JPH04367145A - System for selecting transmission root - Google Patents

Abstract

PURPOSE:To decide the optimum root capable of dealing with the generation of fault such as double fault without necessitating a special operation even when the extension or the move of the station. CONSTITUTION:A data originating station a transmits a control signal composed of a self-station address and originating time periodically with time interval T+alpha longer than the maximum delay time T of the network from ports P1, P2, and P3 to roots L1, L2, and L3 of all stations B, C, and F connected to the station A. A repeating station B finds the time necessary for the incoming from the control signal received by the ports B-P1, B-P2, and B-P3 from the roots L1, L4, and L5 between all stations A, C, and D and its reception time and stores the results to a table memory 2. The transmission part finds the root L1 minimum in the stored incoming required time, and returns a transmission enable signal to a call originating station to the only port B-P1. The received control signal selects a root with minimum transfer time among plural roots of respective repeater station to be used for the transmission to unreceived stations E, and G and transfers the real data.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a mesh network in which a plurality of communication stations are connected to each other by transmission paths, and in particular, the present invention relates to a mesh network in which a plurality of communication stations are connected to each other by transmission paths, and particularly in the case of transmitting data from one station to another in the network. This invention relates to a transmission route selection method for a relay station.

0002

[Prior Art] Selection of a transmission route when transmitting data from one station to another in a mesh network is
Since there are multiple relay stations between the transmitting station and the receiving station, there is not only one route for transmitting data at each relay station.
There will be multiple routes. Conventionally, which route from a plurality of routes each relay station selects is determined by a table that is initialized in advance in each relay station. If a failure occurs in the currently used transmission route, a selection method has been adopted in which data is transmitted by switching to the transmission route with the next highest priority according to the table.

0003

[Problem to be Solved by the Invention] In the conventional transmission route selection method described above, in the event of a failure in the transmission route that is assumed in advance, it is relatively easy to select the next priority using a table set in advance for each relay station. Although it is possible to determine the ranking route, when an unexpected failure such as a double failure occurs, it is impossible to deal with it. In addition, when adding or relocating relay stations in a mesh network, it is necessary to recreate a new table for route selection and load control data into all stations, and the control data in the table created in this way must also be used. There was a possibility that the best route for that network was not necessarily determined. Furthermore, creating the table requires information on the entire network, so there is a problem in that a huge amount of work is required to create the table. The purpose of the present invention is to be able to cope with the occurrence of unexpected failures such as double failures at each relay station in a mesh network, and to eliminate the need for new work when adding or relocating stations within the network. The purpose of this invention is to provide a transmission route selection method that always determines the best route for the network.

0004

[Means for Solving the Problems] The basic structure of the present invention for achieving this object is shown in the principle diagram of FIG. In Figure 1, 1 represents stations A, B, C, D, and E of the mesh network.
, F, G at a time interval T+ larger than the maximum delay time T of the network.
A control signal CDA consisting of the address (A) of own station A and a timestamp (S1) representing the transmission time is periodically transmitted at α.
to the routes L1, L2, and L3 of all relay stations B, C, and F connected to own station A, and the corresponding ports P1, P2, and P3.
It is a means of sending from. 2 is provided in each relay station that receives and transmits data from transmitting station A; for example, in the case of relay station B, it is provided in its receiving section to indicate the routes of stations A, C, and D connected to station B. Based on the control signal CDA received from the corresponding ports B-P1, B-P2, and B-P3 of L1, L4, and L5 and their respective reception times t1, t2, and t3,
This is a table memory that calculates and stores the times T1, T2, and T3 required for incoming calls for each route. 31 determines the route L1 with the minimum time T1 among the required call arrival times for each route L1, L4, and L5 stored in the table memory 2 provided in the relay station B, and selects the route L1 of the corresponding port of the route L1. This is a means for having only B-P1 send back an actual data transmission permission signal to transmitting station A. 32 is provided in the relay station B and transmits the control signal CDA received on the route L1 to the corresponding ports B-P4, to the stations E and G that have not received it.
This is means for transmitting from B-P5 to each route L7, L8.

[0005]

[Operation] In the present invention, the means 1 corresponds to the stations A, B, C, D,
The control signal CDA, which is provided in the transmitting station A in the mesh network of E, F, and G and consists of the address (A) of the transmitting station A and a timestamp (S1) representing the transmission time, is transmitted by the maximum delay time of the entire network. Periodically, at a time interval T+α larger than T, it is transmitted to relay stations B, C, and F connected to local station A from corresponding ports P1, P2, and P3 to routes L1, L2, and L3. Each relay station that receives and transmits data from transmitting station A, for example, relay station B, has a table memory 2 provided in its receiving section.
is the route L1 of stations A, C, and D connected to own station B,
Based on the control signal CDA received from L4 and L5 and the respective reception times t 1 , t 2 , t 3 , the time T required for the control signal CDA from the originating station A to arrive for each route is calculated.
1, T2, and T3 and store them. Then, a means 31 provided in the relay station B calculates a route L1 having the minimum time T1 among the call arrival times T1, T2, and T3 for each route stored in the table memory 2, and selects the route L1 of the corresponding port of the route L1. Only B-P1 is allowed to send back an actual data transmission permission signal to the originating station A, and ports B-P2 and B-P3 of routes L4 and L5 other than the route L1 with the minimum required time are sent back to the transmitting station A.
The actual data transmission permission signal is not transmitted to the . Then, the means 32 transmits the received control signal CDA of the route L1 having the minimum time to the unreceived station E.
, G from the corresponding ports B-P4, B-P5 to each route L
7, transmit by L8. Therefore, when transmitting data from any source station A to any receiving station E in the mesh network, each intermediate relay station always selects the route with the minimum transmission time among multiple routes and transmits the actual data. Therefore, the conventional problem is solved.

[0006]

[Embodiment] FIG. 2 is a connection state diagram of a mesh network showing the configuration of a transmission route selection method according to an embodiment of the present invention, in which station A is the source station of actual data, and stations B, C, and D
, F, and G are relay stations, and station E is a receiving station. FIG. 3 is a time chart for explaining the operation, and is a time chart of the operation of relay station B and receiving station E. FIG. 4 is a layout diagram of the control signal CDA transmitted from the originating station A, which consists of a station address (A) and a timestamp (S1) of the originating time. FIG. 5 shows an example of the contents of the table memory provided in relay station B, and is an example where station A is the originating station. In the connection state diagram of the mesh network of the embodiment shown in FIG. 2, data from the transmitting station A to the receiving station E is A → B → E, A → B → G → E,
A → B → D → E, A → C → D → E, A → C
There are multiple routes such as →B →E. On the other hand, in this network, the maximum propagation delay time of the transmission path is
If time is T, each station becomes a transmitting station, then T + α
At regular intervals of time (α>0), a control signal containing the address of the local station and a time stamp indicating the transmission time is sent to all ports connected to the station. Therefore, transmitting station A
As shown in Fig. 4, the control signal CDA consisting of the address (A) of the own station and the transmission time (S1) is sent from the corresponding ports P1, P2, P3 connected to the own station A to each route L1, L.
2, Send to L3. Each relay station B, C, F receives and transmits data from a transmitting station A, for example, relay station B is
The table memory 2 of the present invention provided in the receiving section stores routes L1, L4,
The transmission time S1 and the respective reception time t of the control signal CDA received from ports B-P1, B-P2, and B-P3 of L5
1, t 2, t 3, the time required for the control signal CDA from the originating station A to arrive for each route T1, T
2, T3 is determined and stored as in the example of FIG. Relay stations C and F are stored in the same way, and relay station D is also stored in each table memory. Then, for example, a comparator of the means 31 of the present invention provided in relay station B calculates the required call arrival time T1 for each route (directly to A station, via C station, via D station), which is stored in the table memory 2 of own station B. T2 and T3 are compared to find the route L1 with the minimum time T1 among them, and only the corresponding port B-P1 of that route L1 is made to return an actual data transmission permission signal to the originating station A. Then, route L other than port B-P1 of route L1 with the minimum required time
The actual data transmission permission signal is not transmitted to ports B-P2 and B-P3 of 4 and L5. Then, the transmitting unit of the means 32 of the present invention transmits the control signal CDA received on the route L1 of the minimum required time to the unreceived next stations E and G from the corresponding ports B-P4 and B-P5 to each route L7, Send to L8. Then, at receiving station E, in the same way, port C-
P1 is caused to transmit an actual data transmission permission signal from transmitting station A. Therefore, when transmitting data from a transmitting station A to an arbitrary receiving station E in the mesh network of the embodiment shown in FIG. 2, the intermediate relay station B selects the route L1 with the shortest transmission time among the multiple routes. , receiving station E is route L
7 will be selected to transmit the actual data.

[0007]

As explained above, according to the present invention, when transmitting and receiving data at each relay station of a mesh network with multiple communication paths, each relay station always selects the optimal route with the minimum transmission time. Since it is possible to perform relaying while selecting, it is possible to realize data communication with low delay time, and in the event of a failure of a certain route, it is possible to immediately select a route that bypasses the failure point and continue communication. Therefore, the effect of improving the reliability of the entire network can be obtained.

[Brief explanation of the drawing]

[Fig. 1] Principle diagram showing the basic configuration of the transmission route selection method of the present invention,

[Fig. 2] Connection state diagram of each station of the mesh network according to the embodiment of the present invention,

FIG. 3 is a time chart for explaining the operation of the embodiment of the present invention;

[Figure 4] Time allocation diagram of control signals transmitted from transmitting station A

[Figure 5] Example of contents of table memory provided in relay station B

[Explanation of symbols]

1 is a means provided in the transmitting station to send out a control signal of its own station address and transmission time to all routes; 2 is a means provided in the relay station for storing the received control signal from the transmitting station and the reception time for each route. A table memory 31 is a means for determining the route with the minimum required time for incoming calls for each route stored in the table memory and returning a transmission permission signal for actual data from the originating station only to the corresponding port; 32 is a relay station that requires incoming calls; This is a means of transmitting the control signal received from the route with the shortest time to the corresponding port to the station that has not received it.

Claims (1)

[Claims] [Claim 1] A certain station (A) of a mesh network in which a plurality of communication stations (A to G) are connected to each other by transmission paths transmits a signal to each relay station (B, C, D, F, G). Through a certain station (
E) A transmission route selection method for each relay station when transmitting data up to
T + α), a control signal (C
DA) to all stations (B) connected to the local station (A).
, C, F) from the corresponding port (P1, P2, P3) to the route (L1, L2, L3), and each relay station (1) that receives and transmits data from the originating station (A).
B) All stations (A, C, D,) connected to the relay station
from the route (L1, L4, L5) to the corresponding port (B-
P1, B-P2, B-P3) received control signal (
CDA ) and the time when each was received (t1, t2, t3)
a table memory (2) for determining and storing the time (T1, T2, T3) required for the arrival of the control signal (CDA) for each route; Find the route (L1) with the minimum time required for receiving a call for each route, and send a permission signal for transmitting actual data to the originating station (A) only to the corresponding port (B-P1) of that route (L1). means (31) for sending back the control signal (CDA) received on that route (L1) to the corresponding port (E, G) to the station (E, G) that has not received it.
B-P4, B-P5) to each route (L7, L8), and each relay station transmits data from the originating station (A
) A transmission route selection method characterized by selecting the route with the minimum transmission time among multiple routes from ) and relaying the actual data.