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The following chapter describes the Parlay X 2.1 Call Notification communication service in detail:
The Call Notification communication service implements the Parlay X 2.1 Call Notification set of interfaces. For the exact version of the standard this communication service supports, see “Appendix A: Standards and Specifications” in the Concepts and Architectural Overview, another document in this set.
Using the Call Notification communication service, an application can:
Note: | The operations made available by Call Notification communication service are concerned only with monitoring and in some cases making certain changes to calls. This communication service is not used to setup new calls, only to reroute or terminate calls already in progress. |
In order for an application to receive notifications about call setup attempts from the network, it must register its interest in these notifications by setting up a subscription in Network Gatekeeper. A subscription, or a notification, is defined by a set of addresses and a set of criteria. The criteria define the events in which the application is interested.
Note: | The addresses may possibly be translated by some mechanism in the telecom network prior to reaching Network Gatekeeper. |
Two types of notifications exist:
An application can register to be notified about the following events as the call between the caller and the callee is set up:
In addition to monitoring the state of call setup, an application can also choose to make certain changes to the call under certain conditions. An application can:
In addition, if one of the monitored events occurs (busy, not reachable, does not answer), an application can:
Requests (that is, registration for notifications) using the Call Notification communication service flow only in one direction: from the application to Network Gatekeeper. Thus this communication service only supports network triggered requests.
Note: | The Call Notification communication service manages only the signalling, or controlling, aspect of a call. The media, or audio, channel is managed by the underlying telecom network. Only parties residing on the same network can be controlled, unless: |
Off-the shelf, the Parlay X 2.1 Call Notification communication service can be configured to support the following network protocol:
When Network Gatekeeper is configured to use this protocol it connects to the SIP network. Network Gatekeeper acts as a SIP Back-to-Back-User-Agent. Although from a signalling point-of-view three parties are involved - the caller, the callee, and Network Gatekeeper - from the SIP perspective, the media channel (the actual call) that is established is purely peer-to-peer.
Communication services share many common features, covered in the “Introducing Communication Services” chapter of the Concepts and Architectural Overview, but each one has a few characteristics that are specific only to that service. This section describes those specific features for the Parlay X 2.1 Call Notification communication service, including:
The CDRs generated by the Parlay X 2.1 Call Notification to SIP communication service belong to two basic groups. They occur when the following criteria are met:
The following are lists of EdrIds
created by the Parlay X 2.1 Call Notification to SIP communication service. This list does not include EDRs created when exceptions are thrown. For more information, see Events, Alarms, and Charging..
The table below outlines the correlation between the methods being invoked from either the application (in application-initiated requests) or the telecom network (in network-initiated requests) and the transaction type collected by the statistics counters in Network Gatekeeper for the Parlay X 2.1 Call Notification to SIP communication service:
Note: | Method names for network-initiated requests are specified by the internal Gatekeeper name, which is not necessarily the same as the message from the network. |
The Parlay X 2.1 Call Notification-SIP communication service supports the tel:
address scheme.
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