Method for establising TCP connecting according to NAT behaviors

Abstract

The present invention is to provide a method for establishing TCP connection according to NAT (Network Address Translation) behaviors, which is applied to a network system having a NBA (NAT Behavior Aware Server) located in the Internet and connected to two NATs in two private networks respectively. The method enables two network devices in the respective private networks to send testing messages to the NBA via the respective NATs. In response, the NBA sends reply messages to each network device to test the behaviors of the NATs respectively. Afterward, each network device generates a test result message according to each behavior of the corresponding NAT and sends the same to the NBA. Based on the test result messages, the NBA selects an optimal traversal technique from candidate traversal techniques, thereby allowing the network devices to respectively and directly traverse the NATs and establish a direct TCP connection therebetween.

Description

technical field [0001] The invention relates to a method for establishing a transmission control protocol connection, especially a method for establishing a transmission control protocol connection according to the behavior of a network address translator. Background technique [0002] According to, peer-to-peer Internet technology (peer-to-peer, hereinafter referred to as P2P) is one of the commonly used technologies at present. Through the network architecture formed by P2P, the user's network device (such as: desktop computer) can Directly establish a connection with other users' network devices to share and exchange files (such as pictures, music, video), distributed computing or collaborative work... and many other applications. [0003] However, P2P still faces some problems in practical application, mainly due to the rapid development of the Internet (Internet), the current Internet Protocol (Internet Protocol, referred to as IP) addresses will soon be insufficient. I...

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Problems solved by technology

[0007] According to investigation, many researches have proposed a variety of TCP NAT traversal technologies, such as: Establish the SYN-in (abbreviated as ESi), SYN with Normal-TTL (abbreviated as SNT), SYN with Low-TTL (abbreviated as SLT) and forwarding (Relay ), etc. However, under different network environments, the characteristics of each NAT are different, so that the aforementioned NAT traversal technology is not applicable to each NAT. Therefore, when two network devices need to pass through the corresponding NAT, When trying to establish a TCP direct connection path, two methods are usually used to find the most suitable NAT traversal technology. One is Sequential Connectivity Check with Initiator Changes, that is, the two network devices will test each of the aforementioned NAT traversal techniques one by one. technology, until a certain NAT traversal technology can establish a connection path, but this will lead to a lengthy overall connection test time, causing users to wait too long; the second is ParallelConnectivity Check with Initiator Changes, that is, two network devices will simultaneously Test each of the aforementioned NAT traversal technologies until a certain NAT traversal technology can establish a connection path, but this will cause a large increase in the amount of information exchanged by network devices at the same time, causing network devices to consume too much network resources

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