Since UDP communication is unpredictable and if ports are unreachable, then
getting portunreachable exception can be delayed, due to this failover will not
work. From JDK layer portunreachable exception is thrown when next attempt is
made to send or receive data on same destination if jdk has already received
ICMP portunreachable packets.
This is fixed on 1.0 and needs to be ported to 2.0 with some enhancements.