z/Server itself does not use any sysplex services. It relies on the ability to connect to an IP address specified using a TCPIP header. This is normally done under the covers by an Eclipse client:
- The Eclipse client asks for "Connect" to an IP address (or symbolic name) using a port specified in the client. This port corresponds to the PORT parameter that the scheduler address space listens on. As a response, z/Server sends back the IP address of the system that this particular scheduler address space runs on.
- The next transaction initiated from the client (which includes the TCPIP function connect - different from the function "Connect" in 1.) uses this IP address for further communication and (IP-)connection.
- As long as the network is set up in such a way that usage of this IP address will guarantee connection to the same host system, the first connection used (from the Eclipse function "Connect") z/Server functions without problems.
Note that it is mandatory to have a one-to-one relation between the IP address and the system name. A configuration where an IP address can resolve to different systems (for load balancing, for instance) is not supported. (See also
VIPA).
