CN105227276A - A method of peer-to-peer network data transmission based on UDT - Google Patents

Abstract

The invention discloses a kind of peer-to-peer network data transmission method based on UDT, comprise the following steps: A, client and server connect, become in peer-to-peer network the node having Unique ID; B, client, as recipient node, connect with the multiple sending nodes preserving self resource requirement; C, multiple sending node send the packet comprising different resource content respectively to receiving node, and sending node is the amount of bandwidth that transmitting channel distributes according to the type decided sending data; D, receiving node receiving package containing the packet of resource requirement content, and notify the packet of sending node retransmission of lost.The present invention, by distinguishing the data type transmitted between peer network node, takes different transmissions and receive mode to the transmission of real time data and general data, effectively improves transmission rate and the transmission reliability of real time data.

Description

A method of peer-to-peer network data transmission based on UDT

technical field

The invention relates to the technical field of peer-to-peer network node communication in a streaming media on-demand system, in particular to a UDT-based peer-to-peer network data transmission method.

Background technique

At present, the mainstream online transmission protocol usually adopts the TCP protocol at the transport layer, but the TCP protocol has the following disadvantages: First, TCP cannot perform NAT (Network Address Translator, Network Address Translation) penetration, while the internal nodes of the peer-to-peer network and the external network communicate normally. When communicating, it may be necessary to use NAT penetration technology. If other transmission protocols that reuse the TCP protocol are used, codes need to be added in the application layer, and the implementation process is quite complicated. Secondly, TCP is a reliable connection-oriented transport layer protocol, but online transmission such as Video-on-demand and other major requirements require a smooth picture. The congestion control algorithm of TCP can ensure the reliability of transmission. However, for real-time data, retransmitting lost data packets is of little significance. TCP’s continuous retransmission of data can only aggravate network congestion. Causing video playback freezes and affecting user experience.

UDT is a UDP-based data transfer protocol (UDP-basedDataTransferProtocol, referred to as UDT), UDP is an unreliable transfer protocol for connectionless, itself has NAT penetration function, using it to transmit real-time data can guarantee the transmission speed. Applying UDT to peer-to-peer network data transmission can support reliable data stream transmission and partially reliable datagram transmission at the same time, but there is no distinction between real-time data and ordinary data during transmission, and real-time data cannot be guaranteed when it is transmitted online sexual demands.

Contents of the invention

The purpose of the present invention is to provide a UDT-based peer-to-peer network data transmission method, which can improve the transmission efficiency of real-time data between peer-to-peer network nodes and ensure the reliability of online transmission.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A UDT-based peer-to-peer network data transmission method, comprising the following steps: A, the client sends a connection request to the server, after establishing a connection with the server through the four-way handshake protocol, the client obtains a unique ID mark and becomes a peer-to-peer network A node in , then go to step B;

B. The client sends a request containing the required resource information to the server, and the server selects all nodes containing the required resource information from the node list saved by itself according to the request sent by the client, and feeds back the ID number of the selected node to The client, the client establishes connections with multiple resource nodes according to the received node ID number, wherein the client is used as the receiving node, and the multiple resource nodes connected with the client are used as the sending nodes, and then enters step C;

C. Multiple sending nodes in step B send data packets containing different resource contents to the receiving node respectively. Data type flags are added to the data packets. The data type flags are used to distinguish real-time data from ordinary data. When the sending node does not receive When sending data from other nodes, the sending channel of the sending node occupies the entire bandwidth. When the sending node receives data from other nodes at the same time, if the data sent by the sending node is real-time data, the sending node allocates more than 1/2 of the sending channel bandwidth, if the data sent by the sending node is ordinary data, the sending node allocates less than 1/2 of the bandwidth for the sending channel, and then enters step D;

D. The receiving node receives the data packet containing the required resource content. When a data packet is lost, the sequence number of the lost data packet is stored in the lost link list of the receiving end, and the receiving node sends a negative response signal to the sending node to notify the sending node to retransmit the packet.

In the described step D, the receiving node judges its data type according to the data type flag bit of the lost data packet, if the lost data packet is real-time data, directly the sequence number of the lost data packet is deleted from the receiving end loss linked list, and the receiving node sends a message to the sending node Sending the discarding signal of the lost data packet means notifying the sending node that it does not need to retransmit the data packet. If the lost data packet is normal data, the receiving node sends a negative acknowledgment signal to the sending node to notify the sending node to retransmit the data packet.

In the step B, the client receives the ID numbers of a plurality of resource nodes, and the client sends a handshake request packet to the resource nodes corresponding to all node ID numbers, and sets the number N of resource nodes to be connected, and the resource After receiving the handshake request packet, the node sends a handshake response packet to the client respectively, and the client establishes a connection with the N resource nodes that sent the above handshake response packet according to the first received N handshake response packets.

In the step B, when the client sends a handshake request packet to the resource node, if the resource node is provided with a firewall, the server forwards the handshake request packet to the resource node instead of the client to perform NAT penetration, and the resource node receives the handshake Send a handshake response packet to the client after the request packet.

The invention applies the UDT protocol to the data transmission of the peer-to-peer network, so that it can support reliable data stream transmission and partially reliable datagram transmission at the same time, and by distinguishing the data types transmitted between peer-to-peer network nodes, real-time data and common The transmission of data adopts different transmission methods, which effectively improves the transmission rate and reliability of real-time data.

Description of drawings

Fig. 1 is a schematic flow chart of the present invention.

detailed description

As shown in Figure 1, a kind of UDT-based peer-to-peer network data transmission method of the present invention comprises the following steps: A, the client sends a connection request to the server, after establishing a connection with the server through the four-way handshake protocol, the client Obtain a unique ID token, become a node in the peer-to-peer network, and proceed to step B.

B. The client sends a request containing the required resource information to the server, and the server selects all nodes containing the required resource information from the node list saved by itself according to the request sent by the client, and feeds back the ID number of the selected node to The client, the client establishes connections with multiple resource nodes according to the received node ID number, wherein the client is used as the receiving node, and the multiple resource nodes connected with the client are used as the sending nodes, and then enters step C.

In step B, because the client receives all the node ID numbers containing the required resource information saved by the server, in order to improve the efficiency of establishing a connection, the client can send a handshake request packet to the resource nodes corresponding to all node ID numbers, and at the same time Set the number N of resource nodes to be connected to. If the resource node is equipped with a firewall, the server forwards the handshake request packet to the resource node instead of the client, and the resource node sends a handshake response packet to the client after receiving the handshake request packet. According to the first received N handshake response data packets, the client correspondingly establishes connections with the N resource nodes that sent the above handshake response data packets.

C. Multiple sending nodes in step B send data packets containing different resource contents to the receiving node respectively. Data type flags are added to the data packets. The data type flags are used to distinguish real-time data from ordinary data. When the sending node does not receive When sending data from other nodes, the sending channel of the sending node occupies the entire bandwidth. When the sending node receives data from other nodes at the same time, if the data sent by the sending node is real-time data, the sending node allocates more than 1/2 of the sending channel bandwidth, if the data sent by the sending node is normal data, the sending node allocates less than 1/2 of the bandwidth for the sending channel, and then enters step D.

In step C, since the peer-to-peer network node using UDT protocol may have multiple sockets, the sending node can also receive data from other nodes while sending data. If the data sent by the sending node is real-time data, and the real-time data Transmission requires high real-time performance, so priority should be given to ensuring the real-time data transmission rate between the sending node and the receiving node, that is, by judging whether the sending node is receiving data from other nodes and the type of data that the sending node is sending, the allocation to the sending node is determined. The bandwidth of the channel is sufficient to ensure the transmission rate of real-time data.

D. The receiving node receives the data packet containing the required resource content. When a data packet is lost, the sequence number of the lost data packet is stored in the lost link list of the receiving end, and the receiving node sends a negative response signal to the sending node to notify the sending node to retransmit the packet.

Since the transmission of real-time data requires real-time arrival, if the real-time data is lost during transmission, it is of little significance for the sending node to retransmit the data, which will instead increase the burden of network transmission and even lead to network congestion. In step D, the receiving node can judge its data type according to the data type flag bit of the lost data packet. If the lost data packet is real-time data, directly delete the sequence number of the lost data packet from the lost link list of the receiving end, and the receiving node sends the data type to the sending node. The discarding signal of the lost data packet is to notify the sending node that the data packet does not need to be retransmitted. If the lost data packet is normal data, the receiving node sends a negative response signal to the sending node to notify the sending node to retransmit the data packet.

In the present invention, the receiving node selectively sends a negative acknowledgment signal of the missing data packet to the sending node by distinguishing the data type of the missing data packet, so that the lost data packet retransmitted by the sending node is limited to ordinary data, which is conducive to improving the efficiency of real-time data transmission. Efficiency, especially for the transmission of online data such as video on demand, can achieve better playback effects. The invention adopts different sending and receiving modes for the transmission of real-time data and ordinary data by distinguishing the data types transmitted between peer-to-peer network nodes, thereby effectively improving the transmission rate and reliability of real-time data.

Claims (4)

1. A peer-to-peer network data transmission method based on UDT, it is characterized in that, comprises the following steps: A, client sends connection request to server, after setting up connection with server by four-way handshake protocol, client obtains a unique ID flag, become a node in the peer-to-peer network, and then enter step B; B. The client sends a request containing the required resource information to the server, and the server selects all nodes containing the required resource information from the node list saved by itself according to the request sent by the client, and feeds back the ID number of the selected node to The client, the client establishes connections with multiple resource nodes according to the received node ID number, wherein the client is used as the receiving node, and the multiple resource nodes connected with the client are used as the sending nodes, and then enters step C; C. Multiple sending nodes in step B send data packets containing different resource contents to the receiving node respectively. Data type flags are added to the data packets. The data type flags are used to distinguish real-time data from ordinary data. When the sending node does not receive When sending data from other nodes, the sending channel of the sending node occupies the entire bandwidth. When the sending node receives data from other nodes at the same time, if the data sent by the sending node is real-time data, the sending node allocates more than 1/2 of the sending channel bandwidth, if the data sent by the sending node is ordinary data, the sending node allocates less than 1/2 of the bandwidth for the sending channel, and then enters step D; D. The receiving node receives the data packet containing the required resource content. When a data packet is lost, the sequence number of the lost data packet is stored in the lost link list of the receiving end, and the receiving node sends a negative response signal to the sending node to notify the sending node to retransmit the packet. 2. a kind of UDT-based peer-to-peer network data transmission method as claimed in claim 1, is characterized in that: in the described step D, receiving node judges its data type according to the data type sign position of loss data packet, if loss data The packet is real-time data, directly delete the sequence number of the lost data packet from the lost linked list of the receiving end, and the receiving node sends the discarding signal of the lost data packet to the sending node, that is, notifies the sending node that it does not need to retransmit the data packet, if the lost data The packet is normal data, and the receiving node sends a negative acknowledgment signal to the sending node to notify the sending node to retransmit the data packet. 3. a kind of UDT-based peer-to-peer network data transmission method as claimed in claim 2, is characterized in that: in described step B, client receives the ID number of a plurality of resource nodes, and client sends all node ID numbers The corresponding resource node sends a handshake request packet, and sets the number N of resource nodes to establish a connection. After receiving the handshake request packet, the resource node sends a handshake response packet to the client respectively. The N handshake response data packets correspondingly establish connections with the N resource nodes that sent the above handshake response data packets. 4. a kind of UDT-based peer-to-peer network data transmission method as claimed in claim 3 is characterized in that: when the client sends the handshake request packet to the resource node in the described step B, if the resource node is provided with a firewall, Then the server forwards the handshake request packet to the resource node instead of the client to perform NAT penetration. After receiving the handshake request packet, the resource node sends a handshake response packet to the client.