JP2002183014A - Contents distribution system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contents distribution system which distributes contents by using a network by which more clients are brought together in one multicast group and the same contents can be distributed to them at a time. SOLUTION: Multiple edge servers 102 to 104 are arranged on a client side of the network and transfers a request for contents from a client to a center server, which reserves the kind and destination of the received requested contents; when the same contents are requested by multiple clients, the destinations of the clients are reserved as the destinations of the contents, the reserved contents are read out of a storage means and multicast when there are multiple destinations, and the received contents are transmitted to the clients at the destinations after being converted to communication rates at which the clients can receive the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a content distribution technique for distributing content using a network.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional distribution system in which a client can obtain desired contents from a server via a network. 201 is a server, 202 is a network, and 203 to 211 are clients. When the client 203 sends a packet requesting content to the server 201, the packet is transmitted to the network 202.
Is delivered to the server 201. The server 201 decrypts the received request and transmits the requested content to the client 203. This content is network 2
02 to the client 203, and the client 203 can receive this content.

For example, when the client 203 and the client 207 request the same content from the server 201 at the same time, the server 201
07 as one multicast group, the same content can be delivered to the clients 203 and 207 by multicast at one time.

[0004] However, in order to distribute as one multicast group at a time, clients included in one multicast group must be able to receive contents at the same speed. Since the bandwidth of the network between the clients, especially the bandwidth of the access line, is different, the conventional distribution method has a problem that the number of clients that can be combined into one multicast is small.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to group more clients into one multicast group and distribute the same content to more clients at once. By doing so, the server can efficiently distribute more contents.

[0006]

According to the present invention, in a content distribution system for distributing requested content from a center server to a plurality of clients via a network, a plurality of edge servers are arranged on a client side of the network. The center server receives the request for the content from the client, reserves the type and destination of the content, and stores the destination of the content when the same content is requested by a plurality of clients. A means for reserving destinations of a plurality of clients, a means for reading out reserved content from a storage means, and transmitting the content by multicast when there are a plurality of destinations. The edge server requests a content from a client. To the center server And stage receives the content from the center server, the received to the destination of the client content, characterized in that it comprises means for transmitting the converted communication speed to the client can receive.

[0007] The present invention further provides a method for distributing requested content from a center server to a plurality of clients via a network, wherein a plurality of edge servers are arranged on the client side of the network, and the edge server transmits the content from the client. To the center server, the center server receives the content request from the client, reserves the type and destination of the content, and if the same content is requested by multiple clients, the destination of the content The destination is reserved for a plurality of clients, the reserved content is read out from the storage means, if there are a plurality of destinations, the content is transmitted by multicast, the content transmitted from the center server is received by the edge server, and the received content is To the destination client Client and characterized in that transmits the converted communication speed to be received.

[0008] The network may include means for sending a packet of the content transmitted from the center server to the edge server with the highest priority.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of a content distribution system according to the present invention. 101 is a center server, 102 to 104 are edge servers, 105 is a network connecting the center server 101 and the edge servers 102 to 104, and 106 to 114 are clients. FIG. 2 is a configuration diagram of an embodiment of the center server 101 of the content distribution system shown in FIG. 115 is a receiving unit, 11
Reference numeral 6 denotes a transmission unit, 117 denotes a reservation management unit, and 118 denotes a content storage unit. FIG. 3 shows an example of a reservation list managed by the reservation management unit 117 of the center server 101. FIG. 4 shows FIG.
2 is a configuration diagram of an edge server 102 of the content distribution system shown in FIG. 1, and other edge servers 103 and 104 have the same configuration. 119 is a receiving unit, 120 is a transmitting unit, 1
21 is a buffer.

The edge servers 102 to 104 have access lines of clients 106 to 114 connected to a network 105.
Installed near the client connected to. The network 105 includes the center server 101 and the edge server 1
From 02 to 104, a certain resource for content transmission is secured, and the content can be transmitted from the center server 101 to each edge server at the same speed.

The client 106 is the center server 101
When the client requests the content, the client first transmits a content request packet to the edge server 102 to which the client is connected. When receiving the content request packet from the client 106, the receiving unit 119 in the edge server 102 passes the address and the content name of the client 106 to the transmitting unit 120. The transmitting unit 120 transmits the content request information to the center server 101 as the client 10
6 and the content name are transmitted together with the address of the edge server 102. This content request information is delivered to the center server 101 via the network 105. Upon receiving the content request information from the edge server 102, the receiving unit 115 in the center server 101 passes the address of the client 106, the address of the edge server 102, and the content name to the reservation management unit 117.

The reservation management section 117 has a reservation list shown in FIG. In the reservation list, the distribution order of the requested content, the content name, and the destination are entered. When there are a plurality of distribution destinations of one content, a plurality of destinations are entered for one content. Reservation management unit 117
Receives the content request information, searches the reservation list to see if the same content has already been reserved. When the same content is not reserved, the reservation management unit 117
Determines the order of transmission, and writes the content name, the client address and the edge server address as the destination in the reservation list.

In FIG. 3, the client 106 requests the content A, the reservation management unit 117 determines that the transmission order is the third, and the address 106.117.56.165 of the client 106 and the address of the edge server 102 are set as the destination 1 of the reservation list. Ten
An example with 6.117.56.210 entered is shown.

Next, the client 110 is connected to the center server 1
When requesting the same content as the client 106 to the client 01, the client first transmits a content request packet to the edge server 103 to which the client is connected. The edge server 103 operates in the same manner as the edge server 102, and sends the address and the content name of the client 110 to the center server 101 as content request information.
Sent with the address of 03. This content request information is delivered to the center server 101 via the network 105. Upon receiving the content request information from the edge server 103, the receiving unit 115 in the center server 101 receives the address of the client 110 and the edge server 10
3 is passed to the reservation management unit 117. The reservation management unit 117 searches the reservation list to determine whether the same content has already been reserved. Client 1 already
Since 06 has reserved the same content, the reservation management unit 17 writes the address of the client 110 and the address of the edge server 104 as the distribution destination of the content in addition to the destination already reserved in the reservation list.

In FIG. 3, the client 110 requests the same content A as the client 106, and the reservation management unit 1
7 is an address 140.75.1 of the client 110 as the destination 2 of the content A already reserved as the transmission order 3.
An example in which 6.146 and the address 140.75.16.130 of the edge server 103 are entered is shown.

Next, the reservation management unit 117 notifies the transmitting unit 116 of the information reserved in the reservation list, that is, the content name and the destination address in the transmission order. For example, when the order of transmitting the content A in the transmission order 3 in the reservation list shown in FIG.
06 and 110 and Edge Servers 102 and 103
To the transmitting unit 116. The transmitting unit 116 assigns a multicast address to the content A, and notifies the network 105 of the multicast address and the addresses of the destination edge servers 102 and 103 as network setting information. The network 105 sets a router or a switch so that the packet with the notified multicast address is transmitted to the edge servers 102 and 103. When the setting is completed, the network 105 notifies the receiving unit 115 of the completion of the setting, and the receiving unit 115
Notifies the transmitting unit 116 that the setting of the network 105 has been completed. Further, the transmission unit 116 transmits the address of the client 106, the content name, and the multicast address thereof to the edge server 102 as distribution information.
03, the address of the client 110, the content name and its multicast address are notified.

[0017] The reservation management unit 117 includes the content storage unit 11.
8 to send the content A to be transmitted to the clients 106 and 110 to the transmitting unit 116. The content storage unit 118 sends the content A to the transmission unit 116, and the transmission unit 116 sends the content A to the edge servers 102 and 103.
Send The network 105 sends the content A to the edge servers 102 and 103 by multicast. When the transmission is completed, the transmission unit 116 notifies the reservation management unit 11 of the end of the transmission.
Notify 7. In response, the reservation management unit 117 notifies the transmission unit and the content management unit 118 of the next reservation information.

When the receiving unit 119 of the edge server 102 starts receiving the content A, the receiving unit 119 notifies the transmitting unit 120 of the reception start together with the address of the client 106 and the content name. Then, the received content A is stored in the buffer 12.
Save to 1. Upon receiving the start of reception, the transmission unit 120 reads the content A from the buffer 121 at a speed corresponding to the processing capacity of the client 106 and the bandwidth of the access line, and transmits the content A to the client 106.

The edge server 102 has a client 106
As a method of transmitting content to the client 106 at a speed according to the processing capacity of the client or the bandwidth of the access line,
For example, there is a method using TCP (Transmission Control Protocol). When using TCP, client 1
06 receives the content packet and returns an acknowledgment ACK notifying the reception to the edge server 102. Upon receiving the ACK, the edge server 102 transmits the next packet of the content to the client 106.
The content is transmitted by repeating this operation. When the ACK is received, the edge server 102 gradually increases the transmission speed by shortening the transmission interval of the next packet. If the client 106 fails to receive the packet due to the processing capacity of the client 106 or the restriction on the bandwidth of the access line, the edge server 102 knows that the packet was not received because no ACK is returned, and extends the packet transmission interval. And reduce the transmission speed.
Then, the non-received packet is retransmitted. By using TCP in this manner, the edge server 102 can transmit contents to the client 106 at a speed that matches the processing capability of the client 106 and the bandwidth of the access line.

That is, the edge server 102 converts the content addressed to the client 106 received from the center server 101 via the network 105 into a speed that can be received by the client 106 and transmits the content to the client 106. The edge server 103 operates in the same manner as the edge server 102, so that the center server 101
5 and is converted into a speed that can be received by the client 110 and transmitted to the client 110.

The network 105 connecting the center server and the edge server may be a physically different network from the network used for other communications. Also,
The network 105 may be a network that is logically configured by securing resources among other networks used for communication. The network 10
5 is a network used for other communications,
The network may be set so that the packet transmitted from the center server is transmitted with the highest priority. As a method of giving the highest priority to a packet transmitted from the center server 101, the network 105 can be set by a switch or a router that can set the priority according to the source address.
DiffServ (Differentiated Servicing), which determines the order of processing according to the mark of each packet by sending a packet with a mark indicating the priority order
es).

[0022]

In the content distribution system described above, the center server can transmit the content to all the edge servers at the same speed.
More clients can be bundled into one multicast group and distributed at once. Therefore, the center server can efficiently distribute more contents than the conventional distribution method.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a content distribution system according to the present invention.

FIG. 2 is a configuration diagram of an embodiment of a center server 101 of the content distribution system shown in FIG.

FIG. 3 is a diagram showing an example of a reservation list managed by a reservation management unit 117 of the center server 101.

FIG. 4 is a configuration diagram of an edge server 102 of the content distribution system shown in FIG.

FIG. 5 is a configuration diagram of a conventional content distribution system.

[Explanation of symbols]

 101 center server 102-104 edge server 105 network 106-114 client 115 receiving unit 116 transmitting unit 117 reservation management unit 118 content storage unit 119 receiving unit 120 transmitting unit 121 buffer

Claims (4)

[Claims] 1. A content distribution system for distributing requested content from a center server to a plurality of clients via a network, wherein a plurality of edge servers are arranged on a client side of the network, wherein the center server stores the content. Receiving the content request from the client, reserves the type and destination of the content, and reserves the destination of multiple clients as the destination of the content when the same content is requested by multiple clients Means for reading the reserved content from the storage means and transmitting the content by multicast when there are a plurality of destinations, wherein the edge server transfers a content request from the client to the center server. From the center server Means for receiving the content, converting the received content to a destination client to a communication speed that can be received by the client, and transmitting the converted content. The network allocates certain resources between the center server and all edge servers. A content distribution system having a function of securing the content and transmitting the content by multicast from the center server to the edge server. 2. The content distribution system according to claim 1, wherein said network includes means for transmitting a packet of the content transmitted from the center server to the edge server with the highest priority. 3. A method for distributing requested content from a center server to a plurality of clients via a network, wherein a plurality of edge servers are arranged on a client side of the network, and the edge server receives a request for content from the client as a center. Transfers to the server, the center server receives the content request from the client, reserves the type and destination of the content, and if the same content is requested from multiple clients, multiple clients as the destination of the content The destination is reserved, and the reserved content is read from the storage means. If there are a plurality of destinations, the content is transmitted by multicast. If the center server transmits the content by multicast, the network is transmitted to the center server and all the edge servers. Between and multi That the edge server receives the content sent from the center server, converts the received content to the destination client at a communication speed that can be received by the client, and sends it. Characteristic content distribution method. 4. The content distribution method according to claim 3, wherein the network is set to transmit a packet of the content transmitted from the center server to the edge server with the highest priority.