High Rate of Sockets -> No buffer space availible errors

[Kingsbury, Michael]

I have a network testing application that is opening & closing sockets with
other machines at a high rate (multi-threaded,  1000 opens & closes a second
with ~20 machines.)  There's a seperate thread per machine its connecting
to, and each thread opens a socket, transmits 8k, and closes. 

The problem lies with an error of 'No buffer space availible' within the
first couple of seconds.  I've tried the SO_SNDBUF&  SO_RVCBUF, but that
doesn't make sense in my head anyways.  Anyone seen problems like this under
similar conditions & maybe any remedys?

-mike