Patent ID: 9374264
Filing Date: 2016-06-21
CPC Classification: H04L

Claim Text:
1. A system for transmitting and receiving Session Initiation Protocol (SIP) messages, comprising: user equipment (UE) including an SIP client configured to generate an SIP message, and an external transport configured to receive the SIP message from the SIP client, generate a packet by combining a tunneling header with the received SIP message, and transmit the generated packet to an SIP broker server; and the SIP broker server configured to assign a port among assignable ports to the UE in response to a port assignment request received from the UE, remove the tunneling header from the packet received from the external transport through the assigned port, and transmit the SIP message from which the tunneling header has been removed to a communication counterpart of the UE, wherein, when a connection between the SIP broker server and the UE is abnormally terminated after the SIP broker server assigns the port, the SIP broker server determines whether a port reassignment request is received from the UE during a predetermined period, and wherein the SIP broker server releases the port assigned to the UE when no port reassignment request is received during the predetermined period, and reassigns the port assigned to the UE when the port reassignment request is received during the predetermined period.