WebSphere brand IBM WebSphere Telecom Web Services Server, Version 7.1

Integrating with Parlay X Call Handling over SIP/IMS

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:
  1. A user agent is attempting to make a call from IMS SIP signaling network.
  2. The IMS SIP signaling network dispatches a call request to the Call Handling SIP servlet in the proxy server.
  3. 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.
  4. After rule processing, the Call Handling SIP servlet provides a usage record for later billing.
  5. The Call Handling SIP servlet will proxy the call to the resolved destination address.
  6. The call is passed on to either the P-CSCF or I-CSCF control plane.
  7. 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.



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