CN101567769A - Data retransmission method, system and peer-to-peer node - Google Patents

Abstract

The embodiment of the invention discloses a data retransmission method, system and peer node. The method is applied in the P2P field, and includes the following steps: receiving a retransmission request message sent by a client, and querying whether the retransmission data requested by the retransmission request message is locally stored according to the retransmission request message; When the data requested to be retransmitted by the data retransmission request message is stored, the data is sent to the client. The embodiments of the present invention can realize data packet loss and error packet retransmission without a large amount of participation of the content source, improve transmission efficiency, and reduce the burden of the content source and the peer node acting as its agent.

Description

Data retransmission method, system and peer node

technical field

The present invention relates to network communication technology and is applied in the field of P2P technology, in particular to a data retransmission method, system and peer-to-peer node.

Background technique

Using P2P (Peer-to-Peer, peer-to-peer network) technology, two or more PCs or other devices located in the P2P network can directly communicate or cooperate, and share resources (such as processing power, storage space and data, etc.). The essence of P2P technology is distributed computing. Its biggest feature is that the capabilities of each computer (especially the client device) on the network can be fully utilized, reducing the number of problems in the traditional Client/Server (client/server) network system. In the structure, the expensive expenditure (including software, hardware, communication, and human input, etc.) required by the server also avoids problems such as computing capacity bottlenecks and single point failures that may be caused by the use of servers. After adopting P2P technology, the network system has lower operating costs and higher expansion capabilities.

Referring to Figure 1, it is a schematic diagram of a P2P overlay network (P2P Overlay) network with a Peer (node)-Client (client) structure. Among them, all Peer nodes form a P2P overlay network, which has functions such as P2P search and routing; the Client is hung under the Peer node, and interacts with other Peers or Clients through the routing and search functions of the Peer node. A relatively stable network device that supports P2P technology can be used as the Peer node of the P2P overlay network, which is responsible for distributed storage and search indexed by resource content in the P2P overlay network. The network devices of the nodes conduct interactive negotiation without the need to perceive the specific topology and operating mechanism of the P2P overlay network. In this way, the interaction between the terminal nodes connected to different network devices is isolated through the relatively stable network device, and the mutual influence caused by the interaction is reduced. Each network device saves a local resource table, a transaction table, a forwarding table, and a key/value pair (Key/Value) table, etc.; among them, the local resource table is used to record the local (each terminal node attached to the network device) that can provide services The resource information; the transaction table is used to manage the forwarding information corresponding to each resource content; the forwarding table is used to provide forwarding information when the network device hardware forwards; the Key/Value table is used to record the resource information published on the P2P overlay network (for each A resource can be uniquely identified by an identifier key, such as hashing the file name through a hash function, a key that uniquely identifies the file can be obtained, etc.). Using network devices supporting P2P technology as Peer nodes can intelligently act as an agent for terminal node business needs and provide corresponding network services.

When the real-time service (such as IPTV) is transmitted on the P2P network, the P2P network needs to provide QoS guarantee, so the real-time service is sensitive to the delay, packet loss and error packet of the P2P network. But there is currently no practical solution in the industry to solve this problem.

Contents of the invention

Embodiments of the present invention provide a data retransmission method, system, and peer-to-peer node to solve the problem of data retransmission after packet loss or packet error occurs on a transmission path from a data source to a terminal user in a P2P network.

The data retransmission method described in the embodiment of the present invention includes:

Receive the retransmission request message sent by the client,

Query whether the retransmission data requested by the retransmission request message is locally stored;

When the data requested to be retransmitted by the data retransmission request message is locally stored, the data is sent to the client.

The system described in the embodiment of the present invention includes:

The client is used to send a retransmission request message;

The first peer node is configured to receive the retransmission request message sent by the client, and query whether the retransmission data requested by the retransmission request message is locally stored; When uploading data, send the data to the client.

The peer-to-peer nodes described in the embodiments of the present invention include:

a receiving unit, configured to receive a retransmission request message;

a query unit, configured to query whether the retransmission data requested by the retransmission request message is locally stored;

A sending unit, configured to send the data requested by the retransmission message when the query unit determines that the data requested by the retransmission message is locally stored. The embodiment of the present invention is based on the current situation that the performance of the P2P network is not too stable. By setting a storage module or a side-mounted storage server on the peer node as the client and the content source agent in the P2P network, data errors occur during the content transmission process. Or when it is lost, the client only needs to send the retransmission request message to the peer node serving the client. When the peer node serving the client stores the data requested by the client for retransmission, there is no need for a large number of content sources Participation can realize data packet loss and error packet retransmission, which improves transmission efficiency and reduces the burden on content sources and peer nodes acting as their agents.

Description of drawings

FIG. 1 is a schematic diagram of a P2P overlay network with a Peer-Client structure provided by the prior art;

FIG. 2 is a schematic structural diagram of a data retransmission system provided by an embodiment of the present invention;

FIG. 3 is a flowchart of a data retransmission method provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a peer node provided by an embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in FIG. 2 , it is a schematic structural diagram of a data retransmission system provided by an embodiment of the present invention. The system includes a content provider 201, which is used to provide content to the P2P network; peer nodes (202, 203) are network devices supporting P2P technology, and serve as network nodes of the P2P overlay network, providing content for the client 206 and the content provider 201. Connect to the business interface of the P2P overlay network, the proxy client 206 and the content provider 201 participate in P2P network activities and provide network services to the client 206, specifically in this embodiment, the peer node 202 connected to the content provider 201 is used to use The content information provided by the content provider 201 is published on the P2POverlay, and the data is provided to the storage server 204 and the peer node 203 receiving the data at the same time when the data is transmitted; the peer node 203 connected to the client 206 is used to The request of the client 206 provides services to it, and after receiving the retransmission request message of the client 206, data retransmission is performed to the client 206; the storage server 204 is used to store the content received by the peer node 202, and the storage server 205 uses To store the content received by the peer node 203; the client 206 is used to initiate a content request, and perform packet loss and error packet detection while receiving the requested content. The node 203 initiates a retransmission request message, and receives the data retransmitted by the peer node 203.

The above-mentioned storage servers (204, 205) also have a packet loss and error packet detection function, which is used to initiate a retransmission request message to the peer node (202, 203) connected to it after finding a packet loss and error packet, and receive the peer node Retransmit the data of (202, 203).

The above-mentioned devices detect packet loss by detecting the serial number of the data, and detect error packets by detecting the checksum of the data.

As shown in FIG. 3, it is a flow chart of the data retransmission method provided by the embodiment of the present invention. The method of this embodiment is applied in P2P Overlay. The P2P Overlay does not require the content provider and client to support P2P technology, but the peer-to-peer node (Peer) that supports P2P technology and acts as a node (Peer) of the P2P network acts as an agent for the content provider and client to complete information interaction with other devices. That is, content providers and clients only need to know the peer nodes they are connected to, and they can obtain services from the P2P network without knowing other nodes in the P2P Overlay.

When the client 206 needs to obtain a certain resource from the P2P Overlay, such as a movie resource named Q, the client 206 sends a request to obtain the movie Q to the peer node 203, and the peer node 203 finds The movie Q can be found through the peer node 202, so a request to obtain the movie Q is sent to the peer node 202. Since the movie Q is actually stored on the content provider 201, the peer node 202 needs to obtain the movie Q from the content provider 201 , and store the content of the movie Q on the storage server 204 and send it to the peer node 203 at the same time, and the peer node 203 stores the content of the movie Q on the storage server 205 and send it to the client 206 at the same time. In the above process of transmitting the movie Q, in order to solve the problems caused by avoiding packet loss and error packets, the data retransmission method adopted in the embodiment of the present invention includes the following steps:

S301, the client 206 detects the received data while receiving data from the peer node 203 connected to it, and after finding data loss (packet loss) or data transmission error (wrong packet), it sends a retransmission to the peer node 203 Send a request message, carrying packet loss/error packet information, requesting to retransmit lost data or send wrong data.

Specifically, the client 206 detects the serial number of the data (according to the different transmission protocols, it may be the serial number of the real-time transport protocol (Real-time Transport Protocol, RTP) or the serial number or byte serial number of other transmission protocols) Packet loss is found, and error packets are found by checking the checksum of the data.

S302. After receiving the retransmission request message, the peer node 203 inquires whether the storage server 205 stores the retransmitted data requested by the retransmission request message. If yes, execute step S303; if not, execute step S304.

S303 , the peer node 203 obtains from the storage server 205 the data requested by the client 206 for retransmission, and then sends the data to the client 206 .

S304. The peer node 203 searches for a peer node that provides the content requested by the client 206, that is, the movie Q, and finds the peer node 202.

S305. The peer node 203 sends a retransmission request message to the peer node 202 providing the movie Q, requesting to send the data requested by the sending client 206 for retransmission.

S306. After receiving the retransmission request message, the peer node 202 inquires whether the storage server 204 stores the retransmission data requested by the retransmission request message. If yes, execute step S307; if not, execute step S309.

S307 , the peer node 202 sends the data to the peer node 203 after acquiring the data requested by the peer node 203 to retransmit from the storage server 204 .

S308. After receiving the data, the peer node 203 sends the data to the storage server 205 and the client 206, and the storage server 205 stores the data.

S309. The peer node 202 sends a retransmission request message to the content provider 201, requesting to send the data requested by the peer node 203 for retransmission.

S310. After receiving the data requested for retransmission from the content provider 201, the peer node 202 sends the received data to the peer node 203 and the storage server 204. After receiving the data, the peer node 203 sends the data to the storage server 205 and the client 206, and the storage server 205 stores the data.

S311. The storage server 204 stores the received data.

In this embodiment, the content provider 201 first informs the peer node 202 that it can provide the movie Q, and the peer node 202 records the corresponding relationship between the content provider 201 and the movie Q, and publishes that it can provide the movie on the P2POverlay Q news.

In the embodiment of the present invention, the storage server may also have the capability of packet loss/error packet detection. When the storage server detects data loss or data transmission error, it sends a retransmission request message to the peer node connected to itself. After the peer node connected to the storage server receives the data retransmission request message sent by the storage server, if it connects The content provider requests the content provider to retransmit the data requested by the storage server. If it is not connected to the content provider, it requests other peer nodes that provide the content to retransmit the data requested by the storage server. The storage server stores the retransmitted data requested by itself.

The storage server in the embodiment of the present invention may be a storage module integrated on the peer node, or may be an independent storage server connected to the peer node.

As shown in FIG. 4, a schematic structural diagram of a peer-to-peer node provided by the embodiment of the present invention includes:

A receiving unit 41, configured to receive a retransmission request message;

A query unit 42, configured to query whether the retransmission data requested by the retransmission request message is locally stored;

A sending unit 43, configured to send the data when the query unit 42 determines that the data requested by the retransmission message is locally stored;

The storage unit 44 is configured to store the data received by the receiving unit.

The embodiment of the present invention is based on the current situation that the performance of the P2P network is not too stable. By setting a storage module or a side-mounted storage server on the peer node as the client and the content source agent in the P2P network, data errors occur during the content transmission process. Or when it is lost, the client only needs to send the retransmission request message to the peer node serving the client. When the peer node serving the client stores the data requested by the client for retransmission, there is no need for a large number of content sources Participation can realize data packet loss and error packet retransmission, which improves transmission efficiency and reduces the burden on content sources and peer nodes acting as their agents.

The above is only a preferred embodiment of the present invention. For those of ordinary skill in the art, without departing from the principles of the present invention, any modifications, equivalent replacements and improvements should be included in this document. within the scope of protection of the invention.

Claims (15)

1, a kind of data repeating method is applied to it is characterized in that in the P2P network, comprising:

Receive the retransmission request message that client sends,

Whether inquiry is local stores the data of described retransmission request message institute request retransmission;

When this locality stores the data of described data re-transmission request message institute request retransmission, described data are sent to client.

2, data repeating method according to claim 1 is characterized in that, described method also comprises:

When described data are not stored in this locality, send described retransmission request message to the data source end, receive the described data that described data source end resends, described data are sent to client.

3, data repeating method according to claim 1 is characterized in that, before client sent retransmission request message, described method also comprised:

Client receives data according to own content of being asked, and the data that receive are detected, when detecting loss of data or error in data, and the structure retransmission request message.

4, data repeating method according to claim 2 is characterized in that, the retransmission request message that described reception client sends is specially:

The peer node of serving client receives the retransmission request message that client sends;

Describedly send described retransmission request message to the data source end and be specially:

The peer node of serving client sends retransmission request message to the peer node of serving content providers.

5, data repeating method according to claim 4 is characterized in that, the data that described reception data source end resends are specially:

The peer node of serving client receives the data of the peer node transmission of serving content providers.

6, data repeating method according to claim 3 is characterized in that, the retransmission request message that described reception client sends is specially:

The peer node of serving content providers receives the retransmission request message of the client transmission of the peer node forwarding of serving client;

Sending described retransmission request message to the data source end is specially:

Serve the peer node of content providers and transmit the retransmission request message that receives to content providers.

7, data repeating method according to claim 6 is characterized in that, the data that reception data source end resends are specially:

Serve the data of the peer node received content provider transmission of content providers;

Described data are sent to client to be specially:

The peer node of serving content providers sends to client by the peer node of serving client with described data.

8, according to any described method in claim 1 or 2, it is characterized in that, be specially according to the local data that whether store described retransmission request message institute request retransmission of described retransmission request message inquiry:

Inquire about the data that whether store described retransmission request message institute request retransmission on locally-attached caching server according to described retransmission request message.

9, method according to claim 1 and 2 is characterized in that, receives after the described data that described data source end resends, and described method also comprises: the described data of buffer memory on local or locally-attached caching server.

10, a kind of network system is characterized in that, comprising:

Client is used to send retransmission request message;

First peer node is used to receive the retransmission request message that client sends, and whether inquiry is local stores the data of described retransmission request message institute request retransmission; When this locality stores the data of described data re-transmission request message institute request retransmission, described data are sent to client.

11, network system according to claim 10 is characterized in that, described client also was used to detect the data of reception before sending retransmission request message, when detecting loss of data or error in data, generates retransmission request message;

Described network system also comprises the data source end, when described data are not stored in described first peer node this locality, sends retransmission request message to described data source end;

Described data source end is used to receive the retransmission request message that first peer node sends, and sends the data that it is asked to first peer node.

12, network system according to claim 10 is characterized in that, described data source end is second peer node or content providers;

Described first peer node is the peer node of serving client;

Described second peer node is the peer node of serving content providers;

Described content providers also is used for providing content by described second peer node to described network system.

13, according to claim 10 or 11 described network systems, it is characterized in that, also comprise:

First storage device is used to store the data that first peer node receives;

Second storage device is used to store the data that second peer node receives.

14, a kind of peer node is characterized in that, comprising:

Receiving element is used to receive retransmission request message;

Query unit is used to inquire about the local data that whether store described retransmission request message institute request retransmission;

Transmitting element is used for when query unit determines that this locality stores the data that described resend messages asks described data being sent.

15, peer node according to claim 14 is characterized in that, described receiving element also is used to receive data;

Described peer node also comprises memory cell, is used to store the data that receiving element receives.

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