Patent ID: 7505421

Claim:
A method for use in establishing communications in a private network for a mobile communication device, the mobile communication device having a communications application for the communications which utilize a session initiation protocol (SIP), the method comprising the following acts which are performed upon initiation of the communications application when the mobile communication device is connected in a communication network outside of the private network: causing a request for a virtual private network (VPN) connection with the private network to be communicated from the mobile communication device; while the mobile communication device is connected in the communication network and the VPN connection is being established: refraining from registering, for a predetermined period of time, with a SIP server for the communications of the communications application using a public IP address assigned to the mobile communication device in the communication network; if the VPN connection is established within the predetermined period of time: receiving a private IP address assigned to the mobile communication device for the VPN connection with the private network; causing a request for SIP registration using the private IP address to be communicated to a SIP server in the private network; if the VPN connection is not established within the predetermined period of time: causing a request for SIP registration using the public IP address to be communicated to a SIP server; and after SIP registration with the SIP server, causing communications of the communications application to be established using the SIP.