JP2001257688A - Network device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network device which can use its sleep function without depending on other network devices even when a service application being used requires answers to the periodical inquiries or requires the periodical transmission of information on a LAN. SOLUTION: The latest reception frame 27 that arrives at a network device 1 is stored in a receiving frame storage 13 when the CPU resource 19 of the device 1 is active. Meanwhile, the latest transmission frame 26 sent from the resource 19 is stored in a transmitting frame storage 12 in response to the frame 27 stored in the storage 13. When the resource 19 enters a sleep mode, a new reception frame 27 is compared with the frame 27 stored in the storage 13 at a comparison part 14. When both frames are equal to each other, the frame 26 stored in the storage 12 is transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a network device connected to a local area network, and more particularly to a network device compatible with energy saving.

[0002]

2. Description of the Related Art In recent years, a computer such as a personal computer has been provided with a network interface, for example, a local area network (hereinafter referred to as LA) such as Ethernet (registered trademark).
N (abbreviated as N).

FIG. 9 is a block diagram showing a general configuration example of a computer having a network interface. In the figure, 31 is a CPU, 32 is a bus bridge, 33 is a main memory, 34 is a keyboard / mouse interface, 35 is an HDD interface, 36 is an image interface, 37 is a network interface, 38 is a keyboard and mouse, 39 is an HDD, 40 Is CRT, 4
1 is a network, 42 is a bus. The computer shown in FIG. 9 is connected to a network 41 via a network interface 37.
Can exchange data with other network devices connected to the server.

In recent years, designs have been made to include a power saving mechanism in order to cope with energy saving. Therefore, if there is no access to any device of the computer within a predetermined time, each device is It is possible to put the device in a standby state (sleep mode) to suppress power consumption. For example, when data input from an input device such as a keyboard / mouse 38 has been lost for a certain period of time, the CPU 31
6 and the HDD interface 35, the CRT 40 receiving the request turns off the screen display, and the HDD 39 stops the motor. Furthermore, CPU3
1 is to reduce the clock frequency of itself, or to shut down by shutting down the power supply.
31 itself shifts to the sleep mode. The network interface 37 shifts to the sleep mode with only the network interface 37 energized so that it can respond to an access request from another computer. Such a method for energy saving is disclosed in JP-A-6-37765.

However, regarding transmission and reception of frames on a network, each time transmission or reception is performed,
In many cases, a received frame is interpreted using a CPU resource such as a CPU or a main memory, or a frame for transmission is assembled, and processing for the frame is performed by software. Therefore, depending on the protocol or service used in the network, the network device may not be able to shift to the sleep mode.

[0006] For example, there is a case where the network configuration is such that a frequent inquiry from another network device must be immediately answered. In this case, if the network device does not immediately respond to the inquiry from the other network device, the other network device may determine that the network device does not exist on the network.

As an example of such a case, NetW
A network system using the are protocol will be described. In NetWare, when a computer inquires about services available on a network, a service inquiry frame, SAP (S
service Advertising Protocol
ol) Send the request frame over the network. For example, in a computer, a shell (NETX.COM)
Upon loading, this SAP request frame is sent to know the services available on the network.
In addition, NetWareDOS requester (VLM.EX)
E) sends an SAP request frame to search for the nearest directory server. If no network device responds, it sends another SAP request frame to find the nearest file server. And this SAP
If the server having the corresponding service does not immediately respond when transmitting the request frame, the computer that transmitted the SAP request frame determines that such a service does not exist and suspends the related processing or takes other actions. Processing.

Therefore, in such a case, the CP
A state in which the U resources cannot be completely turned off such as requiring a cold start (system boot) and can be immediately responded, for example, a state in which the clock speed of the CPU is reduced. And the CPU resource cannot be put into the sleep mode.

Furthermore, unless a computer periodically broadcasts its information on a network, other servers, routers, clients, and the like may determine that the network device does not exist on the network. For example, in a network system using the NetWare protocol, various servers such as a file server, a print server, a NetWare access server, and a remote control server are provided on the network. These servers must broadcast their own service list every 60 seconds as an SAP information frame. If the server does not broadcast the SAP information frame three minutes after the transmission of the last SAP information frame, all other servers and routers determine that this server cannot be used, and the bindery (database) Delete this server from.

Therefore, even in this case, the CPU resource cannot be set to the sleep mode due to the periodical transmission of frames. Therefore, the introduction of the sleep mode as described above has been limited to a computer that may take a certain amount of time from when a wakeup request is issued to a CPU resource from a network interface to when the system starts up. For example, a computer used as a mere client, TCP /
A computer used as a server of a network system configured only with a communication protocol that does not cause the above-described problems, such as IP, is used.

Therefore, in order to solve the above-mentioned problems, several techniques described below have been proposed. As an example of such a proposal, for example, Japanese Patent Application Laid-Open No. Hei 8-1
As disclosed in JP-A-63127, it has been considered that a LAN adapter responds on behalf of a client. Specifically, in the LAN adapter, when the determination unit determines that the operation has been stopped by using the resume function on the client side,
The signal control unit stops transmission of the signal from the server to the client, and notifies the storage that the signal has been input from the server. When the program stored in the storage unit recognizes that a signal has been input from the server side by the notification of the signal control unit, the program performs a response process or a network process for the signal, and operates as if the client is operating. I do. At this time, the storage unit stores the acknowledgment signal and the response signal from the server in association with each other, and sends the history of communication with the stopped server to the client when the operation of the client is restarted. In this way, the LAN adapter responds on behalf of the client computer, so that the client resume function (sleep mode)
Can be used.

However, in this example, since the program stored in the storage unit behaves as if it were a client, the program must correspond to all kinds of signals and protocols to be supported by the client. Therefore, it is necessary to perform various and complicated processes in the LAN adapter, and the configuration of the LAN adapter becomes considerably complicated. Naturally, such LA
N adapters are expensive. Also, depending on the client, it may be difficult to make all responses in the LAN adapter. Further, such a LAN adapter that performs all responses is provided by a CPU that is in sleep mode.
Since it performs the same function as, it consumes a large amount of power and cannot achieve energy saving.

Another example is disclosed in Japanese Patent Application Laid-Open No. 9-24719.
As disclosed in Japanese Patent Laid-Open Publication No. 4 (1999) -2005, there is an apparatus in which a virtual client created in an area on a server is operated instead of a client. Specifically, at the time of network connection, the client notifies the server whether or not the resume function can be used. In response to this notification, the server
Create a virtual client in an area on the server. When entering the sleep mode, the client notifies the server to that effect. The server assigns a virtual client on behalf of the client. During sleep mode, the virtual client acts on behalf of the client. As a result, even if the client uses the resume function, the server does not recognize that the client has been disconnected. The communication history is stored while the client is in the sleep mode, and the communication history is transmitted when the client returns from the sleep mode. In this way, by operating the virtual client created in the area on the server in place of the client using the resume function, the client can use the resume function.

[0014] In this example, however, the server on which the virtual client is created cannot be put into sleep mode. Therefore, even if energy saving can be achieved on the client side, it is difficult to achieve energy saving for the entire network.

Further, as another example, Japanese Patent Application Laid-Open No. H5-1759
As disclosed in Japanese Patent Publication No. 64, it has been considered that another computer responds in place of the computer entering the sleep mode. Specifically, when a device such as a personal computer having a resume function is turned off and enters a sleep mode, a message is transmitted to other devices that have established a virtual circuit to notify that the device will enter the sleep mode. Thus, the network environment is preserved even after the power is turned off and then on. In addition, the message that informs the user to enter sleep mode includes data that causes other PCs to execute their own network processing functions instead. When the power is turned off, other PCs use their own network processing functions instead. Have it run.
In this way, the sleep mode can be used by another computer taking over the network processing function instead of the computer entering the sleep mode.

However, even in this case, the computer acting as the network processing function cannot be shifted to the sleep mode. Therefore, it is difficult to save energy as a whole network.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and uses a service application that requires a response to a periodic inquiry or a periodic information transmission on a LAN. It is another object of the present invention to provide a network device that can use the sleep function without depending on other network devices.

[0018]

According to the present invention, a reception frame and a transmission frame are stored in a reception frame storage unit and a transmission frame storage unit respectively when communication is being performed, and a new reception frame is stored when a sleep function is performed. The frame is compared with the received frame stored in the received frame storage means, and if they match, the transmission frame stored in the transmission frame storage means is transmitted. For example, CP
If the contents of the reception frame storage unit and the transmission frame storage unit are updated when performing communication using U resources, the periodic reception frame and the transmission frame corresponding thereto are stored in the reception frame storage unit and the transmission frame storage unit. Is done. Therefore, even if the CPU resource stops operating due to the sleep function, for example, it is possible to respond to a periodic inquiry without using the CPU resource and other devices. Therefore, CPU resources of network devices and other devices can be shifted to the sleep mode. Further, since the processing of transmitting the transmission frame when the stored reception frame matches the new reception frame is sufficient, there is no need to perform complicated processing such as frame processing analysis on the reception frame, and low power consumption is achieved. It can be realized by a circuit configuration.

If the newly received frame does not match the received frame stored in the received frame storage means, the sleep function may be canceled without forcibly responding. . In addition, if a frame filter for selecting a received frame is provided, it is possible to prevent the sleep function from being unnecessarily canceled by a received frame irrelevant to the network device.

Further, according to the present invention, a transmission frame transmitted during communication is stored in a transmission frame storage means, and a time interval at which the transmission frame is transmitted is measured or set. Then, at the time of the sleep function, the transmission frame stored in the transmission frame storage unit is transmitted at the measured or set time interval. For example, a transmission frame may need to be transmitted from the network device at a predetermined time interval. Even in such a case, the time interval measured during communication,
Alternatively, the transmitted transmission frame can be periodically transmitted at a set time interval. Therefore, C
PU resources and other devices can be shifted to a sleep mode, and transmission of a transmission frame can be automatically and automatically continued.

[0021]

FIG. 1 is a block diagram showing a first preferred embodiment of a network device according to the present invention. In the figure,
1 is a network device, 2 is an external network side, 11
Is a control unit, 12 is a transmission frame storage unit, 13 is a reception frame storage unit, 14 is a comparison unit, 19 is a CPU resource, 21 is a sleep mode signal line, 22 is an interrupt signal line, 23 is a transmission command signal line, and 24 is A comparison result signal line, 26 is a transmission frame, 27 is a reception frame, and 28 is a wake-up signal line. In FIG. 1, the network device 1 is a server such as a file server or a print server in a network system. The CPU resources 19 in the network device 1 include a CPU that controls the operation of the entire network device 1. Further, the CPU resource 19 can be configured to include, for example, various devices shown in FIG. 9 such as a main memory, an HDD, and a keyboard. The external network 2 is provided with a network to which the network device 1 is connected, and other network devices connected to this network, for example, other servers and clients.

The control unit 11 includes a sleep mode signal line 21
Is constantly monitored, and when a signal indicating a sleep mode is received from the CPU resource 19, the operation at the time of the sleep function is performed. At the time of the sleep function, if the newly received frame matches the received frame stored in the received frame storage unit 13 according to the comparison result signal line 24 sent from the comparison unit 14, the transmission frame storage unit 1
2 to the external network side 2 to transmit a frame 26
Is sent. If the newly received frame and the received frame stored in the received frame storage unit 13 do not match, an interrupt signal to wake up the CPU resources 19 is sent to the CPU resources 19. Also, C
PU resource 19 from wake-up signal line 28
When a signal indicating that the PU resource 19 has been woken up has been sent, the control operation at the time of the sleep function ends.

The transmission frame storage unit 12 stores the transmission frame 26 (response frame) at the same time that the transmission frame 26 (response frame) is transmitted from the CPU resource 19 to the external network 2.
6 is stored. In the transmission frame storage unit 12, the maximum byte length of one frame to be transmitted, for example, Eth
If it is Ethernet, up to 1514 bytes can be stored. Therefore, a new transmission frame 2
6 is sent, the already stored transmission frame 2
6, a new transmission frame 26 is stored. Therefore, the latest transmission frame 26 is always stored in the transmission frame storage unit 12. A transmission frame 26 sent from the network device 1 to the external network side from the network device 1 to the external network side after the data communication with the other device ends the data communication with another device is a response frame which is almost constantly transmitted. Becomes Therefore, as the transmission frame is updated as described above, a response frame that is constantly transmitted is stored in the transmission frame storage unit 12. At the time of the sleep function, according to the transmission command from the control unit 11, the stored transmission frame 2
6 to the external network side 2.

The received frame storage unit 13 stores a received frame 27 (query frame) from the external network 2
The received frame 27 is stored at the same time as being sent to the PU resource 19. In the received frame storage unit 13, the maximum byte length of one frame to be received, for example, E
In the case of the Ethernet, up to 1514 bytes can be stored. Further, when a new received frame 27 is sent from the external network side 2, the new received frame 27 is stored in place of the already stored frame.
Therefore, the latest received frame 27 is always stored in the received frame storage unit 13. Most of the received frames 27 that enter the network device 1 from the end of the data communication of the network device 1 with other devices until the network device 1 enters the sleep mode are inquiry frames that are almost constantly received. Therefore, as the above-described updating of the reception frame is performed, the inquiry frame that is constantly received is stored in the reception frame storage unit 13. At the time of the sleep function, when a new received frame 27 is sent, the stored received frame 2
7 to the comparing unit 14. The received frame storage unit 13
, A semiconductor memory such as an SRAM or a FIFO can be employed.

The comparing unit 14 takes in the received frame 27 (response frame) at the same time as the received frame 27 is sent from the external network side 2 to the CPU resource 19. Then, the received frame 27 is compared with the received frame 27 stored in the received frame storage unit 13. Then, as a result of the comparison, whether or not all of the frames correspond to each other is sent to the control unit 11 as a comparison result signal line 24.

The sleep mode signal line 21 transmits a sleep mode instruction signal from the CPU resource 19 to the control unit 11. The interrupt signal line 22 transmits an interrupt signal for waking up from the control unit 11 to the CPU resource 19.
The transmission command signal line 23 transmits a command for transmitting the transmission frame 26 to the external network 2 from the control unit 11 to the transmission frame storage unit 12. Comparison result signal line 24
Is the new received frame 27 in the comparing unit 14 and the received frame 27 sent from the received frame storage unit 13.
And tell the result of the comparison. Wake-up signal line 28
Informs the control unit 11 that the CPU resource 19 has been woken up. In these signal lines, for example, a command or the like can be transmitted by activating the signal line for one or a predetermined plurality of clocks. Of course, any method of transmitting the command, such as indicating at the “H” level and the “L” level and transferring data, is arbitrary. The sleep mode signal line 21 and the wake-up signal line 28 are connected to the CPU resource 1 by the same signal line.
It is also possible to configure so as to show the state 9.

Next, an example of the operation of the network device according to the embodiment of the present invention will be described. Upon receiving the reception frame 27 to be responded to, the network device immediately returns the corresponding transmission frame 26. At this time, when the reception frame 27 is received, the reception frame 27 is stored in the reception frame storage unit 13. When the corresponding transmission frame 26 is transmitted, the transmission frame 26 is stored in the transmission frame storage unit 12.

Such communication is performed, and the steady reception of the reception frame 27 and the transmission frame 2 corresponding thereto are performed.
6 is repeated at a constant interval, the received frame stored in the received frame storage unit 13 is stored in the transmission frame storage unit 12, and the transmission frame corresponding thereto is stored in the transmission frame storage unit 12. Become. And C
The PU resource 19 shifts to the sleep mode when a predetermined time elapses after only such regular transmission and reception. At this point, a steady reception frame is stored in the reception frame storage unit 13, and a transmission frame for the reception frame is stored in the transmission frame storage unit 12. Then, when the CPU resource 19 shifts to the sleep mode, the control unit 11 performs an operation at the time of the sleep function.

FIG. 2 is a flowchart showing an example of the operation of the control unit in the embodiment of the network device of the present invention. As described above, the control unit 11 monitors the sleep mode signal line 21 from the CPU resource 19 in this example. In S51, it is determined whether or not a signal indicating the sleep mode has been sent from the CPU resource 19. Then, it waits in this step until the CPU resource 19 shifts to the sleep mode.

When the CPU resource 19 shifts to the sleep mode, in S52, it is determined whether or not a signal indicating that the CPU resource 19 has been woken up has been sent via the wake-up signal line 28. Then, when the signal is sent, the process at the time of the sleep function in the control unit 11 is ended, and the process returns to S51. If the CPU resource 19 has not been woken up, it is further determined in S53 whether or not a comparison result has been sent from the comparison unit 14 via the comparison result signal line 24. If the comparison result is not sent, the received frame has not been received and the corresponding processing need not be performed.
Monitor 19 wake-ups.

When a new reception frame arrives, the comparison unit 14 compares the newly arrived reception frame 27 with the reception frame 27 already stored in the reception frame storage unit 13.
To compare. Then, in S54, the control unit 11 receives the comparison result by the comparison unit 14 via the comparison result signal line 24. As described above, the reception frame 27 stored in the reception frame storage unit 13 is a reception frame that is constantly received. Therefore, if the reception frame 27 is compared with a new reception frame 27, the reception frame 27 is stored in the transmission frame storage unit 12. It is possible to easily determine whether or not the transmitted transmission frame 26 should be returned.

In S55, it is determined whether or not the comparison result by the comparing unit 14 matches the newly arrived received frame 27 with the received frame 27 already stored in the received frame storage unit 13. If they match, S56
In step (1), a command to transmit the transmission frame 26 is transmitted from the control unit 11 to the transmission frame storage unit 12, and the transmission frame 26 stored in the transmission frame storage unit 12 is transmitted. Since the transmission frame 26 stored in the transmission frame storage unit 12 is a response frame, it is not necessary to perform an operation for newly generating a response frame.

After transmitting the transmission frame, the flow returns to S52 to wait for the wakeup of the CPU resource 19 in S52 and the arrival of the comparison result in S53.

If the newly-arrived received frame 27 does not match the received frame 27 already stored in the received-frame storage unit 13, the control goes to step S57.
The U resource 19 is woken up, the operation at the time of the sleep function ends, and the process returns to S51. Thereafter, the CPU resource 19 responds to the received frame and performs subsequent communication.

In the above operation example, the control unit 11
Although a signal instructing the sleep mode from the CPU resource 19 is shown as being constantly monitored, it may be configured to start by receiving the signal and stop the operation by sending an interrupt signal.

FIG. 3 shows a first example of the network device of the present invention.
FIG. 13 is an explanatory diagram schematically showing an example of a communication state in the network system using the embodiment. It is assumed that the network device according to the first embodiment of the present invention is a network device 1, and a network 2 and a network N are connected on the same network.

Normally, the network device 1 performs communication such as data transfer with another network device, that is, the network device 2 or the network device N. At this time, since the CPU resources 19 and the like are required, the network device 1 is not in the sleep mode.

When data communication with the network device 2 or the network device N is completed, the network device 1 performs an operation of only returning a response frame to a periodic inquiry frame. Therefore,
The inquiry frame continues to be stored in the reception frame storage unit 13 of the network device 1. Similarly,
The response frame continues to be stored in the transmission frame storage unit 12. The received frame 27 for the inquiry is
As long as the service application to be queried is the same, the frame contents are always the same. Similarly, the contents of the response frame are always the same. This state is shown as A in the figure.

Then, in the network device 1, for example, a state where there is no input such as a keyboard / mouse or the like continues for a certain period of time, and in the network, communication which requires the CPU resource 19, such as data transfer, is completed. When the state where only the frame is received continues, the network device 1 enters the sleep mode. At this time, the power of the CPU resource 19 may be turned off, but the control unit 11 and the transmission frame storage unit 1 shown in FIG.
2. The energized state of the received frame storage unit 13 and the comparison unit 14 is maintained. Then, after the transition to the sleep mode, if the received frame 27 from the network device 2 is the same as that received immediately before entering the sleep state,
The frame transmitted immediately before entering the sleep mode is transmitted to the network device 2. This state is shown as B in the figure. As a result, the network device 2 has a CP
The same response frame as when the U resource 19 was operating is returned. The same applies to the network device N and the like.

If the received frame is different from the frame received immediately before entering the sleep mode as shown as a new transmission frame, the control unit 11 transmits an interrupt signal to the CPU resource 19, and
Wake up 9 And CPU resources 19
Will return a response frame to the received new transmission frame.

As described above, in the first embodiment, a response frame can be returned in response to the inquiry frame even during the sleep function, so that, for example, the server can shift to the sleep mode. is there. Transmission of a response frame corresponding to this inquiry frame can be realized by a very simple configuration as shown in FIG. 1, and power consumption can be suppressed. Therefore, the power consumption can be reduced as a whole by shifting the CPU resources 19 having large power consumption to the sleep mode and performing the processing at the time of the sleep function with the minimum configuration. It should be noted that, for a received frame other than the inquiry frame in the steady state, the CPU resource 19 is woken up to respond, so that there is no trouble in communication.

Further, in the above configuration, it is only determined whether or not the received frame 27 is an inquiry frame.
In other words, the transmission frame corresponding to only one type of received frame is returned, but it may be configured to be compatible with two or more types of frames. For example, two or more reception frame storage units are provided, and different types of reception frames are stored in the respective reception frame storage units. Also, the same number of transmission frame storage units as the reception frame storage unit may be provided, and the transmission frames corresponding to the reception frame storage unit may be stored in association with each other. For example, it may be configured as a table in which the reception frame storage unit 13 and the transmission frame storage unit 12 are associated with each other. And CPU resources 19
After a shift to the sleep mode, when a new received frame comes, the transmission frame corresponding to the received frame may be sent back by referring to the table. This makes it possible to deal with various frames sent from the external network side.

Further, for example, if only a specific protocol is used, the received frames stored in the received frame storage unit 13 and the transmission frame storage unit 12 and the corresponding transmission frames may be fixed data. In this case, the update of the reception frame storage unit 13 and the transmission frame storage unit 12 becomes unnecessary. Further, even if the data is tabulated as described above, it can be easily coped with fixed data.

In the above configuration, the control unit 11
And the like are shown integrally with the CPU resources 19, but the arrangement is not limited to the respective arrangements such as a configuration incorporated in a network interface. 1 is not limited to a server, but may be a client. These points can be adopted in other embodiments described below.

FIG. 4 shows a second example of the network device of the present invention.
It is a block diagram showing an embodiment. In the figure, the same parts as those in FIG. Reference numeral 15 denotes a reception frame filter. Receive frame filter 1
Reference numeral 5 is for transmitting only a received frame required by the network device 1 and discarding an unnecessary frame, for example, a broadcast frame which does not need to respond to the network device. In addition, the reception frame filter 15 can be configured in advance so that the type and pattern of a frame to be transmitted can be designated by a CPU or the like. Other configurations are the same as those shown in FIG.

Next, an example of the operation of the network device according to the second embodiment of the present invention will be described. In the second embodiment, the reception frame filter 15 operates even while the CPU resource 19 is operating, and the CPU resource 19 transmits only a specific frame, performs a reception process, and returns a response frame. The reception frame storage unit 13 stores the reception frames that have passed through the reception frame filter 15. Further, the transmission frame storage unit 12 stores a transmission frame corresponding to the reception frame that has passed through the reception frame filter 15.

The stationary reception of the reception frame 27 and the transmission of the corresponding transmission frame 26 are repeated at regular intervals, and when the CPU resource 19 shifts to the sleep mode, the control unit 11 performs the operation at the time of the sleep function. at this point,
The stationary received frame that has passed through the received frame filter 15 is stored in the received frame storage unit 13, and the transmission frame corresponding to the received frame is stored in the transmission frame storage unit 1.
2 is stored.

The operation of the control unit 11 at the time of the sleep function is substantially the same as that of FIG. When detecting that the CPU resource 19 has shifted to the sleep mode in S51, the process shifts to an operation in the sleep function. And CPU resources 19
It is determined whether or not has been woken up, and if so, the operation in the sleep function ends and the process returns to S51. If the CPU resource 19 is in the sleep state, further, in S53, the receiving frame arrives and the comparing unit 1
It is determined from step 4 whether the comparison result has been input.

When a new received frame arrives, unnecessary frames among the arrived received frames are discarded by the received frame filter 15. Therefore, the discarded received frame does not reach the comparing unit 14, and therefore the comparison signal is not sent to the control unit 11, so that the control unit 11 does nothing. As a result, an unnecessary reception frame arrives and differs from the reception frame stored in the reception frame storage unit 13 in CP.
It is possible to prevent the U resource 19 from being woken up.

When the new incoming received frame passes through the received frame filter 15, the received frame is compared with the received frame 27 already stored in the received frame storage unit 13 by the comparing unit 14, and the comparison result is obtained by the control unit. 1
1 will be passed. Subsequent operations are the same as in the first embodiment.

FIG. 5 shows a second example of the network device of the present invention.
FIG. 13 is an explanatory diagram schematically showing an example of a communication state in the network system using the embodiment. It is assumed that the network device according to the second embodiment of the present invention is a network device 1 and a network 2 and a network N are connected on the same network.

Normally, the network device 1 communicates with another network device, that is, the network device 2 or the network device N, such as data transfer. After the end of the communication, the network device 1 performs only an operation of returning a response frame to the periodic inquiry frame.
The inquiry frame at this time passes through the reception frame filter 15, is processed by the CPU resource 19, and the response frame is transmitted. During this time, the inquiry frame is stored in the reception frame storage unit 13 and the response frame is stored in the transmission frame storage unit 12, as indicated by A in the figure.

After the network device 1 enters the sleep mode, a response frame is transmitted for a periodic inquiry frame passing through the reception frame filter 15. This state is shown as B in the figure.

In such a sleep function, a broadcast frame unrelated to the network device 1 is transmitted from the network device N in FIG. But,
If this broadcast frame does not pass through the reception frame filter 15, even if it reaches the network device 1, it is discarded by the reception frame filter 15. Therefore, it is not processed as a received frame different from the stationary inquiry frame, and the CPU resource 1
9 will not be woken up.

Of course, as shown as a new transmission frame from the network device N, when a reception frame passing through the reception frame filter 15 arrives, a reception frame different from the inquiry frame which is constantly transmitted is received. Then, the CPU resource 19 is woken up. Then, the CPU resource 19 returns a response frame to the received new transmission frame.

As in the above-described example, it is often unnecessary to respond to a broadcast frame, and if such a received frame is discarded by the received frame filter 15, C
Wake-up of PU resources 19 can be avoided. The reception frame filter 15 can be used, for example, when discarding a reception frame of a different protocol. Further, the reception frame filter 15 may be configured to operate only during the sleep function.

FIG. 6 shows a third embodiment of the network device according to the present invention.
It is a block diagram showing an embodiment. In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. 16 is a frame transmission interval measurement unit, 17 is a frame transmission interval storage unit, 18 is a timer, and 25 is a frame interval signal line. The network device illustrated in FIG. 6 is a server such as a file server and a print server in the network system. Further, in this network system, the network device 1 as a server includes:
It is assumed that a broadcast frame is transmitted to the external network side 2 at regular intervals.

The control unit 11 includes a sleep mode signal line 21
When a signal instructing the sleep mode is received, the operation at the time of the sleep function is performed. First, the timer 18 is started, and when the time value of the timer 18 matches the time interval of frame transmission stored in the frame transmission interval storage unit 17, the transmission frame 26 (broadcast frame) stored in the transmission frame storage unit 12 is transmitted. ) To the external network side 2. Also, CP
CP from U resource 19 via wake-up signal line 28
When receiving a signal indicating that the U resource 19 has woken up, the operation in the sleep function is ended.

The transmission frame storage unit 12 operates in the same manner as in the above-described first or second embodiment.
6 is transmitted from the CPU resource 19 to the external network side 2 and at the same time, the transmission frame 26 is stored. At the same time, the frame interval signal line is activated to notify the frame transmission interval measuring unit 16 that the transmission frame has been transmitted. Further, according to a transmission command from the control unit 11, the stored transmission frame 26 is transmitted to the external network side 2. The transmission frame storage unit 12 stores S
A semiconductor memory such as a RAM or a FIFO can be employed.

The frame transmission interval measuring section 16 constantly monitors the frame interval signal line 25 and
Measures the transmission interval of the frame transmitted by. Further, the measured value is transmitted to the frame transmission interval storage unit 17. In addition, since each frame interval differs from time to time, the latest transmission interval is always transmitted. Further, the control unit 11 may calculate a value obtained by averaging several recent frame transmission interval times and use this calculation result, or may calculate and use an average value for a longer period. Alternatively, a statistical method may be used.

The frame transmission interval storage unit 17 stores the measured value of the transmission time interval of the frame transmitted from the frame transmission interval measurement unit 16. Further, the stored measurement value is transmitted to the control unit 11.

The timer 18 starts or stops measuring time under the control of the control unit. In addition to allowing the control unit 11 to refer to the timekeeping state, the control unit 11 may be capable of setting a transmission time interval, and may be configured to notify the control unit 11 when the set transmission time interval has elapsed.

The frame interval signal line 25 is transmitted from the transmission frame storage unit 12 to the frame transmission interval measurement unit 1 as described above.
6 is transmitted to inform that the transmission frame has been transmitted.
Others are the same as FIG. In addition, the first
About the structure similar to embodiment of this, the same deformation | transformation is possible. For example, the sleep mode signal line 21 and the wake-up signal line 28 may be configured by the same signal line, or the transmission frame storage unit 12 may be configured to be able to store a plurality of transmission frames.

Next, an example of the operation of the network device according to the third embodiment of the present invention will be described. In this example, it is assumed that the network device transmits the transmission frame 26 to the external network side 2 at regular intervals. When transmitting the transmission frame 26, the transmission frame is stored in the transmission frame storage unit 12. Each time a transmission frame is stored in the transmission frame storage unit 12, the frame transmission interval measurement unit 16
And the transmission interval of the transmission frame is measured. The measured transmission interval between transmission frames is stored in the frame transmission interval storage unit 17.

When such transmission frames are transmitted periodically, the transmission frames transmitted periodically are stored in the transmission frame storage unit 12 and the transmission intervals are stored in the frame transmission interval storage unit 17. Will be stored. The CPU resource 19 can shift to the sleep mode when a predetermined time elapses after only such a steady transmission. When the CPU resource 19 shifts to the sleep mode, the control unit 11 performs an operation at the time of the sleep function.

FIG. 7 shows a third embodiment of the network device according to the present invention.
9 is a flowchart illustrating an example of an operation of a control unit according to the embodiment. First, in S61, it is determined whether or not a signal instructing the sleep mode has been sent from the CPU resource 19. If the signal is not sent, this determination is repeated.

When a signal instructing the sleep mode is sent from the CPU resource 19, the operation at the time of the sleep function is performed. In step S62, the timer 18 is started to start time measurement. In S63, for example, it is determined whether or not the CPU resource 19 has been woken up by the wake-up signal line 28, and when the CPU resource 19 has been woken up, the operation at the time of the sleep function ends, and the process returns to S61. If the CPU resource 19 is in the sleep state, further in S64,
It is determined whether or not the count value of the timer 18 matches the frame transmission interval stored in the frame transmission interval storage unit 17. Until they match, the process returns to S63, and the CPU resource 1
9 and the monitoring of the timer are repeated.

If it is determined that the count value of the timer 18 matches the frame transmission interval stored in the frame transmission interval storage unit 17 and it is determined that the time to transmit the transmission frame has arrived, then in step S65, the transmission frame storage unit A command to transmit the transmission frame 26 is sent to the transmission unit 12 to cause the transmission frame 26 to be transmitted. Further, in S66, the timer 18 is restarted, and the flow returns to S63 to wait for the transmission timing of the next transmission frame.

As described above, when the CPU resource 19 enters the sleep mode, the transmission frame 27 (broadcast frame) can be transmitted on the network at a constant cycle without the intervention of the CPU resource 19.

FIG. 8 shows a third embodiment of the network device according to the present invention.
FIG. 13 is an explanatory diagram schematically showing an example of a communication state in the network system using the embodiment. It is assumed that the network device according to the third embodiment of the present invention is a network device 1 and a network N is connected on the same network.

Normally, communication such as normal file transfer is performed between the network device 1 and the network device N. At this time, the network device 1 is in the sleep mode because the CPU resource 19 is required. Absent. Also, since the network device 1 has a service as a server, the network device 1 periodically transmits the transmission frame 26 to notify other network devices of its service.
(Broadcast frame).

The network device 1 is a network device N
When the data communication with the
6 will be transmitted. Then, only the transmission frame 26 continues to be stored in the transmission frame storage unit 17 provided in the network device 1. This state is shown as A in the figure. The contents of the transmission frame 26 of the broadcast frame are always the same as long as the service application is the same. The interval at which such a transmission frame 26 is transmitted is measured by the frame transmission interval measurement unit 16, and the result is stored in the frame transmission interval storage unit 17.

When the data communication with the network device N is completed and the input from the input device such as the keyboard and the mouse is stopped for a certain period of time, the network device 1 shifts to the sleep mode. At this time, a signal instructing the sleep mode is notified to the control unit 11 from the CPU resource 19. The control unit 11 transmits the transmission frame 26 stored in the transmission frame storage unit 12 at the frame transmission interval stored in the frame transmission interval storage unit 17. As a result, the transmission frame is transmitted at the same time interval as when the CPU resource 19 is operating. This state is shown as B in the figure.

Of course, when a new frame arrives, the CPU resource 19 wakes up, and the fact is notified to the control unit 11. The control unit 11 ends the process at the time of the sleep function, and stops sending the transmission frame in the transmission frame storage unit 12. The CPU resource 19 transmits a response frame corresponding to the new frame that has arrived. Thereafter, the transmission of the transmission frame by the CPU resource 19 is resumed.

In the configuration shown in FIG. 6, the frame transmission interval measuring section 16 for measuring the transmission interval of the transmission frame is provided, and the configuration for automatically measuring the transmission interval is shown. A configuration for setting a value may be adopted. Such a configuration is effective, for example, when the frame transmission interval is determined in advance.

[0076]

As is apparent from the above description, according to the present invention, the network can be periodically switched on the LAN without modifying other network devices on the LAN and without depending on other network devices. It is possible to use the sleep function of the network device even when it is necessary to respond to a general inquiry or to periodically transmit information. In addition, since the response to the periodic inquiry or the periodic information transmission is realized by a very simple configuration, the power consumption while the CPU resources and the like are in the sleep mode is reduced to a minimum. can do. Therefore, there is an effect of contributing to energy saving of the entire network system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a network device according to the present invention.

FIG. 2 is a flowchart illustrating an example of an operation of a control unit according to the embodiment of the network device of the present invention.

FIG. 3 is an explanatory diagram schematically showing an example of a communication state in a network system using the network device according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a second embodiment of the network device of the present invention.

FIG. 5 is an explanatory diagram schematically showing an example of a communication state in a network system using a network device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the network device of the present invention.

FIG. 7 is a flowchart illustrating an example of an operation of a control unit in the third embodiment of the network device of the present invention.

FIG. 8 is an explanatory diagram schematically showing an example of a communication state in a network system using a network device according to a third embodiment of the present invention.

FIG. 9 is a block diagram illustrating a general configuration example of a computer having a network interface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Network apparatus, 2 ... External network side, 11
... Control unit, 12 ... Transmission frame storage unit, 13 ... Reception frame storage unit, 14 ... Comparison unit, 15 ... Reception frame filter, 16 ... Frame transmission interval measurement unit, 17 ... Frame transmission interval storage unit, 18 ... Timer, 19 ... CPU resources, 21
... sleep mode signal line, 22 ... interrupt signal line, 23
... Transmission command signal line, 24 ... Comparison result signal line, 25 ... Frame interval signal line, 26 ... Transmission frame, 27 ... Reception frame, 28 ... Wake-up signal line, 31 ... CPU, 3
2 bus bridge, 33 main memory, 34 keyboard / mouse interface, 35 HDD interface, 36 image interface, 37 network interface, 38 keyboard and mouse, 39
HDD, 40 CRT, 41 network, 42 bus.

Claims (7)

[Claims] 1. A network device having a sleep function for reducing power consumption, a received frame storage unit for storing a received frame, a transmission frame storage unit for storing a transmission frame, and stored in the received frame storage unit. A comparing unit that compares a received frame with the new received frame; and a notification that the received frame stored in the received frame storage unit matches the new received frame during the sleep function. A control unit for controlling transmission of the transmission frame stored in the transmission frame storage unit when the transmission is performed. 2. The control unit controls the sleep function to be released when a comparison result by the comparison unit does not match a received frame stored in the received frame storage unit with the new received frame. The network device according to claim 1, wherein: 3. The apparatus according to claim 1, further comprising a frame filter for selecting a received frame, wherein said received frame storing means stores only the received frames passing through said frame filter, and said comparing means stores said received frame through said frame filter. 3. The network device according to claim 1, wherein only the received frame obtained is compared with the received frame stored in the received frame storage unit. 4. The reception frame storing means according to claim 1, wherein the received frame storage means replaces the stored received frame with a new received frame each time a received frame is received and stores the received frame. 2. The network device according to claim 1. 5. A network device having a sleep function for reducing power consumption, a transmission frame storage unit for storing a transmission frame, a frame transmission interval measurement unit for measuring a time interval at which the transmission frame is transmitted,
A frame transmission interval storage unit for storing a time interval measured by the frame transmission interval measurement unit; and a transmission frame stored in the transmission frame storage unit during the sleep function, stored in the frame transmission interval storage unit. A network device comprising control means for controlling transmission at time intervals. 6. A network device having a sleep function for reducing power consumption, a transmission frame storage unit for storing a transmission frame, a frame transmission interval storage unit for setting a time interval for transmitting the transmission frame,
A network device, comprising: a control unit that controls transmission frames stored in the transmission frame storage unit at the time intervals stored in the frame transmission interval storage unit during the sleep function. 7. The transmission frame storage unit according to claim 1, wherein the transmission frame storage unit replaces the stored transmission frame with a new transmission frame and stores the transmission frame each time the transmission frame is transmitted. The network device according to claim 1.