JPH0624370B2 - Network wiper - Google Patents

Description

TECHNICAL FIELD The present invention relates to a network simulator for verifying and evaluating a distributed control algorithm in a network.

(Prior Art) In a loosely coupled network, communication nodes basically have autonomy. Therefore, the nodes operate asynchronously and in parallel with each other. For example, a network simulator is used to evaluate the legitimacy of algorithms such as distributed access control and distributed reliability control in such networks, and to evaluate their performance. In this network simulator, it is necessary to simulate the asynchronous parallel operation of the communication node described above, and the delay that always exists in the actual communication path must be taken into consideration. That is, the communication path delay, the execution time of an algorithm such as access control or reliability control executed in a distributed manner in each communication node, the execution order across all communication nodes,
It is necessary to take into account the uncertainty associated with asynchronous concurrency. In a conventional sequential processing type simulator, communication node process means, which is software for simulating a control procedure to be performed by a communication node on an actual network, is sequentially executed at sufficiently small times,
Monitoring the status of this communication node process means,
When the simulation of the sufficiently small time has completed one round for all the node process means, all the states of each communication node process means are collected and set as the state of the network in the time section. Further, by changing the software parameters of the communication node process means, the execution time and execution order of the algorithm, and further the causality of state transitions across communication nodes are simulated in all cases, and the asynchronous parallel operation is performed. And the uncertainty is apparently realized.

(Problems to be Solved by the Invention) In the above-described sequential processing type simulation, the simulation is successively performed at sufficiently small intervals for all communication nodes forming the network. In order to take into account the uncertainties that are essential for simulating more loosely coupled networks, it was necessary to simulate all possible combinations of parameters. For this reason, the structure of the simulator becomes complicated, and the time required for the simulation increases geometrically, especially when the network to be simulated becomes large in scale.

The purpose of the present invention is to provide an environment close to an actual system by making each communication node of the network operate in a completely parallel and asynchronous manner for accurate simulation, and even if the network becomes large, the time required for simulation is unrealistic. It is to be able to perform efficient simulations that increase to the target.

(Means for Solving the Problem) The present invention relates to a plurality of node process means corresponding to communication nodes of a network to be simulated, and an application process for realizing a function in the communication node, which is connected to the node process means. Means, communication path means for connecting all the node process means, execution management means for asynchronously executing the node process means and the application means, and node process means connected to the node process means. Means to connect in any form by the communication path means,
Simulator management means for notifying the user of the network simulator of the operating state of the node process means, and the execution management means activates the simulator management means for a certain period of time for every certain period, The operating condition is notified to the user of the network simulator, and the node process means and the application process means are asynchronously executed when the simulator management means is not executed.

(Operation) As one example of access control in a computer network, polling control in a network configuration as shown in FIG. 4 is widely known. Here, the operation when the network simulator according to the present invention is used to trace how the polling control algorithm is executed will be described.

The computer network shown in FIG. 4 is configured by connecting a plurality of terminal concentrators 402 and 403 to one central processing unit 401 via an input line 410 and an output line 420.
Here, the terminal concentrators 402 and 403 have a function of accommodating a plurality of terminals.

The central processing unit 401 transmits a polling signal to each terminal concentrator. On the other hand, each terminal concentrator can transmit a signal addressed to the central processing unit 401 only when receiving a polling signal addressed to itself. Central processing unit 40
When 1 knows the end of signal transmission from one terminal concentrator, it transmits a polling signal to the next terminal concentrator, and thereafter, polling control is repeated in this manner to communicate with all terminal concentrators.

A case where the execution status of the polling control in the computer network described above is traced using the network simulator according to the present invention shown in FIG. 1 will be described. In a computer network that controls access by polling control, its function is as follows.
A communication node function that controls physical communication such as transmitting a signal to a desired terminal concentrator or receiving a signal from the desired terminal concentrator, and the communication is fair and reliable to all terminal concentrators. It is roughly divided into an access control function for highly reliable operation without conflict. In this network simulator, node process means is provided as the one corresponding to the communication node, and application process means is provided as the one corresponding to the access control function.

The user of the network simulator instructs the simulator managing means 101 shown in FIG. 1 to execute the polling control performed by the central processing unit 401 and the terminal concentrators 402 and 403 as well as the network connection state shown in FIG. To notify. The simulator management means 101 uses, for example, the node process means 110 and the application process means 120 for simulating the operation of the central processing unit 401, and each node process means for simulating the operation of the terminal concentrators 402, 403.
It is assumed that 111, 112 and application process means 121, 122 are used.

Next, the simulator management means 101 logically sets the network connection state as follows. That is,
The simulator managing means 101 sets a logical communication path from the node process means 110 corresponding to the central processing unit 401 to all the node process means 111 and 112 corresponding to each terminal concentrator. Also, a logical communication path is set from the node process means 111, 112, 113 corresponding to each terminal concentrator to the node process means 110 corresponding to the central processing unit 401. FIGS. 5 and 6 show information necessary for setting a logical path corresponding to the computer network shown in FIG. 4 in each communication node process.

FIG. 5 shows logical path setting information of the communication node processing means 140 corresponding to the central processing unit 401 in FIG. The communication node process means 140 sets the output logical path P1 corresponding to the output line 420, and sets its destination as 111, 112.
Two communication node process means. In this logical path, the transmission is performed in the order shown by the arrow in FIG. 5 in consideration of the difference in propagation time to the communication node process means 111 and 112 on the output line 420. In the example of the polling control, the control signal transmitted by the application process means 120 of the central processing unit 401 is transmitted to the two communication node process means 111 and 112 in this order by this logical path P1. It is received by the node process means. Each communication node process means is for simulating only the topology of the network, and the application process means 120 designates the destination in the transmitted control signal as necessary, and each application process means that receives this, The destination is used to determine the transmission right acquisition condition and the like. The output logical path P1 is defined by the communication node process means 111 and 112.
In FIG. 6, the input logical path is set as shown in FIG.

Further, the communication node process means 140 sets the input logical path P2 corresponding to the input line 410 and receives the information transmitted from the communication node process means 111 and 112. In the communication node process means 110, the logical path P2 set for input is the communication node process means 111 and 1
In 12, the output logical path is set as shown in FIG. In this way, the physical communication path of the computer network shown in FIG. 4 is logically set on the network simulator.

Further, the simulator managing means 101 notifies the application process means corresponding to each device of the polling control procedure executed by the central processing unit 401 and the terminal concentrators 402, 403 notified by the user. That is, in the application process means 120 simulating the central processing unit 401, a processing procedure for transmitting a polling signal is given to each terminal concentrator, and each terminal concentrator is processed.
In the application process means 121, 122 for simulating 402, 403, while detecting the polling signal addressed to itself from the observed polling signal, for example, when detecting the polling signal, the signal is transmitted to the central processing unit 401. The procedure to be performed is given.

After the initial setting of the network simulator is completed as described above, the simulator management means 101 instructs the execution management means 100 to start the network simulator.

Execution management means 100 while operating each node process means and each application process means in parallel,
The simulator management means 101 is operated for a certain period of time for each preset constant period, and the simulator management means 101 is operated.
To inquire about the operating state of polling control of each node process means and each application process means. The polling control operation status inquired at this time includes, for example, the identifier of the terminal concentrator being polled at that time, one polling cycle of each terminal concentrator, etc. Based on this information, the user performs the polling control operation. You can grasp the status.

As described above, in the polling control, the correctness of the algorithm itself is already clear. However, if a failure occurs in the central processing unit that is performing the polling control or the communication link itself fails, the above simple polling control cannot recover. Therefore, in addition to the simple polling control described above, a time-out function is added, and further, by adding a control that multiplexes the central processing units and changes to the central processing unit in standby when a failure occurs, high reliability is achieved. It becomes possible to obtain the sex. When the control procedure is complicated in this way,
Although it is difficult to theoretically verify the correctness of the control procedure, according to the network simulator, the correctness can be verified by notifying each application process means of the control procedure and executing it. further,
Since the network status is monitored at regular intervals,
It is also possible to evaluate the time efficiency of this algorithm.

(Embodiment) FIG. 1 is a functional block diagram showing an example of a basic configuration of a network simulator according to the present invention. In FIG. 1, the node process means 110, 111, 112 and the application process means 120, 121, 122 are composed of, for example, independent processor units. The communication pulse means 130 connects the simulator management means and all the node process means by bus type coupling as an example in FIG. In FIG. 1, the execution management means 100 first executes the node process means and the application process means asynchronously. This can be done, for example, by the execution management means 100 by giving independent clocks to the control lines 140, 141, 142, 150, 151, 152 respectively to the processor units constituting the node process means and the application process means. Next, the simulator management means 101 sends the information necessary for the simulation by the communication path means 130 to each node process means. Here, the information is unique to each node process, and indicates, for example, an identifier of an adjacent node process used to set a logical transmission path described below, or an algorithm to be verified.
The algorithm is then sent to the application process by paths 160, 161, 162. Here, the above information is the communication path means 210 from the simulator managing means 201 to the node process means as in the second embodiment shown in FIG.
It is also possible to provide a communication path means 211 in the application process means and separately send the information necessary for simulation to the node process means and the application process means.

For example, in the above example, the identifier of the adjacent node is the communication path means.
At 210, the algorithm to be verified is sent to the node process means, and the algorithm to be verified is sent to the application process means by the communication path means 211. Next, the simulator management means 101
Sets a logical communication path between the node process means so as to form a network to be simulated as follows. First, for example, a bus arbitration device is provided in the simulator management means 101, and the right of use of the communication path 130 is assigned to each node process means in response to the request of the node process means, so that the node process means corresponds to the desired network topology. Allows the message to be sent to the desired node process means. That is, the communication path means 130 shown in the first and second embodiments,
In 1 and 2, since the bus type communication path means for sharing the communication resources by the time division method is used, each communication node process means may set the logical path as shown in FIG. Also, each communication node process means must secure the right to use the bus type communication path means by the bus arbitration device before the communication is started. In this way, a logical communication path forming a network to be simulated on the communication path 130 is set. Further, in order to notify the user of the network simulator of the operating state of each node process means, the execution management means 100 freezes the operating state of all the node process means and the application process means for a fixed time at fixed time intervals, At the same time, the simulator management means 101 is activated, and the communication path means 130 collects the status for each node process and notifies the user.

FIG. 3 shows a third embodiment of the present invention. FIG. 3 shows the case where there are four node process means and four application process means. In the example shown in FIG. 3, four node process means 310, 311, 312, 313 are communication path means 3.
Connected to form a complete graph by 30,331,332,333,434,335. Further, paths 336, 337, 338 and 339 used for collecting information necessary for initialization of simulation and operating states of each node process means are provided between the simulator management means and each node process means. Here, the logical communication path is set as follows. For example, if the node process means 310,312,313,
In order to construct a loop type network connected in order of 311, the simulator management process means 301 first sets the path 336.
Node process means 311 that is adjacent to the node process 310 on the simulated network.
Gives 312 identifiers. Further, those inner node process means 311 also notify that they are located on the upstream side and the node process means 312 are located on the downstream side, respectively. This means, in other words, for the node process means 310,
Node process means 3 connected by communication path means 335
13 is not logically adjacent to each other, and indicates that the message is received from the communication path 330 and the message is transmitted to the communication path 333. By adding these pieces of information to each node process, each node process is logically connected on the loop. In a similar manner, the node process means can be coupled to any form of network configuration, such as mesh type.

(Effect of the Invention) The effect of the simulator as described above will be shown. The simulator of the present invention provides an environment close to a real system by completely and asynchronously operating each communication node of the network for accurate simulation, and the time required for simulation is unrealistic even if the network becomes large. It is possible to perform an efficient simulation without increasing the maximum value.

Further, since the desired network topology to be simulated can be set by logically setting the communication path, it has flexibility for changing the network topology.

[Brief description of drawings]

1 is a functional block diagram showing a first embodiment of the simulator according to the present invention, FIG. 2 is a functional block diagram showing a second embodiment of the simulator according to the present invention, and FIG. 3 is a functional block diagram showing the simulator according to the present invention. FIG. 4 is a functional block diagram showing a third embodiment, FIG. 4 is a diagram showing one access control example in a computer network, and FIGS. 5 and 6 are diagrams showing logical path setting examples in the first embodiment. . In the figure, 110,300 ... Execution management means, 110,111,112,310,311,312,313 ... Node process means, 120,121,122,320,321,322,323 ... Application process means, 130,210,211,330,331,332,333,334,335,336,337,338,33
9 ... Communication path means, 140, 141, 142, 150, 151, 160, 161, 162 ... Control path, 401 ... Central processing unit, 402, 403 ... Terminal concentrator, 410 ... Input line 420 ... Represent output line, respectively.

Claims (2)

[Claims] 1. A plurality of node process means corresponding to communication nodes of a network to be simulated, application process means connected to the node process means for realizing a function in the communication node, and all the nodes. Communication path means for connecting process means, execution management means for asynchronously executing each of the node process means and each of the application means, and the node process means are connected to the node process means by the communication path means. And a simulator management means for notifying the user of the network simulator of the operating state of the node process means, and the execution management means activates the simulator management means for each fixed period for a fixed time. The operation of the node process means Network simulator state notifies the user of the network simulator, with the non-run time of the simulator management means, for causing said node processing means and said application process means asynchronously executed. 2. The simulator management means sets, for each of the node process means, a logical communication path between the node process means and an adjacent node process means based on the form of a network to be simulated. The node process means is notified of the identifier of the communication path means and the access sequence information, and each node process means receives the message input from the communication path means set in the node process means and the message from the node process means. 2. The network simulator according to claim 1, wherein the network simulator is caused to send out to the communication path means based on the access order information so that communication between the node process means is performed.