I move a lot of video files around our apartment, generally over Apple Filing Protocol. All my systems have Gigabit Ethernet, but moving around often shifts me over to much slower AirPort (802.11g) wireless networking.

Apple has a nice reconnection feature that brings connections back up if the network goes away. In my situation, this means that if I'm sitting downstairs with a gigabit connection to my server and unplug the Ethernet, Mac OS X reconnects to the server via AirPort. I then carry my laptop upstairs and plug back in, now connected to the server over the wireless network. Wirelessly, downloading video takes at least 10 times as long.

I can get around this by putting the laptop to sleep before disconnecting Ethernet, but I don't use sleep as a rule, and I have to enter my password to wake up. I have verified that if I plug in via Ethernet, briefly disable AirPort, and then re-enable, Mac OS X will automatically reconnect via Ethernet, but that's awkward (and bounces iChat connections).

Tonight I have settled on a pretty good solution -- an alias that unmounts and remounts all my server volumes; for it to work right I have to make sure I don't have any of these volumes in use, but that's not difficult. The alias is:

alias remount='umount /Volumes/115gb/; umount /Volumes/280gb/; umount \
/Volumes/g5/; umount /Volumes/www/; umount /Volumes/pepper; open \
afp://wwwe/www afp://wwwe/115gb afp://g5e/g5 afp://g5e/280gb'