JP2997492B2 - Network system - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a network system, and more particularly, to a network system capable of adjusting the time of a timer of each device connected to a node. is there.

(Prior Art) Conventionally, in a network system, each device connected to a node has an independent timer, and an operation is performed based on the independent timer.

However, due to an error between the timers, for example, the timing of data transmission / reception between the devices or between the network management device and the devices is shifted, and the shift cannot be ignored for a long period of time, causing a failure in system operation. The problem had occurred.

Therefore, it is conceivable to make the timer of each device extremely accurate.
As the number of devices increases, the number of high-precision timers increases, and the cost of the system increases.

(Problems to be Solved by the Invention) As described above, in the conventional network system, the deviation cannot be ignored for a long period of time due to an error in the timer of each device connected to the node, which causes a failure in the operation of the system. However, there is a problem that changing the timer to a high-precision timer causes an increase in system cost.

The present invention has been made in view of such a problem of the conventional network system, and an object of the present invention is to make it possible to appropriately adjust the time of a timer of each device, thereby enabling a network system capable of appropriately operating the system. Is to provide a system.

[Configuration of the Invention] (Means for Solving the Problems) A network system according to the present invention includes a line network connecting a plurality of nodes to which a device including a timer is connected, and a network management device for managing the line network. Wherein the network management device receives time information of a timer from each of the devices, and based on the time information of the timer that the network management device should refer to the time information corresponding to each device. Using the management means for updating and managing, and the time information managed by the management means, determine whether or not time adjustment should be performed, and send the time information to a required device when necessary including the case based on the determination. And time information sending means for causing the timer to adjust the time.

(Operation) According to the above configuration, even if a time elapses from the time when the time information of the timer is received from each of the devices to the time of time adjustment based on the time difference between the timers, the time corresponding to each of the devices received as described above. Since the information has been updated based on the time information of the timer to be referred to by the network management device, the time information of the timer to be referred to by the network management device at that time and the time information of the updated timer of each device are replaced by the time. It can be detected appropriately regardless of the information receiving time.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of one embodiment of the present invention. In the figure, 2 denotes a network, connecting a plurality of nodes 3 ₁ to 3 _n. Each node 3 ₁ to 3 _n, a personal computer, the device 4, such as a mainframe computer switch is connected,
The devices 4 each have a timer 5. Each node 3 ₁ -
3 _n , the device 4 has a function of performing data communication via the line network 2, a function of reading the time of the timer 5 and sending it to the network management device 1, and a device that receives time information from the network management device 1. Has a function of changing the time of the timer 5 based on this time information. These functions are realized by a processor provided in each device 4 by a program in the main memory.
A network management device 1 is connected to the line network 2 and performs processing such as adjusting a traffic flow in response to an abnormality in the network, and includes a timer 11, a management unit 12, and a time information transmission unit 13. ing. These means are realized by software by a processor. The network management apparatus 1 has a communication function in addition to the above, and when the time adjustment processing routine of the timer 5 of the system is started, the network management apparatus 1 performs an operation according to the flowchart shown in FIG.

That is, when the routine starts, the network management device 1 checks whether it is time to receive time information (200). This period includes, for example, the following two periods. Device 4
When time information is sent autonomously to the network management device 1. When a transmission request for time information is transmitted from the network management apparatus 1 to the apparatus 4, and time information is transmitted in response thereto. At this time, the process branches from step 200 to YES to receive the time information (201), and rewrites the timer value as the management means 12 (202). This timer value is written to a register of the management means 12. This will be described with reference to FIGS. 3 and 4. Here, node x
Of time information with the device y. In FIG. 3, _assuming that the time of the timer 5 of the device y of the node x is _txy1 , the time information _txy1 is autonomously transmitted to the network management device 1, and
T _xy1 is set in the corresponding register T _xy . At this time,
Timer 11 of the network management device 1 indicates the time T _1.

In FIG. 4, the network management device 1 sends a time information transmission request to the device y of the node x. In response, it indicates that time information t _xy1 has been sent.

Next, description will be made returning to FIG. If it is not time to receive the time information (branch to ON in step 200), or
When the step 202 of rewriting the timer value is completed, the management unit 12 counts up the time information (203). That is, the timer value T ₁ of the timer 11 of the network management apparatus as shown in FIG. _{5, T 1 + △ T, ...} , T 1 + n × △
While _{changing to} T, the timer value of the corresponding register T _xy is t _xy1 , t
Rewriting is performed with reference to the timer 11 and _xy1 + ΔT,..., _txy1 + n × ΔT.

Next, the network management device 1 proceeds to step 204 in FIG. 2 and checks whether it is time to perform time adjustment. For example, there are the following four periods. That is, when the difference between the timer value of the timer 11 and the timer value in the register is equal to or greater than a predetermined value. When the difference between the timer values in the set register exceeds a predetermined value. When the network management device 1 forcibly adjusts the time every predetermined time. When the device 4 sends a time adjustment request. At such time, the network management device 1 proceeds to step 205 and
Is connected so as to be able to communicate with a required device 4 via the network 2 (a data link is established), and sends time information to set time (set time) (206). This process is performed by the time information sending means 13.

The processing of steps 205 and 206 will be described with reference to FIGS. In FIG. 6, the timer of the network management device 1
When the 11 timer value T ₁ and a node of the register T _xy device y of x timer value t _xy1 has occurred more than the predetermined amount difference, the network management device 1 gives the time information T ₁ out reading beauty equipment y shows that to set the T ₁ to the timer 5. In FIG. 7, the node x
The difference between the timer value t _xy1 of the register T _xy of the device y of the device y and the timer value t _vw1 of the register T _vw of the device W at the node V is equal to or greater than a predetermined value (the detection of the difference is performed by the register corresponding to each device). The network management device 1 calls the device y to provide the time information T ₁ , causes the timer 5 to set T ₁ , calls the device W, and provides the time information T ₁ . It indicates that to set the T ₁ to the timer 5 Te. 8th
The figure shows that the network management apparatus 1 refers to its own timer 11, calls the apparatus y of the node x at predetermined time intervals, gives time information T _i at each time, and causes the timer 5 to set T _i. . The network management device 1 adjusts the time for the required devices of the other required nodes by the same operation. In FIG. 9, since the device y of the node x has autonomously sent a time adjustment request,
Sending time T ₁ of the timer 11 indicates the case of setting the time T ₁ to the timer 5. Depending on the system, one or two or more of the above four timings are adopted, and the time is adjusted.

Next, the network management apparatus 1 proceeds to step 207, and detects whether the routine is to be ended (for example, the end of time adjustment for all apparatuses) and if the end conditions are not met, the step proceeds to step 207.
Returning to step 200, if the conditions are met, the process ends and the process proceeds to another routine.

In the above embodiment, the timer 11 of the network management device 1 is used as a reference clock. However, depending on the system, for example, a certain node may be provided with a host computer, and the timer may be set to high accuracy. 1 may determine the set time on the basis of the time information obtained from the host computer, and which device's timer is used depends on the system.

[Effects of the Invention] As described above, according to the present invention, even if time elapses from the time when the time information of the timer is received from each device to the time of time adjustment based on the time difference between the timers, Since the received time information corresponding to each device has been updated based on the time information of the timer to be referred to by the network management device, the time information of the timer to be referred to by the network management device at that time and the updated timer of each device. Can be appropriately detected regardless of the time point at which the time information is received, and the time adjustment of the timer provided in the apparatus can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a flowchart for explaining one embodiment of the present invention, and FIGS. 3 to 9 are communication procedures for explaining one embodiment of the present invention. FIG. 1 ...... network management apparatus, 2 ...... network 3 ₁ to 3 _n ...... node, 4 ₁₁ to 4 _n3 ...... device 5 ₁₁ to 5 _n3 ...... timer, 11 ...... timer 12 ...... management unit, 13 ... ... Time information sending means

Claims (2)

(57) [Claims] 1. A network system comprising: a network for connecting a plurality of nodes to each of which a device having a timer is connected; and a network management device for managing the network, wherein the network management device comprises: A management unit that receives time information of a timer from the server, updates and manages the time information corresponding to each device based on the time information of a timer to be referred to by the network management device, and stores the time information managed by the management unit. And time information sending means for sending time information to a required device and adjusting the time of the timer when necessary including the case based on this determination. Characteristic network system. 2. When the time information sending means needs to cause the timer to adjust the time, the difference between the time information managed by the management means and the time information of the timer to be referred to by the network management device becomes a predetermined value or more. When the difference between the plurality of pieces of time information managed by the management means is equal to or greater than a predetermined value, when the time at which the network management device forcibly adjusts the time arrives, or when a time adjustment request is issued from each device. 2. The network system according to claim 1, wherein when it arrives, it is: