JP2000358053A - Path retrieval system for network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a path retrieval system for a network which can easily discriminate an unused transmission line between desired nodes in a ring-shaped network. SOLUTION: First to third nodes 611 to 613 are nodes which constitute part of the ring-shaped network; when a bidirectional path route is set among them, path retrieval information 101 is sent from the 1st node 611 to a free transmission line of a clockwise transmission system 51 and a similar process is performed for a free transmission line even in the section of the next 2nd node 612. When the 3rd node 613 as a return point is reached, the transmission system is switched to a counterclockwise transmission system 52 and similar processes are carried out up to the 1st node 611. Thus, the transmission line up to the 1st node 611 is a path route which can be set bidirectional. In the figure, 4th transmission lines 74 to 84 correspond to it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a network path search system suitable for setting a path route in a network.

[0002]

2. Description of the Related Art A ring-shaped network is sometimes used as a technique for freely connecting a plurality of networks.

FIG. 9 shows an example of a state in which a high-speed ring network is connected to several low-speed networks. In this example, a first low-speed network 11 ₁ is connected to a ring network 13 via a _first node (transmission device) 12 ₁ . Similarly, the second
Slow network 11 ₂ via the second node 12 _2, the third low-speed network 11 ₃ a third node 12 ₃
Through and fourth low-speed network 11 ₄ each ring via a fourth node 12 ₄ of the network 1
3 is connected. Ring network 13 is a network connecting the first to fourth node 12 ₁ to 12 ₄ of the ring.

Now, the first low-speed network 11 ₁ and the second low-speed network 11 ₁
When connecting the low-speed network 11 _2, the first node in the ring network 13 12 ₁ and the second
It may be set path route between the node 12 _2. When connecting the first low-speed network 11 ₁ and the third low-speed network 11 ₃ , the first node 12 ₁ and the third node 12 ₃ in the ring network 13 are connected.
What is necessary is just to set the path route between. That is, the ring network 13 multiplexes the transmission path signal received from the low-speed network 11 outside the ring at each node 12 as a high-speed transmission path signal on the ring, and transmits the signal to the destination node 12. The destination node 12 separates the corresponding signal from the high-speed transmission path signal and transmits the separated signal to the destination low-speed network 11. When a path route is set, it is necessary to check whether a corresponding path is free in the ring network 13.

FIG. 10 shows how a path search is performed in a conventional ring network. Here, it is assumed that an optical fiber in which the _first to _fourth nodes 121 to 124 are connected in a ring shape has transmission paths 21 to 24 for four channels for convenience. Each node 12 ₁ to 12 ₄ includes a control terminal 25. However, in the figure, to simplify the illustration, the third node 12 ₃
Only the control terminal 25 is displayed. Control terminal 25
Represents not only the corresponding node (third node 12 _{3 in} the figure) but also all other nodes (first, second and fourth nodes 12 ₁ , 12 ₂ , 1) in the ring network 13.
₂₄ ) can be controlled. When the control terminal 25 executes the cross-connect setting of each node 12,
Each pass is opened.

At the time of executing the cross-connect, it is necessary to specify to which of the transmission paths 21 to 24 of the ring network 13 a signal of the low-speed network 11 (see FIG. 9) is transmitted. Therefore, the control terminal 25 manages the cross-connect setting information in each node 12 and holds the use state of each of the transmission paths 21 to 24. If such management is not possible, when it becomes necessary to set a path route, the cross-connect setting information of each node 12 is read out using a predetermined control transmission line, and Searching for used transmission path.

[0007] assumed to open the path for example, from the first node 12 ₁ to the third node 12 _3. In this case, 4 of the transmission lines 21 to 24 of the channels, looking for those both unused from the first node 12 ₁ to the third node 12 _3. If there is such a transmission path, one of the transmission paths (for example, the first transmission path 2)
The cross connect is set by using 1). If no such transmission path exists, the path cannot be opened.

Several proposals have been made for monitoring the network path. Among them, in the proposal disclosed in Japanese Patent Application Laid-Open No. 63-164736,
The configuration includes a memory area, a route map, and a search circuit corresponding to each node. The path map expresses all the paths from the entrance path to the exit path, and gives an identification mark to the exit path to distinguish the usable path from the unusable path in the system. Each time the switching state is input from outside, the node switching state memory is referenced to trace from the entrance path to the exit path of the route map, and whether the use state of the systematic path is determined by the identification mark, This is output to an external display or the like.

In Japanese Patent Application Laid-Open No. Hei 10-23052, when determining a path route in a ring network, the path route is set in either direction unless the user specifies clockwise or counterclockwise. Determines whether the number of nodes is small and selects a route with a small number of nodes. Also, the line usage rate is checked, and the one with the lower usage rate is selected.

[0010]

Among the conventional techniques, the former technique requires a special memory or memory area such as a node switching state memory and the like, and an identification mark is added to an exit path. However, there is a problem that not only the device becomes complicated but also the control for identification becomes complicated. In the latter technique, a route having a high probability of occurrence of a free path is selected, and it is not possible to determine whether or not the path route is actually usable by itself. was there.

SUMMARY OF THE INVENTION An object of the present invention is to provide a network path search system capable of easily determining an unused transmission path between desired nodes in a ring network.

[0012]

According to the first aspect of the present invention, there is provided a method for setting a bidirectional transmission path between two specific nodes in a ring network in which a plurality of nodes are connected in a ring. The information indicating these two specific nodes and the information indicating the above-described predetermined direction are incorporated into all the transmission lines that are vacant from any one of these nodes to the next node in a predetermined direction, and a path is established. Path search information transmission start means for transmitting as search information;
It is arranged for each node, takes in path search information and determines whether this is the end point of its own node.If it is not the end point of its own node, it is empty in the same direction as the path search information was sent. In the case where the information indicating these two specific nodes and the information indicating the predetermined direction described above are incorporated into all the transmission paths up to the next node and transmitted as path search information, and the own node is set as the end point In the case where the transmission source of this path search information is not its own node, these two specific nodes up to the next node are shown for all the transmission lines that are vacant in the reverse direction when the path search information is sent. Path search information sending and receiving means for incorporating information and information indicating a direction opposite to the above-described predetermined direction and sending the path search information as path search information; and (c) path search information arranged for each node, If this is the end point of the own node and the transmission source of the path search information is the own node, all the transmission paths from which the path search information has been transmitted are bidirectionally transmitted between these specific two nodes. A network path search system is provided with a bidirectional communicable transmission line determining means for determining a communicable transmission line.

That is, according to the first aspect of the present invention, the path search information transmission start means transmits path search information to check a transmission path that can be used bidirectionally between two specific nodes to form a ring network. Each node transmits the path search information to the next node when the path search information is sent, and performs the transfer of the path search information, or, if the own node is the origin of the path search information, fetches the path search information. A transmission path capable of bidirectional communication is determined. The transfer of the path search information is performed by the path search information transmission and transfer means.
When the path search information has not reached the return point as the node with which the two-way communication is performed, the path search information transmitting and relaying means relays the path search information in the direction of the node. At this time, this path search information is incorporated and transmitted only to those transmission paths which have not been used between adjacent nodes among the transmission paths to which the path search information has been transmitted. As a result, transmission of path search information is interrupted for transmission paths used in the middle of the transmission paths of the ring network. The same applies when returning path search information from the turning point to the node from which the path search information was first sent out by the path search information sending start means. At the node at the return point, the path search information transmission and intermediation means switches the transmission direction to the opposite direction and transmits the path search information to the corresponding transmission path and the one not in use. In this way, the transmission path to which the path search information has returned to the node that has been transmitted first is determined as a transmission path capable of two-way communication.

According to the second aspect of the present invention, (a) when a bidirectional transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, any one of these nodes is set. A path to be transmitted as path search information by incorporating the information indicating these two specific nodes and the information indicating the predetermined direction described above for all the transmission paths that are vacant to the next node in the predetermined direction from Search information transmission start means; and (b) path search information arranged for each node, which fetches path search information and determines whether this is the end point of the own node, and if the own node is not the end point, the path search information The information indicating these two specific nodes and the predetermined direction described above are transmitted to the next node for all the transmission lines that are vacant in the same direction on the same transmission line from which the When the path search information is sent when the source of the path search information is not the own node, the path search information is vacant in the opposite direction when the own node is the end point. For all the transmission paths corresponding to the same transmission path, information indicating these two specific nodes and information indicating the opposite direction to the above-described predetermined direction are incorporated into the next node and transmitted as path search information. Path search information transmission and intermediation means; and (c) placed at each node, fetching path search information, determining whether this is the end point of the own node, and searching the path if the own node is not the end point. When discarding the path search information sent for all the transmission lines that are being used in the same direction on the same transmission line from which the information was sent and discarding the local node, this path When the search information is not transmitted from the own node, the path search information sent is discarded, and the path search information sent for all the transmission paths corresponding to the same transmission path being used in the opposite direction is discarded. Path search information discarding means; and (d) the path search information, which is arranged for each node, fetches the path search information and ends at the own node, and when the source of the path search information is the own node, Bidirectional communicable transmission line discriminating means for discriminating that all the transmitted transmission lines are transmission lines capable of bidirectional communication between these two specific nodes; and (e) a transmission source of the path search information. Even if a predetermined time in consideration of the processing time of each node elapses from the time when the path search information transmission start means starts transmitting the path search information, the path search information based on the transmitted path search information is arranged. And a bidirectional communication inability determining means for determining that there is no transmission path capable of performing bidirectional communication between the specific two nodes when no is transmitted.

In other words, according to the second aspect of the present invention, a path search information discarding means is newly provided in the technical components of the first aspect of the present invention, and the transmission path can transmit the path search information halfway. However, if the state is in use from the position of a certain node, the path search information is discarded for that transmission line at that time. Therefore, the transmission path in which the path search information that has returned to the original node by reciprocating motion is present is a transmission path capable of bidirectional communication. The two-way communication impossible determination means monitors a transmission path for which path search information does not return within a predetermined time, and determines that such a transmission path cannot perform two-way communication. .

According to the third aspect of the present invention, (a) when setting a bidirectional transmission path between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, any one of these nodes is used. From the transmission line that is vacant to the next node in a predetermined direction from
Path search information transmission start means for incorporating information indicating one node, the above-described information indicating the predetermined direction, and identification information of all transmission paths that are vacant to the next node, and transmitting the search result as path search information; B) It is arranged for each node, takes in the path search information, determines whether this is the end point of its own node, and if it is not the end point of the own node, it is in the same direction as the path search information was sent. Information indicating these two specific nodes up to the next node with respect to the vacant transmission path, information indicating the predetermined direction described above, and identification information of all the transmission paths vacant to the next node, And send it as path search information.If the own node is the end point, if the source of this path search information is not the own node, the path search information is sent in the opposite direction. The information indicating these two specific nodes to the next node, the information indicating the opposite direction to the predetermined direction, and the information of all the transmission lines that are vacant to the next node with respect to the next transmission node. Path search information sending and receiving means for incorporating the identification information and sending it out as path search information; and (c) arranging for each node, taking in the path search information, ending at the own node, and sending the path search information Is the own node, all the transmission paths identified from the identification information of all the vacant transmission paths finally indicated by this path search information are bidirectionally transmitted between these two specific nodes. And a bidirectional communicable transmission path determining means for determining that the transmission path is communicable.

That is, in the invention of claim 3, unlike the invention of claim 2, there is no problem that the path search information transmitted between nodes is transmitted through any number of transmission paths. This is because, in the invention described in claim 3, the identification information itself of all the transmission paths that are vacant to the next node is incorporated in the path search information. Claim 2
In the case of the described invention, path search information is actually incorporated into each of the vacant transmission lines to see how long the transmission line with the path search information survives when moving between nodes. On the other hand, in the case of the third aspect of the present invention, the next surviving transmission line among the surviving transmission paths is listed for each node. Therefore, the two-way communicable transmission line discriminating means according to the third aspect of the present invention determines all the transmission lines identified from the identification information of all the vacant transmission lines finally indicated by the path search information. The transmission path is determined to be a transmission path that allows two-way communication between two specific nodes.

According to the fourth aspect of the present invention, (a) when a one-way transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, From the transmission line that is vacant to the next node in a predetermined direction from
Path search information transmission start means for incorporating information indicating one node, the above-described information indicating the predetermined direction, and identification information of all transmission paths that are vacant to the next node, and transmitting the search result as path search information; B) It is arranged for each node, fetches path search information, determines whether this is the end point of the own node, and whether it is transmitted in the same direction as the one-way direction described above. If the path search information is transmitted in the same direction as the above-mentioned one direction, the specific two nodes are transmitted to the next node with respect to a transmission line which is vacant in the same direction as the path search information is transmitted. The information indicating the node, the information indicating the predetermined direction described above, and the identification information of all the transmission paths that are vacant to the next node are incorporated and transmitted as path search information. If the path search information is transmitted in a direction opposite to the one direction, the specific two of these transmission paths are transmitted to the next node with respect to a transmission line that is vacant in the same direction as the path search information is transmitted. The information indicating the node, the information indicating the predetermined direction described above, and the same identification information as the identification information of the transmission path are incorporated and transmitted as path search information. When the path search information is sent when the transmission source is not the own node, the information indicating these two specific nodes and the reverse of the predetermined direction are transmitted to the next node with respect to the transmission path that is vacant in the opposite direction. The information indicating the direction and the identification information of all the transmission paths that are vacant to the next node are incorporated and sent out as path search information, and the path search information is transmitted in the opposite direction to the above-described one direction. If the path search information has been sent, the information indicating these two specific nodes and the direction opposite to the above-mentioned predetermined direction to the next node with respect to the transmission path that is vacant in the reverse direction when the path search information is sent Path search information sending and receiving means for incorporating the information shown and the same identification information as the identification information of the transmission path and sending it out as path search information; and (c) being arranged for each node, taking in the path search information and And if the transmission source of this path search information is its own node, all the transmission paths specified from the identification information of all the vacant transmission paths finally indicated by this path search information are A path search system for a network is provided with a one-way communicable transmission line discriminating means for discriminating that the transmission path is one-way communicable between these two specific nodes.

That is, according to the fourth aspect of the invention, the transmission path capable of one-way communication is determined based on the same concept as the third aspect of the invention. In order to determine a transmission path capable of one-way communication, in the invention according to claim 4,
It is specified from the identification information of all vacant transmission lines in the path search information at the time of reaching the node at the turning point or when returning to the original node by reciprocating from the node at the turning point. All transmission paths are determined to be transmission paths that can communicate in one direction in a desired direction.

According to the fifth aspect of the present invention, in the network path search system according to the first to third aspects, the ring network is a relatively high-speed network, and each node has an independent relatively low-speed network. Is connected, and the transmission path capable of bidirectional communication determined by the bidirectional communication capable transmission path determination means is notified to a terminal that manages bidirectional communication.

That is, in the invention according to claim 5, a relatively high-speed ring network is used for connection between relatively low-speed networks. Since the ring-shaped network is high-speed, there is no large time delay in connecting low-speed networks.

According to a sixth aspect of the present invention, in the network path search system according to the first to fourth aspects, the path search information is arranged in a predetermined time slot of one unit signal transmitted through the transmission path. The predetermined signal sequence constituting the path search information is constituted by identification information indicating that one unit of the signal is a signal specially prepared for the path search. A part or the whole of the signal sequence described above is characterized by individually representing a node to start a search and an end point node to be a destination for switching a transmission direction.

According to the sixth aspect of the invention, the path search information is arranged in a predetermined time slot of a predetermined unit signal such as a frame signal, so that the signal is a special signal for determining a path route. Or a signal for normal data transmission. In addition, since the path search information includes information indicating the start node as a node to start the search and the end node for switching the transmission direction and determining the original node, any of the nodes is regarded as path search information. , It is possible to determine a transmission path through which communication is possible simply by performing a fixed operation.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows the configuration of a ring network to which a network path search system according to an embodiment of the present invention is applied. Since the optical fiber can transmit signals in both directions, the ring network 50 constituting this system includes two transmission systems: a clockwise or clockwise transmission system 51 and a counterclockwise or counterclockwise transmission system 52. It can be considered a union.

In this embodiment, the first to fourth nodes 61 ₁ to 61 ₁ to 61 are also used.
61 ₄ is assumed to be connected in a ring by a single optical fiber 62, respectively, of the four channels respectively in the clockwise and counterclockwise transmission path 71～74,81～
84 are provided. A control terminal 85 is connected to each of the _first to fourth nodes 61 _{1 to} 61 ₄ , but in the figure, the first node 6
Shows miso connections for 1 _1. In this figure, transmission lines 71 to 74 and 81 to 84 are indicated by broken lines when they are in use.
An empty state is indicated by a solid line. For example, the first transmission line 7 in the clockwise transmission system 51 signals in a clockwise direction is transmitted from the second node 61 ₂ to a third node 61 ₃
1 is in use, from the second node 61 ₂ to the fourth node 61 ₄ and has a busy the third transmission line 73. Depending on the form of communication, bidirectional transmission may be performed for the same section, or only one-way transmission path may be occupied. Therefore, also in this embodiment, the transmission lines occupied by the clockwise transmission system 51 and the counterclockwise transmission system 52 are not always the same. In this embodiment it is assumed that setting the two-way transmission path between the first node 61 ₁ and the third node 61 ₃ where the control terminal 85 is connected in FIG.

FIG. 2 shows the configuration of the first node in this embodiment. The first node 61 ₁ includes a CPU (central processing unit) and a control unit 91 which also includes a storage medium (not shown) which is not shown. A control program is stored in the storage medium, and the CPU performs various controls based on the program.

The control unit 91 includes a clockwise high-speed transmission unit 92R and a counterclockwise high-speed transmission unit 92L for transmitting a signal to the optical fiber 62, a clockwise high-speed reception unit 93R for receiving a signal from the optical fiber 62, and Counterclockwise high-speed receiving unit 93
L is connected to the cross-connect unit 94 and the control terminal 85 shown in FIG. 1, and by transmitting and receiving control signals to and from them, the cross-connect unit 94 manages the cross-connect connection state. High-speed transmission unit 9
The 2R and 92L multiplex each frame and transmit the multiplexed frames to the transmission paths 71 to 74 and 81 to 84 of the optical fiber 62, and transmit path search information by a method described later. The high-speed receiving units 93R and 93L are connected to the optical fiber 62.
And monitors the path search information by receiving the frames from the respective transmission paths 71 to 74 and 81 to 84.

[0030] The configuration of the second to the fourth node 61 _{2-61 4} also is substantially the same ₁ and a first node 61,
Illustration of these is omitted. In addition, these nodes 61 ₂
When performing the a to 61 ₄ of description, it will be incorporated as appropriate Figure 2.

FIG. 3 shows the structure of path search information incorporated in each frame of a frame signal transmitted through the ring network shown in FIG.
In the path search system of the present embodiment, path search information 101 defined in advance in the system is incorporated into a header portion (not shown) at the head of a frame signal when searching for a path route. The path search information 101 includes request type information 102, end node ID information 103, and start node ID information 104, and has a predetermined bit configuration. If the path search information 101 is not embedded in a frame, the frame is processed as a normal information transmission. On the other hand, when the path search information 101 is incorporated in a frame, the frame is used to search for a path route.

The request type information 102 indicates whether the search request is a clockwise direction as the first one-way direction for the path route search or a counterclockwise direction as the return direction after reaching the end point node. It consists of the bit string shown.
The end point node ID information 103 is composed of a bit string indicating the end point node 61 of the path to be opened, and includes a start point node ID.
The information 104 is composed of a bit string indicating the node 61 at the start point of the path to be opened.

[0033] In this embodiment, illustrating a search when to open the path from the first node 61 ₁ to the third node 61 ₃ as an example. In this example, by inserting the optical fiber 62 in the first node 61 ₁ transmission direction frame clockwise for Search as a node of the starting point for searching the path route, a third node as the node of the end point 61 ₃ to search the path route by returning to the first node 61 ₁ of the starting point by switching it to the transmission direction of counterclockwise in. Therefore, the end point node ID information 103 and the start point node ID information 104 are incorporated into the path search information 101.

FIG. 4 illustrates the search of the path route in this example. Because it is open a path from the first node 61 ₁ to the third node 61 ₃ are premised, in this figure the first to third nodes 61
Shows a _{1-61 3,} illustration of the fourth node 61 ₄ are omitted.

[0035] Now, the first node 61 ₁ serving as a starting point for search path route in this embodiment, incorporating the path search information 101 for path search with respect to the transmission path of all clockwise unused state Send out the frame. In this embodiment, a node from the first node 61 ₁ at this point of the second 6
1 to ₂ first to fourth transmission lines 71 to 74 are not used all. Therefore, from the first node 61 ₁ path search information to the first to fourth transmission lines 71 to 74 10
1 will be sent out. In the path search information 101, the end point is the third node 61 ₃ (shown as “end point” in the figure), and the start point is the first node 61 ₃ .
Is the information for the node 61 ₁ (shown as “start point” in the figure).

These frames are first stored in the second node 61
Reach ₂ In the second node 61 _2, the control unit 91 shown in FIG. 2 is checked to request type information 102 in the path search information 101 illustrated in FIG.

FIG. 5 shows a state of control of each node. The control unit 91 first checks whether or not the path search information 101 exists in the arrived frame (step S121). If the path search information 101 does not exist, it is not necessary to perform special processing for searching for a path route. Therefore, in this case (N), normal frame processing is performed (step S122). That is, to determine whether that frame is its own node 61 ₂ destined own node 61 processes incorporating this if ₂ destined local node 61 as the next node if not ₂ destined third It will be sent this to the node 61 _3. There is nothing new about this point, and further description is omitted.

On the other hand, the path search information 1
If 01 exists (step S121: Y), the request type information 102 is checked to determine whether "request" is present (step S123).
If "request" is present (Y), the process is performed toward the third node 61 ₃ ("end point") as the end point node as described above (step S12).
4). On the other hand, when there is no "request" (step S123: N), it is checked whether or not the end point node ID and the own node ID match (step S125). This is to check whether or not the path has returned to the starting point of the search for the path route. Otherwise (N), the process is executed toward the first node 61 ₁ (“start point”) as the start point after reaching the third node 61 ₃ (“end point”) as the node of the return point. (Step S12)
6).

FIG. 6 specifically shows the processing shown in step S124. This process is consistent with processing in the second node 61 ₂ currently described. The control unit 91 checks the end-point node ID information 103 in the path search information 101 of the frame arriving, to determine if it matches the second node 61 ₂ ID as the own node (step S131). In this example, the end node ID information 103 is the third node 61
₃ ("end point"). Therefore, the IDs do not match (N). The opposing if, that is, checking whether an empty exists is performed and then the third transmission path toward the node 61 ₃ to advance (step S13
2).

As shown in FIG. 1, the second node 61 ₂
The third node 61 ₃ to one channel in use (transmission line) 141 is present and the second node 61 ₂ from the fourth node 61 channels 142 in other uses to ₄ is present from. These are the first and third transmission lines 71 and 73 used. In FIG. 4, these transmission paths in use are represented by halftone dots. Therefore, in this embodiment, the second and fourth transmission paths 72 and 74 are empty at this time. The control unit 91 determines that an empty transmission path exists (step S132: Y),
The transmitted path search information 101 is transmitted as a frame input device (step S133). In this example, using the second node 61 from ₂ to the third node 61 ₃ second and fourth transmission lines 72 and 74 as shown in FIG. 4, the path search information 101 is transmitted Will be.

[0041] In the third node 61 _3, upon receiving the frame, performs a process of the control unit 91 described in FIG.
Then, for the path route search frame sent by the second and fourth transmission paths 72 and 74, the process for the destination node shown in step S124 is executed. 6 in step S131 of the process shown in the third node 61 ₃ of the control unit 91 determines the end point node ID103 matches the ID of the third node 61 ₃ (Y). In this embodiment, in this case, a process of transmitting the path search information 101 by returning it to the start node side is performed (step S125). For this reason, the control unit 91 sets the second node 61 ₂ as the opposite node in the opposite direction (counterclockwise direction).
It is checked whether or not there is a free transmission path to go to (step S134).

[0042] As shown in FIGS. 1 and 4, the second node 61 ₂ is provided between the first node 61 ₁ One channel in use (transmission line) 143 is present. However, at this point it has all transmission lines 81 to 84 free, from the third node 61 ₃ to the second node 61 _2. Therefore, the control unit 91 of the third node 61 ₃
Path search information 101 received by clockwise high-speed receiving section 93R
Is transmitted to the optical fiber 62 using the counterclockwise high-speed transmission unit 92L instead of transmitting it to the optical fiber 62 by the clockwise high-speed transmission unit 92R (step S135). Transmission line, the second and fourth transmission lines 72 and 74 used in the third node 61 ₃ for path route search using this time
And fourth transmission paths 82 and 84 in the opposite directions corresponding to
Becomes Further, the third node 61 ₃ of the control unit 91 to "request" of the path search information 101 to be inserted at this time "present"
From "none". At this time, the start point ID and the end point ID are also reversed.

Incidentally, if the free is not present in the transmission path of the forward (clockwise direction) opposite at step S132 of FIG. 6, and the path to the third node 61 ₃ as the end point be present If there is no available transmission path in the direction returning to the starting point (steps S132 and S134:
N), the path search information 101 is discarded (step S1)
36). This to make sure that the path search information 101 with that returned to the first node 61 ₁ as the starting point, there is a bidirectional transmission path between the third node 61 ₃ as the end point This is because

The path search information 101 to the second node 61 ₂ using the second and fourth transmission lines 82 and 84 in this way in this embodiment is transmitted. In the second node 61 ₂ , since the “request” has been changed to “no” in step S123 of FIG. 5 (N), the processing toward the first node 61 ₁ (“start point”) is executed. (Step S125).

Specifically, as shown in FIG. 6, the ID of the end node is compared with the ID of the own node (step S13).
1), whether the check free space in the transmission path to the first node 61 ₁ as the next node in the counterclockwise direction is present is performed does not match (step S132). In this example, the above-described manner and the second node 61 ₂ is only one cross-connect is set between the first node 61 _1, the channel in use (transmission line) 143 is present ing. Therefore, the path search information 101 is discarded for the second transmission path 82. For the fourth transmission line 84, no cross-connect has been set. Therefore, the fourth
The path search information 101 is inserted into the frame only for the transmission path 84 (step S133). As a result, the frame for the path route search is to be sent to the first node 61 ₁ to transmit only the fourth transmission line 84.

In the first node 61 ₁ , the destination node ID
Matches its own node ID (step S12).
5: Y), the number of the fourth transmission path 84 as the number of the transmission path that has received the path search information 101 is transmitted to the control terminal 85 that controls frame transmission (step S127). When there are a plurality of vacancies in the transmission path, the control terminal 85 selects one of them and uses it for normal information transmission. In the case where there is only one vacancy in the transmission line as in this embodiment, the transmission line is selected and used for normal information transmission.

FIG. 7 shows the flow of control on the control terminal of the starting node. In this example, the first
The node 61 ₁ of the controller 91 are waiting to request the transmission comes for normal information from the control terminal 85 (step S141). Then, when there is a transmission request (Y), the path search information 101 ending with the node as the return point designated by the control terminal 85 is created and transmitted as described above (step S142). After that, the timing of the time t in which the path search information 101 returns at the end point and returns with some margin is started (step S143). If the path search information 101 is returned before the time t elapses (step S144:
Y), as described in step S135, the available transmission path is notified to the claim terminal (step S14).
5), end the processing. In this case, the control terminal 85 selects a transmission path to be transmitted and sends it to the node.

On the other hand, even if the time t has elapsed, the path search information 1
01 is not received (step S143: N),
The control terminal 85 is notified that there is no available transmission path (step S146), and the process is terminated.

Modification

In the embodiment described above, the setting of the path route in the case of performing the bidirectional transmission has been described. Although this method can be applied to only one communication as it is,
If there is no vacancy in the transmission path on the path from the original end point to the return path to the start point, it is determined that there is no transmission path despite the fact that there is an original communication path. This modification reduces the occurrence of such a problem.

FIG. 8 shows the structure of the path search information used in this modification. This path search information 20
1 includes a request type 102 similar to that of the previous embodiment, two types of node ID information of a first node ID 203 and a second node ID 204, and possible path list information 205. Among them, the first node ID 203 represents the end node ID on the outward route to the end node, and represents the start node ID on the return route. The second node ID 204 indicates the start node ID on the outward route to the end node, and the end node ID on the return route. That is, in the network path search system according to this modification, the first node ID 2
03 and the definition contents of the second node ID 204 are automatically switched, so that these nodes do not need to be rewritten at the end point (return point) node.

In the possible path list information 205, the number of a transmission path on which a path route can be set is written. This writing or changing is performed until the path search information 201 returns to the starting point again in the case of bidirectional communication. That is, the numbers of all the transmission paths for which a path route can be set are written at the time of going from the start node to the next node. An operation of deleting a transmission path from the available path list information 205 is performed.

On the other hand, when only one-way communication is performed, the same operation is performed until the path search information 201 reaches the end node on the outward route, and the return node returns from the end node to the start node. Possible path list information 2 until returning to the node
05 is not deleted. Also, in this return path, the path search information 201 can be incorporated even on a transmission path not listed as the possible path list information 205.
This is because only the state at the time of reaching the end point node on the outward route needs to be reported to the start point side, regardless of the route. When a path route only for the return route is searched, the path search information 201 is transmitted to the node at the end point (return point), and the possible path list information 205 is rewritten on the return route in the same manner as the already described forward route. do it.

Similarly, in this modification, the path search information 201
Need not be inserted into all the transmission paths on which path routes can be set for transmission. This is because information common to each transmission path section is described as the possible path list information 205. However, unless the path is actually set and the path search information 201 (or 101) is sent to the transmission line as in the previous embodiment, the path route may be duplicated when another node searches for the same path route. May be set.

Therefore, when searching for a path route between nodes using, for example, one transmission line while avoiding such a fear, the frame to be searched is transmitted through the optical fiber 62. Thereafter, all nodes may be prohibited from searching for a new path route until a new path route is set. Specifically, the node from which the path search information 201 has arrived may discard the new path search information 201 when it arrives for a predetermined plurality of frame sections. The length of the multiple frame section where search for a new path route is prohibited is
The time is determined in consideration of the time from when the control terminal 85 sets a path route to when a new path route is used.

In the embodiments and the modified examples, a case where a high-speed ring-shaped network is connected to a low-speed network has been described as an example. However, the present invention is not limited to such a case. It can be naturally applied to all the ring networks connected with.

In the embodiment, the path search information 101 is incorporated at the head of each frame. However, it is sufficient that information for path search is incorporated in a predetermined time slot of one unit of signal, and is necessarily called a frame. It need not be a signal sequence.

[0058]

As described above, according to the first and second aspects of the present invention, a signal incorporating path search information is actually transmitted between nodes for which a path is to be set,
Eventually, the transmission path to which the signal incorporating the path search information was sent back was determined to be a transmission path capable of two-way communication. A path search can be realized.

According to the second aspect of the present invention, if the path search information is not sent to the transmission path to which the path search information has been transmitted even after the predetermined time has elapsed, the transmission path cannot perform bidirectional communication. Since it is determined that the transmission path is delayed, for example, it is possible to take a measure of excluding a transmission path that is delayed for a predetermined time or more for some reason from selection targets.

Further, according to the third and fourth aspects of the present invention, the point that path search information is incorporated in a transmission path and transmitted between two specific nodes is the same as the first and second aspects of the present invention. Incorporates the identification information of all the transmission paths that are vacant to the next node in the path search information, thereby eliminating the necessity of incorporating the path search information into all of the vacant target transmission paths. For this reason, if transmission is performed by incorporating path search information into a part of the vacant target transmission paths, some transmission paths can be kept vacant during that time, and these can be kept for a short time. Anyway, it can be used effectively.

According to the fourth aspect of the present invention, since a search for a path in one direction is performed, there is a case where the same transmission path as in the one direction is not available in another direction. Also, it is possible to incorporate the path search information into the currently vacant transmission path and transmit the data, and to detect the vacancy of the transmission path in the desired direction, the path search information is used by the other same transmission path. Therefore, the problem that the detection result cannot be transmitted can be solved.

According to the fifth aspect of the present invention, since the ring network is a relatively high-speed network,
There is no significant time delay in the connection between low-speed networks, and there is an effect that a difference due to transmission delay hardly occurs even if any node of the ring network is used for connection.

According to the sixth aspect of the invention, the path search information is arranged in a predetermined time slot of a predetermined unit signal such as a frame signal, so that the signal is used to determine a path route. It is possible to determine whether the signal is a special signal or a signal for normal data transmission. Therefore, a predetermined unit signal can be switched and used not only for path search but also for maintenance and normal data transmission.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a ring network to which a network path search system according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a first node according to the embodiment.

FIG. 3 is an explanatory diagram showing a configuration of path search information incorporated in each frame of a frame signal transmitted through the ring network shown in FIG.

FIG. 4 is an explanatory diagram illustrating a state of searching for a path route in the search route according to the embodiment.

FIG. 5 is a flowchart illustrating a state of control of each node.

FIG. 6 is a flowchart specifically showing the processing shown in step S124.

FIG. 7 is a flowchart illustrating a flow of control on a control terminal of a starting node in the present embodiment.

FIG. 8 is an explanatory diagram showing a configuration of path search information used in a modified example.

FIG. 9 is a network configuration diagram showing an example of a state in which a high-speed ring network is connected to several low-speed networks.

FIG. 10 is an explanatory diagram showing how a path search is performed in a conventional ring network.

[Explanation of symbols]

Reference Signs List 50 ring-shaped network 51 clockwise transmission system 52 counterclockwise transmission system 61 _{1 to} 61 ₄ first to fourth nodes 71 to 74 (clockwise) first to fourth transmission lines 81 to 84 (clockwise) ) First to fourth transmission paths 85 control terminal 91 control unit 94 cross-connect unit 101, 201 path search information 102 request type information 103 end node ID information 104 start node ID information 203 first node ID information 204 2 node ID information 205 Possible path list information

Claims (6)

[Claims] 1. When a bidirectional transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, from one of these nodes to the next node in a predetermined direction. Path search information transmission start means for incorporating information indicating these two specific nodes and information indicating the predetermined direction into all vacant transmission paths and transmitting the information as path search information; Is located in, to determine whether this is the end point of the own node by taking the path search information,
If the own node is not the end point, information indicating these two specific nodes up to the next node for all the transmission lines that are vacant in the same direction as the path search information has been sent and the predetermined direction Is sent out as path search information, and if the own node is the end point, if the path search information is not sent from the own node, it becomes empty in the opposite direction if the path search information is sent. Path search information sending and receiving means for sending information as path search information by incorporating information indicating these two specific nodes and information indicating the direction opposite to the predetermined direction up to the next node for all transmission paths The path search information is arranged for each node, and the path search information is fetched. If the path search information ends at the own node and the transmission source of the path search information is the own node, the path search information is A network path comprising: a bidirectional communicable transmission path determining means for determining all transmitted transmission paths to be bidirectionally communicable between these two specific nodes. Search system. 2. When a bidirectional transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, from one of these nodes to the next node in a predetermined direction. Path search information transmission start means for incorporating information indicating these two specific nodes and information indicating the predetermined direction into all vacant transmission paths and transmitting the information as path search information; Is located in, to determine whether this is the end point of the own node by taking the path search information,
If the own node is not the end point, information indicating these two specific nodes up to the next node for all the transmission paths that are vacant in the same direction on the same transmission path from which the path search information has been sent. And the information indicating the predetermined direction are incorporated and transmitted as path search information. In the case where the own node is set as the end point, if the transmission source of the path search information is not the own node, the path search information is transmitted in reverse. Incorporating information indicating these two specific nodes and information indicating the direction opposite to the predetermined direction up to the next node for all the transmission lines corresponding to the same transmission line which is vacant in the direction. A path search information transmission agent transmitting means for transmitting as path search information, and arranged for each node, fetching the path search information and judging whether this is the end point of the own node,
If the own node is not the end point, discard the path search information sent for all the transmission paths that are being used in the same direction on the same transmission path to which the path search information has been sent, and In the case of the end point, when the transmission source of the path search information is not the own node, the transmission is performed for all the transmission paths corresponding to the same transmission path which is being used in the reverse direction when the path search information is transmitted. Path search information discarding means for discarding the obtained path search information, and a path search information discarding means disposed for each node, fetching the path search information, ending with the own node, and transmitting the path search information from the own node. A bidirectional communication-capable transmission path determining means for determining that all transmission paths to which the path search information has been transmitted are bidirectionally communicable between these two nodes; The transmitted path search information is located at the transmission source of the path search information, and the path search information transmitted even when a predetermined time considering the processing time of each node has elapsed since the path search information transmission start means started transmitting the path search information. Bidirectional communication impossible determination means for determining that there is no transmission path capable of performing bidirectional communication between specific two nodes when path search information is not sent from a transmission path incorporating information. Characteristic network path search system. 3. When a bidirectional transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, from one of these nodes to the next node in a predetermined direction. The path which incorporates the information indicating these two specific nodes, the information indicating the predetermined direction, and the identification information of all the vacant transmission paths to the next node is incorporated into the vacant transmission path. Path search information transmission start means to be transmitted as search information, arranged for each node, fetching the path search information and determining whether this is the end point of the own node,
If the own node is not the end point, the information indicating these two specific nodes and the predetermined direction are shown to the next node with respect to a transmission line that is vacant in the same direction as the path search information is sent. The information and the identification information of all the transmission paths that are vacant to the next node are incorporated and transmitted as path search information. When the own node is the end point, the transmission source of this path search information is not the own node. In the case where the path search information has been sent, the information indicating these two specific nodes, the information indicating the direction opposite to the predetermined direction, and the information indicating Path search information sending and receiving means for incorporating the identification information of all the transmission paths that are vacant to the node and sending it out as path search information; When the search information is fetched and ends at the own node and the transmission source of the path search information is the own node, the identification information of all the vacant transmission paths finally indicated by the path search information is used. Bidirectional communication-capable transmission path determining means for determining all specified transmission paths as transmission paths capable of bidirectional communication between these two specific nodes. system. 4. When a one-way transmission path is set between two specific nodes in a ring network in which a plurality of nodes are connected in a ring, from one of these nodes to the next node in a predetermined direction. The path which incorporates the information indicating these two specific nodes, the information indicating the predetermined direction, and the identification information of all the vacant transmission paths to the next node is incorporated into the vacant transmission path. Path search information transmission start means to be transmitted as search information; arranged at each node; fetching the path search information and ending at the own node; and transmitting the same in the same direction as the one-way direction And if the path search information is transmitted in the same direction as the one-way direction without ending at the own node, the same as the path search information is transmitted. Information indicating these two specific nodes, information indicating the predetermined direction, and identification information of all the transmission paths that are vacant to the next node up to the next node with respect to the vacant transmission path. Is transmitted as path search information, and when the path search information is transmitted in the opposite direction to the one direction, the transmission path that is vacant in the same direction as the path search information is transmitted is transmitted. The information indicating these two specific nodes, the information indicating the predetermined direction, and the same identification information as the identification information of the transmission path are incorporated into the next node and transmitted as path search information. If the source of the path search information is not its own node, the path search information is sent to the next node to the next node with respect to the transmission path that is vacant in the reverse direction. The information indicating two nodes, the information indicating the opposite direction to the predetermined direction, and the identification information of all the transmission paths that are vacant to the next node are incorporated and transmitted as path search information, and the one-way and If the path search information is transmitted in the reverse direction, the path search information is transmitted, and information indicating these two specific nodes up to the next node with respect to the transmission path that is vacant in the reverse direction is transmitted. A path search information transmission agent that incorporates information indicating a direction opposite to the predetermined direction and the same identification information as the identification information of the transmission path and transmits the path search information as path search information; When the information is fetched and this is the end point of the own node and the transmission source of this path search information is the own node, all the vacant spaces finally indicated by this path search information A unidirectional communicable transmission line determining means for determining that all the transmission lines identified from the identification information of the transmission line are the one-way communicable transmission lines between these two specific nodes. Characteristic network path search system. 5. The ring-shaped network is a relatively high-speed network, and independent relatively low-speed networks are connected to the respective nodes. 4. The network path search system according to claim 1, wherein a transmission path capable of bidirectional communication is notified to a terminal managing bidirectional communication. 6. The path search information is arranged in a predetermined time slot of one unit signal transmitted through a transmission path, and a predetermined signal sequence constituting the path search information is:
The signal of one unit is constituted by identification information indicating that the signal is a signal specially prepared for path search, and a part or all of the other signal sequence constituting the path search information is a node for starting the search. 5. The network path search system according to claim 1, wherein an end point node serving as a destination for switching the transmission direction is individually represented.