Mosh is short for mobile shell, and is useful as an alternative to SSH, especially for poor network conditions, and where one has to frequently switch networks. It works via the UDP port, which has to be specifically enabled. I learnt of mosh through the guys in the #emacs.
I’ve faced frequent trouble due to network issues over SSH connections, with the lag hampering my ability to type, in general, and it is particularly inconvenient to respond on IRC/Weechat.