ORACLE RAC IRULE ISSUES (JDBC QUERY)

I need help on my Oracle Database VIP. It is configured and green,however,when a JDBC call is made to virtual Ip, there is TNS LISTENER ERROR. Part of my irule goes thus, service name is "tpp_n4"

when CLIENT_ACCEPTED { set last_service_name "tpp_n4"

 Change to a non-zero number if your clients are specifying an
 INSTANCE_NAME in their connect stings and you wish to remove it.  This
 allows you to have clients connect through the BIG-IP without the need
 to worry which instance of your database the connection gets load-balanced
 to.  As a result, the individual nodes will not reject a connection
 because of a Instance Name mismatch.
set remove_instance_name 0

 Map service names to the pool on which they run.
 Use lower case instance names since arrays are case-sensitive and we are
 converting everything to lower case when we do comparisons later on.
array set switch_map {
    "tpp_n4"   "ORACLE_11G_PRIMARY"
   }
TCP::collect

}