Features of Connections

Connections can use one of several different interprocess communications (IPC) protocols to transfer messages: TCP/IP or local (non-network).

Connections can execute callback functions at various points while operating on messages to perform user-defined actions.

Connections can detect many kinds of network failures and take steps to recover from these failures.

Connections can be used for request-reply communication by sending and receiving messages.

Connections can send messages with or without guaranteed message delivery (GMD). GMD stores copies of messages in files to enable total recovery from network failures.

Connections are safe to use in multithreaded programs.

Many advanced features of SmartSockets are message-based services available through connections. Connections and messages are flexible, and SmartSockets uses this flexibility to transmit not only user application messages but also many internal SmartSockets messages. The largest example of a message-based service is monitoring, described in Chapter 5, Project Monitoring. GMD is also implemented using internal messages extensively.