JPS5952945A - Network control system - Google Patents

Abstract

PURPOSE:To constitute titled system so that in case when an idle time is generated when a prescribed station is communicating, its communication right is transferred temporarily to other station, and an original station can take back the communication right again even if its communication right does not go round a loop. CONSTITUTION:When wait-processing is generated (S5) by a mechanical operation, etc. in the course of a communicating operation, a station (d) sends (S6) a token instruction to the following station (e) once, and parts with a communication right, but the temporary grant of the communication right is indicated distinctly by setting a flag in a control data area existing in this token instruction data, or changing an instruction code itself in a control data area 4. The communication processing completing in a short time is selected and processed (S24) by the station (e) since it receives the grant of the communication right though it is temporary. Thereafter, the station (e) tries (S25) return of the communication right grant for returning the communication right, to the original station (d), and if the wait-processing is completed (S8) in the station (d), its grant instruction is received, and an affirmative ACK response is sent back to the station (e) from the station (d).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a network, a
Regarding the power formula, especially the token passing formula 3.
This allows multiple communication control to be performed in the equation.

In recent years, with the rise of office automation,
A so-called local area network (LAN) in which a plurality of ijy FFI devices are connected through an inexpensive and easy-to-use communication network transmission line is being actively developed. Generally, in this type of local area network, a large number of terminal stations are branch-connected to a single common network transmission path, and communication between the terminal stations is performed via the shared transmission path. Therefore, simultaneous transmission from two or more terminal stations is possible.
), there is a risk that communication signals will be disrupted, or so-called communication collisions will occur. Therefore, in order to avoid this "collision of traffic", all stations in the network should communicate 4. −; Several control force formulas for adjusting the start timing have been proposed so far.

Among them, TOKEN PASS
The IN-G method is known as one of the superior methods, but this method precludes the ability to monopolize and use the network transmission path. In addition, it is necessary to ensure that there is only one transmitting stage ball in the network that is given this communication right, and to perform the pass (when the transmitting terminal station that has obtained 4 points ends communication, or from the beginning). This method is based on the principle that if there is no terminal station available, the communication right is transferred to another terminal station.Furthermore, in this method, each station in the network (in order to give each station an equal opportunity to communicate, The station passes the communication rights to the neighboring downstream stations one after another, and the communication rights circulate within the network.
o AHEAD) format is adopted as first grade.

Note that such communication control is generally implemented by firmware (microprogram), and therefore each station in the network is usually equipped with a small processor. Additionally, each station in the network typically knows at all times, by polling or otherwise, at least the address of the next downstream station to which it should receive or pass communication rights. In this way, in data communication using the token passing method, there are no unique stations in the δ network that make calls at the same time, so the above-mentioned ``communication collision'' cannot occur.

However, in such a conventional token passing system, it is not possible to perform multiplex communication even when there are sending stations that have idle time during communication operations. In other words, the number of stations connected to the local area network transmission line is the number of users (users).
Because communication often fluctuates depending on the system configuration, there is no guarantee of the amount of time it will take for a given communication right to be returned to the original station after it has circulated to all other stations. Therefore, it is difficult to perform multiplex communication using the conventional token passing method, so once a station has obtained communication rights, it must complete all necessary communication processing operations before receiving communication rights. could not be transferred to another station. However, it often happens that the station to which the communication right has been granted temporarily suspends the communication operation in order for the office equipment under the station to perform mechanical operations such as printing. However, at that time, the following
A problem arose in that communication rights could not be handed over to the ε station, and communication operations on the entire network were temporarily stopped, resulting in a significant drop in communication efficiency.

An object of the present invention is to eliminate the above-mentioned drawbacks and improve the communication rights delegation method of the go-aside type token passing method, so that when a predetermined station is communicating and there is free time, other stations can temporarily 1) A network control method that allows the original station to transfer the paddle and regain communication rights even if the communication rights do not go around the network again, thereby enabling multiple communication processing operations. It is about providing.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 1 shows an example of the structure (former) of communication data used in the network control system of the present invention, and HDLCt:
High-level data link control procedure) Similarly to communication, here 11 (transmission) is the first flag area indicating the beginning of the data, 24 (transmission) (receiving where the address of A destination station or downstream station is written) Station address area, send 3 lines and send 1 station's 7 addresses;
4 ÷ Input sending 4Fr m address area, 4 is (sending)
This is a data/control data area in which either data or control data (l, ) is recorded. Furthermore, numeral 5 is an FCS area for checking the validity of received data, and 6 is a second flag area that indicates the status of transmitted data.

In this example, the complete transfer of communication rights to the station of m is performed by the communication data of 1l JI Okawa as shown in Figure 1. This is called a TOKEN command.The station that received this TOKEN command
It becomes possible to send communication data from oneself. The remaining stations are only capable of receiving these communication data and transmitting response data.

Furthermore, as mentioned above, the receiving station that has received the temporary communication shield or delegation command receives a blank response (hereinafter referred to as AC) from the original transmitting station after completing the specified data transmission.
4±+Ii 4! A response (hereinafter referred to as NACK) is always returned, and the response to the ACK or NAC is stored in the control data area 4.

Figure 21-A and Figure 3 are the same as Figure 1, respectively.
6j? 1#I schematically shows how the communication network according to the present invention is operated, where a is the communication path of the network, and b-g are stations for transmitting and receiving communication data. Also, the arrows in the figure indicate the (a) and (b) direction of the TOKEN command. Like this (ko, tree ita 1
In 1, tshiiyunshu M8 Jsugi state assumes a unidirectional ring shape. FIG. 4 shows the control operation ('
I; (This is an ML diagram showing 5 types of 911. Next, referring to FIG. 4, the control operation of this embodiment will be explained using FIGS. 2 and 3.

First, FIG. 2 shows a network control operation similar to that of the conventional token passing method, but this operation is performed only when no multiplexing operation is performed, that is, when there is no communication request at each station. This corresponds only to the case where the station that received the TOKEN command has completely completed the TOKEN operation and sequentially hands over the communication rights to the next station (steps 5l-54). - In the case where it is necessary to start a multiplex operation at a station that has obtained communication rights by force and TOKEN commands (steps S5 and S6), as shown in FIG.
OKEN t) The way orders are circulated will change.

Here, it is assumed that station d in FIG. 3 requires multiple operations, and one communication operation includes a waiting process due to mechanical operation or other causes. After acquiring communication rights (step 51), one communication operation is started (step S2), and when the waiting process has progressed,
(Step S5), station d once sends a TOKEN command to the next station e (step S6), and traces (
1"i Let go of the paddle, but this TOKEN command data has a flag bit -r't set in a certain control data area 4,
Alternatively, the instruction code itself in the control fJ1 data area 4 is changed to clearly indicate that the communication right is temporarily transferred. This = temporary communication i: Delegation command is now EXPRESS
This will be called the TOKEN (Express 1-Kun) instruction to distinguish it from the normal TOKEN instruction.

Next, station e, which has received the EXPRESS TOKEN order, has been delegated the tsucho-sama, albeit temporarily (step 521), so in order to process the request for the data accumulated within its own station, e.g. It becomes possible to send messages. However, among these data communication requests, station e processes only those that require communication processing to be completed in as short a time as possible, so as not to occupy the network for a long time (steps S22 and 523).

When station e finishes the short-term communication (step 524), it first sends an EXPRESS TOKEN command to station d, which is the original sending station of the EXPRESS TOKEN command.
The PRESS TOKEN command is returned and communication rights return delegation is attempted (step 525).

If the waiting process has already been completed at station d (step S8), the transfer command is accepted and an ACK response with a fixed value of 1 is sent from station d to station e (step 510), and the right to pass 1η is The oldness is returned to station d (step 526). If station d is still in the waiting process, the transfer command is rejected as it is not yet time for data communication, and the NAC of rejection:
A response is returned from station d to station e (steps S8 and S9). At this time, station e determines that it was unable to return the communication right to station d (step 526), and furthermore, since station d's waiting process is still continuing, it uses this time to transfer communication rights to other stations. The stage, which is the next downstream station, can be used effectively.
A second EXPRESS TOKEN command is issued (step 528). What should be noted here is that the sending station address of the EXPRESS TOKEN command issued to station f is not station e, but remains the address of station d, the original hyperactive node (N0DE). It is. Therefore, station f
Directly from station d 4a EXPRES
It will appear as if a STOKEN command has been sent.

Station f performs a short communication process (steps Sl, S21) in the same manner as station e described above.
~524), EXPRESS TOKEN to the original sending station d of the EXPRESS TOKEN command.
Attempts to re-delegate communication rights according to the command (step 525);
If the response from step d is a 6-bit ACK response, the initial state 71. Return to , and if there is a negative NAGK response again,
next downstream sy -shig 7 g te
Ess TOKEN command is issued (step 328
~828). At this time, the sender address of the EXPRESS TOXEN command issued to station g is kept at the address of stage node d, which is the original multi-operation node, as in the case of the station described above. In this way, as long as the NACK of the EXPRESS TOKEN command sent to station d is rejected, the EXPRESS TOKEN command will be sequentially passed on to downstream stations, and the waiting time of station d will be reduced. It continues to be effectively used for communication processing by other stations.

Now, because the waiting time at station d is long, the EXPRESS TOKE that was first sent from station d
Assuming that the N command goes around the network and reaches station C, which is the upstream station immediately before station d, and the communication processing at station C is completed, station C at this time will definitely grant communication rights to one of the stations. It is necessary to delegate. Otherwise, the network connection 11 will be interrupted. Therefore, station C must delegate communication rights to station d.

For this reason, each station is required to perform yet another 1tli process. That is, EXPRES
Each station that has completed the specified data communication in response to the S TOKEN command sends EXPR to the downstream station.
Before issuing the ESS TOKEN command (step 528), be sure to compare the original multi-operation station address with your downstream station address (step 527);
If it is a match, the above EXXPRES 5TOKE
Processing to send the N command is performed (step 828), and if the two addresses match, EXPRESSTOK is sent.
The EN instruction is changed to a TOKEN instruction and this is returned to the original multi-operation station (step 529).
.

Here, since all stations are controlled to always accept the TOKEN command even during multiprocessing operations (step St), station C sends the TOKEN command to station d, and Station d will accept this requirement. At this time, if the waiting process has been completed, station d will resume data communication (step S2), but if the waiting process has not yet been completed, it will stage the EXPRESS TOKEN command and send it again. Step S8
), proceed to the same operation as described in J-. When the communication process is completely completed at station d (step S3), the TOKEN command is passed to station e for the first time (step S3).
4) The normal communication rights acquisition as shown in FIG. 2 returns to the handing state.

In addition, in this example of FIG. 2 and FIG. 3, a two-way network transmission path on a ring is assumed, but if the communication rights transfer command is of a form that logically circulates equally among all stations in the network, The present invention is applicable regardless of the shape of the network transmission path.

In addition, in this example, if the TOKEN command is sent from station C to station d, or if there is a configuration in which all stations store in advance the upstream and downstream relationships of all stations in the work,
EXPRES from station C to station d
S When a TOKEN command is issued and a NACK response is returned, it skips station d and directly sends EXPRESS to the next station e from station c.
It is also preferable to issue a TOKEN command.

As explained above, according to the present invention, when a station that generates an idle period during one communication process is included in a token-pancing-type local station work, the idle time is used for communication processing of other stations. This makes it possible to improve the communication efficiency of remote work.

Further, since the present invention has a simple configuration, it can be easily achieved by simply making predetermined changes to the communication control firmware of each station, and has the advantage that it can be realized at a relatively low cost.

[Brief explanation of drawings]

1 is an explanatory diagram showing an example of the structure of communication data used in the present invention, and FIGS. 2 and 3 are state diagrams showing an example of the flow of communication data at the time of IF1 to which the present invention is applied. Fig. 4 is a flowchart showing an example of the control operation of each station in Figs. 2 and 3. a...Network transmission path, b, c, d, e, f, g... Communication data Transmitting/receiving station, ■... 1st
Flag area, 2... Receiving station address area, 3... Transmitting station address area, 4... Data/control data area, 5... FCS area, 6... Second flag area.

Claims (1)

[Scope of Claims] l) In a 1-Kun passing type network in which only stations that have obtained communication (i'+) can perform data communication independently, the station determines the free time of communication during the data communication. When this occurs, the transmitting station and receiver 4
A temporary communication right transfer means for transferring the communication right to another station via a communication right temporary transfer command including the address of the station, and the communication right-ILI, which is then returned from the station of the above, is transferred. 11. A network control system characterized in that the station comprises: 11) communication right reacquisition means that allows the station to regain the communication right through a command. 2. In the network control system according to claim 1,
After receiving the communication right temporary transfer command, the station transfers the communication right to the station that sent the command after completing its own data communication processing or when no data communication is required. A network control system characterized by comprising a communication right return means for returning a temporary delegation command. 3) 'Patent 1; The acquisition means includes means for transmitting a rejection response indicating that the station is in a waiting process or an acknowledgment indicating that the waiting process has been completed to the station of the acquisition means, and the station of the above-mentioned mode that receives the rejection response further A network control system characterized by comprising means for transferring the communication right temporary transfer command to a downstream station. 4) Special feature 111 - In the network control system set forth in claim 3, +iii, the sending station address of the communication right temporary transfer command sent to the downstream station is the address of the station that first sent the command. A network control method characterized by: