JP2519808B2 - Competitive methods in communication networks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is advantageously applied to a competition method in a communication network, in particular, for example, a local area network (LAN) or a metropolitan area network (MAN) in which contention control is distributed. Regarding the competition method that is done.

(Prior Art) In a local area network composed of a plurality of nodes, the topology of the communication network system can be classified into, for example, a star, a tree, a bus and a loop. Among these connection forms, when distributed control is performed in a distributed manner, the loop form is suitable as a connection form in which each node configuring the system is given access rights evenly. For example, RM Newman, et al., “THE QP
SX Man ", IEEE Communications Magazine, Vol.26, No.4
(April 1988) shows such a conventional technique.

For example, when one center node and a plurality of remote nodes are connected in a loop, each node is connected to an adjacent node by a transmission line that transmits a signal in a clockwise direction and a transmission line that transmits a signal in a counterclockwise direction. It When a remote node sends information to another remote node, it first sends an information transmission request (request) to one transmission line. Then, the transmission information is put in the unused slot sent by the transmission line opposite to the transmission line which sent the request and sent.

For example, as shown in FIG. 8, when n remote nodes (12-1 to 12-n) are connected in a ring shape,
The priority of the information transmission request at each remote node is higher for the younger remote node in the counterclockwise transmission line and higher for the older remote node in the clockwise transmission line. Each remote node has a counter therein, and the timing of information transmission after request transmission is detected by the value of this counter.
That is, when the remote node that made the request recognizes from the count value of this counter that the unused slot for which the self node sends information is sent, it inserts the information into this slot and stores the unused slot information of this slot. It was erased and output to the node.

(Problems to be Solved by the Invention) However, in such a conventional technique, since the priority of information transmission in each node is fixed together with the physical position, there is a large difference in user information transmission delay time between node positions. The conventional technique also has a problem that a ring must be physically formed.

The present invention solves the above-mentioned drawbacks of the prior art and, in a communication network in which contention control is distributed, a competition method in a bus-type and ring-type communication network having fairness in information transmission delay time of each node, and a method therefor. It is intended to provide a remote node forming a.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is configured such that a plurality of remote nodes are respectively connected via a first transmission line and a second transmission line, and a remote node is another remote node. When receiving the information to be transmitted to either the center node or the center node, after making a transmission request for the information to the first transmission line, the unused slot for transmitting this information is identified and the transmission information is transmitted to the second transmission line. In a contention method in a communication network in which contention control for transmission is performed in a distributed manner, a remote node is given an information transmission request priority right to preferentially transmit information at regular time intervals according to a predetermined rule, and a plurality of remote nodes are given priority. If you have priority to send information,
Information transmission requests are given priority according to the position to which each remote node is connected, and each remote node in the communication network has a uniform priority according to the presence or absence of the information transmission request priority and the connection position. Can be sent.

Further, according to the present invention, a plurality of remote nodes are respectively connected via the first transmission path and the second transmission path, and when the remote node receives information to be transmitted to another remote node, the first transmission path is set. After making a request to send information, the unused slot for sending this information is identified and the second
In the contention method in the communication network in which the contention control for sending the transmission information to the transmission path is distributed, the remote node is added when the first transmission request is received from the first transmission path, and is added from the second transmission path. A first counting means that is subtracted when the used slot is received;
Is added when the transmission request is received, and when an unused slot is received from the second transmission line, the second counting means is subtracted when the count value of the first counting means is a predetermined value; The third subtracted when an unused slot is received from the transmission line
And the fourth counting means for subtracting the count value of the third counting means when the unused slot is received from the second transmission line and the information to be transmitted. It has a storage means and a control means for controlling the first, second, third and fourth counting means, and the second counting means and the fourth counting means.
The counting means is also subtracted when the transmission request refusal information is received, and when transmitting the information accumulated in the storage means, the control means makes a transmission request for the information to the first transmission line, and the first counting The count value of the means is input to the third count means and the count value of the second count means is input to the fourth count means, and the count values of the third count means and the fourth count means are set to predetermined values. After that, when an unused slot is input from the second transmission line, the information stored in the storage means is put into the unused slot and transmitted.

(Operation) According to the present invention, when transmitting the information, the remote node makes a transmission request for the information to the first transmission path according to the presence / absence of the transmission request transmission priority right, and the counting of the first counting means. The numerical value is input to the third counting means and the count value of the second counting means is input to the fourth counting means. Then, after the count values of the third counting means and the fourth counting means reach a predetermined value, the second counting means
When an unused slot is input from the transmission line of, the information is put into this unused slot and transmitted.

(Embodiment) Next, an embodiment of a competition system in a communication network according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 2, there is shown a configuration of a local area network system to which an embodiment of the competition system in a communication network according to the present invention is applied. In this embodiment, as shown in the figure, it is a network that is composed of one center node 1 and a plurality of remote nodes 2 and that performs conflict control in a distributed manner. Each node has a downstream transmission line 100 and an upstream transmission line 2
00 is connected to an adjacent node to form a bus type local area network.

Each remote node 2 has, for example, another local area network, a metropolitan area network,
A communication network such as a wide area network or a communication device such as an exchange or a communication terminal is connected (none of them is shown). The communication network or communication device connected to each remote node 2 exchanges information with the communication network or communication device connected to another remote node 2 via the network shown in FIG.

FIG. 3 shows the format of the signal 300 transmitted on the transmission lines 100 and 200 in FIG. The signal 300 is formed by a plurality of fixed length slots 310, each fixed length slot 310 having control information 312 and user information 314. The user information 314 is a data area in which transmission information of a user to be transmitted to another remote node 2 or center node 1 is recorded.

The control information 312 includes a user information transmission request (request) A that represents an information transmission request from a node having priority, or a user information transmission request (request) B that represents an information transmission request from a node that does not have priority, and user information. Includes transmission request priority (request transmission priority) movement information, unused slot information, and request rejection information. Control information 312
Also includes, for example, the remote nodes 2-1 to 2-n or the individual identification number of the call. Each remote node 2 determines whether or not it is its own node based on this identification number, and when it indicates its own node, fetches the transmission information from the other remote node described in the user information.

FIG. 1 shows a functional block diagram of the remote node 2. The remote node 2 includes a control circuit 20, an up / down counter 22A that counts the number of nodes, which have the request transmission priority upstream of the own node, waiting for transmission in accordance with the information transmission request (request) A, the own node. Information transmission request (request) B indicating the number of nodes waiting for transmission on the upstream side that do not have the request transmission priority.
Up-down counter 22B that counts according to the request, down-counter 24C that counts the number of waiting slots for a node that has request transmission priority until the node can transmit data, according to request A, until the node can transmit data It is composed of a down counter 24D for counting the number of waiting slots for a node which does not have the request transmission priority right in accordance with the request A, switches 26 and 28, and a buffer 30. The control circuit 20 is a control circuit that controls each component of the remote node 2, and performs transmission processing of the information accumulated in the buffer 30 according to the priority of the remote node 2 at that time.

The control circuit 20 is connected via the signal line 150 to the node input 100-i of the transmission line going downstream and via the signal line 172 to the node input 200- (i + 1) of the transmission line going upstream. The control circuit 20 controls the up / down counters 22A, 22B and the down counters 24C, 24D according to the contents contained in the control information 312 of the fixed length slot 310 (FIG. 3) received via these node inputs.

That is, when the control information 312 input via the signal line 150 indicates the request A transmitted from the remote node 2 having the request transmission priority right, the control circuit 20 transmits the up / down counter 22A via the control line 156. Count up the value of. When the control information 312 indicates the request B transmitted from the remote node 2 which does not have the request transmission priority right, the up / down counter 22B is counted up via the control line 158.

The control circuit 20 also outputs an up / down counter when the control information transmitted from the remote node on the downstream side and input through the signal line 172 includes unused slot information.
If the value of 22A is "0", the up / down counter 22B is counted down, and if it is not "0", the counter 22A is counted down. When the unused slot information is identified, if the value of the down counter 24C is "0", the value of the down counter 24D is counted down via the control line 162, and if it is not "0", the counter is counted via the control line 160. Count down 24C.

Further, the control circuit 20 identifies whether the priority transfer information is included in the control information 312 via the signal line 150 or 172. The node 2 loses the request priority when the priority transfer information is input via the signal line 150 when there is the request priority, and the signal line 17 when there is no request priority.
Entering this via 2 has request priority. Therefore, when the priority transfer information is included in the control information 312, the control circuit 20 erases the priority transfer information according to the presence / absence of the priority and outputs the slot 310. After a certain period of time, the priority transfer information is sent to the switch on the side where the priority transfer information is input, the switch is controlled via the switch switching control signal line 154 or 164, and the control information 312 of the slot 310 is sent. Write the priority transfer information to and send it.

The buffer 30 is a storage device that is connected to a communication device (not shown) such as an exchange via a data input line 168 and stores information sent from the communication device. Control circuit
When the information to be transmitted is stored in the buffer 30, the 20 controls the switch 26 and sends a user information transmission request from the output 152 to the node output 100- (i + 1). Then, the value of the up / down counter 22A is transferred to the down counter 24C, and the value of the up / down counter 22B is transferred to the down counter 24D. When the count values of the down counters 24C and 24D both become 0, the upstream node sends them. Since it indicates that there is no information, the own node 2 judges that an unused slot 310 capable of transmitting information has been transmitted from the node input 200- (i + 1). The control circuit 20 uses the node input 200 as an unused slot to which the node 2 can send the transmission information.
When sent from-(i + 1), the information stored in the buffer 30 is sent from the output 170 to the switch 28. And
The switch 28 is controlled via the slot switching control output line 164, and the transmission information is transmitted from the node output 200-i.

Returning to FIG. 2, the user information 314 sent to the remote nodes 2-1 to 2-n is transferred using the transmission lines 100-1 to 100-n in the signal format shown in FIG. The user information 314 sent from the remote nodes 2-1 to 2-n is also transferred using the transmission lines 200-1 to 200-n according to the signal format shown in FIG.
The transmitted user information 314 is first transmitted to the transmission line 100.
The user information transmission request is output to the transmission line 200
Sent to.

Only one fixed-length slot 310 can have one remote node 2 that can make a user information transmission request. The priority of the remote node 2 that can make the user information transmission request is the upstream side of the remote nodes 2 having the request transmission priority, in other words, the transmission priority of the remote nodes 2-1 to 2-n. Among the remote nodes that it has, priority is given in order from the younger side of the number (2-1 to 2-n), and then from the upstream side of the nodes that do not have the request transmission priority right, it is given priority in order.

FIG. 4 shows a flow chart of information transmission in this embodiment. Each of the remote nodes 2-1 to 2-n has user information to be sent (400), and if the request has not been sent (402), when sending the request, first, it is determined whether or not there is a request sending priority right. Yes (404). If there is a request priority (404) and the control information 312 (FIG. 3) flowing downstream does not include the information transmission request A (406), this request A
Is described in the control information 312 and transmitted. If there is a request A in the control information 312 (406), the request A cannot be sent and the next slot 310 is waited for.

If there is no request priority (404) and there is no request A or B in the control information 312 (420), the request B is sent to the control information 312 (422). If there is the request A or B (420), the request B cannot be sent to the control information 312 and the next slot 310 is waited for. When a request is sent, one of the information stored in the buffer 30 (Fig. 1) is sent, or the next request is not sent until request rejection information is sent to the remote node 2 itself. Can not.

If the request rejection information is not included in the control information 312 of the slot 310 (410, 412) when the information transmission timing of the own node 2 comes, one piece of information accumulated in the buffer 30 is transmitted to the transmission line 200. (414). When the information is transmitted, the unused slot information shown in the control information 312 of the slot 310 is erased.

In FIG. 2, the remote node 2-n, which is the most downstream node, has both requests A and B (including the request from the node 2-n) flowing toward the downstream (the own node 2 is trying to send out). Control information 312 (third request A included), transmission line 200-n (third)
Request rejection information is shown in the figure) and sent. When the remote nodes 2-1 to 2- (n-1) respectively receive the request refusal information, the remote nodes 2-1 to 2- (n-1) judge whether or not the request refusal information is for the self node.

If it is the request refusal information for the own node, the request refusal information is erased, and the request is retransmitted according to the above procedure. If the request rejection information is not for the own node, each remote node 2 sends the received request rejection information as it is to the upstream remote node.
It should be noted that each remote node determines that it is request rejection information for its own node when the unused slot input when the information transmission timing arrives shows the rejection information.

The request transmission priority order in the remote node 2 logically moves at a predetermined timing according to the priority right transfer information described above. That is, for example, the request transmission priority is given to the remote node 2-1 at a certain timing.
~ 2-n waits for node 2-2 at the next timing
~ 2-n waits, and 2-3 ~ 2- at the next timing.
n waits. In this way, the request transmission priority right is sequentially lost from the remote node on the upstream side.

When only the remote node 2-n has the request transmission priority, the nodes 2- (n-1) to 2-n have the request transmission priority at the next next timing, and at the next timing. Remote node 2- (n-
2) to 2-n have priority. In this way, the request sending priority is sequentially obtained from the remote node 2 on the downstream side. When the request transmission priority becomes the remote nodes 2-1 to 2-n again, the remote node 2-1 loses the request transmission priority at the next next timing. By repeating the above process, the request transmission priority in the remote node 2 moves at each of the predetermined timings.

FIG. 5 is an operation flow of the counter in the remote node 2, respectively. FIG. 5A shows the counter flow when the fixed length slot 310 is input from the downstream transmission line 100, and FIG. 5B shows the fixed length slot 3 from the upstream transmission line 200.
The counter flow when 10 is entered is shown. The remote node 2 inputs 100-
When request A is fetched from i (Fig. 1) (500),
Counts up / down counter 22A (50
2). Also, if request B is fetched from this ((50
4) Count up the up / down counter 22B (506).

The remote node 2 receives the transmission line node input 20 from the downstream.
If unused slot information is fetched from 0- (i + 1), (5
10), if the up / down counter 22A is "0" (51
2) Count down the up / down counter 22B (514). If the up / down counter 22A is not "0" (512), the counter 22A is counted down (51
6). Furthermore, if the down count 24C is "0" (51
8), count down the down counter 24D (520),
When the counter 24C is not "0" (518), this taunter
Count down 24C (522).

When the request rejection information is fetched from the node input 200- (i + 1) (524), both the up / down counter 22B and the countdown 24D are counted down (526). Here, the up / down counters 22A and 22B and the countdowns 24A and 24B do not take negative values.

In FIG. 1, when the information desired to be sent to the remote node 2 is generated, this information is sent via the data signal input 168 and stored in the buffer 30. When the information is stored in the buffer 30, the information is sent out according to the operation flow shown in FIG. That is, the request is switch 26
When the node 2 is sent to the node output 100- (i + 1) via the node, the node 2 enters a sending waiting state for sending information. Then, the value of the up / down counter 22A is set to the down counter 24C.
Then, the value of the up / down counter 22B is input to the down counter 24D.

In the node 2, thereafter, the unused slot information or the request refusal information is fetched, and the values of the down counters 24C and 24D both decrease and become "0". When the unused slot information is input from the node input 200- (i + 1) after the values of these counters 24C and 24D both become "0", the information accumulated in the buffer 30 is stored in the slot 310 (third). (Figure). And this slot 310
After erasing the unused slot information of No. 1, the slot 310 is sent to the node output 200-i via the switch 28, and the sending waiting state is released.

When the request sent by the node 2 is request B, the request rejection information is input to the node 200- (i +) after the values of the down counters 24C and 24D both become “0”.
When it is fetched from 1), it is judged that it is request refusal information for the own node 2. At this time, the remote node 2
Enters the flow for erasing the input request refusal information of the slot 310, sending this out from the node output 200-i, releasing the sending waiting state, and sending out the request again.

If node 2 has the request priority right,
When the slot 310 in which the request priority transfer information is indicated at the position of the control information 312 (FIG. 3) is input from the node input 100-i, the priority transfer information is erased. Then, the request priority transfer information is written to the slot 310 sent after a fixed time and sent to the node output 100- (i + 1) to lose the request priority.

When the node 2 does not have the request priority right, the slot 31 in which the request priority transfer information is shown from the node input 200- (i + 1) to the position of the control information 312 is also shown.
If you enter 0, the priority transfer information is deleted. Then, the request priority transfer information is written in the control information 312 of the slot 310 input after a fixed time, and this is sent to the node output 200-i to have the request priority.

The remote node 2-n, which is the most downstream node, inputs the slot 310 in which the request priority transfer information is indicated at the position of the control information 312 from the node input 100-n, and transfers the priority to the slot 310 after a fixed time. Information is written and output from the node output 200-n.

In addition, the remote node 2-1 which is the most upstream node
When the slot 310 in which the request priority transfer information is indicated is input from the node input 100-1 to the position of the control information 312, the priority transfer information is written in the slot 310 after a fixed time, and this is output to the node output 200-2. Output from.

FIG. 6 shows another embodiment in which the competition method in the communication network according to the present invention is applied to a ring type network. As shown in the figure, the center node 1 and the remote nodes 2-1 to 2-n are connected to a transmission line 100 that transmits a signal in the counterclockwise direction and a node adjacent to the transmission line 200 that transmits a signal in the clockwise direction and a node. Connected. In this way, the remote node 2 can be applied to a ring network.

Thus, according to these embodiments, the remote node 2
Since the priority of requesting transmission of information of -1 to 2-n changes depending on the predetermined timing, it is possible to maintain fairness of the information transmission delay time of each node 2. For example, FIG. 7 shows a graph (61) in the present embodiment in which the vertical axis represents the user information transmission delay time and the horizontal axis represents the node position.
0) and the prior art graph (600) are shown respectively. As shown in the figure, in the conventional technique, the difference in the user information transmission delay time largely depends on the position of the node 2. On the other hand, in these embodiments, the user information transmission delay time can be kept substantially constant without being affected by the position of the node 2.

(Effect of the Invention) As described above, according to the present invention, a priority order for requesting user information transmission is given to a remote node, and the priority order is changed at a certain fixed time so that all remote nodes are uniformly requested for user information transmission. Since the right is given, the effect of reducing the difference in the user information transmission delay time can be expected. Furthermore, since the direction in which the user information is transmitted is one direction, it is not necessary to physically form a ring structure.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of a remote node in an embodiment of a competition method in a communication network according to the present invention, and FIG. 2 is a system configuration diagram to which an embodiment of the competition method in a communication network according to the present invention is applied. FIG. 3 is a diagram showing a signal format exchanged on a transmission line in the present embodiment, FIG. 4 is a flow chart showing an information transmission operation in the remote node shown in FIG. 1, FIG. 5A and FIG. 5B is a flow chart showing the counter operation in the remote node shown in FIG. 1, FIG. 6 is a system configuration diagram to which another embodiment of the competition system in the communication network according to the present invention is applied, FIG. FIG. 8 is an explanatory diagram showing the relationship between the node position and the user information transmission delay time in this embodiment and the prior art, and FIG. 8 is a system diagram in the prior art. It is a Temu configuration diagram. Description of main part code 1 …… Center node 2 …… Remote node 20 …… Control circuit 22A, 22B …… Up / down counter 24C, 24D …… Down counter 26,28 …… Switch 30 …… Buffer 310 …… Fixed Long slot 312 …… Control information 314 …… User information

Claims (3)

(57) [Claims] 1. A plurality of remote nodes are respectively connected via a first transmission line and a second transmission line, and the remote node receives information to be transmitted to any one of other remote nodes and a center node. , In a communication network in which contention control is performed in a distributed manner after making a transmission request for the information to the first transmission line, identifying an unused slot for transmitting the information, and transmitting the transmission information to the second transmission line In the contention method, the plurality of remote nodes connect information including information transmission request priority transfer information for moving the information transmission request priority of each remote node to the first transmission path or the second transmission path. Then, the priority transfer information is deleted from the received information and transferred to the next node. Depending on whether or not the user has the priority, the information transmission request priority is lost when the priority is held, and the information transmission request priority is acquired when the priority is not held. , The information transmission request priority right movement information is written in the information input at the next predetermined timing, and the information in which the priority movement information is written is used as an upstream remote when the information transmission request priority is acquired. When the information transmission request priority is lost, the information transmission request priority is transferred to a remote node on the downstream side, and the information transmission request priority is controlled to be acquired or lost at each remote node. When the information transmission request priority has been acquired by a plurality of remote nodes, the remote node having a predetermined priority order among the plurality of remote nodes having acquired the information transmission request priority. The information transmission request is preferentially performed, and each remote node of the communication network determines whether or not the information transmission request priority changes with the movement of the information transmission request priority and the priority order of each remote node. , A method of competing in a communication network, characterized in that each remote node requests transmission of the information with equalized priority. 2. The competing method according to claim 1, wherein the remote nodes forming the communication network are connected in a bus shape by a first transmission line and a second transmission line, and the priority order of each remote node. Is a method of competing in a communication network, characterized by being defined by the location to which each remote node is connected. 3. A plurality of remote nodes are respectively connected via a first transmission line and a second transmission line, and the remote node receives information to be transmitted to any one of another remote node and a center node. , In a communication network in which contention control is performed in a distributed manner after making a transmission request for the information to the first transmission line, identifying an unused slot for transmitting the information, and transmitting the transmission information to the second transmission line In the contention method, the remote node is added when receiving the first information transmission request from another node requesting the transmission of the information from the first transmission line, and the second node is added.
A first counting means that is subtracted when an unused slot is received from the transmission line of No. 1, and a second information transmission request from another node that requests transmission of the information from the first transmission line, Second
Second counting means, which is subtracted when the count value of the first counting means is a predetermined value, when the unused slot is received from the second transmission path, and is subtracted when the unused slot is received from the second transmission path. Third counting means, a fourth counting means for subtracting a count value of the third counting means when the unused slot is received from the second transmission path, and a fourth counting means for transmitting the information. And a control means for controlling the first, second, third and fourth counting means, wherein the second counting means and the fourth counting means receive the transmission request refusal information. When the information stored in the storage unit is transmitted, the control unit requests the transmission of the information to the first transmission line, and the count value of the first counting unit is set to the third value. The counting value of the second counting means is input to the fourth counting means. When an unused slot is input from the second transmission line after the count values of the third counting means and the fourth counting means reach a predetermined value, the unused slot is stored in the storage means. A remote node characterized by including and transmitting information.