Transmission control protocol type session media stream transmission method and system

Abstract

A transmission control protocol type session media flow transmission method and system, when the signaling plane access control unit determines that the UE is behind a NAT device, if the offer-SDP message body of the SIP signaling plane control message contains a=setup :xxx line, then modify the value of a=setup line according to the predetermined rules; when receiving the answer-SDP message body of the SIP signaling plane control message contains a=setup:xxx line, the answer-SDP message body and offer ‑The a=setup:xxx line contained in the SDP message body is compared. If the comparison result does not match, a simulated TCP link establishment notification message is sent to the media gateway device controlled by it, and the media gateway device is notified to perform a simulated TCP link establishment. The invention can realize end-to-end high-efficiency transmission of TCP type media flow under the NAT networking environment.

Description

technical field [0001] The present invention relates to the field of communication technology, in particular to a transmission control protocol type session media stream transmission method and system. Background technique [0002] IP Multimedia Subsystem (IMS for short) is the development direction of the core network of the next generation communication network, aiming to realize the integration of fixed and mobile communication networks, and provide rich data and multimedia services for fixed and mobile users. [0003] IMS adopts SIP (Session Initiation Protocol, Session Initiation Protocol) as the session control protocol, and SDP (Session Description Protocol, Session Description Protocol) as the session description protocol. control. [0004] IMS uses the IP network as the bearer network. In the IP network, due to various reasons, such as: the number of IPv4 addresses is exhausted day by day, network security, etc., NAT (Network Address Translation, network address tr...

AI Technical Summary

Problems solved by technology

[0023] First, in current practical applications, for some businesses that use the TCP protocol as the bearer, the size of the media data flow may be massive, such as file transfer, multimedia short message, etc., and the data size involved in a single session may be dozens of megabytes. (Mega) to several G (gigabytes) bytes, etc. When deploying an IMS network, operators do not want these media streams to be introduced into the core network, because these massive data may bring serious network problems to the core network. The impact of data traffic causes delays in related business processing. It is required to realize end-to-end transmission of TCP media streams, and the bypass is outside the core network.

[0024] Second, using the intermediate TCP media server as the forwarding center of the TCP media stream requires each media terminal to establish a TCP connection with the TCP media server first, which will consume a large amount of resources of the TCP media server and make it a potential communication bottleneck. , media stream forwarding at the application layer is relatively inefficient

[0025] In the presence of NAT devices, such as image 3 As shown, if the TCP media stream is simply sent directly from the calling terminal to the called terminal, then when the called terminal is located behind the NAT device, due to the directionality of the NAT device, the TCP link establishment request SYN message from the calling terminal It will not be able to pass through the NAT device corresponding to the called terminal, resulting in the failure to establish a TCP connection and TCP media communication failure

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