Hi Amar,
Remoting detects an apparent network problem by sending pings from the client to the server and waiting for a reply. If the reply doesn't arrive within the configured time frame, Remoting informs JBossMessaging. The relevant configuration parameters are
<attribute name="validatorPingPeriod" isParam="true">60000</attribute>
<attribute name="validatorPingTimeout" isParam="true">30000</attribute>
"validatorPingPeriod" determines how often the ping is sent, and "validatorPingTimeout" determines the window within which the response must arrive. So the ping could get sent anywhere from 0 to 60 seconds after the plug is pulled, and the problem detected anywhere from 30 to 90 seconds after the plug is pulled. So, I can explain why the problem detection could take up to 90 seconds. I can't explain how it could happen within 5 seconds, unless some other problem had prevented the server from sending a response to a ping that had already been sent, say 25 seconds before you pulled the plug. Just a stab in the dark.
-Ron