Dialog Management Layer

A dialog is a persistent peer-to-peer SIP relationship between two user agents. A dialog facilitates the sequencing of messages and the proper routing of requests between the user agents. The use of dialogs is optional. Dialogs hold state information, which can be used to construct a request within a session. An application can implement its own dialog management layer instead of using the layer that the SIP stack provides. If the stack manages the dialog, it automatically creates and updates dialogs for incoming and outgoing SIP messages. The stack also delivers the matching dialog to the application with the incoming message.