Patent ID: 8374178
Filing Date: 2013-02-12
Classification: H04L

Abstract:
1. A method for operating an exchange for supporting Network Address Translation (NAT) traversal in a Voice over Internet Protocol (VoIP) system, the method comprising: receiving a registration message from at least one Internet phone, determining whether the corresponding at least one Internet phone is located in a public network or a private network based on a comparison of an IP address of a packet included in the registration message with an IP address of the corresponding at least one Internet phone, and registering the IP address of the corresponding at least one Internet phone in association with the corresponding Internet phone if the corresponding Internet phone is determined to be located in the public network and registering the IP address of a packet included in the registration message with an IP address of the corresponding at least one Internet phone if the corresponding Internet phone is determined to be located in the private network; performing first mapping of an IP address and a User Datagram Protocol (UDP) port of a calling Internet phone to a first embedded Media Proxy Solution (eMPS) IP address and UDP port, when receiving a setup request signal from the calling Internet phone; relaying a setup request of the calling Internet phone comprising the first eMPS IP address and UDP port information to a called Internet phone; receiving a response signal comprising an IP address and an UDP port of the called Internet phone, from the called Internet phone in response to the setup request; performing second mapping of the IP address and UDP port of the called Internet phone to a second eMPS IP address and UDP port; relaying a response signal comprising the second eMPS IP address and UDP port information to the calling Internet phone in response to the setup request and receiving media data from at least one of the calling Internet phone and the called Internet phone, and upon reception of the media data, comparing the UDP port from which the media data is communicated with the mapped UDP port stored in association with the corresponding at least one of the calling Internet phone and the called Internet phone, and updating the mapped UDP port with the UDP port from which the media data is communicated if the UDP port being used differs from the mapped UDP port, wherein the UDP port of a calling Internet phone is equal to the UDP port of the called Internet phone, and the first eMPS UDP port and the second eMPS UDP port is not equal to the UDP port of a calling Internet phone or the called Internet phone, the first eMPS UDP port is not equal to the second eMPS UDP port, and wherein the calling Internet phone and the called Internet phone each correspond to one of the at least one registered Internet phones.