In a Web telephony session, users can make phone calls
using the ClicktoCall widget in their Web browsers. The call flow
diagram illustrates the Communications Enabled Applications (CEA)
call flow.
Note: The system application
must first be configured with the IP
private branch exchange (PBX) address.
The following configuration
applies to this call flow:
- A user clicks the ClickToCall widget,
which sends an HTTP REST
request.
- The Web container calls the system application.
- An HTTP servlet interprets the REST request.
- The
system application sends SIP messages to the IP PBX using
the ECMA TR/87 standard protocol.
In addition to TR/87, PBX vendors
can choose to expose a web service interface based on a Web Services
Description Language (WSDL) file that is provided with CEA. This WSDL
file is included in the installation path, app_server_root/systemApps/commsvc.ear/commsvc.rest.war/WEB-INF/wsdl/ControllerService.wsdl.
Using this WSDL file enables you to configure CEA to call out to a
PBX through a web service instead of relying on TR/87.
Restriction: The IP PBX must support the ECMA TR/87 protocol
or the CEA web service interface.
- The IP PBX notifies
the user agent client (UAC) to call the user
agent server (UAS).
- A call is established between the two
users.
Note: UAC and UAS
are SIP instances.
Figure 1. CEA call flow
