JP2003152789A - Method, program and device for controlling stream relay and medium with the program recorded thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently respond to request processing of each client in the case of distributing a large scale stream. SOLUTION: A stream information analyzing part 210 extracts a maximum UDP (user datagram protocol) packet size of stream contents from a stream information packet transmitted from a stream server, and a resource managing part 209, on the basis of the maximum UDP packet size, calculates a contents copying processing time needed to copy and distribute a stream data packet about the stream contents, and further calculates the total copying processing time to calculate the number of processable retransmission requests. If a request packet analyzing part 204 receives a retransmission request message packet from a client, the request packet analyzing part 204 judges whether or not the number of processable retransmission requests exceeds the number of retransmission requests during processing, and the retransmission request is accepted if the number of processable retransmission requests does not exceed the number of retransmission requests during processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stream relay control method for efficiently realizing a large-scale stream data distribution service on a network, a program thereof, a medium recording the program, and a stream relay control device.

[0002]

2. Description of the Related Art Conventionally, when stream distribution is performed on the Internet, generally, a stream setting protocol for requesting and setting stream content, a stream distribution protocol for distributing stream content based on the setting, and a stream content packet being distributed. A stream control protocol is used to notify the delivery status and delivery quality, and the connection status between the server and the client.

IETF (Internet Engine)
RTSP (Real Time S) is a protocol defined by the "Eering Task Force".
streaming Protocol: RFC232
6), RTP (Real-time Transport)
t Protocol: RFC1889) and RTCP
(RTP Control Protocol: RFC
1889).

Also, when stream distribution is performed using a protocol other than these, a protocol having the above function is used. Examples include Microsoft's MMS protocol, Real Network's RD.
T, PNA protocol and the like.

In any of the protocols, it is common to have a mechanism called retransmission, in which when a packet is discarded in the network up to the client, the packet is transmitted again from the server to recover the missing packet. is there. This mechanism is shown in Figure 1.
Will be explained.

FIG. 1 shows an example of a stream relay network (stream distribution network) and packets and messages transmitted and received between them. In the figure, 101 and 102 are clients, 200 is a stream relay control device, and 300.
Is a stream server.

(Stream distribution setting process) When the client 101 transmits a reception request message a of a specific stream content to the stream relay control device 200, the stream relay control device 200 determines whether the stream content is already distributed by itself. If it is not being distributed, the stream reception request message a ′ is transmitted to the stream server 300.

The stream server 300 that has received the message normally responds to the stream relay control device 200 with a stream reception permission message b. The stream relay control device 200 transmits the message b ′ to the client 101.

Upon completion of this sequence processing, the stream server 300 transmits the stream (data) packets 1, 2, ... To the stream relay control apparatus 200, and the stream relay control apparatus 200 that has received the stream packet is currently Of the stream packets 1, 2, ...
To send.

Next, when the client 102 also wants to receive the stream content, the client 102 sends a reception request message c for the stream content to the stream relay control device 200.

Upon receiving the message, the stream relay control device 200 confirms that the stream content is already being distributed by itself, and sends a stream reception permission message d to the client 102.

Upon completion of this sequence processing, when the stream relay control device 200 receives the stream packet transmitted from the stream server 300, the stream relay control device 200 duplicates the packet and transmits it to the clients 101 and 102.

(Retransmission request processing) If a specific packet is dropped during stream packet reception due to discarding in the relay network, the client requests the upstream server or the like to retransmit the packet. In the case of FIG. 1, the client 101 recognizes that the stream packet 3 could not be received, and transmits the retransmission request message e of the stream packet 3 to the stream relay control device 200. The stream relay control device 200 receives the message e, analyzes the content, and
Retransmit stream packet 3 requested for 1.

[0014]

When performing the above-mentioned retransmission processing, depending on the communication quality situation of the network, message processing due to a large number of retransmission requests from each client in the stream relay control device 200 or stream server 300. Congestion may occur. In this case, the stream packet copy process itself cannot be performed due to the interruption of the stream packet copy process by the resend request process corresponding to the message, and the resend request may occur frequently.

In addition, depending on the client, the network quality may be so deteriorated that a large amount of resend request messages may be sent. Even if resend request processing is performed for such a client, the packet is retransmitted. There is a possibility that discarding will occur, and retransmission requests for the same packet will occur frequently, and there is a possibility that the retransmission request processing resources of the stream relay control device and the like will be wasted.

In order to solve the above problem, a method may be considered in which the number of requests for retransmission request processing is set in advance and the processing is not performed when the number of requests exceeds the number, but in that case, in practice, Despite having resources that can accept more requests, the viewing quality of the client will deteriorate because request processing is not performed, or conversely, it will no longer be possible to allocate retransmission request processing resources. However, there is a problem that the processing capacity is exceeded because the retransmission request processing is accepted and a new packet is discarded.

As described above, according to the conventional technique, when retransmission request processing from each client occurs frequently due to a large amount of stream packets being discarded due to deterioration of network quality, etc., the stream server or stream relay control device However, there is a problem that the request processing resources are exceeded, and as a result, the server itself discards the packet, which causes a further retransmission request.

In order to solve this, when the request reception processing is performed according to the predetermined number of retransmission request processing receptions,
Due to the difference from the actual processable resources, there is a problem that the client's viewing quality is deteriorated or a new retransmission request is caused at the client due to the server's own processing capacity being exceeded.

The present invention has been made in view of such a background, and it is an object of the present invention to efficiently respond to request processing for each client in a situation where large-scale stream distribution is performed.

[0020]

To achieve the above object, in the stream relay control method of the present invention, a packet transmitted from a client is received, the packet is analyzed, and a content viewing request or a content viewing stop request is issued. At some point, the number of simultaneous deliveries of the content is calculated, the amount of delivery processing resources is calculated, the amount of retransmittable resources is estimated, the packet sent from the client is received, the packet is analyzed, and a packet resend request is made. At this time, a comparison calculation process is performed to determine whether or not retransmission processing is possible, and when retransmission processing is possible, the requested packet is transmitted to the client.

Further, the present invention is characterized in that the stream information element is analyzed from the stream data packet transmitted from the stream server, and the distribution processing resource amount is calculated.

Further, the present invention is characterized in that the amount of retransmittable resources is estimated according to the value of the stream information element.

Further, according to the present invention, the number of request packets is analyzed from the packet resend request message sent from the client, and a comparison calculation process is performed according to the number to determine whether resend request processing is possible. The transmitted packet is sent to the client.

Further, according to the present invention, the stream data packet size and the
Estimate the time to copy the stream data packet from the maximum transferable packet size, calculate the copy processing time of the entire stream relay control device when the number of simultaneous viewing of the stream content increases or decreases, and resend Estimate the number of requests that can be processed, and if a retransmission request is generated from the client, compare the current number of times retransmission processing is in progress and the number of retransmission requests that can be processed, and if the number of retransmission requests that can be processed is greater, accept the request. The feature is that the request is not accepted when the number of retransmit request processes is smaller.

Note that these stream relay control methods can also be realized by a program for executing the above-described processes on a computer, or a computer-readable medium recording the program.

Further, in the stream relay control device of the present invention, means for receiving the stream data packet transmitted from the stream server, a common memory for storing the stream data packet, and the stream data packet for at least one client. A means for transferring, a means for receiving the packet transmitted from the client, a means for analyzing the information of the packet, a means for calculating the request receivable resource amount, a means for judging the acceptability of the resend request, Means for transferring a stream data packet for the request to the client.

Further, the present invention is characterized by comprising means for analyzing the stream information element from the packet transmitted from the stream server.

As a result, by processing the stream packet retransmission request from the client according to the remaining resource amount of the stream relay control device, it becomes possible to efficiently perform the large-scale stream distribution.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows the main block configuration of the stream relay control device. In the figure, 201a and 201b are lines to the outside, 202a and 202b are line termination units, and 203.
a and 203b are packet distribution units, 204 is a request packet analysis unit, 205 is a retransmission request processing unit, 206 is a copy processing unit, 207 is a retransmission request reception unit, 208 is a common memory, 209 is a resource management unit, and 210 is stream information. It is an analysis unit.

The structure of the entire stream relay network and the packets and messages transmitted and received between them are the same as in the conventional case.

(Resendable Number Calculation Process) First, the resendable number calculation process will be described.

In the stream relay control device 200,
When the stream information packet including various properties of the stream transmitted from the stream server 300 is received via the line 201a and the line termination unit 202a, the packet distribution unit 203a analyzes that the packet is a stream information packet. (Step s1 in FIG. 3), and outputs it to the stream information analysis unit 210 (see FIG.
In step s2), the information element of the stream content is extracted. Specifically, the maximum UDP packet size (Max Pack) of the stream content is
et Size).

Then, in the resource management unit 209,
Regarding the stream content, the content copy processing time (Cont) required to copy and deliver the stream packet transmitted from the stream server 300.
ent Copy Cost) is calculated according to the following formula (steps s11 and s12 in FIG. 4).

Content Copy Cost i = (CCAlfa * (MTU + CCBeta) * RD + (CCAlfa * (MPS i-MTU * RD) + CCB eta) (1) However, RD = Round Down (MPS i / MT
U) MPS i: Max Packet of the content i
Size MTU: MTU size of content reception IF CCAlfa, CCBeta: constant for calculation Next, total copy processing time (Total Copy)
Cost) is calculated according to the following formula (step s13 in FIG. 4).

Total Copy Cost: = Total Copy Cost + Copy Cost i (at the time of new connection) (2) Total Copy Cost: = Total Copy Cost-Copy Cost i (during disconnection) (3) However, when the client newly connects to the content, the calculation is performed by the equation (2), and when the disconnection request is made, the calculation is performed by the equation (3).

Next, the number of resend requests that can be processed is calculated according to the following formula (step s14 in FIG. 4).

Remain Num = (100-Total Copy Cost) / Process Time (4) However, Process Time: Retransmission request processable time Note that if the number of client connections fluctuates after that, each time, The total copy processing time and the number of retransmit request processes that can be processed are recalculated (steps s15 and s1 in FIG. 4).
6, s17).

(Resend Request Acceptance Process) Next, when a resend request message packet is transmitted from the client,
The flow of retransmission request acceptance processing in the stream relay control device 200 will be described.

First, the packet from the client is received via the line 201b and the line terminating unit 202b.
The packet distribution unit 203b identifies that the packet is a stream packet retransmission request packet from the client,
The request packet analysis unit 204 is notified (steps s1 and s3 in FIG. 3).

Next, the request packet analysis unit 204 determines whether or not the retransmission request can be accepted according to the following determination formula (step s21 in FIG. 5).

If Remain Num-Resen
If d Process Num> 0, the resend request is accepted (however, Resend Process Nu
m: number of retransmission processes in progress).

When the resend request is accepted, the resendable number is subtracted by 1 (step s22 in FIG. 5), and the resend request number (Resend Process Num) is incremented by 1 (step s23 in FIG. 5). In addition, Remain
Num-Resend Process Num ≦ 0
If so, the request-denied packet is transmitted to the client (step s24 in FIG. 5).

When the resend process is completed, the resend request number (Resend Process Num) is decremented by 1 (step s31 in FIG. 6).

According to the first embodiment described above, it becomes possible to perform the stream packet retransmission request process from the client according to the processing resource of the stream relay control device.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIG. The first
Descriptions of parts that perform the same processes as those in the embodiment may be omitted.

FIG. 7 shows a main block configuration of the stream relay control device. Here, in addition to the configuration of the first embodiment shown in FIG. 1, a request number analysis unit 211 is provided. Is characterized by.

(Retransmission Request Acceptance Process) The flow of the retransmission request acceptance process in the stream relay control device 200 when a retransmission request message packet is transmitted from the client will be described.

The request packet analysis unit 204 analyzes the stream packet retransmission request packet from the client, and then notifies the request number analysis unit 211 of the stream packet retransmission request message information. Request number analysis unit 21
In 1, the number of retransmission request UDP packets stored in the message is analyzed. As a result, if one retransmission request message contains a certain number or more of retransmission request packets, the request from the client is not accepted.

According to the second embodiment described above, the request of the client is not accepted in response to a large number of retransmission requests due to the discarding of a large number of stream packets due to the network quality of the client being significantly deteriorated. As a result, it is possible to prevent waste of resources that can be resent by the stream relay control device 200. Further, by this processing, it is possible to prevent the retransmission processable resource of the stream relay control device 200 from being wasted even in the case of a stream packet retransmission request from an abnormal client that frequently issues a retransmission request.

In the above description, the case of Expression (1) has been described as the copy cost calculation expression.
It is easily possible to use the copy cost calculation formula proportional to the Packet Size, or to calculate the copy cost with a fixed value, and then to calculate the retransmittable number.

[0052]

As described above, according to the present invention,
In a situation where a large-scale stream distribution is performed, it becomes possible to efficiently respond to the request processing for each client according to the resource amount of the stream relay control device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of packets and messages transmitted and received between a stream relay network and the stream relay network.

FIG. 2 is a configuration diagram showing a first embodiment of a stream relay control device of the present invention.

FIG. 3 is a flow chart of packet distribution processing.

FIG. 4 is a flowchart of a process for calculating the number of retransmittable processes

FIG. 5 is a flowchart of a resend request acceptance process.

FIG. 6 is a flowchart of retransmission processing end processing.

FIG. 7 is a configuration diagram showing a second embodiment of a stream relay control device of the present invention.

[Explanation of symbols]

101, 102: client, 200: stream relay control device, 201a, 201b: external line, 20
2a, 202b: line termination unit, 203a, 203b: packet distribution unit, 204: request packet analysis unit, 205: retransmission request processing unit, 206: copy processing unit,
207: Retransmission request receiving unit, 208: Common memory, 20
9: resource management unit, 210: stream information analysis unit,
211: Request number analysis unit, 300: Stream server.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigehiko Ushijima             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Shinya Hanano             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Tatsuro Kimura             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 5C056 FA05 HA04 HA11                 5C064 BA07 BB05 BC11 BC18 BC20                       BD02 BD08                 5K030 GA01 HA08 HB02 JT04 LA01                       LD07

Claims (13)

[Claims] 1. A stream relay control method in a stream relay control device for receiving a stream data packet transmitted from a stream server and transmitting the stream data packet to at least one client, the packet being transmitted from a client. When the packet is received, the packet is analyzed, and when it is a content viewing request or a content viewing stop request, the delivery processing resource amount is calculated after counting the number of simultaneous delivery of the content, and the retransmittable resource amount is estimated. The feature is that it receives a transmitted packet, analyzes the packet, performs a comparison calculation process to determine whether a retransmission process is possible when the packet is a retransmission request, and transmits the requested packet to the client when the retransmission process is possible. Stream relay control method. 2. The stream relay control method according to claim 1, wherein the stream information element is analyzed from the stream data packet transmitted from the stream server, and the distribution processing resource amount is calculated. 3. The stream relay control method according to claim 2, wherein the retransmittable resource amount is estimated according to the value of the stream information element. 4. The stream relay control method according to claim 1, wherein the number of request packets is analyzed from the packet resend request message transmitted from the client, and a comparison calculation process is performed according to the number to determine whether resend request processing is possible. A method for controlling stream relay, which comprises transmitting a requested packet to a client when retransmission processing is possible. 5. The stream relay control method according to claim 1, wherein, when estimating a retransmittable resource amount, a time for copying the stream data packet from a stream data packet size and a maximum transferable packet size. When the number of simultaneous viewing of the stream content increases or decreases, the copy processing time of the entire stream relay control device is calculated, the number of resend requests that can be processed is estimated, and if a resend request is generated from the client, The number of retransmission requests being processed is compared with the number of retransmission requests that can be processed, and if the number of retransmission requests that can be processed is larger, the request is accepted, and if the number of retransmission requests that can be processed is smaller, the request is not accepted. Stream relay control method. 6. A stream relay control program in a stream relay control device for receiving a stream data packet transmitted from a stream server and transmitting the stream data packet to at least one client, the program being a stream relay control device. On the computer that configures, the packet sent from the client is received, the packet is analyzed, and when it is a content viewing request or a content viewing stop request, the distribution processing resource amount is calculated after counting the number of simultaneous distribution of the content. Calculate, estimate the amount of resources that can be retransmitted, receive the packet sent from the client, analyze the packet, and when the packet is a retransmission request, perform a comparison calculation process to determine whether the packet can be retransmitted. If the requested packet The stream relay control program and executes the process of sending to the client. 7. The stream relay control program according to claim 6, wherein the stream information element is analyzed from the stream data packet transmitted from the stream server, and the distribution processing resource amount is calculated. 8. The stream relay control program according to claim 7, wherein the retransmission processable resource amount is estimated according to the value of the stream information element. 9. The stream relay control program according to claim 6, wherein the number of request packets is analyzed from the packet resend request message transmitted from the client, and a comparison calculation process is performed according to the number to determine whether resend request processing is possible. A stream relay control program, which transmits a requested packet to a client when retransmission processing is possible. 10. The stream relay control program according to claim 6, wherein a time for copying the stream data packet from the stream data packet size and the maximum transferable packet size when estimating the retransmittable resource amount. When the number of simultaneous viewing of the stream content increases or decreases, the copy processing time of the entire stream relay control device is calculated, the number of resend requests that can be processed is estimated, and if a resend request is generated from the client, The number of retransmission requests being processed is compared with the number of retransmission requests that can be processed, and if the number of retransmission requests that can be processed is larger, the request is accepted, and if the number of retransmission requests that can be processed is smaller, the request is not accepted. And a stream relay control program. 11. A computer-readable medium on which the stream relay control program according to claim 6 is recorded. 12. A stream relay control device for relaying a stream data packet between a stream server and a client, comprising: a means for receiving the stream data packet transmitted from the stream server; and a common means for storing the stream data packet. A memory, a means for transferring the stream data packet to at least one client, a means for receiving the packet transmitted from the client, a means for analyzing the information of the packet, and a means for calculating the request acceptable resource amount A stream relay control device comprising: means for determining acceptability of a retransmission request; and means for transferring a stream data packet for the request to a client. 13. The stream relay control device according to claim 12, further comprising means for analyzing a stream information element from a stream data packet transmitted from a stream server.