JP2002152197A - Device and method for network control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the efficient use of a network when data are distributed from a server to multiple clients. SOLUTION: This network controller controls the distribution of multicast data by a hierarchical network composed of multiple layers including upper and lower networks; and a router proxy 203 judges whether or not the multicast data are distributed from the upper network to the lower network on the basis of a specific criterion and distributes the multicast data according to the judgement result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In a system in which data is distributed by multicast from a data distribution server connected to a fixed network and data is received by a mobile host having a wireless communication function, a distribution route is changed according to the movement of the mobile host. The present invention relates to a network control device and method for changing.

[0002]

2. Description of the Related Art When data is distributed from a data distribution server and the number of recipients of the data is large, it is possible to reduce network load by applying multicast communication.

[0003] IP (Internet Protocol)
1) In IG, which is a routing control protocol between an IP multicast (IP multicast) and an IP multicast router defined in RFC1112.
MP (Internet Group Management)
ent Protocol). IP multicast is a network in which routers are connected in a hierarchical structure, and sets a distribution route of multicast data between routers from a data transmission host to a data reception host based on a data reception request from a host connected to a certain router. Thus, data is distributed to a router having a data receiving host, and data is not distributed to a router having no data receiving host.

In Japanese Patent Application Laid-Open No. H11-313059, "Multicast communication method and system, and storage medium storing multicast communication program", a relay server is installed at each layer of the hierarchical structure, and a data reception request from a reception host is received. On the other hand, a multicast distribution method in which a relay server sets a route, relays data, reduces the load on a data transmission host for sending to a plurality of data reception hosts, and ensures scalability and responsiveness of the system is invented. Have been.

[0005]

In recent years, by combining a computer and wireless communication means, the communication environment of the computer has become not only fixed but also mobile. Wireless communication connects to a fixed network via a wireless network endpoint called a base station. In order to cover a wide area wirelessly with such a network, it is necessary to install a plurality of base stations. For this reason, when a computer having wireless communication means is mounted on a moving automobile or the like, it moves between a plurality of base stations. This means that movement to a different network is repeated.

[0006] Also, consider an application that runs on a moving car. For example, when data is distributed to a vehicle moving on a highway, the distribution data has time and geographical characteristics. For example, this is noticeable during busy periods such as homecoming rush. in this case,
A group of vehicles leaving the city go to each destination,
Move on the road. Therefore, the transmission destination for transmitting the distribution data also moves on the road.

[0007] IP multicast and JP-A-11-313
059 “Multicast communication method and system, and storage medium storing multicast communication program”
Achieves the purpose of distributing data to data receiving hosts.For example, when many receiving hosts are connected to the same router in a concentrated manner, network utilization efficiency increases. Even in a case where data is distributed, a route is set for a reception request, so that even if the data distribution itself is inefficient for a network, data transmission cannot be stopped. .

Returning to the example of the automobile described above, it is efficient that the vehicle at the center of the group distributes the multicast data to a dense area, but the multicast data distribution to the sparse area at the end of the group is efficient. Doing so is inefficient. In such a case, it is necessary to evaluate the necessity and efficiency of the distribution of the data together, and to be able to execute and stop the distribution.

SUMMARY OF THE INVENTION It is an object of the present invention to increase the efficiency of use of a network when distributing data from a server to a plurality of clients by treating a set of hosts that receive a plurality of moving data as a group. I do.

[0010]

A network control device according to the present invention is a network control device for controlling distribution of multicast data in a hierarchical network including a plurality of layers including an upper network and a lower network. It is determined whether or not to distribute the multicast data from the upper network to the lower network based on the criterion described above, and the multicast data is distributed based on the determined result.

The network control device receives a reception request for distribution of multicast data, and, based on a predetermined criterion, determines whether to transmit the multicast data whose distribution is requested in the received reception request to a lower network. It is characterized by having a proxy for judging whether or not it is.

The proxy exists in the lower network, receives the reception request, accumulates the received reception request, and transmits the accumulated reception request to the upper network. And
Each of the plurality of first proxies receives the received request, analyzes the received request, selects a network located between the upper network and the lower network based on the analysis result, and distributes the received request. A second proxy that transmits the requested multicast data to the selected network; and a second proxy that exists in the selected network, has the predetermined criterion, receives multicast data from the second proxy, And a third proxy that selects a first proxy existing in the lower network that transmits the multicast data and transmits the multicast data to the selected first proxy based on the determination criterion.

The second proxy generates destination information on a destination to which multicast data is to be transmitted from the received reception request, and transmits the generated destination information to the third proxy existing in the selected network in addition to the multicast data. Wherein the third proxy receives the destination information in addition to the multicast data, and selects a lower network to transmit the multicast data based on the predetermined criterion and the received destination information. .

[0014] The second proxy counts the number of hosts that have transmitted the reception request, transmits the totaled number of hosts to the third proxy while including the number of hosts in the destination information, and the third proxy receives the received request. A lower network for transmitting multicast data is selected by using the number of hosts included in the destination information.

The third proxy uses the number of hosts and a predetermined threshold as the predetermined criterion.

[0016] The third proxy uses the number of hosts, the total number of reception requests received by the second proxy, and a predetermined threshold as the predetermined criterion.

The second proxy has a plurality of criteria, and selects and uses one of the plurality of criteria for each request for receiving multicast data.

The network control device includes a plurality of third proxies, wherein the second proxy selects at least one third proxy for each request for receiving multicast data, and the selected third proxy selects a multicast A lower network for transmitting multicast data is selected for each data reception request.

The second proxy designates a predetermined range of the network in advance, and selects a third proxy existing within the predetermined range.

The first proxy has a reception request table for storing a reception request, transmits the reception request stored in the reception request table to the second proxy, and the second proxy receives the reception request based on the received reception request. And a destination information table for generating the destination information and storing the generated destination information.

If the plurality of first proxies do not receive a reception request again from an arbitrary host within a predetermined period, the plurality of first proxies delete the reception request of the arbitrary host from the reception request table. And

The network control device includes a gateway, a router, and a plurality of base stations, each of the plurality of first proxies is provided in each of a plurality of base stations, and the second proxy is provided in a gateway. The third proxy is provided in a router.

[0023] The network control method according to the present invention comprises:
In a network control method for controlling distribution of multicast data in a hierarchical network including a plurality of layers including an upper network and a lower network, the multicast data is distributed from the upper network to the lower network based on a predetermined criterion. Or not, and multicast data is distributed based on the result of the determination.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment of the present invention will be described. FIG. 1 shows a network configuration of the present invention. 101 and 102 are application servers. 103 and 104 are network gateways including a wireless network. 105 to 112 are routers. Reference numerals 113 to 119 denote base stations for connecting a wireless network and a wired network. 120, 121
Is a mobile host with a wireless device. Reference numeral 122 denotes a public network. The network of FIG. 1 has an access network including a wired network and a wireless network that connects a mobile host with a gateway at the top, and each access network and an application server are connected by a public network. It has a hierarchical structure.

In FIG. 1, the public network 122 has an IP (I
Internet Protocol) can be used. It is also assumed that IP can be used in the wired network part of the access network. In the wireless network portion of the access network, I
It is assumed that a communication protocol that supports unicast and multicast other than P can be used. Of course, I
P is also acceptable. The public network 122 is not limited to the public network, but may be a LAN (Local Area Network).
k) or a dedicated line may be included, and any communication network that can distribute data may be used. The system shown in FIG. 1 is intended to perform multicast data distribution from the application servers 101 and 102 to a plurality of mobile hosts 120 and 121.

FIG. 2 shows the connection of the components operating in each device of FIG. 201 is a server application. 202 is a gateway proxy (second proxy). 203 is a router proxy (third proxy)
It is. 204 is a mobile proxy (first proxy). 205 is a mobile application. Each proxy described above is a mechanism for relaying data transfer on a network, and is described on the assumption that it can be realized by software.

The server application 201 runs on any of the application servers 101 and 102. The gateway proxy 202 is a gateway 1 of an access network to which multicast data is distributed.
03,104. The router proxy 203 includes gateways 103 and 104 of the access network, all routers 105 to 112, and base stations 113 to 119.
Works with The mobile proxy 204 also operates on all base stations 113-119 of the access network. The mobile application 205 runs on all the mobile hosts 120 and 121. The function of each software will be described later.

First, the operation of distributing multicast data in the entire system will be described. In the operation of this system, a server application running on the application servers 101 and 102 performs multicast data distribution, and a mobile application 205 running on the mobile hosts 120 and 121 makes a data reception request (also referred to as a “delivery request”). When the multicast data distribution is performed, the mobile application 205
Is sent to

FIG. 3 shows the flow of multicast data between software. A request for delivery of multicast data from the mobile application 205 is sent to the gateway proxy 202 via the mobile proxy 204.
It is transmitted to. The gateway proxy 202 designates the router proxy 203 including the requested mobile proxy 204 below the hierarchy as a relay proxy, and at the same time,
Router proxy 2 that has become a relay proxy for multicast data transmitted by server application 201
03. The router proxy 203 transmits multicast data to the requested mobile proxy 204, and the mobile proxy 204 transmits multicast data to the wireless network to which the mobile application 205 belongs. In this way, the multicast data is distributed.

Incidentally, just because the mobile application 205 makes a request to receive multicast data, the multicast data is not always transmitted to the mobile application 205. The three proxies, the gateway proxy 202, the router proxy 203, and the mobile proxy 204, control the route of the multicast distribution of the server application, and execute and stop the distribution to the mobile application.

Next, a description will be given of distribution path control performed in the course of multicast distribution. In this embodiment, the multicast distribution path control implements the following two path controls. The first distribution route control is performed by the gateway proxy 202. Based on the data reception request from the mobile proxy 204, the gateway proxy 202 includes all the mobile proxies 204 that are making the reception request, and designates a relay proxy to the router proxy 203 in a hierarchy close to the mobile proxy 204. . In FIG. 1, when a request for receiving multicast data is issued from the mobile proxy 204 of the base station 113 to the gateway 103, the base station 113
Router proxy 203 becomes a relay proxy. When there is a reception request from the base stations 113 and 114, the router 10
7 is a relay proxy. From the base stations 113, 114, and 116, the router proxy 203 of the gateway 103 serves as a relay proxy.

As described above, a plurality of router proxies 203 exist in the access network (the number thereof depends on the network configuration), but the router proxy 2 that operates as a relay proxy for a certain multicast address
03 is one for each access network, and this determination depends on the designation of the gateway proxy 202. As described above, the movement of the mobile hosts 120 and 121 receiving the multicast data causes the mobile host 12 and 121 to move.
Since the base stations used by 0 and 121 move, the relay proxy also moves on the access network. By the way,
The router proxy 203, which is not a relay proxy,
It becomes dormant. Hereinafter, the router proxy 203 that has become a relay proxy is referred to as a relay router proxy, and a router proxy that is in a sleep state and does not become a relay proxy is referred to as a dormant router proxy 203.

The second distribution route control is based on the relay router proxy. The relay router proxy determines, for each mobile proxy 204, whether to execute or stop data distribution to the mobile proxy 204 below the network hierarchy according to the implemented criteria. In addition, the mobile proxy 204 always transmits data received from the router proxy 203 to the mobile application 205, so that the distribution route control is performed by the relay router proxy.

The above-mentioned criterion in this embodiment is as follows.
The determination is made based on the number of simultaneous reception requests in the mobile proxy 204. Therefore, the gateway proxy 202
Is the mobile proxy 2 to the relay router proxy.
04 is provided. In this embodiment, the following two are used as criteria. However, it is not limited to these.

The first criterion will be described. When the number of receptions at the mobile proxy 204 exceeds a specified threshold, data is delivered to the mobile proxy 204. For example, if the threshold is set to 10,
When the number of reception requests (the number of mobile applications requesting reception) at the mobile proxy 204 at that time is 10 or more, the relay proxy performs data distribution to the mobile proxy 204.

The second criterion will be described. When the number of received multicast addresses of all the mobile proxies 204 (the total number of absolute requests) is the denominator, when the ratio of the number of received packets at a certain mobile proxy 204 exceeds a prescribed threshold value, To distribute data. For example, if the threshold is set to 0.7 and if all mobile applications requesting reception of the same multicast address are 100, one mobile proxy 204 can receive 70 or more reception requests. When there is, the relay proxy performs data distribution to the mobile proxy 204.

These criteria are to distribute to the mobile proxy 204 where multicast distribution requests are concentrated and not to distribute to the sparse mobile proxy 204, or to reduce the absolute number of requests. However, the distribution is not performed, so that the multicast is not always distributed, and the network is not distributed efficiently. It is used for.

In addition to the criterion described above, a simple criterion such as distribution for all mobile application requests or no distribution at all is also applicable. In addition, by realizing the algorithm of the judgment criterion in the router proxy 203, this can also be used.

Next, the multicast address will be described. The multicast address is defined by a network protocol. For example, in the case of IP multicast, the multicast address is 224.
The range is from 0.0 to 239.255.255.255. The sender and the receiver of the multicast data transmit and receive data using an arbitrary common address among them. In the present embodiment, the protocol of the wireless network portion is not IP, but the mobile host 120 recognizes, as a receiver, a multicast address to which the server application of the sender transmits data. Further, in the public network 122, since there is a possibility of being mixed with other applications, 224.0.0.0 to 239.255.2 defined in the network are used.
Of the 55.255 multicast addresses, it is necessary to define an address that can be used in the present system. Here, for convenience, 224.0.1.1 to 224.0.1.
The range of 254 is a multicast address used in the system. For this multicast address,
Gateway proxy 202, router proxy 203,
A common definition is provided for each component of the mobile proxy 204.

The protocol and the multicast address of the wireless network will be described. As a protocol in a wireless network, a protocol that supports unicast and multicast communication is used. Earlier, in the section of the multicast address, it was stated that this mobile application receives data at the IP multicast address, but the IP multicast address is the multicast address of the network protocol used between the mobile proxy and the mobile application. To map. In the present embodiment, 224.0.1.1 to 224.0.1.
The multicast address 254 of 254 is made to correspond to the network protocol multicast address.

That is, when the mobile proxy 204 transmits data to 224.0.1.1 in a wireless network section, the mobile proxy 204 converts the data to a network multicast address corresponding to the data and transmits the data. For the mobile application, the server application is 224.
When the data transmitted to 0.1.1 is received via a wireless network, 224.0.1.1 is converted to a network multicast address, as in the case of the mobile proxy 204. Receive multicast data. in this way,
IP multicast addresses are used to identify destinations in networks that combine different network protocols.

The data transmitted and received by multicast will be described. In IP multicast, the structure of a packet transmitted by multicast is defined as a datagram packet. However, the data stored in the user data portion of the packet is completely dependent on the user application. Server application 20
1 and the mobile application 205, the data structure to be stored in the user data section is defined. The gateway proxy 202, the router proxy 203, and the mobile proxy 204 are located between the server application 201 and the mobile application 205, and transmit the user data transmitted by the server application 201 to the mobile application 205. This means that when the wireless network section is not an IP network, the data section (data section) excluding the header section containing the protocol-dependent information is the data to be received.

Next, the operation of the components shown in FIG. 2 for distributing multicast data will be described. The operation of the server application 201 will be described. The server application 201 transmits data to the multicast address. As described above, the multicast address is an address in a space defined in advance in the system, and is an address known to the mobile application 205 as well. In the present embodiment, multicast data transmission is performed using a normal IP.
Follow the multicast procedure.

The operation of the gateway proxy 202 will be described. As shown in FIG. 3, the gateway proxy 202 performs two main processes. One is to transmit the multicast data received from the server application 201 to the relay router proxy, and the other is to specify the relay proxy of the router proxy 203.

The transmission of the multicast data to the relay router proxy will be described. FIG. 4 is a flowchart of the processing. This flowchart describes the processing for one multicast address. In this embodiment, in order to handle a plurality of multicast addresses,
Actually, this processing is executed in parallel with the number of multicast addresses that handle the processing.

FIG. 5 shows an example of the relay router proxy table. The relay router proxy table is a table that stores a correspondence between a multicast address and a relay router proxy. The relay router proxy table is provided in the gateway proxy 202.

Step 401 (S401 in the figure; hereinafter,
In “S” is indicated by “step” or “S”), the reception of the multicast data from the server application 201 is checked. If data has been received, the process proceeds to step 402 for transfer processing. Otherwise, return to step 401. In step 402, a search is made for a relay router proxy as a transmission destination. The search for the relay router proxy is performed using the relay router proxy table shown in FIG. The section of the multicast address described in the table is searched to obtain the relay router proxy address and the port number of the corresponding relay router proxy. In step 403, data is transmitted to this address.

The relay proxy designation process of the router proxy 203 will be described. In this process, all the multicast addresses are processed in one sequence. The relay router proxy table is also generated by this process. FIG. 6 is a flowchart of this processing. Step 601
Then, it is checked whether a mobile application reception request table has been received from the mobile proxy 204. If there is no reception, a multicast data reception request table transmission process of steps 605 and 606 is performed.

FIG. 7 is a mobile application reception request table (reception request table). According to this table, the mobile proxy 2 that generated this table
A list of mobile hosts requesting reception of all multicast addresses in 04 can be obtained. The network mobile host address indicates a unicast address of the mobile host in the wireless network, but is not used here and is ignored. Also,
The request reception time describes the time at which the mobile proxy made a request to receive a multicast address from the mobile application, but is also ignored here because it is not used here. What is needed is how many of each multicast address are required.

On the other hand, if there is a reception in step 601, the multicast data reception request table is updated in step 602. FIG. 8 is a multicast data reception request table (destination information table). This table is a table showing the number of reception requests for each multicast address from the mobile application 205 in each mobile proxy 204. According to this table, for a certain multicast address, the number of reception requests for each mobile proxy is sequentially added, so that it is possible to know how many reception requests are for each mobile proxy 204. Now, step 602
Then, the reception request for each multicast address is counted in the mobile application reception request table received in step 601 to generate a multicast data reception request table.

In steps 603 and 604, a relay router proxy is determined. First, in step 602, it is determined whether the relay router proxy needs to be moved. This determination refers to the multicast data reception request table and selects, for each multicast address, the router proxy 203 that includes all the mobile proxies 204 that are making a reception request and has a hierarchy close to the mobile proxy 204 as a relay proxy. I do. At this time, by selecting the relay proxy from among the router proxies 203 in the setting range to be set in advance, the data distribution range can be forcibly limited.

At this time, the data distribution range can be forcibly limited by selecting the relay proxy from among the router proxies in the set range in which the relay proxy is selected in advance. FIG. 9 is a relay router proxying permitted router proxy address table. This table describes, for each multicast address, a list of router proxy addresses that are permitted to become relay router proxies.
If the address of a router proxy is described in this table, it is permitted to use the router proxy as a relay router proxy. Conversely, a router proxy not described in this table cannot be a relay router proxy. Since mobile proxies exist under the router proxy hierarchy, by permitting a specific router proxy to become a relay router proxy, the mobile proxy under that router proxy hierarchy can be limited as a data distribution target range. it can.

When this table is used, the selection of the relay router proxy includes all the mobile proxies requesting reception for each multicast address with reference to the multicast data reception request table, and
The router proxy that is described in the relay router proxy-allowed router proxy address table and is close to the mobile proxy is selected as the relay proxy. The selection of the relay router proxy is performed for each multicast data distribution request. Further, the selection of the relay router proxy can be performed based on a different criterion for each distribution of the multicast data. If the relay proxy is changed for each address, in step 604, the relay router proxy table is updated, and a relay router proxy designation notification is sent to the new relay router proxy. Send a sleep notification to the proxy.

Steps 605 and 606 are the multicast data reception request table transmission processing. The multicast data reception request table is transmitted periodically to the relay router proxy. In step 605, it is determined whether a specified time has elapsed since the last transmission of this table, and if so, in step 606, the table is transmitted.

The operation of the router proxy 203 will be described. The router proxy 203 largely has two states: a dormant router proxy and a relay router proxy. FIG.
Indicates a transition between two states. In the case of a dormant router proxy, it becomes a relay router proxy when a relay router proxy designation notification is received. In the case of a relay router proxy, when a sleep notification is received, it becomes a sleep router proxy.
Both notifications are received from the gateway proxy 202. In the case of the sleep state, no processing is performed.

The operation of the relay router proxy will be described. Router proxy 203 in the relay router proxy state
Is the gateway proxy 202 as shown in FIG.
To transmit the multicast data received from the mobile proxy 204 to the mobile proxy 204. At this time, the destination mobile proxy 204 is determined by the mobile proxy table. FIG. 11 is a diagram illustrating an example of the mobile proxy table. The mobile proxy table is a table in which, for each multicast address, the address and port number of the mobile proxy to which this address is transmitted are described. The relay router proxy
A process for generating the mobile proxy table is performed.
In the present embodiment, since a plurality of multicast addresses are handled, these processes are executed in parallel by the number of multicast addresses that handle this process.

First, a process of transmitting multicast data to the mobile proxy 204 will be described. FIG.
Is a flowchart showing this operation. In step 801, first, it is checked whether or not the apparatus is in a sleep state. If it is dormant, the process returns to the first process. Otherwise, in step 802, check the reception of the multicast data from the gateway proxy 202, and if there is no data, return to the beginning. If you receive data,
In steps 803 and 804, a process of transmitting data to the mobile proxy 204 is performed. In step 803, a search process for the mobile proxy 204 that is the transmission destination is performed.
This is based on the mobile proxy table. In step 804, data is transmitted to the mobile proxy 204 determined from the mobile proxy table.

Next, a procedure for creating a mobile proxy table will be described. FIG. 13 is a flowchart showing this operation. In step 1001, it is checked whether its own router proxy 203 is in a sleep state. If not, in step 1002, it is checked whether a multicast data reception request table is received from the gateway proxy. If received, the mobile proxy 204 to be distributed is determined in step 1003.

The determination process for determining the mobile proxy 204 (S1003 in FIG. 13) is as follows.
The type will be described. The relay router proxy performs one of the two determination processes described below. However,
The determination process other than the two types described below may be performed. FIG. 14 shows a first determination process. This determination process is performed based on the multicast data reception request table. In step S1101, the table is read line by line, and
At 1102, it is checked whether the number of multicast address requests in the mobile proxy exceeds a predetermined threshold. If it exceeds, the mobile proxy 204 is added to the mobile proxy table as a distribution target. If it is determined in step S1101 that processing has been completed for all rows, this determination processing ends.

FIG. 15 shows another determination process. This determination process also uses the multicast data reception request table as before, but since the table cannot be processed as it is, a multicast data request frequency table is created as an intermediate table in step 1201. FIG.
Is a multicast data request frequency table. For the address and port number specifying the mobile proxy 204, the ratio of the request for the multicast address from the mobile proxy 204 to all requests for the same address is stored as the request frequency. This is because in the multicast data reception request table,
It can be created by calculating the total sum of the absolute number of requests for each mobile proxy 204 for the multicast address of interest, and calculating the ratio for each mobile proxy 204. Thereafter, similarly to the processing of FIG. 14, each row of the multicast data reception request frequency table is compared with a threshold value (step 1203), and
If it is more than that, it is described in the mobile proxy table as a distribution target (step 1204).

Next, the operation of the mobile proxy 204 will be described. The mobile proxy 204 has two roles shown in FIG. One is to multicast the data received from the relay router proxy to the wireless network. The other is to collect a distribution request of multicast data received from the mobile application 205, create a mobile application reception request table, and transmit it to the gateway proxy 202.

First, processing of multicast transmission to a wireless network, which is the first role of the mobile proxy 204, will be described. FIG. 17 is a flowchart of the processing. In step 1401, it is checked whether or not multicast data to be transmitted has been received. If there is data received from the relay router proxy, the multicast data is converted into a network multicast address in step 1402, and the multicast data is transmitted to the network multicast address in step 1403. FIG. 18 is a network multicast address conversion table used in conversion from a multicast address to a network multicast address. It is a correspondence table between multicast addresses and network multicast addresses.

Next, transmission processing of the mobile application reception request table, which is the second role of the mobile proxy 204, will be described. FIG. 19 is a flowchart of the processing. In step 1501, it is checked whether there is a request for receiving multicast data from the mobile application. If there is no request, step 1505
Then, the request reception time of each row in the mobile application reception request table is checked, and rows that have passed a predetermined time or more since the previous request reception are deleted. This is to detect that the mobile host 120 has escaped from the wireless zone, and this determination is made when there is no request for a certain period. As a result, even if the mobile host 120 moves to another wireless zone and issues a reception request there, the institution that duplicates the request is within the specified timeout time.

Next, if the request is received in step 1501, it is determined in step 1502 whether the request is an existing request or a new request. If the request is a new request, the network address of the mobile application 205 making the request is determined in step 1503 And the request reception time are registered in the mobile application reception request table. If the request is an existing request, the request reception time in the table is set to the current time. This is a process for extending the timer for timeout determination performed in step 1505. In step 1503 or 1504 or 1505, the update processing of the mobile application reception request table has been completed. Subsequently, step 150
At 6,1507, a periodic transmission process of the table is performed. In step 1506, it is determined whether a specified time has elapsed since the previous table transmission. If the time has elapsed, the table is transmitted to the gateway proxy.

Next, the operation of the mobile application 205 will be described. Mobile application
A request process for receiving multicast data and a process for receiving the requested data are performed. The reception process is performed by monitoring a network multicast address corresponding to the requested multicast address. This receiving process depends on the network protocol used. The conversion from the multicast address to the network multicast address is the same as the procedure in the mobile proxy.

Next, the reception request processing of the multicast data will be described. FIG. 20 is a flowchart of the operation. This reception request is made periodically within the timeout period detected by the mobile proxy 204. In step 1701, it is determined whether a specified time has elapsed as the request transmission interval. If it has elapsed, in step 1702, a request for receiving multicast data is made to the mobile proxy 204 that has designated the multicast address. The timeout time is
Mobile proxy 204, mobile application 2
05 recognizes a common value, and the request transmission interval is shorter than this timeout time.

As described above, in the hierarchical network, the network control apparatus determines whether to perform multicast distribution to a lower network or not, by integrating a reception request from a host receiving multicast data in network units. A proxy, a second proxy that accumulates the accumulated reception requests from the first proxy, and determines a third proxy based on the accumulated reception requests, or incorporates the first proxy into the distribution path as a lower network, Or a third proxy that determines whether or not to exclude, based on appropriate criteria, and distributes multicast data to be delivered to the network of the host requesting reception via the second, third, and first proxy in order. It is characterized by multicasting.

When the host receiving the multicast data is connected to the network of a certain first proxy, the network control device issues a request for distribution of the multicast data to the first proxy. When connected to the network of the first proxy, the multicast data distribution request information of the host moving between the networks of the first proxy is transmitted by making a multicast data distribution request to the new first proxy. It is the information of the route control between the second, third and first proxies in the network system.

As described above, the first criterion is that the number of hosts requesting reception of the same multicast data for each network of the first proxy is determined by the third proxy via the second proxy. The third proxy uses absolute request number information and distribution threshold information determined for each distribution of the same multicast data as a criterion for distribution path control for the first proxy.

The second criterion is that the number of hosts requesting reception of the same multicast data for each network of the first proxy is notified to the third proxy via the second proxy. Then, the third proxy uses relative request frequency information for each network and distribution threshold information defined for each distribution of the same multicast data as a criterion for distribution path control for the first proxy.

Embodiment 2 In the first embodiment, the description has been made on the assumption that each proxy shown in FIG. 3 is software, but the present invention is not limited to this. Each of the above proxies may be realized by hardware or firmware.

[0072]

According to the present invention, efficient use of the network is achieved by suppressing inefficient distribution as a network by using an appropriate evaluation for a request to receive multicast data. Is possible.

In addition, even when a mobile host that receives multicast data moves between base stations, an inefficient distribution as a network is achieved by using an appropriate evaluation for a request to receive multicast data. By suppressing this, efficient use of the network can be achieved.

Further, by applying the criterion to the distribution route control, it is possible to suppress the inefficient distribution of the network and thereby to use the network efficiently.

Further, even when a plurality of multicast distributions distinguished by a multicast address are mixed in the system,
By using an appropriate evaluation for a request to receive multicast data, it is possible to suppress the inefficient distribution of the network, thereby enabling efficient use of the network.

Further, in addition to the effect obtained when a plurality of multicast distributions are mixed, by selecting and using a plurality of algorithms, it is possible to change the evaluation criterion for each characteristic of the data to be distributed. .

Further, based on the meaning of distribution data and geographical conditions, it is possible to limit the distribution area to an area where the data is distributed and meaningful.

The software of the application server that performs data distribution can be used without changing the existing multicast protocol interface.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a network configuration according to an embodiment;

FIG. 2 is a diagram illustrating an example of a connection status of software operating in each device on a network.

FIG. 3 is a view showing an example of a relation between the operations of the software shown in FIG. 2;

FIG. 4 is a flowchart illustrating an example of an operation in which a gateway proxy transmits multicast data to a relay router proxy.

FIG. 5 is a diagram illustrating an example of a relay router proxy table.

FIG. 6 is a flowchart illustrating an example of an operation in which a gateway proxy specifies a router proxy as a relay router proxy.

FIG. 7 is a diagram illustrating an example of a mobile application reception request table.

FIG. 8 is a diagram illustrating an example of a multicast data reception request table.

FIG. 9 is a diagram illustrating an example of a relay router proxy permission permitted router proxy address table.

FIG. 10 is a diagram showing a state transition of a router proxy.

FIG. 11 is a diagram illustrating an example of a mobile proxy table.

FIG. 12 is a flowchart illustrating an example of an operation in which a relay router proxy transmits multicast data to a mobile proxy.

FIG. 13 is a flowchart illustrating an example of an operation in which a relay router proxy generates a mobile proxy table.

FIG. 14 is a flowchart illustrating an example of an operation (first determination process) in which the relay router proxy generates a mobile proxy table.

FIG. 15 is a flowchart illustrating an example of an operation (second determination process) in which the relay router proxy generates a mobile proxy table.

FIG. 16 is a diagram illustrating an example of a multicast data request frequency table.

FIG. 17 is a flowchart illustrating an example of an operation in which the mobile proxy multicast-transmits data received from the relay router proxy to the wireless network.

FIG. 18 is a diagram illustrating an example of a network multicast address conversion table.

FIG. 19 is a flowchart illustrating an example of an operation in which a mobile proxy collects a distribution request of multicast data received from a mobile application, creates a mobile application reception request table, and transmits the table to a gateway proxy.

FIG. 20 is a flowchart illustrating an example of an operation in which a mobile application requests reception of multicast data.

[Description of Signs] 101, 102 Application Server, 103, 1
04 gateway, 105-112 router, 113
~ 119 base stations, 120, 121 mobile hosts,
122 public network, 201 server application, 2
02 gateway proxy (second proxy), 203
Router proxy (third proxy), 204 Mobile proxy (first proxy), 205 Mobile application.

Claims (14)

[Claims] 1. A network control apparatus for controlling the distribution of multicast data in a hierarchical network comprising a plurality of layers including an upper network and a lower network, comprising: A network control device, which determines whether or not to distribute multicast data, and distributes the multicast data based on a result of the determination. 2. The network control device receives a reception request for requesting distribution of multicast data, and transmits, to a lower network, multicast data whose distribution is requested in the received request based on a predetermined criterion. The network control device according to claim 1, further comprising a proxy that determines whether or not to perform the operation. 3. The plurality of first proxies, which exist in a lower network, receive the reception requests, accumulate the received reception requests, and transmit the accumulated reception requests to the upper network; And receives the received requests accumulated by each of the plurality of first proxies, analyzes the received request, and selects a network located between the upper network and the lower network based on the analysis result. And a second proxy that transmits multicast data for which distribution is requested to the selected network, and that is present in the selected network, has the predetermined criterion, and receives multicast data from the second proxy. Then, based on the predetermined criterion, it exists in the lower network transmitting the multicast data. The network control device according to claim 2, further comprising: a third proxy that selects an existing first proxy and transmits multicast data to the selected first proxy. 4. The second proxy generates destination information on a destination to which multicast data is to be transmitted from the received reception request, adds the generated destination information to the multicast data, and sends the generated destination information to a third proxy existing in the selected network. Transmitting, the third proxy receives the destination information in addition to the multicast data, and selects a lower network to transmit the multicast data based on the predetermined criterion and the received destination information. The network control device according to claim 3, wherein 5. The second proxy tabulates the number of hosts that have transmitted a reception request, transmits the total number of hosts included in the destination information to the third proxy, and the third proxy receives the reception request. 5. A lower network for transmitting multicast data is selected using the number of hosts included in the destination information.
The network control device according to claim 1. 6. The network control device according to claim 5, wherein the third proxy uses the number of hosts and a predetermined threshold as the predetermined criterion. 7. The method according to claim 7, wherein the third proxy uses the number of hosts, the total number of reception requests received by the second proxy, and a predetermined threshold as the predetermined criterion. 6. The network control device according to 5. 8. The method according to claim 3, wherein the second proxy has a plurality of criteria, and selects and uses one of the plurality of criteria for each request for receiving multicast data. A network control device according to any one of the above. 9. The network control device comprises a plurality of third proxies, wherein the second proxy selects at least one third proxy for each request for receiving multicast data, and wherein the selected third proxy is 9. The network control device according to claim 3, wherein a lower-level network for transmitting the multicast data is selected for each multicast data reception request. 10. The network control device according to claim 3, wherein the second proxy designates a predetermined range of the network in advance, and selects a third proxy existing within the predetermined range. 11. The first proxy includes a reception request table for storing a reception request, transmits the reception request stored in the reception request table to the second proxy, and the second proxy receives the reception request. The network control device according to claim 4, further comprising a destination information table that generates destination information based on the destination information and stores the generated destination information. 12. If the plurality of first proxies do not receive a reception request again from an arbitrary host within a predetermined period, delete the reception request of the arbitrary host from the reception request table. The network control device according to claim 11, wherein: 13. The network control device includes a gateway, a router, and a plurality of base stations, each of the plurality of first proxies is provided in each of a plurality of base stations, and the second proxy is a gateway. The network control device according to claim 3, wherein the third proxy is provided in a router. 14. A network control method for controlling distribution of multicast data in a hierarchical network composed of a plurality of layers including an upper network and a lower network, comprising: from the upper network to the lower network based on a predetermined criterion. A network control method comprising: determining whether to distribute multicast data; and distributing the multicast data based on a result of the determination.