JP2002091843A - Server selection device, server selection method, and recording medium recording server selection program - Google Patents

Abstract

(57) [Summary] [Problem] Considering the amount of resources required for service provision,
In addition, a server that is close to the user is selected. A distance obtaining unit that obtains a distance between a user and a server from user identification information and a server identification information, a remaining resource amount obtaining unit that obtains a remaining resource amount of the server from server identification information, User identification information,
A server list and a required server resource amount are input, and a remaining resource amount is obtained by the remaining resource amount obtaining means for each of the servers described in the server list, and the server resource amount for which the remaining resource amount is required is obtained. Server selecting means for preferentially selecting a server having a shorter distance to the user obtained by the distance obtaining means from among the surpassing servers and outputting server identification information as a server selection result. is there.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a server selecting method and apparatus for selecting a server apparatus to be accessed by a user who uses the service when a plurality of server apparatuses on a communication network provide the same service. In particular, the present invention relates to a technique for ensuring that a selected server can secure resources required for providing a service and ensuring that a distance from a user is short.

[0002]

2. Description of the Related Art With the explosive spread of the Internet in recent years, an increase in the load on a server device that processes requests from clients on the Internet has become a serious problem. In order to solve this, a server load distribution method is generally used in which a plurality of servers having the same function are prepared, and processing requests from clients are evenly distributed to the plurality of servers. The conventional method related to server load distribution is explained in more detail. The simplest method is to have multiple servers that provide the same service,
URLs of those servers (Uniform
Resource Locator). If the processing speed is slow enough for a user who accesses one of these servers to feel uncomfortable, a high-speed service can be enjoyed by accessing another server at his / her will.

However, in this method, it is necessary to notify a user of a plurality of servers in advance, and it becomes difficult to notify a user in accordance with a change, addition, or deletion of a server depending on a means of the notification. The most common notification method is HTML
(HyperText Markup Language) This is a method to write links to multiple servers on the page. However, every time a server is added, changed, or deleted, the link destination written on the HTML page must be changed. , It is inconvenient from the viewpoint of homepage maintenance. Further, in this method, since the server is selected only by the user's judgment, it is impossible to distribute the load equally for each server, and it is difficult to adjust the server load based on the intention of the service provider.

[0004] At present, a server load balancing device for solving these problems has been put to practical use. The server load distribution device generally has a function extended to a DNS (Domain Name System) server. The server load balancer includes means for receiving an address resolution request of a certain URL from a client and selecting one server from a group of servers to be managed by the server load balancer by random or round robin. ,
A means is provided for notifying the client of the IP address. With this function, processing requests to the server can be distributed based on the intention of the service provider, not the intention of the user.

[0005] Also, Nikkei Electronics 2000 3
According to the description of the issue of the month 20 issue p.114, the server selection method is not limited to the above-described method using random numbers and round robin, but also a method of weighting round robin, a method of assigning a priority order to servers, and a method of connection. There is a server load balancing device that selects a server based on various parameters, such as a method of allocating a server with the smallest number, a method of allocating a server with the fastest response time, and a method of allocating a server with the lightest CPU load. As one of the server selection methods used in this server load distribution device, etc., a paper "Locat
ing Nearies Copies of Replicated Internet Serv
ers ”(computer communication review vol.25, no.4 p.
288 (1995)), a method of determining the distance (hop count) between the server and the client and selecting the server with the shortest distance as the server corresponding to the processing of the client. The server selection device is provided with means for holding path information (router address) from the server selection device to each server to be controlled and acquiring path information from the server selection device to the client. From these pieces of information, an evaluation value reflecting the distance (hop count) between the server and the client is obtained, and the server having the smallest evaluation value is selected. As a result, the user can access the nearest server, and it is possible to suppress a decrease in response due to network congestion.

The above-mentioned method is a method mainly used for a server selecting device for realizing load distribution processing for a current Web server, and is different from a Web server in that the number of simultaneous accesses and the number of server licenses are used. This method is effective in distributing the load to servers of a relatively loose type. However, in the future, conditions such as conferencing servers, moving image splitter servers, and streaming servers that have not been sufficiently considered as load balancing targets, such as restrictions on the number of license access and transmission rate restrictions, will be imposed. You must also consider relatively demanding servers. When selecting a server from among these servers, a server that can provide a service (for example, a server whose access number does not reach the upper limit determined for each server, or a transmission rate at which the content can be transmitted at a content rate) Server that does not reach the upper limit).

At present, there are not many examples of a server selection device having such a function, for example, Japanese Patent Application Laid-Open No. H11-4158.
As disclosed in Japanese Patent Application Laid-Open No. 7-41, there are a plurality of video servers for transmitting moving images to a client, and the video management apparatus described in Japanese Patent Application Laid-Open No. H11-41587 discloses a method for distributing a video title from a client. There is an invention in which upon receiving a request, a server with a small load is selected from a plurality of servers to which the video title can be delivered. With this mechanism, the client can use a video server with a light load, and the delivery efficiency can be improved.

[0008] Further, the server selection device itself has a problem that when the requests from the client temporarily increase, the server selection processing is delayed, and the response speed of the server selection processing is reduced. In order to solve these problems, at present, two or more server selection devices are duplicated and deployed at the same base, or for example, as in the case of the Distribute Director, a load balancing device manufactured by the United States Cisco, the United States Cisco
Combining the local load balancer, Local Director, to determine which regional server group to process
Determined by the tribute director, which server to select from the servers in a certain area
There is also a method of geographically distributing the server selection devices according to the method determined by the ctor.

[0009]

However, the server selection device described above has the following problems. In the conventional server load distribution device, a server is selected from a group of servers registered in advance in the load distribution device, regardless of whether the selection target server is in a state capable of providing the service requested by the user. A commonly used server selection method is based on various parameters such as random or round robin, weighted round robin, and server processing load (CPU load, response speed, etc.). It does not have a function to specify and select an appropriate server from servers whose remaining resource amount exceeds the required resource amount.

Therefore, in practice, a server that cannot provide a service cannot be excluded from server candidates, and a server that is difficult to provide a service may be selected. It becomes difficult for a user who has newly accessed such a server or another user who has been using the server before accessing the server to prevent the service quality from deteriorating due to a shortage of server resources.

When a server having a function of not accepting a new server use request when the remaining resources of the server is not sufficient is the server to be selected, the server which is selected by the server load balancer and which has insufficient resources is accessed. The user cannot enjoy the service. Server selection as described above must be avoided.

[0012] In particular, the above-mentioned article "Locating Nearb"
This paper describes the problem of "y Copies of Replicated Internet Servers". This system selects a server that can minimize the number of hops (the number of routers) between the server and the client, which greatly affects communication quality. However, if the nearest server does not leave enough resources to provide the service, the service quality cannot be maintained depending on the type of server or the server does not accept the service use request, and the user enjoys the service. The quality of service that can be performed deteriorates

On the other hand, Japanese Patent Application Laid-Open No. H11-41587 discloses a method of selecting a server which has the smallest possible video transmission rate of a video server and the minimum number of simultaneous channels.
According to this method, it is possible to perform the allocation in consideration of the remaining resources of the server, but since the required resource amount cannot be specified for each server selection processing request as in the above example, the remaining resources are There is a possibility that a server that does not exceed the limit may be selected.

Another problem is that even if a server whose remaining resources exceed the required resources is selected, no consideration is given to the distance from the user. May be selected. This increases the number of hops between the user and the server, and causes quality degradation on the network. As a result, it is difficult for the user to maintain service quality.

Next, a problem when a conventional server selection method is introduced into the server selection of a server providing pay contents will be described. It is assumed that a provider of paid content has introduced a business model for performing billing and settlement before enjoying the service.

In this case, the server location solution request is issued to the server selection device not by the client owned by the user, but by the EC provided by the provider that provides the paid content.
(Etened Control) server. The EC server charges the contents by controlling the interaction with the user. When the client accesses the URL of the server notified by the EC server after charging is completed and the remaining resource amount of the server is not enough to provide the service, the service having deteriorated quality despite charging is performed. There is a problem that the service is received or the service cannot be received at all.

Originally, a site that distributes paid content needs to determine whether a server selected for a user is in a state in which a service can be provided before charging a fee. There is no server selection device provided. Also, it may take some time before the user actually accesses the selected server after the billing / settlement process by the EC server. In order to prevent a situation in which another client accesses the server during that time and the former client becomes inaccessible, if the server has a temporary reservation function, temporary reservation information is sent to the server selected at the time of server selection. A function to notify is required.

However, the conventional server selection method does not have means for notifying the user of the provisional reservation by using the provisional reservation function of the server when selecting the server. In order to further enhance security and provide services in a more limited form, it is necessary to have a function of notifying the selected server of the user's authentication information. Since there is no means for notifying the authentication information, this cannot be handled.

As a specific example of the problem when the server selection device itself is decentralized, the USC described in the server selection method for the server in which the number of remaining resources must be considered.
Distribute Direc, a load balancer manufactured by isco
A case in which a server selection method based on a combination of tor and local director is applied will be described.

As described above, in the conventional server selection method, the number of remaining resources of a server is compared with the number of required resources, and only a server whose remaining resources exceed the required resources cannot be selected as a server selection candidate. Also in this example, the Local Director cannot select a server by comparing the remaining resources of the server to be load-balanced with the required resources, and furthermore, allocates the required resources to the Distribute Director.
There is no function to notify Director. For example, Loca
l Even though all servers managed by Director cannot provide services,
The tor may cause the local director to perform server selection processing, and as a result, a server that cannot provide the service may be selected.

These problems can be summarized into the following four points. Problem 1: In the existing server selection method, there is a possibility that a server whose remaining resource amount is equal to or less than a resource amount required for providing a service may be selected. When a client accesses such a server, the processing of the entire server cannot be performed normally, so that the service quality of all users who use the server deteriorates or the connection of the client is rejected. Either cannot be enjoyed.

Problem 2: There is a server selection method of selecting a server with the least server load, but since the distance between the client and the server is not considered at all, the server is located far from the client. Server may be selected. If the distance (the number of routers on the route, etc.) increases, a delay or the like occurs on the network. As a result, even if a server with the smallest server load is selected, the service quality deteriorates.

Problem 3: In the existing server selection method, even if the server to be selected has the provisional reservation function, it cannot be notified when the server is selected. If the selected server is not provisionally reserved, the server is accessed by another client between the time the client obtains the server selection result and the time the server is accessed. When the number of accesses has been reached, access may be denied even if the client accesses the server.

Problem 4: In the existing server selection method, even if the server to be selected has an authentication function, it cannot be notified when the server is selected. In the conventional server selection method, if a server requiring user authentication is to be selected, there is no other method than distributing user authentication information to all servers that may be selected in advance. Is premised on that all client information is registered in advance, and is not suitable for services intended for an unspecified number of users. Also,
This is inefficient because the same authentication data must be registered in all servers.

An object of the present invention is to solve the above-mentioned four problems and to provide a server selection technique capable of selecting a server close to a user in consideration of the amount of resources required for service provision. Is to do. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0026]

The outline of the invention disclosed in the present application is briefly described as follows.
The first invention is a means for solving the problems 1 and 2 described above. The server selection device of the present invention includes a distance obtaining unit that obtains a distance between a user and a server from user identification information and a server identification information, and a remaining resource amount that obtains a remaining resource amount of the server from the server identification information. Obtaining means, user identification information, a server list, and a required server resource amount, and obtaining the remaining resource amount by the remaining resource amount obtaining means for each of the servers described in the server list; A server that preferentially selects a server having a shorter distance to a user obtained by the distance obtaining unit from among servers whose amount exceeds the required server resource amount, and outputs server identification information as a server selection result. And selecting means. By providing such a mechanism, it is guaranteed that the server selected by the server selection device of the present invention has the remaining resource amount exceeding the required server resource amount and has a short distance from the user. Is done.

The second invention is a one-distance acquisition technique in the distance acquisition means of the first invention, and provides a specific method for solving the above problem 2. The distance acquisition means of the present invention comprises: a path information table for storing identification information of a relay device existing on a path from the server selection device of the present invention to each server included in the server list; and a server selection device of the present invention. Relay device information processing means for acquiring the identification information of the relay device on the route to the user from the user, and for each user included in the server list based on the identification information of the relay device obtained by the relay device information processing device, to the user. It is characterized by including means for obtaining the distance of By providing such a mechanism, both the route information from the server selection device to the user and the route information to the server can be acquired, so that the distance between the user and the server can be estimated and the server can be selected accordingly.

The third invention is a one-distance acquisition technique in the distance acquisition means of the first invention, and provides a specific method for solving the second problem. The distance acquisition unit of the present invention includes: a position acquisition unit that acquires position information of a user; a position table of a server that stores position information of each server; It is characterized by comprising means for calculating the distance between the server and the user using the position information. According to the present invention, even if the distance between the server selection device and the managed server or the user is large, the server can be used.
Since the distance between users can be accurately measured, it is guaranteed that the server selected by the server selection device is a server that can truly provide the nearest service to the user.

A fourth invention is characterized in that the remaining resource acquisition means in the server selection device of the present invention includes a remaining resource management table indicating a remaining resource amount for each server managed by the server selection device. As a result, even for a server having no function of outputting the remaining resource amount in response to a request from an external device, the server selection device of the present invention enables resource allocation in consideration of the required resource amount, and the server according to the present invention. The applicable area of the selection method is expanded.

According to a fifth aspect of the present invention, the maximum number of terminals that can be connected to the server at the same time is defined as the maximum number of simultaneous connections, and the remaining resource amount is obtained by calculating the number of terminals connected to the server from the maximum number of simultaneous connections of the server. It is characterized in that it is a subtracted value. As a result, if the number of connected users has reached the maximum number of simultaneous connections determined by the server, it is determined that the server has no remaining resources, and this server is excluded from the selection candidates. The above client can be prevented from connecting to the server.

According to a sixth aspect of the present invention, the total sum of the maximum transmission rates executable by the server is defined as the maximum total rate, and the remaining resource amount is obtained by subtracting the total sum of the data transfer rates being executed from the maximum total rate of the server. It is characterized by being a value. As a result, it is determined that there is no remaining resource for a server in which the difference between the maximum total rate of the server and the data transfer rate currently being executed by the server is lower than the data transfer rate to be started from now on. Is excluded from the selection candidates, so that the client can avoid accessing a server for which the transfer rate required for providing the service cannot be secured.

According to a seventh aspect of the present invention, a sum total of data transfer rates to and from the outside of a site where a server group installed at the same site can be executed is determined as a maximum total site rate, and the remaining resource amount is defined as
It is characterized in that it is a value obtained by subtracting the sum of the rates of data transfer to and from the outside of the site where the server group of the server is being executed from the maximum total rate of the site where the server is installed. As a result, it is determined that there is no remaining resource for a site where the difference between the maximum total rate of the site and the total sum of the data transfer rates outside the current site is lower than the data transfer rate required for providing the service. . Therefore, a server group located at a site where a transfer rate required for providing a service cannot be secured is excluded from selection candidates.

According to an eighth aspect, in the fourth aspect, the remaining resource amount of the server selected by the server selecting means among the remaining resource amounts stored in the server resource management table is input to the server selecting means. And a remaining resource subtracting means for subtracting only necessary resources. Thus, even when the server managed by the server selection unit does not provide information necessary for calculating the remaining resource amount, the remaining resource amount indicated by the server resource management table is equal to the actual remaining resource amount. Therefore, it is possible to realize allocation in consideration of the remaining resources.

According to a ninth aspect, in addition to the fourth aspect, the identification information of the service provided by the server and the server selected by the server selecting means are input, and the service is provided based on the input. A service providing time obtaining unit that obtains a required time (service providing time) and outputs the service providing time; a service providing time output by the service providing time obtaining unit; and a server selected by the server selecting unit. Enter the identification information and the required resource amount, and after the service providing time elapses from when these are input, the remaining server resource amount for the selected server indicated by the server resource management table is equal to the required server resource amount. A server resource management type for updating the server resource management table so as to increase It is characterized in that a chromatography unit. Accordingly, even when the server does not have a function of outputting information about the remaining resources to the external device, it is possible to realize server selection in consideration of the remaining resources of the server.

According to a tenth aspect, when the server to be managed by the server selection device has a temporary reservation function for temporarily securing server resources for the user's access, the server selection means With the input of the identification information of the selected server, the identification information of the user, and the identification information of the service, which are the outputs of the above, information for setting a temporary reservation for the server (hereinafter referred to as temporary reservation setting information) A provisional reservation information notifying unit that generates the provisional reservation setting information based on the information, outputs the provisional reservation setting information, and outputs the identification information of the selected server as a server selection result after the provisional reservation setting is normally completed. It is characterized by the following. Thereby, the provisional reservation information of the user is notified only to the limited server, so that the service can be reliably provided only to the limited user who accesses the limited server.

According to an eleventh aspect, when a server to be managed by the server selection device has a user authentication function for restricting user access, the selected server, which is an output of the server selection means, is selected when a server is selected. Enter the server identification information, the user identification information, and the service identification information that have been set, and provide information (hereinafter, authentication setting information) for performing user authentication settings for the user to the server based on these information. An authentication information notifying means for generating, outputting the authentication setting information, and outputting the identification information of the selected server as a server selection result after the authentication setting is normally completed. As a result, the authentication information of the user is notified only to the limited server, so that the service can be reliably provided only to the limited user accessing the limited server.

According to a twelfth aspect of the present invention, when the identification information of a user is input, the server selection device determines, based on the position information of the user, whether or not the server can be selected by the server, and determines to perform the selection. The server selection processing by the server selection means is continued, and when it is determined not to perform the selection, the identification information of the server selection device which is a candidate for server selection for the user is output, and the server selection processing is performed. It is characterized by comprising a server selectable / impossible determining means for interrupting. This makes it possible to execute the server selection operation by decentralizing the server selection program. Hereinafter, embodiments of the present invention (examples)
This will be described in detail with reference to the drawings.

[0038]

FIG. 1 is a block diagram showing a functional configuration of a server selecting apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an operation procedure of the server selecting apparatus according to the present embodiment. As shown in FIG.
The server selection device 100 includes a server selection unit 1, a distance acquisition unit 2, and a remaining resource amount acquisition unit 3. In FIG. 1, U is user identification information, S is server identification information, SL is a server list (list of server identification information), R is the required server resource amount, and SS is the server selected by the server selection means. Identification information, D
(US) is distance information between the base U and the base S, R (S)
Is the remaining resource amount of the server S.

The operation of the server selection device 100 of this embodiment will be described with reference to FIG. First, the server selection device 100 of the present embodiment, at the time of startup, the user identification information U,
Server list SL and required server resource amount R
Is input to the server selection means 1 (101). The server selecting means 1 obtains the remaining resource amount using the remaining resource obtaining means 3 for all the servers described in the input server list SL (102). For the server (103) whose remaining resource amount exceeds the required server resource amount R (103), the distance between the user and the server is obtained by the distance acquisition means 2 (104). The above operation is performed for all the servers described in the input server list. The above operation is performed for all the servers, and among the servers whose remaining resource amount exceeds the server resource amount, the server closer to the user is preferentially output as the selection result of the server selection device 100 (105). By performing such an operation, a server whose remaining resource amount is less than the required server resource amount is excluded from candidates for server selection. In addition, the server which has the shorter distance to the user obtained by the distance acquisition unit 2 is selected preferentially from the servers which have not been excluded and the result of the server selection is selected. Is guaranteed to be greater than the required server resource amount and the distance from the user is short, so that the problems 1 and 2 can be solved simultaneously.

Next, the internal mounting configuration of the server selection device according to the present embodiment and the environment surrounding the server selection device will be described. FIG. 3 is a block diagram showing a functional configuration of a general-purpose computer having the server selection device according to the present embodiment according to the present invention. As shown in FIG. 3, a general-purpose computer 50 having a server selection device according to the embodiment of the present invention is connected to a communication line 52 having a router device 51. The communication line 52 is connected to a management target server 53 of a server selection device, and a predetermined router device 51 is connected to a plurality of client devices 54 having client software 54A. The internal configuration of the general-purpose computer 50 includes a server selection program 50A and a database 5 referenced by the server selection program 50A.
0B, the server selection program 50A
Are the reception processing routine 50A1, the main routine 50A
2 and a server selection routine 50A3.

UR with client software 54
L to the server selection program 5
FIG. 4 shows a protocol stack used when requesting 0A.
Table 1 shows examples of messages used at that time. FIG. 4 and Table 1 are examples in which http and rtsp are used as upper protocols in the protocol stack. In FIG. 4, the layers below IP are omitted because the subsequent description is independent of the data link layer and the physical layer.

After selecting the server, the server selection device of the first embodiment notifies the client software of the server selection result using the protocol stack shown in FIG. Table 2 shows an example of a message of the upper protocol at the time of notification of the result. In the client software receiving the message, the character string “Lo” described in the message is written.
By sending a service use request to the URL in the line where “cation:” is described, the client device can access the target server by reflecting the server selection result. Transferring the process to the server is called redirection.

[0043]

[Table 1]

[0044]

[Table 2]

Further, the environment assumed inside the server selection device will be described in detail. As shown in FIG. 5, when the server selection program receives the service use request, it starts a child process that executes the main routine, causes all server selection processing to be performed there, and the server program that is the parent process again executes another client process. A server selection request from the server.

FIG. 6 shows a flowchart in the main routine. When the main routine is started, first, the IP address of the client device is obtained (201). It is also assumed that the information shown in Tables 3 and 4 is stored in the database, and that the U
The URL of the server corresponding to the RL, the URL of the service, and the resource amount necessary for providing the service are acquired (20).
2). After acquiring these pieces of information, the server selection routine is started (203). The main routine and the server selection routine use a common programming language and standard C / C ++
/ JAVA (registered trademark).
In such a case, the server selection routine is realized by a function as shown in FIG. 7, and the server selection routine can be started by incorporating this function into the main routine or the like (20).
4). The server selection routine has a function of changing the format of the server selection result to the format shown in Table 2 and notifying the client software of the server selection result.

[0047]

[Table 3]

[0048]

[Table 4]

An embodiment of the server selection program described above will be described below. (Embodiment 1) A server selection routine according to the first aspect of the invention, wherein the distance acquisition means uses the second aspect of the invention,
An embodiment in which the remaining resource amount recognized by the server selection routine is defined as in the above fifth invention will be described.

FIG. 8 shows an assumed network. FIG.
In the above, SS 'is a server selection device in which the server selection program according to the present invention is installed. Ra, Rb, R
c, Rd, and Re are all general-purpose router devices. FIG.
The IP address of the router device is expressed as Ra0, Rb1, using numerical values described near the network connection part of the router device in the middle. Sa, Sb, Sc, Sd,
Se is a server to be selected by SS '. Also,
U ′ is a user who makes a use request of the server.

FIG. 9 shows a functional configuration diagram of the server selection device realized in the first embodiment. In FIG. 9, 1 is a server selection means,
2 is a distance acquisition unit, 3 is a remaining resource amount acquisition unit, U is a user IP address (user identification information), S is a server URL (server identification information), and SL is a server URL.
List (server identification information list), R 'is 1 "connection"
(Required server resource amount), SS is the URL of the selected server (identification information of the selected server), D (U.
S) is distance information between the base U and the base S, and R (S) 'is the number of possible simultaneous connections at the present time.

As shown in FIG. 9, the server selection routine 100A according to the first embodiment includes a server selection unit 1, a distance acquisition unit 2, and a remaining resource amount acquisition unit 3. The server selection routine according to the first embodiment is based on the user's IP.
The address U and the URL list SL of the server to be selected are input, and the SS of the URL of the selected server is output. In addition, the user's IP address U and the server URL list S input to the server selection routine 100A.
L and 1 “connection” R ′ are input to the server selection means 1. The server selection unit 1 obtains the remaining resource amount acquisition unit 3 for all servers described in the server URL list SL.
And the number of possible simultaneous connections of each server at the moment R (S) '
To get.

At this time, the number of possible simultaneous connections R (S) ′ is 1
If the distance is equal to or greater than the “connection” R ′, the distance acquisition unit 2 acquires the distance D (US) between the user and the server. The server selecting means 1 selects, as an output of the server selecting routine, a server having the shortest distance to the user from among the servers whose remaining resource amount exceeds the necessary server resource amount.

The details of each means will be described below. First, a specific example of the distance acquisition unit 2 will be described. As a first step, route information between the server selection device and the user is obtained. Here, a generally known program called traceroute is used as the route information acquisition means. The traceroute program is a program that, when a target IP address is input, outputs the IP addresses of the router devices through which the packet reaches the IP address in order from the one closest to the program execution machine. By using the traceroute, the I of the transit router between the server selection device and the user is
The P address can be obtained.

FIG. 10 shows the traceroute execution result in the case of the network configuration as shown in FIG. This is temporarily stored as distance information of the user. As a second stage, server distance information is acquired for each server described in the URL list of the server.
In the first embodiment, as described in the second aspect, it is assumed that the distance acquisition unit of the server selection device includes a route information table that stores identification information of the server selection device and the relay device. Here, the relay device is a router,
The identification information is used as the address of the router. Table 5 shows an example in which the route information table is described in the network configuration shown in FIG. The route information table is defined as server distance information, and is temporarily stored. As a third step, the distance Lsu between the server and the user is obtained using the following equation (1) using the distance information of the user and the distance information of the server temporarily stored. In this case, the “distance” is the number of transit routers on the route.

[0056]

Lsu = A + B−2 × (C−D) +1 A = the number of routers on the path between the server selection device and the user B = the number of routers on the path between the server selection device and the server C = route between server selection device and user and server selection device D = number of routers common in route between servers The result of finding distance Lsu between server and user by the formula of Equation 1 is shown in Table 6. . This is defined as distance information between the server and the user, and is temporarily stored.

[0057]

[Table 5]

[0058]

[Table 6]

The remaining resource amount acquisition means 3 is provided with a server UR
L is input, and the number of possible simultaneous connections of the server at the present time is output. It is assumed that the current number of possible simultaneous connections of the server can be obtained by inquiring the server.
The remaining resource amount acquiring means 3 is provided by a library file and an API for inquiring the server.

The server selecting means 1 uses the temporarily stored distance information between the server and the user, and uses the remaining resource amount obtaining means 3 for the server in which the distance information between the server and the user is described. Get resources. In the first embodiment, the remaining resource amount is a value obtained by subtracting the number of terminals connected to the server from the maximum number of simultaneous connections defined in the fifth invention. Since the resource amount is "1 connection", the server selecting means 1 may select the nearest server from those in Table 7 where the remaining resource amount is not 0. Therefore, when the remaining resource amount is as shown in Table 7, the URL of the server selected by the server selecting means 1 is the URL of Sa. This URL is the output URL of the server selection program
Becomes

[0061]

[Table 7]

As described above, a server selection program having such a mechanism can select a server closest to the user and capable of accommodating the user at the present time from a plurality of server lists.

(Embodiment 2) Embodiment 2 according to the present invention will be described below in which the above-mentioned embodiment 1 is modified and the resources to be handled are set to the server band as shown in the sixth invention. The assumed network configuration is the same as that shown in FIG. FIG. 11 shows a functional configuration diagram of a server selection routine realized in the second embodiment. In FIG.
100B is a server selection routine according to the second embodiment, 1 is a server selection unit, 2 is a distance acquisition unit, 3 is a remaining resource amount acquisition unit, U is a user IP address, and S is a server UR.
L and SL are URL lists of the server, R ″ is the network bandwidth required for the server, SS is the URL of the selected server, D (US) is distance information between the base U and the base S, R (S) '' is the maximum possible transmission rate at the present time.
The difference from the first embodiment is that, as shown in FIG. 11, the bandwidth R ″ required for providing the service is added as an input to the server selection routine 100B, and the remaining resources are the maximum possible transmission of the server at the present time. That is, the rate R (S) ''.

The band R ″ required for providing the service is “bi
t / sec ”is input from the main routine to the server selection routine. The server selection unit uses the remaining resource amount acquisition unit 3 for each of the servers listed in the URL list SL of the input server to obtain the maximum possible transfer rate. R (S) '' is obtained. Table 8 shows an example of the remaining resource amount of the server. The possible maximum transfer rate R (S) '' and the bandwidth R '' required for providing the service required for each server are shown. A comparison is performed, and servers whose R (S) ″ is lower than R ″ are excluded from server selection candidates.

[0065]

[Table 8]

The other processes are the same as those in the first embodiment, and the description is omitted. As described above, a server selection program having such a mechanism can select a server closest to the user and capable of accommodating the user at the present time from a plurality of server lists.

(Embodiment 3) The server device according to the first aspect of the invention, wherein the distance acquisition means uses the third aspect of the invention, and the remaining resource amount recognized by the server selection device is determined by the seventh aspect of the invention. A description will be given of a third embodiment in which the definition is made as follows. FIG. 12 shows an assumed network. FIG. 12 shows a state where the bases indicated by Aa, Ab, Ac, Ad, Ae, As, and Au are connected via a router device.

FIG. 13 is a functional block diagram of the server selection routine realized in the third embodiment. The server selection routine 100C of the third embodiment inputs the name of the base to which the user belongs, the URL list of the server to be selected, the free bandwidth required for the line extending from each base to the backbone, and outputs the URL of the selected server. . The service selection routine 100C includes a server selection unit 1, a distance acquisition unit 2, and a remaining resource amount acquisition unit 3.

First, the distance obtaining means 1 will be described.
The first step uses the user's IP address and calculates a numerical value that makes the user's position relative to the topology in the network. Here, the IP address is x. y.
z. When expressed as w (0 <x, y, z, w <256), a numerical value obtained by relativizing the position of the user by the following expression 2 is temporarily stored.

[0070]

[Equation 2] (x & m1) × 256 ³ + (y & m2) × 256 ² +
(z & m3) × 256 + (w & m4) where net mask is m1. m2. m3. m4 (0 ≦ m1, m2, m3, m
4 <256). a & b is defined to mean a logical sum for each bit. That is, a = 0x15, b
= 0xbb (where 0x indicates a hexadecimal number), a & b = 0x11. In the second step, an IP address is obtained from the URL of the server, a numerical value obtained by relativizing the position of the server is obtained based on the above equation, and the numerical value is temporarily stored. In the third step, a distance between the user and the server is obtained from the numerical value obtained by temporarily storing the relative position of the user and the numerical value obtained by relativeizing the position of the server, and this is temporarily stored. . Table 9 shows the relative values of the servers assuming the IP addresses and subnet masks of the servers described in Table 9. Also assume that the user's IP address is 11.14.5.12 and the subnet mask is 255.255.255.0. The relative value of the user in this case is 18579560.

[0071]

[Table 9]

Next, the remaining resource amount obtaining means 3 will be described. Table 10 shows a table held by the remaining resource amount acquiring unit 3. The third embodiment is an example in which the resource is a band of a network line from a base. The feature of the table shown in Table 10 is that the table is not held for each server but is managed for each site.

[0073]

[Table 10]

Next, the server selecting means 1 will be described. The server selecting means 1 has a table as shown in Table 11 that associates a server with a base. After calculating the distance between the server and the user by using the table of Table 11 and the information of the relativized numerical value of the server user according to the following equation 3, and checking whether the server has remaining resources, The server which can provide the service and has the shortest distance to the user is the output of the server selection program.

[0075]

| (Numerical value of user relative) − (numerical value of server relative) | Table 12 shows the relative value of the user and the relative value of the server and the available bandwidth shown in Table 10. The following table is described. From Table 12, the server selection program has the shortest distance and the free bandwidth is the required bandwidth (here, 6 Mbit / se).
c) are found to be the servers of Sb0 and Sb1. Although the server selection means 1 may select a plurality of servers at the same base as in the above-described example, in the third embodiment, a random number corresponding to each server is obtained and a server having a large random number value is selected. Shall be determined. That is, in the above example, random number acquisition is performed twice,
The first result is defined as the result of Sb0, and the second result is defined as Sb.
As a result of 1, a server having a large random number value is determined as a selected server. It is assumed that the random value has a fixed minimum value and a maximum value, and is uniformly distributed within the range.

[0076]

[Table 11]

[0077]

[Table 12]

With the server selection program having the above-described mechanism, a server which is closest to the user and which can accommodate the user at the present time can be selected from a plurality of server lists.

(Embodiment 4) In order to cope with the case where the server to be managed by the server load distribution program has no means for notifying the external device of the current remaining resource amount, the above-described fourth invention and the fourth embodiment Embodiment 4 in which the invention of the eighth and the ninth invention is applied will be described. The fourth embodiment is assumed to be an extension of the first embodiment. That is, the input of the server selection routine is the user's IP address and the URL list of the server, and the output is the URL of the selected server. Also, the amount of server resources required to be handled in the server selection routine is the number of connections to the server, and is one connection.

FIG. 14 shows the functional configuration of the server selection routine according to the fourth embodiment. In FIG. 14, 100D is a server selection routine of the fourth embodiment, 1 is a server selection unit, 2 is a distance acquisition unit, 3 is a remaining resource amount acquisition unit, 4 is a server resource management timer unit, U is a user IP address, S is the URL of the server, SL is the URL list of the server, R 'is 1 "connection", SS is the URL of the selected server, D
(US) is distance information between the base U and the base S, R
(S) 'is the number of possible simultaneous connections at the present time, TS is a timer start notification (notification of the URL of the selected server), RSS is notification of remaining resource subtraction (notification of the URL of the selected server), and RAS is remaining resource. This is an addition notification (the URL of the selected server is also notified). As shown in FIG. 14, the server selection routine 100D according to the fourth embodiment includes a server selection unit 1, a distance acquisition unit 2, a remaining resource amount acquisition unit 3, and a server resource management timer unit 4. Here, it is assumed that the distance acquisition unit 2 is the same as the distance acquisition unit described in the first embodiment.

Remaining resource acquisition means 3 in the fourth embodiment
Will be described. First, the remaining resource obtaining means 3
Contains a server resource management table. The server resource management table is described in relation to the server name and the number of possible connections. Table 13 shows an example of the server resource management table. The table itself is realized using a database or the like.

[0082]

[Table 13]

The remaining resource obtaining means 3 provides a function for obtaining and changing the contents of the server resource management table to other functional blocks. C
Table 14 shows examples of functions when it is assumed that programming is performed in the / C ++ / JAVA programming language.

The server selecting means 1 according to the fourth embodiment will be described. FIG. 15 shows a processing flow of the server selection means. It is assumed that the server list input to the server selection program and the user-server distance information obtained by the distance obtaining means 2 are temporarily stored. As the first stage, the server list temporarily stored is referred to, and the number of possible connections of each server described in the server list is obtained from the remaining resource amount obtaining means 3 (3
01).

[0085]

[Table 14]

The acquisition method is as follows:
source function. As a second step, a server closest to the user is selected from the servers having the possible number of connections of one or more based on the temporarily stored user-server distance information (302). The part corresponding to the second stage is the same as the method described in the first embodiment. As a third stage, the remaining resource subtraction instruction of the selected server is issued to the remaining resource amount acquisition means 3 (303). The subtraction instruction is the deleteResource described in Table 14.
Use functions. As a fourth step, the server resource management timer means starts timer processing for the selected server (304). As the fifth step, the selected server is output (305), and the processing of the server selecting means 1 is terminated.

The server resource management timer means 4 according to the fourth embodiment will be described. FIG. 16 shows a processing flow of the server resource management timer means 4. As a first step, the server resource management timer 4 is started in the fourth step of the server selecting means 1 (401). At the time of startup, the URL of the server selected is notified. As the second stage, the time required for providing the service is acquired (40
2). As a premise, the server resource management timer means has an estimated service providing time table indicating a relationship between the URI, the protocol, and the estimated service providing time estimated to be required for providing the service. Table 15 shows an example of this estimated service provision time table. This estimated service providing time table is implemented using a database or the like.

[0088]

[Table 15]

In order to express the variation in the estimated service providing time due to the server's processing capability and the protocol used, the server resource management timer means 4 is provided with a server in which the relation between the server name, the protocol and the processing capability coefficient is described. It has a processing capacity coefficient table. By multiplying the estimated service providing time described in the estimated service providing time table by the processing capacity coefficient, the estimated service providing time for the selected server and the protocol to be used can be obtained. Table 16 shows the server processing capacity coefficient table.

[0090]

[Table 16]

The table shown above is prepared, the URL of the selected server is decomposed into a protocol, a server name, and a URI, the estimated service providing time is obtained from the decomposed protocol and the URI, and the processing is performed based on the server name and the protocol. An estimated service providing time for the URL can be obtained by obtaining a capacity coefficient and multiplying the estimated service providing time by the processing capacity coefficient. For example, UR
L is rtsp ///osaka.ntt.co.jp/ne
Assuming that ws / 0705 / special.mpg, the protocol is rtsp, and the server name is osaka.ntt.c.
o.jp, URI is / news / 0705 / speci
Since the file is al.mpg, the estimated service providing time for the URI is 1 hour, 5 minutes, and 30 seconds from Table 15;
The processing capacity coefficient is 1.5 from Table 16. Therefore,
The estimated service provision time for this URL is 1 hour 38 minutes 15 seconds.

As the third stage, the time to wait after the server resource management timer means 4 shifts to the waiting state until the next processing is performed is determined (403). Usually the UR
Although the value is the same as the estimated service providing time for L, an arbitrary margin value may be added. Example 4
, A 10% margin is added. That is, when the estimated service providing time is 1 hour, 38 minutes, and 15 seconds, the waiting time is calculated as 1 hour, 48 minutes, and 5 seconds (less than one second is advanced). As a fourth step, the execution of the processing in the next fifth step is interrupted for the waiting time.
(404).

In the fifth stage, after the waiting time,
The remaining resource amount acquisition means 3 is instructed to add the remaining resources of the selected server (405). The addition instruction is executed by an addResource function shown in Table 14. When the processing of the fifth step is completed, the processing of the server resource management timer is completed. Note that the server resource management timer process can execute a plurality of timer processes in parallel. In the fourth embodiment, server selection can be realized in consideration of the remaining resources of the server without inquiring the server of the status of the remaining resource amount.

(Embodiment 5) In order to cope with a case where a server to be managed by a server load balancing program has a provisional reservation function and a user authentication function, the above-described tenth and eleventh inventions are applied. A fifth embodiment will be described.

First, the definition of the “temporary reservation” of the server is defined. Temporary reservation of a server means that when a server provides a service to a specific user, the resources of the server necessary for providing the service are reserved in advance, and the resources of the server are used only by the specific user Is an operation that guarantees

Next, the "user authentication" of the server will be defined. "User authentication" refers to checking whether the user who has accessed the server is actually the user who has been given the right to use the server, and if the user has been given the right, provides the service and grants the right. If the user has not been requested, this function rejects the user's request.

Since the server has the function of executing the provisional reservation and the user authentication defined above, it is possible to reliably provide the service only to the limited users.
A fifth embodiment using the tenth and eleventh inventions to implement a server selection program for selecting a server having a provisional reservation / user authentication function will be described below. It is assumed that the fifth embodiment is positioned as a function extension of the first embodiment.

First, prior to the description of the server selection program according to the fifth embodiment, the assumption of a server to be selected by the server selection program will be described. It is assumed that the server to be selected is a server whose maximum number of simultaneous connections is determined by the number of software licenses. Further, a provisional reservation function for designating a user's IP address and a URI and a protocol of a service to be used to secure resources for the user indicated by the IP address, and a user's IP address and a URI and a protocol of a service to be used are provided. It is assumed that the system has a user authentication function for authenticating the user indicated by the designated IP address. A library is provided for controlling the server from a remote device, and an API is provided.
It is assumed that the server selection routine can fetch the server control program through (Application Programming Interface).

FIG. 17 shows the relationship between the library and the server selection routine. In FIG. 17, 100D ′ is a server selection program, 100D is a server selection routine, 10 is a server control library, 20 is a server group to be selected, 20A
Is a server to be selected. Table 17 shows functions (temporary reservation function, authentication information function) provided by the library.

[0100]

[Table 17]

FIG. 18 shows a functional configuration of a server selection routine according to the fifth embodiment. In FIG. 18, 100E is a server selection routine of the fifth embodiment, 1 is a server selection unit, 2 is a distance acquisition unit, 3 is a remaining resource amount acquisition unit, 5 is a provisional reservation information notification unit, 6 is an authentication information notification unit, U is the IP address of the user, S is the URL of the server, SL is the URL list of the server, R 'is 1 "connection", and SS is the UR of the selected server.
L and D (US) are distance information between the base U and the base S,
R (S) 'is the number of possible simultaneous connections at the present time, IRA is the information notification result from the provisional reservation information notification means, and IRB is the information notification result from the authentication information notification means.

The server selection routine 100E according to the fifth embodiment.
As shown in FIG. 18, the server includes a server selecting unit 1, a distance obtaining unit 2, a remaining resource amount obtaining unit 3, a provisional reservation information notifying unit 5, and an authentication information notifying unit 6. The distance acquisition unit 2 and the remaining resource amount acquisition unit 3 are the same as those of the first embodiment.
Same as In the fifth embodiment, the resources handled by the server selection routine are the same as in the first embodiment. That is, it is assumed that the remaining resources of the server are the maximum number of possible connections at the present time, and the number of server resources required per service provision is one.

Hereinafter, each functional block will be described.
First, the server selection means 1 will be described. FIG.
9 shows a flowchart of a processing procedure of the server selecting means 1 according to the fifth embodiment. The first stage and the second stage are the same as those described in the fourth embodiment and will not be described (501, 502). In the third stage, the URL of the selected server and the IP of the user are
The address is notified (503). Temporary reservation information notification means 5
It is checked whether the processing result of the temporary reservation setting has succeeded (504), and if the processing result of the temporary reservation information notifying means 5 indicates that the temporary reservation setting has failed (NO), this server selection The processing in the means 1 is stopped (505).
When the processing result indicates that the provisional reservation setting is successful (Y
es), and proceed to the next fourth stage. In the fourth stage, the URL of the selected server and the IP address of the user are notified to the authentication information notifying means 6 (506). Next, it is checked whether or not the processing result of the authentication information notifying means 6 succeeds in setting the authentication information (507). If it indicates that the setting has failed (NO), the temporary reservation setting is canceled (508).
The processing in the server selecting means 1 is stopped (50
9). If the processing result indicates that the authentication information setting is successful (Yes), the process proceeds to the next fifth step. In the fifth stage, the URL of the selected server is output (510), and the processing of the server selecting means 1 ends.

The provisional reservation information notifying means 5 will be described. FIG. 20 shows a processing flow of the provisional reservation information notifying means 5. The URL notified from the server is rtsp: // tok
yo.ntt.co.jp/news.mp2. First
In the stage, the type of the server used for providing the service is specified from the URL notified from the server selecting means 1 (6).
01). It is assumed that the provisional reservation information notifying means 5 has prepared a correspondence table between server types, protocols, and file names shown in Table 18. Note that * in the table indicates a character string composed of one or more characters.

[0105]

[Table 18]

In the case of the above URL, the server type is specified as mpeg2_server according to Table 18. In the second stage, a temporary reservation notification program corresponding to the specified server is started (602). Temporary reservation information notification means 5
Shows a correspondence table between server types and provisional reservation notification program names as shown in Table 19. In the third stage, the URL of the server that has selected the execution result of the provisional reservation setting is output (603), and the processing of the provisional reservation information notification means 5 ends.

[0107]

[Table 19]

Also, as an example, the program mp2Pre
FIG. 21 shows a processing sequence of Reserve. First, the server name and the URI are obtained from the URL (70
1). When mpeg2_server provides a function as shown in Table 17, information necessary for provisional reservation setting is a server name, a URI, a user address, and an expiretime. Here, expiretime is defined as a time during which the provisional reservation is valid, and it is assumed that the provisional reservation is canceled if there is no access after the provisional reservation information is notified.

The expiretime is the same as that of the fifth embodiment.
Is fixed at 1 minute. Obtain the server URI and server name from the server URL. Using the URI, server name, and user address as arguments, setPre
A Reserve function is executed (702). The function setPre described in Table 17 together with this and the user address
Notify as an argument of Reserve. This execution result is notified (703), and the execution of mp2PreReserve ends. It should be noted that all programs shown in Table 19 are represented by “(OS prompt) program name URL
It is assumed to be started in the form of "user address". The output values of the execution result are as shown in Table 20.

[0110]

[Table 20]

In the third stage, the output value of the execution result is used as it is as the output of the provisional reservation notifying means 5, and the processing of the provisional reservation notifying means 5 ends. Next, the authentication information notification means 6 will be described. FIG. 22 shows a processing flow of the authentication information notification means 6. Rt the URL notified by the server
sp: //tokyo.ntt.co.jp/news.mp
Let it be 2. Also, change the user's IP address to 10.20.3.
0.100. In the first stage, the type of server used for providing the service is specified from the URL notified from the server selection means 1 (801). It is assumed that the authentication information notification means 6 has a correspondence table between server types, protocols, and file names shown in Table 21. The table shows that any character string is included.

[0112]

[Table 21]

In the case of the above URL, the server type is specified as mpeg2_server according to Table 21. In the second stage, an authentication information notification program corresponding to the specified server is started (802). In the third stage, the URL of the server that has selected the execution result of the authentication information is output (803), and the execution of mpeg2_server ends. The authentication information notification means 6 describes a correspondence table between server types and authentication information notification program names as shown in Table 22.

[0114]

[Table 22]

As an example, the program mp2Aut
FIG. 23 shows the processing sequence of the hentication. First, the server name and the URI are obtained from the URL (9
01). When mpeg2_server provides a command as shown in Table 17, information necessary for provisional reservation setting is a server name, a URI, a user address, a user name, and a password. The server URI and the server name are acquired from the URL of the server, and are used as arguments of the functions described in Table 17. Further, a user name and a password are obtained from the user address (902). In the fifth embodiment, it is assumed that a user management database (DB) is provided in addition to the server selection device 100, and the relationship between the user address, the user name, and the password is described in the user management database (DB). And Using these together as an argument of the command setAuthentication described in Table 17, execute SetAuthentication (903) and notify the authentication information. This setAut
hentication execution result (90
4) The execution of mp2Authentication ends. All the programs shown in Table 22 are
It is assumed that the program is started in the format of “(OS prompt) program name URL user address”. The output values of the execution results are as shown in Table 23.

[0116]

[Table 23]

In the third stage, the output value of the execution result is used as it is as the output of the authentication information notifying means 6, and the processing of the authentication information notifying means ends. In the fifth embodiment, a server selection routine corresponding to a case where the server has the provisional reservation function and the user authentication function can be configured. This can be expected to bring the following advantages. -The URL passed to the user as a result of the server selection is a U that is guaranteed that the user can always receive the service.
RL. -Even if there is a slight time lag before the user accesses the server after selecting the server, the user allocated time after selecting the server will not be occupied by other users. The user can certainly enjoy the service even when accessing the server

(Embodiment 6) An embodiment using the twelfth invention when the server selection program is distributed in order to cope with an increase in the load on the server selection device itself in which the server selection program is installed. 6 is shown.
FIG. 24 shows a prerequisite network configuration. FIG.
Among them, SS ₁ and SS ₂ are server selection devices, Ra to Re are router devices, Sa to Se are selection target servers, and U is a user. Also, there are two regions enclosed by the dotted line (gray area) is, one is a management range of SS _1, another is assumed to be the control range of the SS _2. As another premise of the sixth embodiment, the sixth embodiment is realized by expanding the first embodiment.

FIG. 25 shows the functional configuration of the server selection routine according to the sixth embodiment. Server selection routine 1 of the sixth embodiment
00F is the server selection routine 100A of the first embodiment.
And a server selection determination unit 7. Example 6
FIG. 26 shows the processing flow of this server selection routine.
As shown in FIG. 26, the server selection routine 100F of the sixth embodiment is executed by the user.
Judge whether it is appropriate to select a server in A (1
001) As a result, if it is determined that it is more appropriate to leave it to another server selection device (NO), a URL of a server selection device that is considered to be more suitable for server selection for the user is obtained (1002). The URL of the server selection device is output (1003). If the result of the determination is that the user is suitable for selecting a server in the server selection routine 100F (Yes
s), the server selection routine 100A of the first embodiment is started, and a URL indicating the server selection result is obtained (100)
4), and output the URL of the server selection result (100)
5). Thus, the execution of the server selection program ends.

Here, the server selectability judging means 7 in the sixth embodiment will be described. First, the server selectability determining means 7 includes a table for storing in advance path information to an area for which another server selection device is to perform processing. Table 24 shows an example in which a table for holding the route information up to the area to which the processing is assigned is described for the network configuration shown in FIG.

[0121]

[Table 24]

When the server selectability determining means 7 receives the user's IP address, it executes traceroute. When the execution result of the traceroute includes any one of the address lists of the passing routers described in the routing information holding table described in Table 24, the URL of the redirect destination server selection device described in the table is output to select the server. The availability determination processing is terminated. Here, a case where the user U requests the SS ₁ to select a server will be described as an example. First, trace from SS ₁ to user U
Execute route. Table 25 shows the traceroute execution results.

[0123]

[Table 25]

[0124] Table 25 Results of because it contains the routing information of the first line of Table 24 (1), without SS ₁ The server selection process, to redirect according to the first line of Table 24 (1) and outputs the value of SS ₂ is a server URL. Then, the user will be described when requesting a server selected for SS _2. First, the trac from SS ₂ to U
Execute erase. Table 26 shows the traceroute execution results.

[0125]

[Table 26]

Since this result does not include any of the route information shown in Table 24 (2), it can be determined that the user is to select a server with the server selecting apparatus. Therefore, the server selection program described in the first embodiment is started, and the server selected as a result is output. According to the sixth embodiment, it is possible to execute a server selection operation by dispersing a server selection program by using the present invention.

(Embodiment 7) In this embodiment 7, it is assumed that a paid service is provided by using the server selection device of the present invention, and EC (Electric Commerce) for performing charging and settlement for the server selection device and the service is provided. An example of cooperation with a server will be described. As a premise, a service for streaming distribution of moving image content for a fee is assumed. There are a plurality of moving image distribution servers, and the maximum number of simultaneous connections is determined by the number of licenses of the server software.
When a user accesses a free homepage equivalent to a catalog of contents and selects contents to view for a fee, the user interactively exchanges information required for charging between the EC server and the user terminal. UR for browsing paid content
L is notified by the EC server. Note that the server selection program of the fifth embodiment is used for the server selection device. Further, it is assumed that the name of the user and the password of the user are registered in the EC server.

FIG. 2 shows the overall sequence of service provision.
FIG. The system that provides this service includes a client that is prepared by a user who wants to receive paid content and an E that is provided by an information provider that provides paid content.
C server and EC server database in which customer information is stored, a server selecting device that is close to the client among a plurality of moving image servers and selects a server that can provide a service, and a moving image to be selected by the server selecting device It consists of an image distribution server. According to the sequence shown in FIG. 27, the server resources of the user are provisionally reserved immediately before the contract between the user and the information provider is concluded (accepting the billing). Troubles such as not being able to enjoy the service if the user accesses the URL notified after the charge, and can more reliably provide a paid service. Also, since the user authentication information is notified only to the server selected by the server selection device, it is not necessary to previously store a copy of the same contents as the EC server database in all servers, and the server cost can be reduced.

As described in the present embodiment, the server selection device using the present invention can be applied to a server that provides a paid service, and can easily realize cooperation with an EC server that performs billing and settlement. The processing program of each of the embodiments is recorded on a computer-readable recording medium,
It may be used again. Here, the "computer-readable recording medium" is a floppy (registered trademark) disk, a magneto-optical disk, a ROM, a CD-ROM.
And a recording device such as a hard disk incorporated in a computer system. As described above, the invention made by the inventor has been specifically described based on the embodiment (example). However, the present invention is not limited to the embodiment (example).
However, it is needless to say that various changes can be made without departing from the scope of the invention.

[0130]

The effects obtained by the invention disclosed in the present application will be briefly described as follows.
According to the present invention, when a plurality of server devices provide the same service on a communication network, and a user intends to use a service provided by a server group, the plurality of server devices are used as servers to be accessed by the user. Resources required for service provision can be reliably secured from server devices,
In addition, a server close to the user can be selected.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram of a server selection device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of the server selection device of the embodiment.

FIG. 3 is a functional configuration diagram of a general-purpose computer having a server selection device according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a protocol stack used between a client device and a server selection device according to the present embodiment.

FIG. 5 is a diagram illustrating an environment assumed inside the server selection device according to the embodiment.

FIG. 6 is a flowchart illustrating a processing procedure of a server selection program according to the embodiment.

FIG. 7 is a diagram illustrating an implementation example of a server selection routine according to the embodiment;

FIG. 8 is a diagram showing a network assumed in a first embodiment according to the present invention.

FIG. 9 is a functional configuration diagram of a server selection routine according to the first embodiment.

FIG. 10 shows traceroute in the first embodiment.
It is a figure showing an example of a result of execution.

FIG. 11 is a functional configuration diagram of a server selection routine according to a second embodiment of the present invention.

FIG. 12 is a diagram illustrating a network assumed in a third embodiment according to the present invention.

FIG. 13 is a functional configuration diagram of a server selection routine according to the third embodiment.

FIG. 14 is a functional configuration diagram of a server selection routine according to a fourth embodiment of the present invention.

FIG. 15 is a flowchart illustrating a processing procedure of a server selection unit according to the fourth embodiment.

FIG. 16 is a flowchart illustrating a processing procedure of a server resource management timer unit according to the fourth embodiment.

FIG. 17 is a diagram illustrating a relationship between a server selection routine and a server control library according to the fifth embodiment of the present invention.

FIG. 18 is a functional configuration diagram of a server selection routine according to the fifth embodiment.

FIG. 19 is a flowchart illustrating a processing procedure of a server selection unit according to the fifth embodiment.

FIG. 20 is a flowchart illustrating a processing procedure of a provisional reservation information notifying unit according to the fifth embodiment;

FIG. 21 is a flowchart illustrating a processing procedure of an mp2PreReserve program started by a provisional reservation information notifying unit according to the fifth embodiment.

FIG. 22 is a flowchart illustrating a processing procedure of an authentication information notification unit according to the fifth embodiment.

FIG. 23 is a flowchart illustrating a processing procedure of an mp2Authentication program started by the authentication information notification unit according to the fifth embodiment.

FIG. 24 is a diagram showing a network assumed in a sixth embodiment according to the present invention.

FIG. 25 is a functional configuration diagram of a server selection routine according to the sixth embodiment.

FIG. 26 is a flowchart illustrating a processing procedure of a server selection routine according to the sixth embodiment.

FIG. 27 is a diagram illustrating a sequence between a client, an EC server, a server selection device, and a moving image distribution server assumed in a seventh embodiment according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Server selection means 2 ... Distance acquisition means 3 ... Remaining resource amount acquisition means 4 ... Server resource management timer means 5 ... Temporary reservation information notification means 6 ... Authentication information notification means 7 ... Server selection availability determination means 10 ... Server control library 20 ... Servers to be selected 20A ... Servers to be selected 50 ... General-purpose computer 50A ... Server selection program 50B ... Reference database 51 ... Router 52 ... Communication line (network) 53 ... Servers to be managed by server selection device 54 ... Client device 54A ... Client software 100: server selection device 100A to 100F: server selection routine of this embodiment U ': user making a server use request U: user identification information S: server identification information SL: server list (server identification information List) R: Required server lithography Source amount SS ': Server device on which the server selection program is installed SS: URL (identification information) of the selected server D (U.S.): Distance information between base U and base S R (S): Server S SSY ... Server identification information when selectable SSN ... Server identification information when not selectable SY ... Message indicating selectable

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuyuki Takaya 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term (reference) in Nippon Telegraph and Telephone Corporation 5B045 GG02 5B089 GA11 GA21 JA35 JB14 KA06 KB04 KB06 MA03 MA07 5K030 GA13 GA15 HA08 HC01 HD03 JT06 KA05 LC09 LC11 LD20 LE05 LE17

Claims (25)

[Claims] 1. A server selecting device for selecting a server to be accessed by a user from among a plurality of servers distributed and deployed, the server selecting device inputting identification information of the user and a server list as a list of the servers. Distance acquisition means for acquiring a distance from the user for a plurality of servers;
The remaining resource amount obtaining means for obtaining the remaining resource amount of the server for the predetermined server, the user identification information, the server list, and the required server resource amount are input and included in the server list. And the distance between the user indicated by the input obtained by the distance obtaining means, from among servers whose remaining server resource amount obtained by the remaining resource amount obtaining means exceeds the required server resource amount. A server selecting means for preferentially selecting a server having a shorter server length and outputting server identification information as a server selection result. 2. The distance acquisition unit acquires, for each of the plurality of servers, a path information table that stores identification information of a relay device on a path from the server selection device to the server, and identification information of the relay device. A relay device information acquiring unit, and a distance calculating unit that calculates a distance to the user for each of the plurality of servers based on the relay device identification information acquired by the relay device information acquiring unit. 2. The server selection device according to 1. 3. The server according to claim 1, wherein the distance obtaining unit obtains position information of the user from identification information of the user, a server position table storing position information of the server for each of the plurality of servers, Based on the identification information of the user obtained by the position obtaining means and the position information of each of the servers stored in the server position table, including means for obtaining a distance to the user for each of the servers. The server selection device according to claim 1, wherein: 4. The server according to claim 1, wherein the remaining resource amount acquisition unit includes a server resource management table that stores remaining resource information indicating a remaining resource amount for each of the plurality of servers. Item 2. The server selection device according to item 1. 5. The number of terminals that can be connected to the server at the same time is defined as a maximum number of simultaneous connections, and the remaining resource amount is determined by calculating the number of terminals connected to the server from the maximum number of simultaneous connections of the server. The server selection device according to claim 1, wherein the server selection device is a value obtained by subtracting the following. 6. The total sum of data transfer rates executable by the server is defined as a maximum total rate, and the remaining resource amount is calculated from the maximum total rate of the server by a data transfer rate being executed by the server. 5. A value obtained by subtracting the sum of
The server selection device according to the paragraph. 7. The sum of the rates of data transfer to and from the outside of the site where the server group installed at the same site can be executed is defined as the maximum site total rate. 5. The server according to claim 1, wherein a value obtained by subtracting a total sum of data transfer rates with the outside of the site where the server group of the server is executed is subtracted from the maximum total rate of the site. A server selection device as described. 8. Remaining resource subtraction for subtracting the remaining resource amount of the server selected by the server selecting means from the remaining resource amounts stored in the server resource management table by the required resource input to the server selecting means. 5. The server selection device according to claim 4, further comprising means. 9. Inputting the identification information of the service provided by the server and the server selected by the server selecting means, and acquiring the time required for providing the service (hereinafter referred to as service providing time) based on the input. Inputting the service providing time obtaining means for outputting the service providing time, the service providing time output by the service providing time obtaining means, the identification information of the server selected by the server selecting means, and the required resource amount And
After the service providing time elapses from when these are input, the server resource management table is updated so that the remaining server resource amount for the selected server indicated by the server resource management table increases by the required server resource amount. 5. The server selection device according to claim 4, further comprising a server resource management timer. 10. When a server to be managed by the server selection device has a provisional reservation function for temporarily securing server resources for the user's access, the server selection means outputs the data when the server is selected. The identification information of the selected server, the identification information of the user, and the identification information of the service are input, and information for setting a temporary reservation for the server (hereinafter referred to as temporary reservation setting information) is referred to as the information. And a temporary reservation information notifying unit having a function of outputting the temporary reservation setting information, and outputting the identification information of the selected server as a server selection result after the temporary reservation setting is normally completed. 10. The method according to claim 1, wherein:
The server selection device according to any one of the above. 11. When a server to be managed by the server selection device has a user authentication function for restricting user access, identification of the selected server, which is output from the server selection means, when selecting a server. Information, user identification information, and service identification information, and generate information (hereinafter, authentication setting information) for performing user authentication settings for the user with respect to the server based on the information. 11. An authentication information notifying means for outputting authentication setting information and outputting identification information of a selected server as a server selection result after the authentication setting is normally completed. A server selection device according to any one of the above. 12. When inputting identification information of a user and determining whether or not a server can be selected by the server selection device based on the position information of the user by calculation, and determining to perform the selection, the server If the server selection processing by the selection means is continued and it is determined not to make a selection,
12. The server according to claim 1, further comprising: a server selection determination unit that outputs identification information of a server selection device that is a candidate for performing server selection for the user and interrupts server selection processing. 2. The server selection device according to 1. 13. A server selection method for selecting a server to be accessed by a user from among a plurality of servers distributed and deployed, the method comprising: inputting identification information of the user and a server list that is a list of the servers; Obtaining the distance from the user for a plurality of servers, obtaining the remaining resource amount of the server for the predetermined server, inputting the identification information of the user, the server list, and the required server resource amount, Among the servers included in the server list and having the obtained remaining server resource amount exceeding the required server resource amount, a server having a short distance to the user indicated by the input is preferentially selected. And outputting the server identification information as a server selection result. 14. The distance obtaining step includes, for each of the plurality of servers, storing identification information of a relay device on a path from a target server selection device to a server, obtaining the identification information of the relay device, 14. The server selection method according to claim 13, further comprising a step of calculating a distance from each of the plurality of servers to the user based on the identification information of the relay device. 15. The distance obtaining step includes obtaining position information of the user from the identification information of the user, storing position information of the server in a server position table for each of the plurality of servers, 14. The server according to claim 13, further comprising a step of obtaining a distance to the user for each of the servers based on identification information and position information of each of the servers stored in the server position table. Selection method. 16. The method according to claim 13, wherein the remaining resource amount obtaining step includes a step of storing remaining resource information indicating a remaining resource amount for each of the plurality of servers in a server resource management table. A server selection method according to any one of the preceding claims. 17. The number of terminals that can be connected to the server at the same time is defined as the maximum number of simultaneous connections, and the remaining resource amount is determined by calculating the number of terminals connected to the server from the maximum number of simultaneous connections of the server. 17. The server selection method according to claim 13, wherein the value is a value obtained by subtracting the following. 18. The total sum of data transfer rates executable by the server is defined as a maximum total rate, and the remaining resource amount is calculated from the maximum total rate of the server by a data transfer rate being executed by the server. The server selection method according to any one of claims 13 to 17, wherein a value obtained by subtracting the sum of 19. The sum of data transfer rates outside the base where the servers installed at the same base can be executed is defined as the maximum total base rate, and the remaining resource amount is:
17. The method according to claim 13, wherein a value obtained by subtracting a total sum of data transfer rates with a server group at the installation site of the server from outside the site is subtracted from a maximum total rate of the installation site of the server. The server selection method according to any one of the above. 20. Remaining resource subtraction for subtracting the remaining resource amount of the server selected by the server selection method from the remaining resource amounts stored in the server resource management table by the required resource input to the server selecting means. 17. The server selection method according to claim 16, comprising a procedure. 21. Input of identification information of a service provided by the server and server identification information selected by the server selection method, and based on the input, a time required for providing a service (hereinafter, referred to as a service providing time). After calculating the service providing time, the server identification information selected by the server selecting method, and the required resource amount, and after the service providing time elapses from the input, the server resource management 17. The server resource management timer procedure according to claim 16, further comprising a server resource management timer procedure for updating the server resource management table so that the remaining server resource amount related to the server selected from the table information increases by the required server resource amount. The server selection method described. 22. When a server to be managed by the server selection method has a temporary reservation function for temporarily securing server resources for the user's access, the server is selected by the server selection method when selecting a server. Of the server, the user's identification information, and the service's identification information, and information for setting a tentative reservation for the server (hereinafter referred to as tentative reservation setting information) based on these information. Generating a temporary reservation setting information, outputting the temporary reservation setting information, and outputting the identification information of the selected server as a server selection result after the temporary reservation setting is normally completed. 22. The server selection method according to any one of Items 13 to 21. 23. When a server to be managed by the server selection method has a user authentication function for restricting user access, when selecting a server, identification information of the server selected by the server selection method; User identification information and service identification information are input, and information for setting user authentication for the user with respect to the server (hereinafter referred to as authentication setting information) is generated based on the input information. 14. An authentication information notifying step of outputting the generated authentication setting information and outputting the identification information of the selected server as a server selection result after the authentication setting is normally completed. 23. The server selection method according to any one of 22. 24. When the user's identification information is input and the server selection device determines whether or not a server can be selected by the server selection device based on the user's position information, and the server selection is determined, the server is selected. If the server selection processing by the selection means is continued and it is determined not to make a selection,
23. The server selecting apparatus according to claim 13, further comprising a server selection determination step of outputting identification information of a server selection device that is a candidate for server selection for the user and interrupting the server selection process. Server selection method described in the above. 25. A computer-readable recording medium recording a server selection program for causing a computer to execute the processing procedure of the server selection method according to claim 13.