Outbound and Inbound Gateway Autotasks

Each gateway session consists of:
  • Two gateway autotasks on each system:
    • One autotask for handling information outbound from a system, called the outbound gateway autotask. This establishes and maintains all connections to other systems. It sends messages, commands, and responses to one or more systems.
    • One autotask for handling information incoming from another system, called the inbound gateway autotask. A system can have one or more inbound gateway autotasks, depending on the number of systems to which it is connected.
Figure 1 shows a single gateway between two SA z/OS agents, ING01 and ING02.
Figure 1. Single Gateway Example
Single Gateway Example
There is one task handling all outbound data. This task is set up at SA z/OS initialization time. Normally the task has a name that begins with GAT and ends with the domain name. So for ING01, the gateway task is GATING01.

When VTAM® becomes active, the gateway task (GATOPER) issues a CONNECT call to the remote system, ING02 in our example. If the GATING01 task on the remote system is not already active, it will be started automatically by NetView.

All requests initiated by system ING01 and destined for system ING02 use the task pair GATING01. Likewise all requests that originate on system ING02 and are destined for system ING01 use the pair GATING02. In other words the communication is half-duplex. There is one task pair responsible for the outbound traffic while another task pair is in charge of the inbound traffic. Each pair consists of a sender - running on the local system and receiver that runs on the remote system.

Disallowing the starting of the receiver task protects the local system from getting requests from the remote system.

The task structure is similar when using XCF as the communication vehicle. Using the "GATxxxx" task as the receiving and processing task on the remote side gives a dedicated task pair for the communication between the two systems. This task pair exists twice, once for each outbound communication. It is important to notice that the standard RPCOPER is not used for the processing of the remote procedure call.

In the automation policy for each system in an automation network, you need to define only the outbound gateway autotask (see IBM Z® System Automation Defining Automation Policy). However, in the NetView DSIPARM data set member DSIOPF, you must define all gateway autotasks, both inbound to and outbound from a system, as operators.

You define the outbound gateway autotask by defining the GATOPER policy item for the Auto Operators policy object in the customization dialog. You must specify an operator ID associated with the GATOPER function in the Primary field on the Automation Operator NetView panel. See IBM Z System Automation Defining Automation Policy for more information.

For this example, the operator ID for the system CHI01 outbound gateway autotask is GATCHI01. Similarly, any operator ID for an inbound gateway autotask is the prefix GAT combined with the inbound gateway domain name.

Figure 2 shows three systems: CHI01, ATL01, and ATL02. System CHI01 is the focal point for forwarding messages from target systems ATL01 and ATL02. In Figure 2, gateways are designated as follows:
O
Outbound gateway autotask
I
Inbound gateway autotask.
Figure 2. Example Gateways
Example Gateways