physical link status checking

Hi, =

  I shall be highly grateful to you if you kindly help me on the
following problem.
  =

  I've written a UDP client-server module in which the server receives
data from the client at every 100ms interval. The server and the client
are running on different machines.

  I want to include an error checking code into my program so that
whenever the ethernet chord is disconneted from the server or client
m/c,a message comes up stating that there is physical link failure.

  I'll wait for your mail with alacrity.
 =

Thanks & Regards,
Avik Ghosh =

+91-09332005778 ( mobile)