IBM z13s, Technical Manual

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Appendix D. Shared Memory Communications
487
򐂰 CICS to CICS connectivity through Internet Protocol interconnectivity (IPIC)
Optimized Sysplex Distributor intra-sysplex load balancing
Dynamic virtual IP address (VIPA) and Sysplex Distributor support are often deployed for high
availability (HA) and scalability in the sysplex environment.
When the clients and servers are all in the same sysplex, SMC-R offers a significant
performance advantage. Traffic between client and server can flow directly between the two
servers without having to traverse the Sysplex Distributor node for every inbound packet,
which is the current model with TCP/IP. In the new model, only connection establishment
flows must go through the Sysplex Distributor node.
Sysplex Distributor before RoCE
Figure D-9 shows a traditional Sysplex Distributor.
Figure D-9 Sysplex Distributor before RoCE
The traditional Sysplex Distributor has these characteristics:
򐂰 All traffic from the client to the target application goes through the Sysplex Distributor
TCP/IP stack.
򐂰 All traffic from the target application goes directly back to the client using the TCP/IP
routing table on the target TCP/IP stack.