Patent ID: 8711782

Claim:
A session transfer method, comprising: after receiving a session transfer request sent by a first user or a second user, wherein the second user is in an Internet Protocol multimedia subsystem (IMS) domain, sending, by an application server (AS), a release message to the first user in the IMS domain that is currently in a first call with a third user which is in a circuit switched (CS) domain to terminate a session between the third user in the CS domain and the first user in the IMS domain; negotiating, by the AS, media information of the third user in the CS domain and media information of the second user in the IMS domain to establish a session between the third user and the second user; wherein before the receiving the session transfer request sent by the first user or the second user, the method further comprising: receiving, by the AS, the first call initiated by the third user in the CS domain to the first user; connecting, by the AS, the first call to the IMS domain after determining that the first user is a dual network user in the CS domain and the IMS domain by querying internal relevant data according to a number of the first user upon receiving an Initial Detection Point (IDP) message sent by a Mobile Switching Center (MSC) of the first user; receiving, by the AS, a second call sent by a Call Session Control Function (CSCF) in the IMS domain to the first user and routing the second call to the CS domain after adding an access code for preventing repeating a service processing that has been performed by the AS to the first call; and receiving, by the AS, a third call sent by a gateway mobile switching center (GMSC) in the CS domain to the first user, performing no service processing that has been performed by the AS after determining that the access code for preventing repeating the service processing that has been performed by the AS is comprised in the third call, deleting the access code for preventing repeating the service processing that has been performed by the AS, and delivering a connection message to initiate the first call to the first user, so as to establish the session between the third user and the first user.