JPH06177879A - Network congestion control method - Google Patents

Abstract

PURPOSE:To provide a network congestion control method which minimizes deterioration of the service grade and at the same time recovers the congestion state as soon as possible in a multiple destination simultaneous multi-address communication system. CONSTITUTION:The same video information is simltaneously distributed to the terminals 14 and 15 via a network 13 by a network congestion control method in a multiple destination simultaneous multi-address communication system. An image distribution center 11 contains a means which detects the congestion state of the network 13. When the congestion state of the network 13 is detected, the quality of the images to be distributed are deteriorated and then restored when the congestion state is recovered (the 1st method). Meanwhile the non-preferential terminals are cut when the congestion state of the network 13 is detected (the 2nd method). Furthermore the 1st and 2nd methods are combined together in accordance with the degree of congestion. That is, if the congestion state is not recovered dispite deterioration of the image quality, the non-preferential terminals are successively cut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network congestion control method in multi-point simultaneous broadcast communication for simultaneously distributing the same video to a plurality of terminals via a network.

[0002]

2. Description of the Related Art In the conventional network congestion control method, when a network is congested, a new call connection is refrained from or a connection is rejected even if a call connection request is made.

FIG. 3 shows an example of a system configuration in a conventional multi-point simultaneous broadcast communication. FIG. 4 is a communication sequence chart in FIG. 3, where 21 is a video distribution center, 22 is a distribution exchange node, 23 is a network, and 24 is a network. And 25 are terminals.

The network congestion control method relates to the network 23, and relates to the video distribution center 21 and the distribution switching node 2.
2. It relates to the distribution exchange node 22, the terminal 24 and the terminal 25.

In FIGS. 3 and 4, the terminal 24 and the terminal 2 are shown.
It is supposed that the distribution of the video information to the 5 is performed by the distribution exchange node 22 in the network 23.
It is also possible to distribute directly at the video distribution center 21 without providing the above.

In FIG. 3 and FIG. 4, first, the terminal 24
It is assumed that the video information 26 is started to be received from the video distribution center 21 via the distribution exchange node 22.

This is started after the terminal 24 makes a call connection to the video distribution center 21 via the distribution switching node 22.

After this, it is assumed that the network 23 becomes congested and the distribution switching node 22 detects this congestion.

When the distribution exchange node 22 is not provided, the video distribution center 21 has a congestion detection function.

When the distribution switching node 22 detects congestion,
Until it recovers from the congestion state, it will not accept call connection requests from new terminals.

In FIG. 3 and FIG. 4, there is a call connection request 27 from the terminal 25, but this is rejected 28 by the call connection.

When the recovery from the congestion state is detected, the call connection request from the new terminal is accepted.

3 and 4, the congestion is finally recovered, the call connection request 29 from the terminal 25 is accepted, the call connection is completed 30, and the terminal 25 can also receive the video information.

For example, an ATM (Asynchronous Transfer Mode) network expected as a next-generation network will be described as an example.

In an ATM network, cells are discarded when a congestion occurs in a switch.

A cell is a 53-byte packet, and video information is carried by the cell.

When a congestion state occurs, cell delay also increases.

[0018]

Therefore, in the conventional network congestion control method, when a congestion state is detected, only a new call connection request is withheld, so that the congestion state may last for a long time. However, there is a problem in that it is difficult to continuously provide the video distribution service because not only the video quality is greatly deteriorated due to delay or loss within the network, but also call disconnection occurs.

For example, in an ATM network, when a congestion state occurs, cells are discarded or delay time becomes large, so that the image quality at the terminal is greatly deteriorated and the real-time property cannot be guaranteed. is there.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a network congestion control method capable of recovering from a congestion state as soon as possible while minimizing deterioration of service grade. Especially.

[0021]

In order to achieve the above object, the network congestion control method of the present invention is provided with means for detecting a network congestion state in a video distribution center, and when the network congestion state is detected, The feature is that the distributed video quality is lowered, and when the congestion state is recovered, the distributed video quality is restored.

Further, the mode characterized in that the non-priority terminal is disconnected when the congestion state of the network is detected is effective.

Furthermore, depending on the size of the congestion state,
For example, when the congestion state is detected, the video quality is first lowered, and when the congestion state is not recovered, the mode is characterized in that the non-priority terminals are sequentially disconnected.

[0024]

According to one aspect of the present invention, when a congestion state is detected, the image quality is lowered to reduce the information amount of the video information transferred on the network, so that the congestion state can be quickly recovered. .

When the congestion state is recovered, the video quality to be distributed is restored, so that the video quality can be kept high.

The image quality can be reduced in N steps.

According to another aspect of the present invention, when the congestion state is detected, the non-priority terminal is disconnected, so that the information amount of the video information transferred on the network is reduced, so that the congestion state can be recovered. it can.

It is also possible to divide the priority into M stages and disconnect the non-priority ones in order.

Yet another aspect of the present invention is a combination of the above two aspects, and when a congestion state is detected,
First, the video quality is lowered, and when the congestion state continues, the non-priority terminal is disconnected, so that the congestion state can be quickly recovered.

The video quality can be reduced in N steps, and non-priority terminals can be disconnected in M steps.

Embodiments will be described below with reference to the drawings.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an example of a system configuration in multipoint simultaneous broadcast communication for explaining an embodiment of the present invention, and FIG. 2 is a communication sequence chart in the embodiment of the present invention of FIG.

Reference numeral 11 is a video distribution center, 12 is a distribution exchange node, 13 is a network, and 14 and 15 are terminals.

In FIG. 1 and FIG. 2, first, the terminal 14 and the terminal 1
5 via the distribution switching node 12 and the network 13,
It is assumed that the video distribution center 11 is connected.

It is also conceivable that the terminals 14 and 15 are directly connected via the network 13 without going through the distribution and exchange node 12.

It is assumed that the distribution exchange node 12 detects the congestion of the network 13 after the distribution of the video information 16.

The video distribution center 11 may detect the congestion.

When the distribution exchange node 12 detects a congestion state, it sends a congestion notification 17 to the video distribution center 11.

The video distribution center 11 knows the congestion state,
First, the network load is reduced by lowering the image quality.

As a result, when the congestion of the network 13 is released, the distribution switching node 12 detects this,
The image distribution center 11 is notified of that fact.

When the video distribution center 11 knows the recovery from the congestion state, it can restore the video quality.

FIGS. 1 and 2 show that even if the image quality is lowered, the congestion state is not recovered.

In this case, the distribution exchange node 12 informs the video distribution center 11 of a congestion notification 18 indicating that congestion is continuing.

It should be noted that the fact can be known by not being notified that the recovery has been made within the fixed time.

The video distribution center 11 then disconnects the call 19 of the non-priority terminal 15.

When there are a plurality of non-priority terminals 15, the call is disconnected until the congestion state is recovered.

It is also possible for the distribution switching node 12 to sequentially disconnect the calls from the non-priority terminals 15.

In FIGS. 1 and 2, the call disconnection recovers from the congestion state, the distribution switching node 12 detects the recovery from the congestion state, and notifies the video distribution center 11 of the congestion recovery notice 20 to that effect.

When the video distribution center 11 knows the recovery from the congestion state, it restores the video quality.

In the above embodiment, the image quality is lowered at the image distribution center, but it is also possible to reduce the image quality only to the terminal of the congestion ground at the distribution exchange node.

When disconnecting a call to a non-priority terminal,
It is conceivable to disconnect the terminal at the congestion ground first.

It is conceivable that the image quality is divided into a plurality of stages or the priority is divided into a plurality of stages to perform finer grained control.

Further, it can be considered to use it in combination with a conventional congestion control method.

[0054]

As described above, according to the present invention,
The video distribution center is equipped with a means for detecting the congestion state of the network, and when the congestion state is detected, the quality of the video information is lowered or the connected non-priority terminal is disconnected to transfer the data on the network. Since the amount of information can be reduced, it is possible to quickly recover from the network congestion state.

The video quality can be uniformly lowered and the non-priority terminal is disconnected, so that the degradation of the service grade can be suppressed as low as possible.

Further, when the congestion state is recovered, the image quality can be restored to the original level, so that the deterioration of the service grade can be suppressed to a low level.

[Brief description of drawings]

FIG. 1 is an example of a system configuration in multipoint simultaneous broadcast communication according to an embodiment of the present invention.

FIG. 2 is a diagram showing a communication sequence chart in the embodiment of the present invention.

FIG. 3 is a system configuration example in a conventional network congestion control method.

4 is a diagram showing a communication sequence chart in the conventional system configuration of FIG.

[Explanation of symbols]

 11, 21 Video distribution center 12, 22 Distribution switching node 13, 23 Network 14, 15, 24, 25 Terminal 16, 26 Video information 17, 18 Congestion notification 19 Call disconnection 20 Congestion recovery notification 27, 29 Call connection request 28 Call connection Reject 30 Call connection completed

Claims (3)

[Claims] 1. A network congestion control method in multi-point simultaneous broadcast communication, wherein the same video information is simultaneously distributed to a plurality of terminals via a network, the video distribution center comprising means for detecting a congestion state of the network. A network congestion control method characterized in that when the congestion state is detected, the distributed video quality is lowered, and when the congestion state is recovered, the distributed video quality is restored. 2. A network congestion control method in multi-point simultaneous broadcast communication for simultaneously distributing the same video information to a plurality of terminals via a network, the video distribution center comprising means for detecting a congestion state of the network. A network congestion control method characterized by disconnecting a non-priority terminal when the congestion state of the above is detected. 3. A network congestion control method in multi-point simultaneous broadcast communication for simultaneously distributing the same video information to a plurality of terminals via a network, the video distribution center comprising means for detecting a congestion state of the network. When the congestion status of the above is detected, the distributed video quality is reduced, and when the congestion status is recovered, the distributed video quality is restored, and the method of disconnecting the non-priority terminal is combined. A network congestion control method characterized in that it is used properly according to the size of the network.