|
|
|
When two programs communicate using APPC, they do so via a communication path called a conversation. All activity that occurs as a result of APPC communication is called a transaction and the programs involved are known as transaction programs. Terms such as client/server processing or distributed transaction processing, are often used to describe this form of data processing.
One feature of APPC is that two programs do not have to be running to start communications. APPC allows a program in any LU to request the invocation of a program in any other LU to fulfill its processing requirement. The program achieves this through a process known as allocation, which establishes a conversation, and sends an attach request that the nominated program be invoked to service the remote LU of the conversation.
The invoked program is said to be attached in the remote LU. An attached program can itself attach other programs. These all form part of the same transaction, but each communication instance between programs is considered a separate conversation.
Within the product region, any NCL procedure can issue an allocation request to start a conversation with another procedure or program. These can be in the same or another network LU. When the region receives an incoming request to attach a program, an NCL procedure is started to service the conversation.
| Copyright © 2010 CA. All rights reserved. |
|