WO2009033324A1

WO2009033324A1 - A method of real-time medium data transmission based on tcp protocol

Info

Publication number: WO2009033324A1
Application number: PCT/CN2007/002712
Authority: WO
Inventors: Guoli Yin
Original assignee: Coobol Technologies Co. Ltd
Priority date: 2007-09-13
Filing date: 2007-09-13
Publication date: 2009-03-19

Abstract

A method of real-time medium data transmission based on TCP protocol is provided. Especially a method of medium data crossing the network firewall for real-time data transmission is provided. The method mainly solves the problem that the real-time medium data transmission can not be ensured in the firewall environment that only allows the TCP protocol to go through. The method mainly comprises the steps as follows: connecting the both communication sides through standard TCP protocol stack firstly, then directly sending and receiving data at the both sides through bottom network protocol interface, cutting off the connection after the accomplishment of medium data transmission. The method is able to work with the standard TCP protocol stack in the operating system, which strengthens the practicability of the method. Although the transmission mode can not ensure the reliability of the transmission, it has good capability of real-time transmission, which can improve the quality of medium communication under said network environment.

Description

Method for real-time transmission of media data based on TCP protocol

The present invention relates to the field of network voice/video communication technologies, and in particular, to a method for real-time data transmission through a network firewall that allows only TCP protocol transmission. Background technique

With the development of multimedia processing technology, multimedia applications based on streaming media transmission have been rapidly developed. Media streams such as voice/video require high real-time transmission. Therefore, UDP-based RTP is usually used for transmission. However, in some network environments, network firewalls do not open UDP ports and only allow TCP data. The packet passes, which hinders the transmission of media streams such as voice/video, and limits the voice/video intercommunication between the client in the firewall and the client on the Internet.

In order to enable voice/video communication in this case, it is necessary to use TCP to transmit media data. The existing related solutions include HTTP proxy, SOCKET4/5 proxy, etc., and they solve the transmission problem to some extent, such as QQ. In this case, MSN, etc., can use the proxy to access the Internet, but they are essentially based on the standard TCP protocol, because the reliability guarantee mechanism such as packet loss retransmission of the TCP protocol occupies a large amount of resources and time in the execution process. The overhead of TCP makes the transmission of media data inefficient. Therefore, in this environment, the transmission of media data such as voice/video cannot guarantee real-time performance, and it is difficult to obtain better communication quality.

1

Confirmation Summary of the invention

In view of the above drawbacks of the prior art, the main object of the present invention is to propose a basis based on

The method of transmitting media data in real time by the TCP protocol ensures the real-time transmission of media data under the condition that only the data packets of the TCP protocol are allowed to pass through the firewall, and has good media communication quality.

The invention is realized by the following technical solutions: A method for real-time transmission of media data based on a TCP protocol, first establishing a connection between two communication parties through a standard TCP protocol stack, and then directly transmitting and receiving data through the underlying network protocol interface, media data After the transfer is complete, disconnect.

The method includes the following steps:

A. Two-way connection: The local communication party (source) directly establishes a connection with the other party (target end) through the standard TCP protocol stack; acquires the socket pair information of the connection (source IP, destination IP, source port, target port) , and the SEQ value, ACK value, etc. of the TCP packets of both parties;

B. TCP data packet: The packet module at the source end uses the obtained information to split the data to be sent into an appropriate size according to the MTU value of the network, and encapsulates it into a TCP packet;

C. TCP data transmission: The sending module at the source end delivers the encapsulated TCP data packet to the underlying network protocol interface and sends it to the target end;

D. TCP data processing: The receiving module of the target end receives all TCP data packets, and determines whether the data packet belongs to the TCP data packet constructed by the method. If yes, it is handed over to the application layer for processing, otherwise, it is directly handed over to the system TCP/ Processing of the IP protocol stack; E. Broken connection: After the media data transmission is completed, both parties send the data packet with the FIN flag to disconnect the two parties.

The underlying network protocol interface is located below the TCP layer, above the network card; the operations of the source and destination are interchangeable.

The advantages of the invention are:

1. Instead of using the constructed packet three-way handshake method to establish a TCP connection, the TCP protocol stack provided by the system is directly used to implement the connection with the other party, thus effectively avoiding conflicts with the system selection port number;

2. After both ends of the communication establish a connection through the standard TCP protocol and transfer the status of the data packet directly to the transceiver, the TCP packets are not sent through the interface of the standard TCP protocol stack, but are directly sent through the underlying network interface; The data packet does not pass through the interface of the standard TCP protocol, but directly searches for the data packet sent by the peer end through the underlying protocol interface, and sends the found data packet directly to the application layer for processing;

3. After the data packet is directly sent and received, all packets sent through this standard TCP connection will be discarded to avoid interference from the system's TCP packets to the data packet transmission and reception of this method.

4. This method works with the system standard TCP protocol stack. DRAWINGS

1 is a schematic diagram of a working protocol layer of the present invention;

2 is a flow chart of connection/emission/receipt according to an embodiment of the present invention. detailed description

In order to facilitate the understanding and implementation of the present invention by those skilled in the art, the embodiments of the present invention are further described below in conjunction with the drawings.

Since the transmission of media streams such as voice/video based on the standard TCP protocol consumes a large amount of resources and time overhead, the efficiency of TCP transmission of media data is not high, but the UDP-based RTP protocol transmits media streams such as voice/video. It is often difficult to successfully pass through a firewall that only allows packets of the TCP protocol to pass.

Therefore, the present invention provides a method for real-time transmission of media data based on the TCP protocol, and the media data is converted into a TCP data packet, which can realize efficient transmission of media data through a firewall but bypassing a standard TCP protocol. The purpose of the invention.

The following is an implementation example of the present invention in the Windows 2000/XP environment: Figure 1 is a schematic diagram of the working protocol layer of the present invention, located under the TCP layer and above the network card. Embodiments of the present invention use NDIS intermediate layer drivers to perform packet transmission of TCP, as well as filtering reception of data packets. The NDIS middle layer is between the TCP protocol layer driver and the small port (network card) driver. The upper TCP layer is represented by a virtual microport network card structure, and the lower network card is represented by a protocol layer structure. Therefore, whether it is the data packet received and uploaded by the network card, or the data packet sent by the upper layer (TCP protocol layer) to the network card, it will pass through the NDIS intermediate layer without exception, so it can intercept all network data packets. The invention can thus be implemented and the objects of the invention achieved.

2 is a flow chart of connection/emission/receipt according to an embodiment of the present invention. The specific process is as follows: 1. The sender (source) establishes a connection with the receiver (target end) through the system standard TCP protocol stack at the application layer; 2. The sender (source) application layer obtains the socket pair information of the connection, including the source IP, the destination IP, the source port, and the destination port, and transmits the information to the lower layer driver (NDIS intermediate layer);

3. Establish the data structure information of the connection channel in the driver (NDIS middle layer), allocate the transmission buffer and receive buffer of the channel, maintain a connection channel information link table, and enter the packet capture mode to obtain the MAC addresses of the connection: Seq, Ack and other information;

4. The sender (source) application layer informs the driver (NDIS middle layer) to enter the intercept mode, and internally receives the RST packet in the driver to reset the respective TCP connections.

5. The sender (source) constructs a TCP packet using the obtained socket pair information, transmits it using NDIS technology, and blocks the transmission of system standard TCP packets on the connection.

6. After receiving all the data packets, the receiver (target end) determines whether the data packet belongs to the TCP data packet constructed by the method. If yes, first determine whether the connection has an outstanding IRP read request, if yes, directly The request, otherwise put the data packet into the receiving buffer queue of the connection, and inform the application layer that the data packet has been received; if not, directly release the data packet to the upper layer TCP/IP protocol stack of the system for processing.

7. After the data communication is completed, the active shutdown party can send a data packet with the FIN flag to instruct the other party to disconnect the connection.

In the present invention, the operations of the source end and the target end are interchangeable.

The invention has been tested and implemented, the real-time transmission is good, the speech is very clear, and the object of the invention is achieved.

The above is a preferred embodiment of the present invention, and some similarities and alternatives that can be clearly conceived by those skilled in the art according to the disclosure of the present invention fall within the protection scope of the present invention.

Claims

Claim

A method for real-time transmission of media data based on a TCP protocol, characterized in that a connection between two communication parties is established through a standard TCP protocol stack, and then data is directly transmitted and received through an underlying network protocol interface, and after the media data transmission ends, Open the connection.

The method for transmitting media data in real time based on the TCP protocol according to claim 1, comprising the following steps:

A. The two parties connect: The source directly establishes a connection with the target through the standard TCP protocol stack, and obtains the socket pair information of the connection, and the SEQ value and ACK value of the TCP packets of both parties;

B. TCP data packet: The source packet module uses the obtained information to split the data to be sent into an appropriate size according to the MTU value of the network, and encapsulates it into a TCP packet;

C. TCP data transmission: The sending module at the source end sends the encapsulated TCP data packet to the underlying network protocol interface and sends it to the target end;

D. TCP data processing: The receiving module of the target end receives all TCP data packets, and determines whether the data packet belongs to the TCP data packet constructed by the method. If yes, it is handed over to the application layer for processing, otherwise, it is directly handed over to the system TCP/ Processing of the IP protocol stack;

E. Disconnect: After the media data transmission is completed, the party requesting to turn off sends a packet with the FIN flag to inform the other party to disconnect.

The method for transmitting media data in real time based on the TCP protocol according to claim 2, wherein the step B is further performed before the source end notifies the underlying driver to enter the intercept mode.

The method for transmitting media data in real time based on the TCP protocol according to claim 2, wherein the step C is further performed, and the source end notifies the underlying driver to block the transmission of the system standard TCP data packet on the connection.

The method for transmitting media data in real time based on the TCP protocol according to claim 2, wherein the step D is further performed, before determining whether the connection is incomplete before the TCP packet is handed over to the application layer for processing. The IRP read request, if any, completes the request directly, otherwise the packet is placed in the receive buffer queue of the connection and the application layer is notified that the packet has been received.

The method for real-time transmission of media data based on a TCP protocol according to claim 2 or 3 or 4 or 5, wherein the underlying network protocol interface is located below the TCP layer and above the network card.

The method for real-time transmission of media data based on a TCP protocol according to claim 2 or 3 or 4 or 5, wherein the operations of the source and the destination are interchangeable.