This section gives an overview of the three major types of OpenTP1 computer configurations:

• client/server configurations that use remote procedure calls for communication
• MCF message-exchange configurations
• MQA message-queuing configurations

• Overview of client/server configurations and remote procedure calls
  In a client/server configuration, a client application makes a request to a server application to perform some processing, and the server returns the results of the processing to the client. In OpenTP1 systems, a client/server configuration is usually in a LAN in which the UAPs (user application programs) use the TCP/IP protocol to communicate via remote procedure calls
  
• Overview of MCF message-exchange configurations
  An MCF message-exchange configuration enables messages to be exchanged between OpenTP1 and non-OpenTP1 systems using communication protocols other than (or including) the TCP/IP communications protocol. For example, a non-OpenTP1 system might be a network controlled by a large-scale host computer, and the communications protocol is the protocol used in that network. A UNIX workstation could use the OpenTP1 message facilities to send data to be processed on the large-scale host computer, and the host can use messages to send processed data back to the workstation. OpenTP1 provides compatibility with a number of communications protocols.
  
• Overview of MQA message-queuing configurations
  In communication that uses MQA message queuing, messages can be exchanged between systems that have queue managers. OpenTP1 uses the TCP/IP protocol to support the communication using MQA message queuing. OpenTP1, XDM, and MQSeries all use queue managers. For further details, see 2.4 Processing in an MQA message-queuing configuration.