fsh is a drop-in rsh-compatible replacement for ssh that
automatically resuses ssh tunnels.
Logging in to a remote system with a cryptographic solution
such as lsh or ssh takes time, due to the computationally
expensive key exchanges that occur when the connection is
established. It is common to trigger a lot of remote logins
while using remote CVS, which makes it painfully slow
compared to having the repository locally.
The solution: reuse the secure tunnel once it has been
established.