US Patent:
20110093542, Apr 21, 2011
Inventors:
Priscilla Lau - Fremont CA, US
Loc Ba Vo - Pleasant Hill CA, US
Assignee:
VERIZON PATENT AND LICENSING, INC. - Basking Ridge NJ
International Classification:
G06F 15/16
Abstract:
A device monitors a session description protocol (SDP) parameter associated with a voice over Internet protocol (VoIP) call provided via a network and a user equipment, and determines, based on the SDP parameter, whether the VoIP call changed from an active state to a hold state or from a hold state to an active state. The device also sends, after the VoIP call is determined to change from an active state to a hold state, a session initiation protocol (SIP) keep alive message to the user equipment to prevent the user equipment from entering a dormant state and to prevent a radio link connection between the user equipment and the network from being released.