', meaning there is something wrong, I tried simply rebooting the TC.
That did the trick!! My network came back and everything. Bam! All is happy in Networkville and I didn't have to reconfigure the modem's default settings. Yay.