Transmission system and method for network address translation traversal

Abstract

A transmission system and a transmission method for network address translation traversal are provided. The transmission system includes a private network device, a network address record device, a public network device and a network address translation server. The network address record device records an inner network address of the private network device and an outer network address corresponding to the inner network address. The public network device inquires the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generates a packet according to the inner network address and the outer network address corresponding to the inner network address. The network address translation server receives the packet from the public network device, and transmits the packet to the public network device.

What is claimed is: 
     
         1 . A transmission system for network address translation traversal, comprising:
 a private network device;   a network address record device, being configured to record an inner network address of the private network device and an outer network address corresponding to the inner network address;   a public network device, being configured to inquire the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generate a packet according to the inner network address and the outer network address corresponding to the inner network address; and   a network address translation server, being configured to receive the packet from the public network device and transmit the packet to the private network device;   wherein the network address record device is a session initiation protocol (SIP) server and is configured to label and record the inner network address of the private network device and the outer network address corresponding to the inner network address respectively according to a session initiation protocol.   
     
     
         2 . The transmission system as claimed in  claim 1 , wherein the inner network address of the private network device further comprises an inner port, and the outer network address corresponding to the inner network address further comprises an outer port. 
     
     
         3 . The transmission system as claimed in  claim 1 , further comprising a core network server, wherein the core network server is configured to perform a predetermined procedure with the private network device to create the inner network address of the private network device and the outer network address corresponding to the inner network address. 
     
     
         4 . The transmission system as claimed in  claim 3 , wherein one of the private network device and the core network server transmits the inner network address of the private network device and the outer network address corresponding to the inner network address to the network address record device. 
     
     
         5 . The transmission system as claimed in  claim 1 , wherein the public network device inquires the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device according to the session initiation protocol. 
     
     
         6 . A transmission method for network address translation traversal, the method comprising:
 (a) a network address record device recording an inner network address of a private network device and an outer network address corresponding to the inner network address;   (b) a public network device inquiring the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device, and generate a packet according to the inner network address and the outer network address corresponding to the inner network address; and   (c) a network address translation server receiving the packet from the public network device and transmit the packet to the private network device;   wherein the network address record device is an SIP server and the step (a) further comprises the network address record device labeling and recording the inner network address of the private network device and the outer network address corresponding to the inner network address respectively according to a session initiation protocol.   
     
     
         7 . The transmission method as claimed in  claim 6 , wherein the inner network address of the private network device further comprises an inner port, and the outer network address corresponding to the inner network address further comprises an outer port. 
     
     
         8 . The transmission method as claimed in  claim 6 , further comprising:
 (d) a core network server, prior to the step (a), performing a predetermined procedure with the private network device to create the inner network address of the private network device and the outer network address corresponding to the inner network address.   
     
     
         9 . The transmission method as claimed in  claim 8 , further comprising:
 (e) one of the private network device and the core network server, after the step (a) but before the step (d), transmitting the inner network address of the private network device and the outer network address corresponding to the inner network address to the network address record device.   
     
     
         10 . The transmission method as claimed in  claim 6 , wherein the step (b) further comprises:
 (b1) the public network device inquiring the inner network address of the private network device and the outer network address corresponding to the inner network address from the network address record device according to the session.