As I was deploying lots of osx to a 2012 windows AD,
we started having up to 60 sec delay on loggin in to macbook pros when they where offline or not wired.
This line fixed it , and wow did it take long time to find.
You can play around with the end value ( 5 ) which is the timeout to wait for the bind to complete.
sudo defaults write /Library/Preferences/com.apple.loginwindow DSBindTimeout -int 5
Funny that Apple does not post these commands under their howto