Policy control and billing support for call transfer in a session initiation protocol (sip) network

A system comprising:

• a memory device to store profile information relating to a plurality of users of a telecommunications network, where the profile information for each of the plurality of users includes at least one of call policy information or account information;
• and
• a session information protocol (SIP) server including a processor and a memory storing executable instructions that, when executed by the processor, cause the processor to:
• receive, from a first user of the plurality of users, a first SIP message for initiating a call transfer relating to a second user, of the plurality of users, and a third user, of the plurality of users,
• perform a lookup, in the memory device, first call policy information associated with the first user and second call policy information associated with the third user,
• authorize, using the first call policy information and the second call policy information, the call transfer,
• create, based on the authorization, a digital signature identifying the SIP server,
• generate, using account information for the first user, billing information related to the call transfer,
• append the billing information and the digital signature to the first SIP message,
• analyze the appended digital signature to validate the SIP server,
• complete the call transfer based on the validation of the SIP server, and
• determine whether to bill the first party, with respect to the completed call transfer, based on the appended billing information.

A system comprising:

• means for receiving, from a first party device, a first session initiation protocol (SIP) message associated with initiating a call transfer relating to a second party and a third party;
• means for performing a look up, in a call policy information memory, first party call policy information and third party call policy information;
• means for authorizing, using the first call policy information and the third call policy information, the call transfer;
• means for creating, based on the authorizing, a digital signature identifying a SIP server;
• means for generating, using account information for the first party, billing information related to the call transfer;
• means for appending the billing information and the digital signature to the first SIP message;
• means for receiving a second SIP message initiating a call related to the call transfer, the second SIP message including the digital signature;
• means for validating the appended digital signature;
• and
• means for generating, based on the appended billing information and the validation, an indication of how the first party is to be billed for the call.