EMBEDDING DATA OBTAINED FROM A CALLER IN SIP SIGNALLING MESSAGES AND PASSING THIS DATA ON DURING A CALL TRANSFER

摘要

Embedding data obtained from a caller in SIP signalling messages and passing this data on during' a call transfer. The present invention is directed to a method for propagating contextual data (state) in an audio communication by storing the contextual data (state) obtained from a calling party (User 12) in an extensible mark-up language formatted text document. A telephone call between a first party (User 12) and a second party (Call Center 80) is converted to a session initiation protocol based voice over internet protocol communication, and the stored text document is attached to session initiation protocol messages REFER and INVITE, that control the voice over internet protocol communication. The document is attached to the signaling messages REFER and INVITE by embedding the text document in a session description payload associated with the session initiation protocol message. The attached document is propagated with the audio communication, including when the signaling messages are used to transfer the audio communication from the second party (Call Center 80) to a third party (Call Center 84) or to add one or more addition parties to the audio commun ication.