KR20030070797A - Developing of VOD Server using Distributed Proxy - Google Patents

Abstract

PURPOSE: A VOD(Video On Demand) server is provided to transmit high definition video and audio data to clients by using low priced distributed proxy servers which does not impose a large load on a network. CONSTITUTION: The system comprises a VOD multicast transmission server, and a switching agent. The VOD multicast transmission server includes a HEN(Head End Node) near a client side which stores data requested by one client, and instantly transmits the stored data to other client without connecting the client to a server if the stored data is requested. The switching agent checks the video data stored at all the HENs and the data on the clients requesting the video data, and plans a proper HEN rearrangement strategy.

Description

Developing VOD Server using Distributed Proxy

Once the user has requested a video to watch, the server and the user must prepare to send and receive data. At this time, if you use web-caching, you can eliminate unnecessary server connection. HEN is a near-caching device that stores some data before sending the data sent from the server to the user. In this caching operation, if the video data requested by the user is in the local HEN, the requested data can be transmitted without connecting to the server. However, if it is not in the local HEN, you need to find out if the user requested data is in another local HEN. The SA stores this data, searches it, and teaches the user the address. If you are in another HEN, you can also receive data without connecting to the server. But if you have the same movie, but the other part, that is, a few minutes of time difference, not the first part, you will receive that part and receive the first part of the data on the server. At this time, the SA records and controls the movement of all data.

If none of the above is true, then the same movie is not stored in any of HEN, so it will connect to the server and retrieve the data.

The present invention is to transmit high quality video and audio data to a user using an inexpensive server without increasing the network load in a complex network environment.

Media development has continued to be data materials that mainly used text and images of the past, while materials that use various multimedia covering audio and video based on existing media are increasing. These various types of data are widely used in all fields of medicine, education, entertainment, finance, etc., and their usage is increasing rapidly. Moreover, on-demand service is inevitable, because users' demands are not only one-sided delivery like conventional television broadcasting but also two-way data delivery and real-time that can be delivered at a desired time.

On-demand services are becoming more diverse, allowing you to watch news and lectures from entertainment video on-demand, news on-demand, education on-demand, teleconference, home shopping, electronic games, location information systems, and electronic books. It is being developed in many multimedia fields. Among them, VOD service is a field that provides smoothly the movies that users want.

The on-demand service currently provided is mainly developed for movies and news, but it has technical challenges that are not enough to attract users' attention. The networks that users subscribe to still have insufficient bandwidth to transmit large amounts of data, and the server's ability to handle users' needs, store data, and transmit appropriate data is very important. For this reason, technologies such as real-time search, data compression, and large data storage technology should be preceded. This led to the use of proxies. What the proxy does is when there is a request for data between the user and the server, and if the proxy has some data on the server and the user requests the data, the server needs to request the data. It is not. In the past, this proxy was placed near the server, so the speed improvement was not noticeable, so there was no benefit for the user, and the network bandwidth was saved only in the proxy-server section, which is relatively shorter than the user-proxy section.

In order to overcome the limitations of the prior art, having a large number of distributed proximities close to the user side shortens the user-proxy time distance, thereby improving the service speed, as well as allowing users to connect to the server to provide services. Since the service is provided only by connecting to the proxy of, the saving effect of the network bandwidth between the proxy and the server becomes prominent.

The implementation of the VOD server using the multicasting transmission method through a network that allows multiple users to be serviced simultaneously without depleting scarce network resources consists of a server, a large storage device, and a switching agent. It can be composed of a client side consisting of the server side and the network portion responsible for the transmission of data and the receiving device, which is shown in [Fig. 1], the action is shown in [Fig.

1. Video server and storage

The video server and the storage device store various moving images according to the characteristics of the video or the user's taste and also transmit a data stream to the network. You need the ability to process the data that users have requested.

2. Switching Agent (SA)

Transmitting data to multiple users in a VOD system requires several controls. There is a need to know which video data is stored in which proxy, which video the user requested is about which movie, and so on. If this information is left to the server, greater capacity is required of the server to transmit video data for multiple user requests. Therefore, the SA is in charge of this data transfer control, and when requested by the user, it checks which movies are subscribed to, finds out if the data is in a distributed proxy, and if so, consumes server and proxy time network bandwidth by letting the proxy provide data. If no data is found, the server sends the data.

3. Network

You need to implement effective multicast transmissions and have enough bandwidth to provide QoS to your users. Sufficient bandwidth here means bandwidth required per channel serviced from the server, and the VOD server must be able to support hundreds of channels. In addition, control of transmission of control signals such as video service request, stop and cancel functions from the client, transmission of data from the server to the requested stream, authorization of service requests, and caching of other streams transmitted on different channels. It provides bidirectional communication to carry signals.

4. Receiver

The receiver receives the transmitted data stream, stores it in a buffer, decodes the received compressed stream, displays the video streams on a monitor, and simultaneously drives the speaker. The receiving device must be equipped with a buffer that buffers the reserved video of the user group that made the service request to the server when it is serviced on another channel, and caches them under the control of the server, and is currently being served from the unicast channel. When the requested video ends, the requested video data is displayed from the added buffer without being connected to the server through the network.

Therefore, the proposed method can directly service the reserved video data from the buffer without depleting the scarce network resources, i.e. without allocating a new channel, so that the server does not have a new disk access to the video data already stored in the buffer. This greatly reduces the load on the server.

1 is an overall view of the HENs connected to the VOD server, SA management thereof.

2 is a view in which streams are distributed and stored in each HEN.

3 is a processing procedure for a user request

The server consists of a few server-class computers, which store and transmit data to be sent when a user requests a service, which is connected to a switching agent (SA) through a network. In this part, the network load is greatly saved if there is user request video in the proxy. SA is connected to each HEN (Head-End-Node), each HEN is connected to a number of users. The user requests data from the HEN to which he is connected, and if the video data exists in the HEN, the user is sent immediately and the HEN only needs to transmit the fact to the SA. If the data does not exist, the SA is asked if there is an HEN that has the data. If it is not present in another HEN, it is transmitted from the server. If it is already cached in another HEN, it is not connected to the server through the network. The data stored in the system will be serviced alternately. Such a configuration is shown in [Fig.

Using distributed proxy, VOD service through network reduces scarce network resources, and at the same time, it greatly reduces server load by applying load distribution through data distribution to terminal nodes. A large amount of data travels in the network between the user and the proxy, saving network bandwidth to the server. In particular, if the data requested by users is popular data, the number of requests is increased, and the probability stored in the proxy located on the user side increases, resulting in a reduction in network bandwidth, and the VOD because the buffer size used is small. We believe that there is an economic advantage to the system implementation.

Claims (1)

VOD multicast transmission server that stores the data requested by the user and places HEN on the user's side for quick transmission without accessing the server when another user requests this data. At this time, all HEN movie data storage information, identifying the user who requested the data, and a switching agent (SA) to establish a proper relocation strategy.