The Communications Subsystem is the set of IBM Smalltalk classes that support communications over the internet, local area network (LAN) or via a 3270 emulator. VisualAge exploits the Communications Subsystem to provide easy to use parts for application construction.
The Communications Subsystem is divided into three layers:
Each layer exploits the services provided by the next lower-level
layer.
Dialog Layer |
System Layer |
System Interface Layer |
The layered design gives you the flexibility to implement applications that use network-protocol-independent application logic. The Communications/Transactions feature supports the following communication protocols by creating a specialization of this subsystem: