DE102008028591A1 - Method for uninterruptible video stream communication from server computer to client computer, involves executing application program transmitted from computer to client computer, and utilizing offered service by client computer - Google Patents

Abstract

The method involves transmitting a network address of a corresponding computer (2.1) from a server computer (10) to a client computer (1.1). The client computer is connected to the computer so that the computer is a father node of the client computer. A request is forwarded from the server computer to the computer. An application program (11) e.g. Java(RTM: object-oriented programming language) applet, enabling use of a service is transmitted from the computer to the client computer. The program is executed, and the offered service is used by the client computer.

Description

The The invention relates to a method for uninterrupted data transmission, in particular of video streams, of at least one server computer to a client machine.

Known Audio servers, such as iTunes, or video servers, like You-Tube the possibility the audio or video files worldwide and at any time of day and night to download and to listen or to watch. However, need the users have a corresponding player that downloaded that must be installed and configured. Also, if the player already installed on the computer of the user is the audio / video file only completely downloaded. This means live transmission in real time not possible.

Furthermore It is a goal of such video servers to reach as many users as possible. Will the user capacity reached a video server, the operator must be a set up, install and finance another video server to continue for the users stay attractive.

at an explosive access to a specific video file, for example the latest music video from Coldplay, users inform others Interested about the presence of such a video, what in the shortest possible time Time great Requests from the server must be coped with. This is called as an unwanted denial of service attack. As a denial of service (DoS, for example German: refusal of service) one calls one Attack on a host (server) or other computer in one Data network with the aim of rendering one or more of its services unable to work. This happens just by overload.

With known client / server streaming system is only the possibility sufficient server set up to cope with such a rush to be, d h. the system must be designed in such a way that this also a maximum access is sufficiently dimensioned. However, this is very high Costs connected. With minimal access, the unused resources are of the network broke.

Of the The invention is based on the object of providing a method for that live broadcasts in real time and cost-effective is.

The The object is solved by the feature of independent claim 1.

The The invention relates to a method for uninterrupted data transmission from at least one first server computer with a service at least a first client computer. First, the first client computer sends a request for the service to the first server computer. The server computer transmits the network address a corresponding computer to the first client computer. To Receiving the network address will be the client machine with the appropriate Computer connected such that the corresponding computer is a parent node of the first client computer. The first server computer can do this manage and maintain the network structure, ie the connection of the first client computer to the appropriate computer can in the first Server computer to be deposited. The request of the first client computer is forwarded from the first server computer to the appropriate computer. Next follows the transfer an application program, such as a plug-in for one Browser or a Java applet, from the appropriate computer to the first client computer, wherein the application program uses the Service allows. The transfer the application program can be done automatically, and then it possible If this program is also successful after the transfer has taken place to start.

The Idea of the invention is based on that home network meanwhile high data bandwidths of up to 16 Mbit download and up to 4 Mbit upload has. Future are even higher Data bandwidths to be expected. So-called flaterates are lump sum payments for the Use of the Internet access, whereby the connection costs are independent of the connection duration to the Internet or the amount of data transferred. With the present invention, thus a real-time audio / video data transmission be realized from client to client, in which the decentralized computer the users and their Internet bandwidths are exploited. Alone the Server computer managed and monitored the network structure of such peer-to-peer streaming. Corresponding the server computer responds to, for example, natural failures. Of the Invention underlying tree structure grows accordingly when needed and thus binds all the more private computers into the tree structure one the higher access to the services; especially videos, are. Thus is only one server needed who has the corresponding services including application programs, to allow explosive access to certain data. Furthermore does not have to be big static Network structure maintained and maintained.

Further advantageous embodiments of the invention are given in the dependent claims.

A advantageous embodiments of the invention is to use the video data streams Real Time Streaming Protocol.

The Real Time Streaming Protocol (RTSP) is a network protocol to Control of continuous and mostly uninterrupted transmission of audiovisual data (streams) or software over IP-based networks. An advantageous embodiment of the invention is as an application program to use a signed Java applet.

These Java applets are small, can be loaded quickly, and run automatically after downloading. Similar applications are DHTML, Microsoft ^® Silverlight and Flash player.

A advantageous embodiments of the invention is the data stream buffers the service so on the first client computer that the service can continue to be used for a certain period of time if the data stream is interrupted is.

This has the advantage that, for example, 30 s long video sequences in Buffer in stock lie to allow the server to restructure the network tree can organize and until the reconnection between one Father and the child node the video is running without interruption. To reconnection between father and child may be the buffer accordingly filled because the data transfer rate is higher as the for the video signal needed Data rate.

A advantageous embodiments of the invention is the first Client computer in dependence of certain parameters as parent node in the tree structure disposal to deliver.

This have the advantage of making the tree structure dynamic, for example to grow as a result of high load levels. It can be a second Client the same file - the same Video - download want and therefore start the inquiry with the server computer. This Detects that the first client has the video file locally there has and transfers accordingly the second client, the network address of the first client, so that the first client opposite the second client acts as a server. The second client will be in the tree structure as a branch or as a child of the first client incorporated. After the application program is also local to the disk of the first client machine can bind to another Calculator to the first client computer this other computer is not only the video streams received from the first client computer but also the application program.

nowadays One finds in almost all households, over a modern Internet connection such as DSL or cable, a small box (the router) used for switching to the Internet responsible is. To allow several computers simultaneous access to the Internet, In most cases, Network Address Translation (NAT) is used. Many private Internet addresses are translated into a few (usually one) public ones. The NAT router maintains then for Each connection contains an entry in a table for incoming packets to assign to the respective internal computer. This works fine, as long as connections are actively opened from within the network (eg retrieving a website).

As soon as but from outside (second client) on a service in the home network - here first Client - access wants, NAT becomes a problem. There no internal computer the connection NAT does not know to which computer incoming Packages should be forwarded. To services in the home network To make accessible, a way has to be found, over which NAT communication with a service. This problem will as the NAT / Firewall Traversal issue designated.

This Problem can be overcome for example by hole-punching technique become. Hole punching is a networking technique for connecting two participants connected to different network structures are and are located behind a firewall. There can be the first and the second client sends a request to the server knows the Server for assigns this IP address and port number and passes these corresponding IP addresses and port number of the one client the other client. Now, the first of them can be data packets to the second client. Because the first client is now using valid port number can, these are accordingly from the Firewall of the second Client approved so that incoming data packets are accepted.

A advantageous embodiments of the invention is the readiness available as a parent node from the running time of the video player, from the network bandwidth of the father node, of the burden of the father node and / or the remaining term of the available dependent service close.

So a newly-integrated client is sent to the reserve bank, as long as these conditions are not fulfilled. This will make unnecessary restructuring the network avoided, which occur when a user only briefly Video has played and then his computer from the tree structure removed by switching off. The knowledge is exploited, that the longer a user watches a video, the more likely it is that this user stays online.

An advantageous embodiment of the invention is, in case of failure of a child node with n children's child node connected the first server computer, the tree structure is redesigned such that a suitable child child node is selected. This selected child child node is the new child node from the remaining child child nodes and this new child node is connected to a parent node, where n ∈ N = {1, 2, ..., n _max } and n _{max is} the maximum allowable number of child nodes at one Father node is.

For example, the second client machine can tolerate only 10 more clients connected to that second client machine without the quality of the service - showing videos - degrading. n _max is different for each client computer, as this number depends among other things on the computer performance, hard disk capacity and / or data bandwidth. The father node can also be the first server computer. It is conceivable to provide a second (or even a third, etc.) server computer, which has the same functions as the first server computer. This would allow these server computers to be deployed at different locations around the world and thus limit the time differences that inevitably occur in data transfers from Australia to Germany.

The Invention is by means of an embodiment with reference to the schematic drawing closer explained. There shows the

figure a tree structure of a peer-to-peer streaming system.

The figure shows a tree structure of a peer-to-peer streaming system. In the upper half of the figure is a first server computer 10 with a java applet 11 and / or a browser plugin 12 , To the server 10 is a first client 1.1 involved. This first client 1.1 is the child node to the server 10 , On this server 10 are a total of m child nodes 1.1 - 1.m integrated (for simplicity, only three computers are shown).

At the very first request to the server 10 No computers are involved at all, so the server 10 at a request from the computer 1.1 whose url (network address) receives.

Again, a request from the computer 2.n on the server 10 so can the server 10 for example, the url of the calculator 1.1 to hand over. This halves the data transmission of the server 10 already half, using only one tree with a depth of one. The depth can be any size.

However, the requests to the server 10 first met directly by this, the server can quickly reach its performance limits. The server 10 recognizes after the calculator 1.1 to 1.m are involved, that he has reached his performance limits.

For example, the calculator starts 2.1 a request to watch a Coldplay video. This coldplay video is already running on the computer 1.1 , The video is already locally on the hard disk of the computer 1.1 , The server hands over the computer 2.1 the internet address of the computer 1.1 , and bind this calculator 2.1 (second client) as a child node to the computer 1.1 (first client). The server stores the source of the data stream (parent node) and the bandwidth of the client.

The computer 1.1 now has two roles. On the one hand, he is the first client and gets his data directly from the server 10 and on the other hand is this calculator 1.1 Server for the computer 2.1 ,

If there are any further inquiries for the Coldplay video, then these computers will work 2.n according to the calculator 2.1 to the computer 1.1 Tied and served by this.

Meanwhile, the Coldplay video is on the computer 1.1 has expired and the user switches off his device, so that this device is no longer available for data transmission.

For example, by sending regular (every 10 seconds) a hard beat message from the first server to the active server - like the machine 1.1 ., recognizes the first server 10 the calculator 1.1 is no longer available. Because the video signal on the child node from the calculator 1.1 locally buffered goods (eg 30 seconds video sequence), the users of the calculator remember 2.1 to 2.n not the failure of the computer 1.1 ,

Since the first server keeps the tree structure up to date, it knows a potential server - like. computer 2.1 , This calculator 2.1 For example, it is set one level higher in the tree structure, taking the place of calculator 1.1 one, ie the first server 10 is now father node of calculator 2.1 , The remaining computers 2.2 to 2.n be directly to the computer 2.1 tethered as a child's knot, as shown in the lower half of the figure hinted. The restructuring is faster than the video sequence stored in the buffer.

Because the first server 10 (P2P management server) knows the current state of the tree structure, the first server 10 Monitor the bandwidth usage or even predict what future bandwidths will be needed. Dement speaking, the tree can be restructured to evenly distribute the load or intercept anticipated loads in the future.

Claims (11)

Method for uninterrupted data transmission from at least one first server computer ( 10 ) with a service to at least a first client computer ( 1.1 ) with the following steps: a.) request for the service from the first client computer ( 1.1 ) to the first server computer ( 10 ), b.) Transmission of the network address of a corresponding computer from the first server computer ( 10 ) to the first client computer ( 1.1 ), c.) connection of the first client computer to the corresponding computer, so that the corresponding computer is the parent node of the first client computer, d.) forwarding the request from the server computer ( 10 ) to the appropriate computer, e.) transmission of an application program ( 11 . 12 ) from the corresponding computer to the first client computer ( 1.1 ), wherein the application program enables the use of the service, and f.) execution of the application program, whereby the service offered by the first client computer is used. The method of claim 1, wherein the service is that of Video streams is. The method of claim 2, wherein the video data streams by means of real time streaming protocol (RTSP). Method according to at least one of the preceding claims, wherein the application program a signed Java applet and / or a plug-in for an internet browser is. Method according to at least one of the preceding claims, wherein in step f) the data stream of the service in such a way on the first client computer ( 1.1 ) is buffered that the service can be continued for a certain time when the data stream is interrupted. Method according to at least one of the preceding claims, wherein in step c) the first client computer ( 1.1 ) is integrated into a network tree structure, wherein the first server computer ( 10 ) forms the root. The method of claim 6, wherein the first client computer ( 1.1 ) is in turn available as a parent node in the tree structure depending on certain parameters. Method according to claim 7, wherein the parameters determine the runtime of the application program ( 11 . 12 ), the network bandwidth of the parent node, the load of the parent node, and / or the remaining term of the service provided. Method according to at least one of claims 6 or 7, wherein a further client computer ( 2.1 - 2.n ) according to the steps a) -f) the data stream from the first client computer ( 1.1 ) and child nodes from the first client computer ( 1.1 ). Method according to at least one of claims 6 to 9, wherein upon failure of a child node with n child child nodes connected, the first server computer ( 10 ii) that selected child child node becomes the new child node of the remaining child child nodes, and iii.) that new child node is connected to a parent node, where n ∈ N = {1 , 2, ..., n _max } and n _{max is} the maximum allowable number of children nodes at a parent node. The method of claim 10, wherein the new child node as parent node the first server computer ( 10 ) Has.