create antother thread 4 each client conneciton, whenever a connection is idle
for a
predefined time(1min) this thread will send an AYT(are you there?) message. so
if
your soket has broken down, you cannot send ayt pdu from soket and this means
your client connection closed with an undefined and un controlled way.if u use
different
kinds of programming env. in your client-server model (like vbasic clients,java
servers...)
u always encounter problems like this.

so the most generic, reliable and the traditional way to check a soket
connection is AYT
messages.