The Parlay X Call Handling over SIP/IMS Web
service implementation provides a mechanism with which applications
can designate how calls are to be handled for a specific telephone
number.
Parlay X Call Handling over SIP/IMS provides
a rule-based processing capability that applications can access through
the following set of operations: setRules, getRules, setRulesForGroup,
and clearRules. This capability provides a simple
way for deciding how applications are to relate to call behavior.
The interface functions on a request/response message from the
Web client to a Web service. When actual calls are routed, the Web
service validates whether the calls are permitted according to rules
that are configured for a given address.
Call flows
The following is an example call
flow showing how the Call Handling over SIP/IMS interfaces are invoked.
In this example the call flow begins when the application client invokes
the Web service by routing the SOAP message over the HTTP to the
Telecom Web Services Access Gateway.
The
Access Gateway acts
as a Web service between the client application and the Call Handling
service. The following steps show how the
Parlay X Call Handling over SIP/IMS Web
service processes the defined rules on incoming Call Notification
or Alert:
- A user agent is attempting to make a call from IMS SIP signaling
network.
- The IMS SIP signaling network dispatches a call request to the
Call Handling SIP servlet in the proxy server.
- The Call Handling SIP servlet looks up a set of rules for the
destination address of the call. It determines whether to accept a
call or routing address.
- After rule processing, the Call Handling SIP servlet provides
a usage record for later billing.
- The Call Handling SIP servlet will proxy the call to the resolved
destination address.
- The call is passed on to either the P-CSCF or I-CSCF
control plane.
- The call negotiation is completed and the user agents can now
start their phone conversation through the established mobile media
connection, or hear the voice message through the established RTP
connection with the media server.
Interfaces
- setRules
- Sets the Call Handling rules for the call destination address.
If a set of rules is already in place for the address, then this operation
will replace the old rules with the set provided in the operation.
The address may not specify a group. If a group is specified, a PolicyException
will return.
- setRulesForGroup
- Sets the Call Handling rules for multiple call destinations. If
a set of rules are already in place for any of the addresses, then
this operation will replace the old rules with the set provided in
the operation. The addresses may include groups with arbitrary prefix
for group which will be resolved in the Access Gateway for
members that use tel:, sip:, and sips: URIs.
- getRules
- Retrieves the Call Handling rules for the call destination. The
address may not specify a group. If a group is specified, a PolicyException
is returned.
- clearRules
- Clears the Call Handling rules associated with the specified address.
If rules have not been set for an address, then the operation silently
ignores the request and does not return a fault message. The addresses
may include groups with members using tel: and sip::
URIs.