JP4967996B2 - Network device, network system, network control method, and network control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To notify an important event as much as possible by limited resources. <P>SOLUTION: This network device 100 for performing event notification for notifying a plurality of clients (201 to 203, etc., ) of a plurality of events includes an event notification request receiving part 71 for receiving an event notification request for requesting event notification transmitted from the plurality of clients, a counting part 72 for counting the number of clients transmitting an event notification request, and an event notification selecting part 73 for controlling whether to perform event notification to clients according to the number of the clients. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a network device, a network system, a network control method, and a network control program.

  In a Web service that provides services to a plurality of clients connected to the network, when implementing an event notification function for notifying its own information, how to realize event notifications to multiple clients without time lag Is a challenge.

  If serial processing is simply performed with one thread, there are cases where it takes time to communicate with one client, or when communication is interrupted due to accidental disconnection (in this case, it will wait until timeout). In such a case, a time lag occurs in event notification to other clients.

  In order to avoid such a problem, when an event is notified to a plurality of clients at the same time, it is necessary to activate a plurality of threads and notify the event in a separate thread for each client. However, due to the resource limitation of the hardware on which the Web service is mounted, a method of initiating an unlimited thread and realizing simultaneous processing is not realistic. In particular, in software embedded in a device, hardware resource restrictions are more strict than in a PC (Personal Computer) or the like, and it is necessary to consider that there is no RAM capacity over or socket exhaustion.

  In order to solve this problem, for example, Patent Document 1 describes a method of load distribution in a system composed of a plurality of servers.

Japanese Patent Laid-Open No. 10-260851

  However, the conventional method has a problem that load cannot be distributed by a single server.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A network device that performs event notification for notifying a plurality of clients of a plurality of events, and receiving an event notification request for requesting the event notification transmitted from the plurality of clients, and the event notification A counting unit that counts the number of clients that have transmitted a request; and an event notification selection unit that controls whether or not to perform the event notification to the client according to the number of clients. Network device to use.

  According to this configuration, when a client system that has transmitted an event notification request to a network device exceeds a predetermined number and becomes in a high load state, the event to be notified can be limited. An event can be notified without time lag.

[Application Example 2]
In the network device described above, each of the plurality of events is assigned a priority, and the event notification selection unit transmits the event assigned the priority according to the number of clients. A network device characterized by

  According to this configuration, the priority of events to be notified can be set according to the number of client systems that have transmitted an event notification request to a network device, so necessary events can be notified to multiple client systems without time lag. can do.

[Application Example 3]
In the network device described above, the network device includes a rewritable event priority table that defines a correspondence between the number of clients, the priority, and the event to which the priority is assigned, and the event notification The selection unit transmits the event to which the priority according to the number of clients is assigned with reference to the event priority table.

  According to this configuration, the priority setting for each event can be changed as necessary, so that the setting according to the load status of the network device can be performed.

[Application Example 4]
In the network device described above, the network device includes a client attribute determination unit that determines an attribute of the client, and the event notification selection unit selects a client that the client attribute determination unit determines to be a network device management client. A network device that notifies all events.

  According to this configuration, all events can be notified to the network device management client without time lag even in a high load situation.

[Application Example 5]
A network system for notifying a plurality of clients of a plurality of events, an event notification request receiving unit for receiving an event notification request for requesting the event notification transmitted from the plurality of clients, and the event notification A counting unit that counts the number of clients that have transmitted a request; and an event notification selection unit that controls whether or not to perform the event notification to the client according to the number of clients. Network system.

  According to this configuration, when a client system that has transmitted an event notification request to the network system exceeds a predetermined number and becomes in a high load state, the event to be notified can be limited. Therefore, it is necessary for a plurality of client systems. An event can be notified without time lag.

[Application Example 6]
An event notification request receiving step for receiving an event notification request for requesting the event notification transmitted from the plurality of clients, the network control method performing an event notification for notifying a plurality of events to a plurality of clients, and the event A counting step for counting the number of clients that have transmitted a notification request, and an event notification selection step for controlling whether or not the event notification is sent to the client according to the number of clients. Network control method.

  According to this configuration, when the number of client systems that have sent an event notification request exceeds a predetermined number and becomes in a high load state, it is possible to limit the events to be notified, so that necessary events can be notified to multiple client systems without time lag. can do.

[Application Example 7]
An event notification request receiving step for receiving an event notification request for requesting the event notification transmitted from the plurality of clients, a network control program for notifying a plurality of events of a plurality of events, and the event A counting step for counting the number of clients that have transmitted a notification request; and an event notification selection step for controlling whether or not the event notification is sent to the client according to the number of clients. Network control program.

  According to this configuration, when the number of client systems that have sent an event notification request exceeds a predetermined number and becomes in a high load state, it is possible to limit the events to be notified, so that necessary events can be notified to multiple client systems without time lag. can do.

  Hereinafter, an embodiment of a Web service system will be described with reference to the drawings.

(First embodiment)
<Configuration of Web service system>
First, the configuration of the network device according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a network device according to the first embodiment. In the present embodiment, the case of a WSD printer 100 that is a printing device compliant with WSD (Web Service for Device) will be described as a network device.

  As shown in FIG. 1, the WSD printer 100 includes a CPU 20, a ROM 30, a RAM 40, an EEPROM 50, and a print engine 60 connected to the internal bus 10. The WSD printer 100 is further connected to a LAN cable 300 and is connected to an administrator PC 200 that manages the WSD printer 100 and client PCs (201 to 203, etc.) that are a plurality of client systems.

  A program 70 for controlling the WSD printer 100 is stored in the ROM 30 and loaded into the RAM 40 at the time of execution. The program 70 includes an event notification request receiving unit 71 that receives an event notification request transmitted from an administrator PC 200 or a client PC (201 to 203), and a client PC (201 to 203) that has transmitted the event notification request. A count unit 72 that counts the number of client PCs, and an event notification selection unit 73 that controls whether an event is transmitted according to the number of client PCs.

  The EEPROM 50 includes a rewritable event priority table 51 that defines the correspondence between the number of client PCs, the priority, and the event to which the priority is assigned.

<Outline sequence of WSD>
Next, a schematic sequence of WSD will be described with reference to FIG. FIG. 2 is a sequence diagram showing a schematic sequence of WSD.

  First, in step S1, the WSD printer 100 sends a Hello command to the client PC (any one of 201 to 203, etc.) activated when the service is started to notify the presence of itself. When the client receives the Hello command, the client recognizes that a new printer has joined the network, and issues a Probe command to the printer in step S2. By receiving this Probe command, the client PC (any one of 201 to 203 or the like) that was activated when the service was activated is recognized by the WSD printer 100.

  Next, in step S3, if the received Probe command is for itself, the WSD printer 100 returns a ProbeMatch command to the client PC (any one of 201 to 203, etc.).

  The client PC activated after activation of the WSD printer service causes the WSD printer to recognize the presence of the client by starting the activation process from step S2, and also recognizes the presence of the WSD printer by receiving the ProbeMatch command from the WSD printer.

  Next, in step S4, the client PC (any one of 201 to 203, etc.) issues a Resolve command in order to resolve the address information of the WSD printer 100 to be used.

  Next, in step S5, when the received Resolve command is intended for itself, the WSD printer 100 returns a ResolveMatch command to the client PC (any one of 201 to 203, etc.).

  Next, in step S6, the client PC (any one of 201 to 203, etc.) issues a WS-Transfer Get command to acquire the MetaData information of the WSD printer 100 that is desired to be used.

  Next, in step S7, the WSD printer 100 returns MetaData information to the client PC (any one of 201 to 203, etc.) using a Get Response command.

  Next, in step S8, the client PC (any one of 201 to 203, etc.) issues a Subscribe command that is a reservation message for reserving an event that the WSD printer 100 wants to notify. The counting unit 72 counts the number of client PCs that have issued the Subscribe command.

  Next, in step S9, the WSD printer 100 registers the subscribe information from the client PC (any one of 201 to 203, etc.) and returns a response command. As shown in FIG. 5, the Subscribe information is composed of a client name that issued the Subscribe command and an event name.

  In step S10, when an event occurs in the WSD printer 100, the WSD printer 100 refers to the subscribed subscription information and notifies the client PC (any one of 201 to 203, etc.) of the event occurrence. To do. The event notification selection unit 73 controls whether to transmit an event according to the number of client PCs counted by the counting unit 72 here.

  Next, in step S11, when the event notification from the WSD printer 100 becomes unnecessary, the client PC (any one of 201 to 203, etc.) issues an Unsubscribe command to request to stop the event notification. When receiving the Unsubscribe command, the count unit 72 subtracts from the number of client PCs.

  Next, in step S12, the WSD printer 100 returns an Unsubscribe Response command to the client PC (any one of 201 to 203, etc.).

  Next, in step S13, the WSD printer 100 issues a SubscriptionEnd command when the service ends.

  Next, in step S14, the WSD printer 100 issues a Bye command when the service ends, and notifies its own end.

<Configuration of event priority table>
Next, the configuration of the event priority table will be described with reference to FIG. FIG. 3 is a table showing the structure of the event priority table. In FIG. 3, it is assumed that there are five client PCs connected to the LAN cable 300.

  As shown in FIG. 3, the event priority table 51 includes the number CNT of client PCs, event priorities, and events to which priorities are assigned. When the number CNT of client PCs is 2 or less, the priority is Low and events EL1 and EL2 are assigned. When the number CNT of client PCs is 3 or more and 4 or less, the priority is Middle, and events EM1 and EM2 are assigned. When the number CNT of client PCs is 5 or more, the priority is High and events EH1 and EH2 are assigned.

  The event priority table 51 is stored in the EEPROM 50 and can be rewritten from the external administrator PC 200.

<Operation of event notification selection unit>
Next, the operation of the event notification selection unit will be described with reference to FIG. FIG. 4 is a flowchart showing the operation of the event notification selection unit. The event notification selection unit 73 will be described with reference to the event priority table 51 of FIG.

  First, in step S100, it is determined whether the number CNT of client PCs is 2 or less. If it is 2 or less, the process proceeds to step S102, and if it is not 2 or less, the process proceeds to step S104.

  Next, in step S102, the low-priority events EL1 and EL2, the middle events EM1 and EM2, and the high events EH1 and EH2 are transmitted in the order of occurrence.

  Next, in step S104, it is determined whether or not the number CNT of client PCs is 4 or less. If 4 or less, the process proceeds to step S106, and if not 4 or less, the process proceeds to step S108.

  Next, in step S106, events EM1 and EM2 with priority Middle and events EH1 and EH2 with high priority are transmitted in the order of occurrence.

  On the other hand, in step S108, priority level High events EH1 and EH2 are transmitted in the order of occurrence.

  As described above, the event notification selection unit 73 sets the events EH1 and EH2 as transmission targets when the number CNT of client PCs is 5 or more, and sets the events EM1, EM2, EH1, and EH2 as transmission targets when the number is 3 or more. 2 or less, all events EL1, EL2, EM1, EM2, EH1, and EH2 are targeted for transmission. In the case of FIG. 5, since the number of client PCs CNT = 3, the events EM1, EM2, EH1, EH2 are targeted for transmission, and the events EL1, EL2 are not transmitted.

  According to the present embodiment described above, the following effects can be obtained.

  In this embodiment, when a client system that has transmitted a reservation message to a network device exceeds a predetermined number and becomes in a high load state, it is possible to limit the event to be notified. Notification can be made without time lag. In addition, since the priority setting for each event can be changed as necessary, it is possible to set according to the addition status of the network device.

  Although the embodiments of the network device have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the scope of the invention. Hereinafter, a modification will be described.

  (Modification 1) Modification 1 of the network device will be described. In the first embodiment, the event priority table 51 is rewritten from the external administrator PC 200. However, the event priority table 51 may be dynamically rewritten according to the load status of the network device. . For example, when the network device is heavily loaded, the lower limit value of the number CNT of priority High client PCs is lowered, and when the load is low, the lower limit value of the number CNT of priority Middle client PCs is raised. .

  (Modification 2) Modification 2 of the network device will be described. In the first embodiment, the priority has been described in three stages of Low, Middle, and High, but may be two stages or may be set in detail in four or more stages.

  (Modification 3) Modification 3 of the network device will be described. In the first embodiment, the case of controlling the event for the client PC (any one of 201 to 203, etc.) has been described. However, the priority of the administrator PC 200 and the client PC (any of 201 to 203, etc.) is given priority. It may be set separately. In that case, in addition to the event priority table 51, a client attribute determination unit for determining the client attribute is added, and all events are notified to the client determined by the client attribute determination unit as the network device management client. You can do it.

  FIG. 6A shows a client attribute table 52 that defines client names and client attributes, and is stored in the EEPROM 50 shown in FIG. FIG. 6B is a flowchart showing the operation of the client attribute determination unit. In step S200, the client attribute determination unit refers to the client attribute table 52 to determine whether the client PC is an administrator. If the client PC is an administrator, all events are transmitted in the order of occurrence as shown in step S202. If the user is not an administrator, the process proceeds to the event notification selection unit 73 shown in FIG.

The block diagram which shows the structure of the network device which concerns on 1st Embodiment. The sequence diagram which shows the general | schematic sequence of WSD. The table figure which shows the structure of an event priority table. The flowchart which shows operation | movement of an event notification selection part. The table figure which shows the structure of Subscribe information. (A) Table figure which shows the structure of a client attribute table, (B) The flowchart which shows operation | movement of a client attribute determination part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal bus, 20 ... CPU, 30 ... ROM, 40 ... RAM, 50 ... EEPROM, 51 ... Event priority table, 60 ... Print engine, 70 ... Program, 71 ... Event notification request receiving part, 72 ... Count part, 73: Event notification selection unit, 100: WSD printer, 200: PC for administrator, 300: LAN cable.

Claims (6)

A network device that performs event notification for notifying multiple clients of multiple events,
An event notification request receiving unit for receiving an event notification request for requesting the event notification transmitted from the plurality of clients;
A counting unit that counts the number of clients that have transmitted the event notification request;
An event notification selection unit for controlling whether to perform the event notification to the client according to the number of clients;
Only including,
Each of the plurality of events is assigned a priority,
The event notification selection unit transmits the event assigned the priority according to the number of the clients.
A network device characterized by that. The network device according to claim 1 , wherein
The network device includes a rewritable event priority table that defines a correspondence between the number of clients, the priority, and the event to which the priority is assigned,
The event notification selection unit transmits the event to which the priority according to the number of clients is assigned with reference to the event priority table.
A network device characterized by that. The network device according to claim 1 or 2 ,
The network device includes a client attribute determination unit that determines an attribute of the client,
The event notification selection unit notifies all events to the client determined by the client attribute determination unit as a network device management client.
A network device characterized by that. A network system that performs event notification for notifying multiple clients of multiple events,
An event notification request receiving unit for receiving an event notification request for requesting the event notification transmitted from the plurality of clients;
A counting unit that counts the number of clients that have transmitted the event notification request;
An event notification selection unit for controlling whether to perform the event notification to the client according to the number of clients;
Only including,
Each of the plurality of events is assigned a priority,
The event notification selection unit transmits the event assigned the priority according to the number of the clients.
A network system characterized by this. A network control method for performing event notification for notifying multiple clients of multiple events,
An event notification request receiving step of receiving an event notification request for requesting the event notification transmitted from the plurality of clients;
A counting step of counting the number of clients that have transmitted the event notification request;
An event notification selection step for controlling whether to perform the event notification to the clients according to the number of clients;
Only including,
Each of the plurality of events is assigned a priority,
Transmitting the event assigned the priority according to the number of clients in the event notification selection step;
A network control method. A network control program for notifying a plurality of clients of a plurality of events,
An event notification request receiving step for receiving an event notification request for requesting the event notification transmitted from the plurality of clients;
A counting step of counting the number of clients that have transmitted the event notification request;
An event notification selection step for controlling whether to perform the event notification to the clients according to the number of clients;
Only including,
Each of the plurality of events is assigned a priority,
Transmitting the event assigned the priority according to the number of clients in the event notification selection step;
A network control program characterized by the above.

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