Using APPC to Communicate with Other Systems › Define APPC Links › Define Dynamic APPC Links

Define Dynamic APPC Links

To define dynamic APPC links identify the components that can take part in APPC communication and their operational requirements to the local domain. These definitions are kept in APPC tables maintained by a set of product commands. The table definitions perform the following functions:

• Relieve NCL from the task of fully specifying all the parameters required to initiate a conversation. This simplifies allocation requests.
• Provide validation for both locally and remotely initiated conversation requests. This provides a level of integrity before allowing communication to take place.
• Include information concerning destination attributes relevant to LU6.2 usage and for controlling resources such as sessions. This information allows your product to modify its behavior to suit a variety of LU6.2 implementations.
• Most importantly, these tables allow on-line maintenance of LU6.2 operational facilities, including aspects of control over NCL transactions without resorting to the modification of NCL procedures.

The APPC tables support the separation of the APPC programming facilities from the session support facilities. This allows NCL procedures to be developed and maintained in isolation from the changing network requirements.

There are four control tables that can be defined:

Transaction Control Table (TCT)

Associates transaction program identifiers with transaction program names

Dynamic Link Table (DLT)

Defines those LUs with which the local domain allows LU 6.2 sessions to be established.

Option Set Control Table (OSCT)

Defines those options, supported by a particular LU, that are connected to your product through LU 6.2 session communication

Mode Control Table (MCT)

Defines mode names, the session characteristics they represent, and the number of sessions they support