Method used by server to send message to client in NAT network

Abstract

The invention provides a method used by a server to send a message to a client in an NAT network. The method comprises the steps that a UDP-S service is turned on in the server to communicate with the client; the client sends a UDP data packet to the UDP-S service of the server to establish a server cache information table; the server judges whether the client is located within the internal network defined by an NAT gateway according to the UDP data packet and returns the client identity; the client responds to the client identity to establish a UDP communication channel between the server and the client; and the server calls the UDP-S service according to the server cache information table to send the message to the client through the UDP communication channel. According to the invention, the bandwidth of the server side is saved, and the communication channel is easily established.

Description

technical field [0001] The present invention relates to the field of computer network communication, and more particularly to a method for sending a message from a server to a client in a NAT network. Background technique [0002] The communication between the client and the server is based on HTTP (Hypertext Transfer Protocol), and HTTP is a stateless communication protocol. Each request-response is based on a newly established HTTP connection, which makes the server actively notify The client becomes a difficult point. [0003] At present, there are two mainstream solutions: one is the client-side polling technology, that is, the client periodically actively accesses the server's public IP address to obtain changes in the server's data status. The problem with this method is: if The server's business data does not change during two consecutive polling requests, and the work of the latter request is actually negative—wasting server-side bandwidth, and no payload is obtaine...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two mainstream solutions: one is the client polling technology, that is, the client periodically actively accesses the public IP address of the server to obtain changes in the data status of the server. The problem with this method is: if The server's business data has not changed during the two consecutive polling requests, and the work of the latter request is actually a negative number - a waste of server-side bandwidth and no payload; moreover, the timing of the client polling process The server interval parameter is also a difficult problem to grasp. Since the business data status of the server needs to be obtained in time, the timing interval parameter setting should not be too long, but if it is too short, the first problem will occur frequently

[0004] Another way is to provide a two-way, full-duplex communication in a TCP channel between the client and the server, that is, to establish a long connection between the client and the server. The problem with this method is: the client needs to A two-way heartbeat mechanism is implemented between the server and the server through Ping-Pong to ensure the reliability of the link, which is complicated to implement and also causes a waste of bandwidth on the server side

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