JP2009027348A - Power management control method in dhcp environment, and information processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a timeout error occurs against a job and a trouble occurs on a network if re-acquiring of the IP address by an information processor takes time, since the information processor has to perform re-acquiring of an IP address so that duplicating of IP address may not occur, if the information processor in a DHCP (Dynamic Host Configuration Protocol) environment returns from a sleep state by access from other device. <P>SOLUTION: When it becomes the time for requiring extension of a lease period, the information processor returns to a standby mode from a sleep mode, and transmits DHCPREQUEST for requesting the extension of the lease period to a DHCP server. If the information processor receives DHCPACK for permitting the extension of the lease period, it returns to the sleep mode again. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to various devices in a local area network (LAN) environment equipped with a resume function.

  In a local area network (LAN), there is a protocol called DHCP (Dynamic Host Configuration Protocol). DHCP is a method in which a DHCP server is installed on a network and an IP address is dynamically assigned to a client PC connected to the network.

  When using a fixed IP, the network administrator must manage the IP address, assign this IP to each client, and the client must set this IP address. In a network environment where this fixed IP address is allocated, the administrator must always manage the network, which places a burden on the administrator, and misconfiguration of the client's IP address can greatly affect the network. There is sex.

  However, in DHCP, it becomes possible for the DHCP server to automatically assign an IP address in response to a request from a client PC connected to the network. For this reason, using DHCP has made it possible to save the trouble of re-setting the IP address each time the network configuration changes.

  DHCP has the following three methods for IP address assignment. In "automatic assignment", DHCP assigns an address that the client can use all the time. In “dynamic allocation”, the DHCP server leases an address to the client PC for a certain period of time. In “manual assignment”, a network administrator determines an IP address to be assigned, and the DHPC server is used only for distributing the IP address to the client PC.

  Among these methods, “dynamic allocation” is a method in which a DHCP server allocates an IP address to a client PC for a certain period. This “dynamic allocation” mechanism requests that a client wants to use an IP address, and when a DHCP server allocates an IP address, the IP address is not allocated to another client. If a client leaves the network, the DHCP server may assign the same IP address to other clients. This reuse operation prevents IP address exhaustion. Since such a limited IP address can be used efficiently, it is most often used.

  On the other hand, in recent years, mobile devices such as notebook computers have become widespread. However, such mobile devices are required to reduce power consumption and be able to be used for a longer time with a built-in battery.

  In addition, recently, there has been a movement to promote a reduction in power consumption worldwide. There are cases where restrictions are set such as not permitting the sale of electrical appliances that have regulations at the national level and that do not meet environmental regulations. In the future, regulations on power consumption will also become stricter.

  For this reason, it is considered necessary to provide a power management function for devices that will be put on the market in the future. While the user is not using the power management function, a part of the function is stopped, power consumption is reduced, and a state called a sleep mode is set. In addition, when a user operation or access from another host used by the user occurs, the normal state is restored. This function is called a resume function.

  As for the network, there is a function called Wake-On-LAN as a method for returning from the sleep mode by access from another host used by the user. This function can wake the device in sleep mode when it receives a specific packet.

  Several specific packets used in this Wake-On-LAN have been proposed. One example is Magic Packet (registered trademark) developed by AMD. This Magic Packet (registered trademark) repeats the Mac address of the device to be activated in the information field of the frame 16 times. The NIC that supports Magic Packet (registered trademark) is designed to respond to the packet pattern, and outputs a signal to start the system when it recognizes its own Mac address. By using this Wake-On-LAN function, power management can be realized even for devices connected to the network.

For example, Patent Literature 1 can be cited as a conventional example.
Japanese Patent No. 3342507

  However, there are problems with using the power management function in a DHCP environment.

  In a DHCP environment, when a client shifts to sleep mode while holding an IP address, there are the following problems.

  The client 1 in the sleep mode cannot respond to the signal from the DHCP server, and therefore cannot receive the lease expired signal DHCPNAK. The DHCP server thinks that the IP address has been released, and assigns the IP address to another client 2. Thereafter, when the client 1 returns from the sleep mode, duplication of the IP address occurs.

  On the other hand, if the method of entering the sleep mode after releasing the IP address at the time of transition to the sleep mode, there are the following problems.

The IP address must be reacquired when the device in sleep mode returns to normal. This reacquisition is
(1) Broadcast a DHCPDISCOVER signal requesting an IP address.

  (2) Receive a DHCPOFFER signal that is a response from the DHCP server.

  (3) Send DHCPREQUEST requesting DHCP server to assign IP address.

(4) Receive a DHCPACK that tells the DHCP server that it has assigned an IP address.
This procedure is necessary.

  If this procedure takes time, if there is no response to the Wake-On-LAN packet, it will time out and communication may not be possible.

  In order to avoid this problem, as disclosed in Japanese Patent No. 3342507, there is proposed a method in which when a certain network device goes into the sleep mode, another network device performs packet processing on behalf of the other patents. Yes. However, with this method, trouble occurs when the proxy network device is in the sleep mode or turned off, or when the network configuration is changed.

  In order to solve this problem, the numerical control device according to the present invention has the following features.

In the first aspect of the present invention, the information processing apparatus having the sleep mode is in a DHCP environment.
If it is determined that the IP address lease period extension request time has elapsed,
Wake up from sleep mode
Proceed with the lease period extension to extend the lease period of the IP address,
It is a power management control method characterized by shifting to a sleep mode.

  This control secures an IP address and realizes stable operation on the network.

The invention of claim 2 is that the information processing apparatus having the sleep mode is in a DHCP environment.
A time management means for determining that the IP address lease period extension request time has elapsed;
A return means for returning from the sleep mode;
Means for extending the lease period of the IP address;
A sleep mode transition means for transitioning to the sleep mode;
A numerical control apparatus comprising:

  This control can provide an apparatus that secures an IP address and realizes stable operation on the network.

  As described above, in the present invention, the following control is performed in a network device having a sleep mode state when used in a DHCP environment.

  When it is time to request the extension of the lease period, it returns from the sleep mode to the standby mode, and sends a DHCPREQUEST requesting the extension of the lease period to the DHCP server. When DHCPACK that allows extension of the lease period is received, it returns to the sleep mode again.

  By performing this control, it is possible to prevent IP address duplication troubles in the network, and it takes time to re-acquire the IP address when returning due to access from the user, resulting in a Time Out Error.

  As a result, an information processing apparatus that performs stable operation in a network environment can be provided to the user.

  Embodiments of the present invention will be described below.

  FIG. 1 is a configuration diagram of an image forming apparatus that performs power management control in a network environment according to the present exemplary embodiment.

  In this embodiment, the image forming apparatus connected to the host is used as an example. However, the present invention is not limited to the image forming apparatus, and other peripheral devices or a host PC may be connected to the network. Any information processing apparatus is included in the rights of this patent.

  In the figure, reference numeral 100 denotes an overall configuration diagram of the image forming apparatus. A controller unit 110 processes data received from the host. An engine unit 120 receives data processed by the controller unit and controls printing.

  A controller CPU 111 controls a controller unit of the image forming apparatus. A ROM 112 stores a program for controlling the controller unit. Reference numeral 113 denotes a RAM, which is a readable / writable memory. Reference numeral 114 denotes an image processing unit which performs image processing and transfers the processed data to the engine unit. A network communication control unit 115 is connected to the network environment, and can receive image data from a host connected to the network environment and print it on the image forming apparatus. Reference numeral 116 denotes an RTC (Real Time Clock), which manages a return time for extending the lease of an IP address. An operation panel I / F unit 118 communicates with the operation panel. Reference numeral 119 denotes an operation panel unit, which includes keys for setting the state of the image forming apparatus, a liquid crystal panel for performing display, and LEDs.

  An engine CPU 121 controls the engine unit of the image forming apparatus. A ROM 122 stores a program for controlling the engine unit. Reference numeral 123 denotes a RAM, which is a readable / writable memory. A communication control unit 124 is connected to the image processing unit 114 via a communication line, and receives image data transmitted from the image processing unit 114. A paper transport motor control unit 125 transports paper by operating a paper feed motor and operating a transport roller. A carriage motor control unit 126 operates the print motor by operating the carriage motor. Reference numeral 127 denotes a head controller. Reference numeral 128 denotes a head unit, which ejects ink onto a medium in response to a signal from the head unit. A desired image can be formed by controlling 125, 126, 127 and ejecting ink to a desired position on the medium.

  A flowchart of communication between the server and the client in this embodiment will be described.

  In this description, T1 time is a lease period extension request time, and when this time elapses from the lease of the IP address, the client requests the server to extend the lease of the IP address. Usually, the time of T1 is half of the lease period.

  First, referring to FIG. 2, a flowchart of communication between the server and the client will be described.

  When the power is turned on, an initialization operation is performed in S211. In S212, a DHCPDISCOVER signal is broadcast to obtain an IP address. When the server side receives the DHCPDISCOVER signal in S201 and can supply an IP address, the server transmits a DHCPOFFER signal to the client in S202. On the client side, a DHCPOFFER signal is received in S213. On the client side, DHCPREQUEST including the selected server information is transmitted in S214. On the server side, DHCPREQUEST is received in S203, and DHCPACK including IP address information assigned when it recognizes that its own server has been selected is transmitted to the client. At S215, the client side receives DHCPACK, sets the IP address based on the information, and enters the standby state. After a certain period of time set for power management control, the client enters a sleep state in S216. If there is any access during the sleep mode, the process proceeds to S250 and the requested predetermined processing is performed. Thereafter, when a certain time has elapsed, the process proceeds to S216 and the operation is repeated. If there is no access during the sleep mode, after a time T1 from S215, the system returns from the sleep mode in S217, and thereafter returns to the process of S214 in FIG. In S214, DHCPREQUEST including information requesting extension of the lease period is transmitted. On the server side, when DHCPREQUEST is received in S203 and an extension of the lease period is requested, it is confirmed that the IP address is usable, and a DHCPACK including the IP address information is transmitted to the client.

It is a block diagram which shows the structural example of 1st Example of this invention. It is a block diagram which shows the flowchart of communication between a server and a client in 1st Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Host part 110 Image processing apparatus 111 Controller CPU
112 ROM
113 RAM
114 Image processing unit 115 Network communication control unit 116 RTC (Real Time Clock)
118 Operation panel I / F section 119 Operation panel section 121 Engine CPU
122 ROM
123 RAM
124 communication control unit 125 paper transport motor control unit 126 carriage motor control unit 127 head control unit 128 head

Claims (2)

An information processing device with a sleep mode is in a DHCP environment.
If it is determined that the IP address lease period extension request time has elapsed,
Wake up from sleep mode
Proceed with the lease period extension to extend the lease period of the IP address,
A power management control method characterized by transitioning to a sleep mode. An information processing device with a sleep mode is in a DHCP environment.
A time management means for determining that the IP address lease period extension request time has elapsed;
A return means for returning from the sleep mode;
Means for extending the lease period of the IP address;
A sleep mode transition means for transitioning to the sleep mode;
A numerical control device comprising:

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