> Is there a tcp based implementation planned in the near future? 

For Coda, this will have to be answered by the Coda people. For AFS,
we (the arla project) have thought about tcp proxy implementations,
but we haven't implemented anything yet. This is of course an issue
when dealing with firewalls.

> What are the reasons of selecting udp as the preferred transport in
> afs or coda?

The RPC packages (RPC2 for Coda, rx for AFS) do their own connection
handling on top of UDP. UDP has very low overhead compared to TCP.

Among other things, if TCP had been used, the servers would have to
have a connection open (with a corresponding fd) to each client. Since
UDP is used, the servers demultiplexes the requests themselves.

There are probably other reasons, but none I can think of right now.

/Magnus
map_at_stacken.kth.se