Patent ID: 8493965
Filing Date: 2013-07-23
Classification: H04L

Abstract:
1. A method comprising: establishing a first call between a first end device and a second end device, where the first end device communicates using an H.323 protocol and the second end device communicates using a SIP protocol; receiving, from the second end device and during the first call, a SIP REFER message for a call transfer of the first call to a third end device; determining, based on the received SIP REFER message, that a call transfer of the first call from the second device to the third device is requested, wherein the SIP REFER message includes information indicating that a new call is to be established between the first end device and the third end device for the call transfer; determining interworking information between the SIP protocol and the H.323 protocol for sending call transfer instructions to the first end device, by identifying fields in the SIP REFER message that are used to provide contextual information to the first end device regarding the call transfer, the identified fields including a first identifier associated with the third end device; generating an H.450.2 message for the H.323 protocol using the interworking information, the H.450.2 message instructing a call transfer from the second end device to the third end device, the H.450.2 message including the first identifier; sending the H.450.2 message to the first end device; terminating the first call between the first end device and the second end device; receiving, from the first end device and in response to sending the H.450.2 message, a signaling message to initiate a second call to the third end device, where the first end device and the third end device communicate using the H.323 protocol, the third end device being identified using the first identifier that is included in the signaling message; and transferring signaling messages between the third end device and the first end device using the H.323 protocol to set up the second call.