When it is not enough to present a set of VTAM messages to your network provider to solve a HPR problem in the IP network, the time has come to learn a second language. Join this session to learn how > IST1494I PATH SWITCH STARTED FOR RTP CNR00062 TO netid.cpname > IST1818I PATH SWITCH REASON: SHORT REQUEST RETRY LIMIT EXHAUSTED translates into the '4 and a half UDP Firewall Filter Rule' problem. Come and understand why a High Performance Routing (HPR) pipe is sometimes performing Low and is still not using LPR protocol. Get to know the underlying architecture of HPR: RTP, ANR, ARB Walk with us through the layers of an EE packet and say Hello to all the bits and bytes that you better call a friend from now on. It will speed up problem resolution in heterogeneous networks as most problems that result in nasty VTAM messages are not to be solved within z/OS!