JPS5885653A - Packet collision node position discriminating system in local network - Google Patents

Abstract

PURPOSE:To decide a position of the own node in a collision node train by a simple circuit, by detecting a position of other nodes, from a direction of a signal from other node, received by each node which has collided. CONSTITUTION:When an optical receiver is connected to each of signal receiving waveguides 5-1, 5-2, a direction of a receiving signal can be discriminated. When plural nodes execute transmission to a transmission line 1 almost simultaneously, in case when a node which causes a collision of a signal is generated in these plural nodes, it can be decided that the node which has caused a collision exists, by receiving some signal in the course of transmission. In this case, it can be decided that a node which has received a signal from the right side only is positioned at the left end of a collision node row, and a node which has received it from the left side only is positioned at the right end. Also, it can be deicded that a node which has received it from both sides is positioned between at least 2 collision nodes. In this regard, in this coupling device, 6-1 and 6-2 denote signal transmitting waveguides used in the right direction and the left direction, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to resolve packet collisions caused by a plurality of nodes including processors, terminal equipment, etc. connected to a local network transmitting signals almost simultaneously onto the local network. This method involves a method for identifying the position of each node in a nine-node sequence by causing packet collisions.

Conventionally, the location of a node has been identified by a signal from a reference node fixedly placed within a local network. (For example, Institute of Electronics and Communication Engineers, Technology-Notification (IEICE) Exchange Method 5E7B-94rxaaarvatt
os ll0bar ygtsoork System Design,'' Omiya et al., December 15, 1978, pp. 23-29) Therefore, when the reference node fails, the entire local network becomes a failure. This method has the disadvantage of requiring a complicated device such as a reference node.

In order to eliminate these drawbacks, the present invention identifies the nodes at both ends of a colliding node string by detecting the position of the other node from the direction of the signals received by each colliding node. The drawings will be explained in detail below.

FIG. 1 is a schematic diagram of an embodiment of the invention. 1 is a transmission line with a bus structure using original fibers, 2-1 to 2-3 are coupling devices, 3-1 to 3-5 are nodes consisting of a processor and a terminal, 4-1.4- 2 is a terminal device. FIG. 2 is a conceptual diagram showing the flow of optical signals in the coupling device. 1 is a transmission path, 5-1 is a waveguide for receiving signals from the left direction, 5-2 is a waveguide for receiving signals from the right direction, 6-1 is a waveguide for transmitting signals to the right direction, 6-2 is a waveguide for transmitting signals to the left direction, 7 is a branch concentrator. By connecting an optical receiver to each of the signal receiving waveguides 5-1 and 5-2, it is possible to identify the direction of the received signal (in which direction the received signal was received, μμ, the transmitting node is the receiving node. This makes it possible to identify whether the object is on the left or right side.

When a plurality of nodes send signals on the transmission path almost simultaneously, and a node (collision node) that causes a signal collision occurs on the other side of the plurality of nodes, the coupling device with the configuration shown in Fig. 2 automatically It can be determined that there are nine nodes when the optical signal transmitted by the node is detected by its own receiving circuit. At this time, the node that received the signal only from the right side is located at the left end of the mate row (collision node row) where the collision node exists, and the node that received the signal only from the left side is located at the right end of the collision node row. It can be determined that a node receiving signals from both sides is located between at least two colliding nodes.

FIG. 5 shows the flow of optical signals in a coupling device according to another embodiment of the present invention, which uses independent transmission paths in the right and left directions. 1-1 is to the right.

1-2 is the transmission path to the left, 5-1 is from the left, 5-
2 is a waveguide for receiving signals from the right, 6-1 is a waveguide for transmitting signals to the right, 6-2 is a waveguide for transmitting signals to the left, and 7 is a branch concentrator. In this case as well, the same operation as in Figure 2 is performed, so depending on the receiving direction of the signal received by the transmitter, each node that caused a collision determines its position in its own mate's colliding node string (left end, right end, other node's position). between) can be identified.

FIG. 4 is a concrete implementation example of the coupling device of FIG. 3 using a polymer optical waveguide. 1-1.1-2 is a transmission line using optical fiber, 5-1.5-216-1.6-2.8-
1.8-2t9-1 to 9-4 are polymer optical waveguides, 10-
1.10-2 uses a photodiode in an optical receiver. 11-1.11-2 is an optical transmitter that uses a laser diode or a light emitting diode. 12-1~12
-4 is a connection cable between the node and the coupling device, 13 is the coupling device housing, 14-1 to 14-4 are connection devices between the coupling device and the connection cable, and 15-1 and 15-2 are transmission lines. It is a connection device with a coupling device.

゛ The optical signal from the left is transmitted from the transmission path 1-1 to the optical receiver [110-1] via polymer optical waveguides 9-1 and 5-1.
and is transmitted as an electrical signal to the node via the connecting cable 12.-1. The signal from the right direction is transmitted from the transmission line 1-2 to the optical receiver 1 via waveguides 9-4 and 5-2.
Detected at 0-2 and connected as an electrical signal to the connecting cable 12
-4 to the node. Therefore, by monitoring the electrical signals on the connection cables 12-1 and 12-2, a node can determine whether the signal it is currently receiving is transmitted from the node on its right side or from the node on its left side. It is possible to identify whether the direction is one direction or both directions.

When using a signal such as an optical signal whose directionality is easy to realize, the coupling device with the directional transmission/reception function necessary for this method uses a polymer optical circuit as shown in the example in Figure 4, or a Hiro prism. , can be realized by a combination of T-kagura using mirrors. coaxial cable.

When using a transmission path such as a twisted pair wire, it is necessary to take some measures to realize the directionality of the signal. FIG. 5 shows an example in which the coupling device shown in FIG. 2 for transmission lines such as identical cables and twisted pair wires is realized using a directional coupling device and a hybrid circuit. 1 (5-1゜16-2 is the transmission line, 17
-1.17-2 is a hybrid circuit, 18-1.18
-2 is a directional coupling device, 19-1, 19-2 are branching devices, 20-1, 20-2 are transmission signal lines, 21-1.2
1-2 is a receiving signal line, 22-1.22-2.25-1.
23-2.24-1.24-2 is a signal line. The signal from the left goes to the hybrid circuit 17-1 and the signal line 2
4-2, 23-2, and 22-2, and is transmitted to the transmission lines 1 and 6-2 via the hybrid circuit 17-2, but is transmitted to the signal lines 24-1, 23-1, and 22-1. It doesn't get across.

Similarly, signals from the right side are signal lines 22-1 and 23-1.
, 24-1. The directional coupling device 18-1 transmits the signal from the right (via the signal line 23-1) and the transmission signal (via the signal line 20-1) to the left, but the signal from the directional coupling device 18-1 There is no signal transmitted to the line 23-1, therefore, only the signal from the right side of the signal line is received from the branching device 19-1. The same goes for the signal coming from the left, and the result is the same operation as in Figure 2.In this case, rather than using a single transmission line in both directions, the coupling device is used as shown in Figure 3. A method using a separate transmission line for each direction eliminates the need for hybrid circuits and is easy to implement.

FIG. 6 shows the location of collision nodes using the present invention.
This is a specific example of the configuration of another device. 25-1, 25-2
is a transmission path, 26 is a coupling device, 27 is a transmission circuit, 28-1
, 28-2 are signal detection circuits from the right and left directions, 29 is a receiving circuit, 30 is a collision detection circuit, and 31 is a position identification circuit. A signal indicating the status of transmission is sent from the transmission circuit 27 to the collision detection circuit 30, and during transmission, the signal from the transmission path is detected by the signal detection circuit 28-1.2.
8-2, the collision detection circuit 6° sends a signal notifying the occurrence of a collision to the node and position identification circuit 51.0 The position identification circuit 61 receives signals only from the right or only from the left when a collision occurs. The node determines whether the node is at the left end, the right end, or between other nodes of the colliding node string, and sends a signal to notify the node of the position, depending on whether the node received the message or from both sources.

As explained above, by identifying the receiving direction of signals from other nodes that each node receives while transmitting a signal, the position of its own node in the colliding node string can be determined using a simple circuit distributed among each node. There are advantages.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is an enlarged view showing the signal flow in the coupling device shown in Fig. 1, and Fig. 3 is a diagram showing the case where independent right and left transmission lines are used. An enlarged view showing the signal flow in the coupling device part. Figure 4 is a concrete implementation example of the coupling device in Figure 3 using a polymer optical waveguide. Figure 5 is a coaxial cable and a twisted pair wire. FIG. 2 shows a specific implementation example of the coupling device when used as a transmission line, and FIG. 6 shows a specific configuration example of a position identification device using the present invention. 1.1-1.1-2...Optical fiber transmission line, 2-1~
2-5... Coupling device, 3-1 to 3-5... Node,
4-1, '4-2...Terminal device, 5-1, 5-
2... Waveguide for signal reception, 6-1.6-2... Waveguide for signal transmission, 7... Branch concentrator, 8-1.8-2
...Waveguides for branching and concentrating lines, 9-1 to 9-4...
Waveguides for connection with transmission lines, 10-1, 10-2
... Optical receiving device, 11-1゜11-2... Optical transmitting device, 12-1 to 12-4... Group for connection with node, 13... Coupling device housing, 14-1 ~14-4...
・Connection device between coupling device and connection cable, 15-1~
15-2... Connection device between transmission line and coupling device, 16-
1゜16-2...Transmission line, 17-1.17-2...
・Hybrid circuit, 18-1, 18-2... Directional coupling device, 19-1.19-2... Branching device, 20
-1, 20-2... Transmission signal line, 21-1, 21
-2... Reception signal line, 22-1.22-2.23-1
．． 23-2.24-1.24-2...Signal line, 25-
1, 25-2...transmission line, 26゛...coupling device,
27... Transmission circuit, 28-1.28-2-... Signal detection device from the right direction and left direction, 29... Receiving circuit,
30...Collision detection circuit, 31...Position identification circuit Patent applicant Nippon Telegraph and Telephone Public Corporation

Claims (1)

[Claims] When a packet collides due to almost simultaneous packet transmission on a local network based on a contention method in which a plurality of nodes including processors or terminal equipment, etc. are connected, In a method for identifying the position of a colliding node in a node string, a signal from another node is received, the direction of the received signal is detected, and the position of the own node is identified based on the detection result. a coupling device for connecting said node and a transmission path having means, and identifying the relative position of said other node to said own node from the reception direction of a signal from said other node received by said own node that has caused a collision. Detects whether the self-node has caused a collision and is at both ends of the nine-sided string, and which end it is. A method for identifying the location of packet collision nodes in a local network.