Communications Partners

In a typical scenario, a user program wants to communicate with a resource manager program. These two programs are called communications partners. In the following figure, A is the partner of B, and B is the partner of A. In a CS collection, user programs can be located on z/VM, DOS, NetWare, Windows®, AIX® , or OS/2® systems. Resource manager programs can be located on z/VM, AIX, OS/2, or NetWare systems.
Figure 1. Communications Partners
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However, there could be a virtual machine in the middle that allows for communications between the two partner programs. This middle virtual machine is called an intermediate server, as shown in the following figure.
Figure 2. Intermediate Servers
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For a connection outside your local system within a TSAF collection, the TSAF virtual machine is an intermediate server. For a connection outside your local system within a CS collection, CP is an intermediate server. For a connection outside of the TSAF collection, the AVS virtual machine is an intermediate server. TSAF and AVS are special types of intermediate servers called communications servers. Note that for terminology purposes, even if a request is routed through one or more intermediate servers, A's communications partner is B because the intermediate servers are transparent.