JP2002111649A - Multicast communication method, server device and client device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method and apparatus capable of easily managing and controlling a receiver of multicast communication data in multicast communication using IGMP. SOLUTION: A content server device for distributing multicast data, a routing device of an IP layer, a key management server device for managing encryption and decryption keys, a reception management server device for managing a client device, and receiving the multicast data Including a client device, the content server device encrypts the multicast data and distributes the data on the IP network, the client device requests the key management server device to obtain a decryption key, and the key management server device receives the decryption key. The reception management server device permits the distribution of the decryption key, the key management server device distributes the decryption key to the client device, and the client device transmits the multicast data. Decrypt the cipher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data communication in an IP network using a routing device, a switch, and the like, and more particularly to a communication method and apparatus for multicast communication that is point-to-multipoint communication.

[0002]

2. Description of the Related Art When performing point-to-multipoint communication in an IP network, techniques such as broadcast and multicast can be used. In particular, when multicast is used, data can be transmitted only to those who want to receive the data, and the bandwidth can be effectively used. As a protocol for realizing the multicast, there are a sender-based protocol and a receiver-based protocol. However, since the sender-based protocol is not implemented in most routing devices and Layer 3 switches, when performing multicast communication, the receiver-based multicast protocol IGMP is often used.

FIG. 1 is a diagram for explaining a multicast communication method using IGMP. In the case of receiving data, for example, the client device 111 desiring to make a reception makes a reception request 142 to the routing device 112 which is the terminal point of IGMP, and the routing device 112 starts data transmission 143. When stopping the data reception, for example, the client device 121 desiring to stop the reception makes a stop request 144 to the routing device 122 that is the terminal point of the IGMP, and the routing device 12
2 stops 145 data transmission.

As described above, in the method using IGMP, both the reception request and the stop request of the client are I
Since this is performed for the terminal routing device of GMP, it is not necessary for the transmitting server to manage communication. Such a method is an effective method in consideration of scalability.

[0005] However, since the server does not perform management, it is impossible to know the client that is receiving data. In addition, IGMP itself does not have a function of performing reception management, while an IGMP routing device manages a reception client, but does not actually specify and manage the client, but rather manages the subnet to which the client belongs. , It is impossible to identify the client. As described above, in the multicast communication using IGMP, there is a problem that it is difficult to perform a charging process, for example, because management and control of the data receiver are difficult.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus capable of easily managing and controlling recipients of multicast communication data in multicast communication using IGMP in view of the above problems. Is to provide.

[0007]

A multicast communication method according to the present invention manages a content server device for distributing multicast data, a routing device of an IP layer, a key management server device for managing encryption and decryption keys, and a client device. A multicast communication method in a multicast communication system including a reception management server device that performs multicast data transmission, and a client device that receives multicast data. The receiving device issues a reception request to the routing device that is the terminal point of the protocol. When the receiving device receives the reception request, the routing device distributes the multicast data to the client device. Requesting the decryption key to the server device, and upon receiving the decryption key acquisition request, the key management server device inquires of the reception management server device whether the decryption key can be distributed. Upon receiving the inquiry about whether or not the distribution of the decryption key is possible, the reception management server device notifies the distribution permission of the decryption key according to the recorded reception status of the client device and holds the reception information, and the key management server Upon receiving the decryption key distribution permission notification, the device distributes the decryption key to the client device, and upon receiving the decryption key, the client device uses the decryption key to distribute the decryption key. Decrypting the encrypted multicast data.

According to the multicast communication method of the present invention, when stopping the multicast communication, the client device issues a reception stop request to the routing device which is the end point of the multicast protocol, and the routing device stops the reception. Upon receiving the request, the distribution of the multicast data is stopped to the client device, the client device notifies the key management server device of the reception stop, and the key management server device receives the reception stop notification from the client device. And notifies the reception management server device of the reception stop, and the reception management server device
Upon receiving the reception stop notification, the received reception information of the client device is deleted, the reception status is recorded, a reception stop notification acknowledgment response is sent to the key management server device, and the key management server device Upon receiving the notification acknowledgment,
The reception stop notification acknowledgment response is sent to the client device, and the client device receives the reception stop notification acknowledgment response and confirms reception stop.

Further, according to the multicast communication method of the present invention, when the decryption key is changed, the content server changes the encryption key, notifies the key management server of the change, and the key management server changes the encryption key. Holding the contents, the client device notifies the client device of the change of the decryption key. Upon receiving the change notification of the decryption key, the client device issues a request for obtaining the decryption key to the key management server device, A modified decryption key is obtained.

Further, a key management server device for managing an encryption / decryption key in a multicast communication system using IP according to the present invention comprises: means for responding to a request for obtaining a decryption key from a client device; Means for inquiring of the server device whether the decryption key can be distributed to the client device, means for distributing the decryption key in response to the response of the reception management server device, and stopping reception of multicast data from the client device Means for receiving the notification, means for notifying the reception management server device of reception stop of the client device, means for receiving a reception stop notification acknowledgment response from the reception management server device,
And a means for performing a reception stop notification acknowledgment response to the client device.

Further, the key management server device of the present invention further comprises means for updating the encryption key at fixed time intervals, means for holding the updated encryption key, and Means may be provided for notifying the client device receiving the multicast data of the change of the decryption key.

Further, a reception management server device for managing reception of a client device in a multicast communication system using IP according to the present invention is adapted to respond to an inquiry as to whether the key management server device can distribute a key to the client device. Means, means for holding the information of the client device according to the content of the inquiry, means for receiving a reception stop notification of the client device from the key management server device,
Means for giving a reception stop notification acknowledgment response to the key management server device, means for deleting the holding information of the client device in response to the reception stop notification, and means for recording the reception status in response to the reception stop notification It is characterized by having.

Further, the client device in the multicast communication system using the IP of the present invention is provided with a means for sending a reception request and a means for making a request for obtaining a decryption key to the key management server device. Means for decoding the multicast data using the decryption key, means for sending a reception stop request, means for notifying reception to the key management server device, and
It is characterized by comprising means for receiving a reception stop notification acknowledgment response from the key management server device.

Further, the client device of the present invention further comprises means for receiving a change notification of the decryption key from the key management server device, and the decryption key to the key management server device in response to the change notification. Means for making an acquisition request.

[0015]

Next, embodiments of the present invention will be described. FIG. 2 is a diagram for explaining an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of a content distribution IP network using a receiving-side base multicast protocol IGMP. In the IP network shown in the figure, a content server device 41 for distributing multicast data, routing devices 12, 22, 32, and 42 for the IP layer, a key management server device 51 for managing encryption and decryption keys, and a client device , And client devices 11, 21, and 31 that receive multicast data. The multicast data is encrypted and distributed 61 from the content server device 41 into the IP network.

Next, an operation when the client device 11 receives multicast data will be described. The client device 11 sends a reception request 71 to the routing device 12 that is the end point of the multicast protocol.
I do. When the routing device 12 receives the reception request,
The distribution 72 of the multicast data to the client device 11 is started. Thereafter, the client device 11 makes a request 73 for obtaining a decryption key to the key management server device 51.
Upon receiving the decryption key acquisition request, the key management server device 51 makes an inquiry 74 to the reception management server device 52 as to whether the decryption key can be distributed. When receiving the inquiry about whether or not the distribution of the decryption key is possible, the reception management server device 52 performs a decryption key distribution permission notification 75 according to the recorded reception status of the client device 11 and holds the reception information. Upon receiving the decryption key distribution permission notification, the reception management server device 52 distributes the decryption key to the client device 11. Upon receiving the distribution of the decryption key, the client device 11 decrypts the distributed multicast data using the decryption key.

Next, an operation when the client device 21 stops receiving multicast data being received will be described. The client device 21 is a routing device 22 that is a terminal of the multicast protocol.
, A reception stop request 81 is made. Routing equipment 22
Receives the reception stop request, the distribution stop of the multicast data to the client device 21 is performed 82. Thereafter, the client device 21 sends a reception stop notification 83 to the key management server device 51. Upon receiving the reception stop notification from the client device 21, the key management server device 51 sends a reception stop notification 84 to the reception management server device 52. Upon receiving the reception stop notification, the reception management server device 52 deletes the held reception information of the client device 21, records the reception status, and sends a reception stop notification acknowledgment response 85 to the key management server device 51. Do. Upon receiving the reception stop notification acknowledgment response, the key management server device 51 sends a reception stop notification acknowledgment response 86 to the client device 21. Client device 21
Receives the reception stop notification acknowledgment and confirms reception stop.

Next, the operation for changing the encryption / decryption key for multicast data will be described. The content server device changes the encryption and decryption keys, for example, at regular intervals, notifies the key management server device of the change, and the key management server device holds the content. For example, it is assumed that the client device 31 has received multicast data for which a decryption key is changed. The key management server device 51 sends a decryption key change notification 91 to the client device 31. Upon receiving the decryption key change notification, the client device 31 issues a decryption key acquisition request 92 to the key management server device 51. Upon receiving the decryption key acquisition request, the key management server 51 makes an inquiry 93 to the reception management server 52 as to whether or not the decryption key can be distributed. When receiving the inquiry about whether or not the distribution of the decryption key is possible, the reception management server 52 issues a decryption key distribution permission notification 94 in accordance with the recorded reception status of the client device 31, and holds the reception information. Upon receiving the decryption key distribution permission notification, the reception management server device 52 distributes the decryption key 95 to the client device 31. Upon receiving the distribution of the decryption key, the client device 31 decrypts the distributed multicast data using the newly obtained decryption key.

According to the above example, the key management server device and the reception management server device receive and process the request for receiving the multicast protocol of the multicast data, the request for stopping the reception, and the request for obtaining the decryption key. The device makes it possible to manage and control the reception status of the client device.

In the above example, the case where the IP network includes one content server device, one key management server device, and one reception management server device has been described, but the IP network may include a plurality of these devices. Of course. Also, three client devices and four routing devices are shown, but the number is of course not limited. Also, an example is shown in which one client device is connected under the routing device at the end point of the multicast protocol. However, it is needless to say that the number is not limited. Also, in the above description, an example in which the key management server device and the reception management server device are separate devices has been described.
It goes without saying that a server device having both functions may be used.

Further, the present invention provides a method for routing information between routing devices, between a routing device and a client device, between a routing device and a content server device, between a routing device and a key management server device, and between a routing device and a key management server device. It does not depend on a communication line, a communication method, and a communication device between the server and the reception management server device. Further, the content distributed from the content server device may be any type of data such as block data and stream.
Further, the order of the reception request and the decryption key acquisition request by the multicast protocol in the client device is not limited to the above example, and can be arbitrarily determined. Similarly, the order of the reception stop request by the multicast protocol and the reception stop notification to the key management server device in the client device is not limited to the above example, and can be arbitrarily determined.

[0022]

As described above, according to the present invention,
In multicast communication, a receiver-based multicast protocol is used, and by combining a key management server that manages encryption and decryption, management and control of a receiver of multicast communication data, which has been impossible in the past, can be performed. Become.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a multicast communication method using IGMP.

FIG. 2 is a diagram for explaining an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 11, 21, 31 Client device 12, 22, 32, 42 Routing device 41 Content server device 51 Key management server device 52 Reception management server device 111, 121, 131 Client device 112, 122, 132 Routing device

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Norihito Ienaga 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5J104 AA01 AA16 EA01 EA04 EA16 MA08 NA02 PA11 5K030 GA15 HA08 HD03 KA06 KX28 LB02 LB03 LD05

Claims (9)

[Claims] 1. A content server device for distributing multicast data, a routing device of an IP layer, a key management server device for managing encryption and decryption keys, a reception management server device for managing client devices, and receiving multicast data A multicast communication method in a multicast communication system that includes a client device that performs a multicast communication method in which a content server device encrypts multicast data and distributes the data on an IP network, and the client device transmits a multicast data to a routing device that is an end point of the multicast protocol. Upon receiving the reception request, the routing device distributes the multicast data to the client device, and the client device requests the key management server device to obtain the decryption key, and Upon receiving the decryption key acquisition request, the management server device queries the reception management server device whether the decryption key can be distributed, and the reception management server device queries the decryption key distribution availability. Upon receiving the notification, the key management server device sends a decryption key distribution permission notification according to the recorded reception status of the client device and holds the received information. The client device distributes a decryption key to the client device. Upon receiving the decryption key, the client device decrypts the distributed multicast data using the decryption key. Multicast communication method. 2. A content server device for distributing multicast data, a routing device for an IP layer, a key management server device for managing encryption and decryption keys, a reception management server device for managing client devices, and receiving multicast data. A multicast communication method in a multicast communication system including a client device that performs a multicast communication, wherein when the multicast communication is stopped, the client device makes a reception stop request to a routing device that is a termination point of the multicast protocol, and the routing device When receiving the reception stop request, the client device stops the distribution of the multicast data to the client device, the client device notifies the key management server device of the reception stop, and the key management server device Upon receiving the reception stop notification, the reception management server device notifies the reception management server device of the reception stop. Upon receiving the reception stop notification, the reception management server device deletes the held reception information of the client device and records the reception status. Performing a reception stop notification acknowledgment response to the key management server device. When the key management server device receives the reception stop notification acknowledgment response, the key management server device performs a reception stop notification acknowledgment response to the client device. A multicast communication method, comprising: receiving a reception stop notification acknowledgment and confirming reception stop. 3. A content server device for distributing multicast data, a routing device of an IP layer, a key management server device for managing encryption and decryption keys, a reception management server device for managing client devices, and receiving multicast data. A multicast communication method in a multicast communication system including a client device that performs a key management, wherein when changing a decryption key, the content server device changes the encryption key, and notifies the key management server device of the changed content; The server device holds the content, and notifies the client device of the change of the decryption key. When the client device receives the change notification of the decryption key,
Requests the decryption key to the key management server device,
A multicast communication method characterized by acquiring a changed decryption key. 4. A key management server device for managing encryption and decryption keys in a multicast communication system using IP, comprising: means for responding to a request for obtaining a decryption key from a client device; Means for inquiring of the device whether the decryption key can be distributed to the client device, means for distributing the decryption key in response to the response of the reception management server device, notification of reception stop of multicast data from the client device Receiving means for notifying the reception management server apparatus of the reception stop of the client apparatus, means for receiving the reception stop notification acknowledgment response from the reception management server apparatus, and A server device comprising means for performing a reception stop notification acknowledgment response. 5. A reception management server device for managing reception of a client device in a multicast communication system using IP, wherein the key management server device responds to an inquiry as to whether a key can be distributed to the client device. Means, means for retaining information of the client device according to the contents of the inquiry, means for receiving a reception stop notification of the client device from the key management server device, and for receiving a reception stop notification acknowledgment response to the key management server device Means for deleting the information held in the client device in response to the reception stop notification, and means for recording the reception status in response to the reception stop notification. 6. A method for managing encryption and decryption keys in a multicast communication system using IP, and
6. A server device for managing reception of a client device in a multicast communication system utilizing the method, wherein the server device includes the units according to claim 4 and 5. 7. The server device according to claim 4, further comprising: means for updating the encryption key at predetermined time intervals; means for holding the updated encryption key; A server device for notifying a client device receiving the multicast data of a change in the decryption key in response to the request. 8. A client device in a multicast communication system using IP, a means for sending a reception request, a means for making a request for obtaining a decryption key to a key management server device, Means for decoding multicast data using a decoding key, means for sending a reception stop request, means for notifying reception stop to a key management server, and key management server A means for receiving a reception stop notification acknowledgment response from the client device. 9. The client device according to claim 8, further comprising: means for receiving a change notification of the decryption key from the key management server device; and responding to the change notification to the key management server device. A means for making a request to obtain a decryption key.