An application can use the PPX service to:
Perform actions on groups of connections in a single transaction.
The following table defines the basic elements of the PPX service:
|
Term |
Definition |
|---|---|
|
Connection object |
An internal data structure maintained by the PPX server that is created when a switch connection is successfully opened. This structure records the state of the connection. In the PPX service, a connection object can be considered as an empty container until talkers and listeners are assigned to it. |
|
Connection handle |
An identifier for a specific connection object. |
|
Connection |
A logical path between two terminus entities. Within the PPX service, a connection can have only one talker but can support multiple listeners. |
|
Terminus |
A single access point to a switch block input or switch block output. A terminus contains a bus, a stream, a switch number, and a timeslot. |
|
Talker |
The terminus that drives the output on the connection. |
|
Listener |
The terminus that receives input from the connection. |
PPX connections and PPX listeners have the following unique properties:
Switch connections established through the PPX service have an ownership property.
When a PPX client creates a connection between two points, only the client that established the connection (who owns it) is allowed to break the connection (which disables output).
Ownership can be overridden by assigning the connection a name, allowing different contexts bound to different clients to operate on the same connection points.
PPX listener points have an associated state value which is either BUSY or NOT_BUSY.
Listener points that are connected to a talker are in the BUSY state. A listener point can be connected to a talker only when that point is in the NOT_BUSY state. Therefore, if talker point A is connected to listener point B, listener point B must be disconnected from talker A before it can be assigned to a new talker point C.