IP address availability in z/OS can be viewed as a progressive evolution. Static VIPA eliminates the problem of an IP address being associated with a single networking hardware point of failure. Dynamic VIPA allows us to move such IP addresses in event of an application, TCP/IP stack, or LPAR failure. Next, dynamic XCF provides automatic generation of links to provide an automated IP layer of connectivity within the sysplex. Finally, sysplex distributor takes advantage of workload balancing.

Sysplex distributor can be viewed as a continued evolution of connectivity improvements. It is a combination of the high availability features of DVIPA and the workload optimization capabilities of WLM.

The implementation has one significant difference: instead of all participating hosts being effectively equal, LPARs can be given specific roles to play. When combined with WLM, the overall effect on availability is exceptional.

Another change with sysplex distributor is that the distribution is possible only with TCP connections. Other layer 4 protocols are not supported.