JP2000134245A - Node system for unidirectional path changeover ring network and m:n multicast communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network independent of a terminal node number where many multicast communication forms are present by a ring network provided with both reliability and cost effectiveness. SOLUTION: This system is provided with a center node detector A for detecting that the present node is a center node, center node right acquisition detectors F and G for detecting that the node which acquires a center node right is present and present node address detectors H and I for detecting whether or not a terminal node address from the center node matches with a present node address. For respective originating node, relay node and arriving node discriminated corresponding to the respective detected results of the respective detectors, selectors B, C, D and E are made to select a contact line, a fall line and an insertion line prepared in the respective nodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a node system of a one-way path switching ring network for realizing M: N multicast communication in which a transmission path is duplicated, and M:
The present invention relates to an N multicast communication method.

[0002]

2. Description of the Related Art Conventionally, in a one-way path switching ring network, when performing N: 1 one-way multicast communication in which data is collected from a plurality of nodes (terminal nodes) to one center node, usually, the center node transmits the data. Transmission paths are individually set to each node, and the data collection is performed by switching the transmission path for data collection at the center node. FIG. 5 is an explanatory diagram showing a parallel transmission / reception switching method of such a conventional one-way path switching ring network. In this case, VC-111 / 2 (1.5 / 6.3 Mb) is used.
(it / s virtual container) is transmitted in parallel, and when a VC-11 / 2 alarm is detected on the operating system bus at the receiving end, the system is switched to the normal system. That is, in this normal state, the path switching of the node 1, node 2, node 3, and node 4 on the one-way path switching ring network is performed by the VC path selector (SEL) of each node 1 and node 3 as shown in the figure. (A) The signal on the low-speed side of the node 1 is transmitted to the nodes 2 and 4 in parallel. (B) The signal from the node 1 passes through the nodes 2 and 4 (pass-through) and reaches the node 3. (C) In node 3,
Signals coming from both directions are selected by the selector (reception end switching) and dropped to the lower speed side.

On the other hand, when a failure occurs, for example, (a) between node 1 and node 4
When the optical signal input disconnection fault (REC) of 0M is detected, (b) by detecting the REC at the node 1,
Path AIS (Alarm Indicati) for VC path
on Signal (alarm instruction signal). Next, (c) using the path AIS as a trigger, switch to a direction in which no fault has occurred in the VC path selector of the node 1. As a result, (d) from node 3 to node 1
The VC path in the direction can be relieved. (E)
The node 4 similarly detects an input signal disconnection failure and transfers the path AIS to all paths. The node 3 also detects the path AIS transferred from the node 4. With this as a trigger, the VC path selector of the node 3 switches from the direction of the node 2 to the input signal.
Thus, the VC path from node 1 to node 3 can be rescued.

[0004]

However, in such a conventional N: 1 one-way multicast communication method, many transmission paths are consumed on the ring network due to the large number of terminal nodes.
There is a problem that the number of terminal nodes is limited by the transmission capacity of the ring network. In addition, when there are many multicast communication modes in which the center nodes are different, it is necessary to set up transmission paths individually by the number of this mode.
There is a problem that the transmission capacity of the ring network is further consumed.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and can realize a network that does not depend on the number of terminal nodes and has many multicast communication modes by a ring network having both reliability and economy and real-time performance. It is an object of the present invention to provide a node system of a one-way path switching ring network and an M: N multicast communication method capable of realizing a communication mode adapted to the traffic of the above.

[0006]

In order to achieve the above object, a node system of a one-way path switching ring network according to the present invention comprises: A center node detector that detects that the node is a node; a center node right acquisition detector that detects that a node that has acquired the center node right exists in the one-way path switching ring network; A self-node address detector for monitoring the terminal node address and detecting whether or not the terminal node address matches the self-node address; the center node detector, the center node right acquisition detector, and the self-node address Source node determined according to each detection result of the detector,
For each relay node and destination node, the selector is made to select a tangent line, a down line, and an inserted line prepared for each of these nodes.

Further, in the node system of the one-way path switching ring network according to the present invention, the center node right acquisition detector monitors center node right issue information, and the center node is located on a multicast transmission path. This is an insertion line carrier detector that acquires one node with the first priority.

Further, in the node system of the one-way path switching ring network according to the third aspect of the present invention, a self-node address for selecting a terminal node is defined in each of the nodes in advance.

Further, the node system of the one-way path switching ring network according to the present invention causes the own node address detector to monitor a terminal node address sent from the center node, and this is used as the own node address. In the case of a match, the selector is operated as a down line of the multicast transmission path to establish communication with the center node.

The terminal node system of the one-way path switching ring network according to the present invention causes the own node address detector to monitor a terminal node address sent from the center node. When the address does not match, the node is operated as a relay node of the multicast transmission path as a connection line of the multicast transmission path.

Further, the node system of the one-way path switching ring network according to the invention of claim 6 terminates communication with the node designated by the center node, cancels the issuance of the terminal node address, and sets the multicast transmission path. The down line is connected to the line, and the selector is switched to perform the operation.

Further, according to the M: N multicast communication method according to the present invention, a plurality of nodes on a one-way path switching ring network use a center node right issue information and a node address to establish one transmission path. The transmission path is shared as a multicast transmission path that can be used in a time-division manner, and duplex M: N multicast communication of the transmission path is performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of each node connected to a one-way path switching ring network according to the present invention. In FIG. 1, A is connected to an insertion line and detects a carrier on the insertion line. , F: G, a carrier detector as a center node detector for detecting that the own node is an originating node as a center node for performing M: N multicast communication
Is a carrier detector as a center node right acquisition detector for detecting the existence of a node that has acquired the source node right in the ring network, and H and I are the destination (self) node address signals sent from the source node. It is a self-node address detector that detects, and determines whether each node on the ring network is a source node, a relay node, or a destination node based on the output of each of these detectors.

B, C, D, and E are selectors for selecting a connected line, a dropped line, and an inserted line prepared for each node based on the determination result.
By controlling D and E, M: N multicast communication can be performed in a time-division manner. As a result, one transmission path can be shared as a multicast transmission path by each node, and a duplex M: N multicast communication of the transmission path by the ring network is realized.
Note that, among the selectors B, C, D, and E, the selector B
Selects one of the insertion line and one-way connection line,
The selector C selects one of the one-way connection and one of the down links, the selector D selects one of the other connection and the other down connection, and the selector E selects the other connection. Select one of the insertion lines. The carrier detector F detects the carrier in the other direction, the carrier detector G detects the carrier in the one direction, the own node address detector H detects the own node address in the other direction, and The address detector I detects the one-way own node address. J is the other-way down-link path AIS detector, and K is the one-way down-link path AIS detector.

Next, the operation will be described. Each node monitors the center node right issue information by the carrier detector A,
On the multicast transmission path, the center node can acquire one node with priority on a starting point. In each node, a node address for selecting a terminal node is defined in advance. At the same time, each node monitors the terminal node selection information sent from the center node by its own node address detectors H and I, and if it is identified that it matches the node address of its own node, it is determined as a terminal node. Selectors B, C, and
D and E are operated to establish communication with the center node. If it does not match the node address of its own node, it operates as a contact line and operates as a relay node of a multicast transmission path. To end the communication with the node specified by the center node, the issuance of the node address specified as the terminal node selection information is stopped, and the selector B, C, D, Operate E and end the communication. continue,
When performing communication with a different terminal node, the designated node address is transmitted on the multicast transmission path, and communication is established by the same operation as described above.

Next, the operation of each node will be described with reference to the flowchart of FIG. First, the selectors B, C, D, and E are switched to the connected line side (step S
1) The presence / absence of a carrier of another node is detected by the carrier detectors F and G (step S2). If there is a carrier of another node, the issuing of the carrier in the own node is prohibited (step S3). If the issuance of such a carrier is prohibited, or if it is determined in step S2 that there is no carrier of another node, the presence or absence of a carrier from the own node terminal is subsequently detected by the carrier detectors F and G. Then, if there is no carrier, selectors C and D select connected lines (step S5). If there is a carrier, selectors C and D select down lines (step S6).

If a contact line is selected in step S5, it is then measured whether or not the node address from the center node matches its own node address (step S7). The insertion line is selected by the selectors B and E (step S8), and if they do not match, the connected line is selected by the selectors B and E (step S8).
9). Further, when the down line is selected by the selectors C and D in step S4, the path in the direction of one of the routes is monitored by the path AIS detector J, and it is determined whether the monitoring result is normal or abnormal ( Step S10). If abnormal, the route selector L selects a dropped line in the other direction (step S11). If this dropped line is selected or if the result of the path monitoring is abnormal in step S10, the path AIS detector is selected. K monitors the path in the other route direction, and determines whether the monitoring result is normal or abnormal (step S12). If it is determined that there is an abnormality, the route selector L causes the route drop in the one route direction to fail. Is selected (step S13). And after each process of step S8, step S1, step S12, and step S13,
Step S1 and subsequent steps are repeated.

Next, the nodes as described above are arranged on a one-way path switching ring network as a source node (center node) P, a relay node Q, and a destination node R as shown in FIGS. , M: N multicast communication will be described. Each node P, Q, R
Are as shown in FIG. First, the node P carrier (carrier input) input to the source node P is relayed to the relay node Q and the destination node R (PQ1, BC
1) At this time, the outgoing node P selects the down line by the selectors C and D (P1), and the relay node Q and the destination node R prohibit the transmission of the carrier respectively (Q1,
R2). For this reason, the source node P acquires the source node right within the ring (P2), and further transmits the selected node address r (PQ2). The selected node address r is relayed by the relay node Q and passed to the destination node R (QR2),
The relay node Q determines that the selected node address r does not match its own node address (Q2), and the destination node R determines that the selected node address r matches its own node address (R2). Select the insertion line.

At this time, the destination node R sends the node R data directly to the node P (RP2) and also sends it to the relay node Q (RQ3), and the relay node Q sends the node R data to the node P. Relay (QP3).
Therefore, the node P receives the node R data from the destination node R (P3), stops sending the selected node address r (PQ4), and the relay node Q and the destination node R receive the selected node address r (QR4, R
P3). At this time, the destination node R is the selected node address r
Is lost, it is determined that there is no match between this and the own node address (R3). Further, the source node P stops sending the node P carrier (PQ5), and the relay node Q and the destination node R eliminate the node P carrier (QR5, RP4). Subsequently, the originating node P relinquishes the originating node right within the ring (P4), and enables carrier transmission at the relay node Q and the destination node R (Q3, R4).
In addition, the sequence procedure in FIG.
T9, and the sequence of bidirectional data reception from the destination node R and the source node P is T10 → T11 → T1.
It becomes 2. 3 and 4, P is a source node, Q
Has been described as a relay node and R is a destination node, but it is possible to change to any communication mode in which one of them is a source node and the other is a destination node in one transmission path. That is, any node can be a source node and a destination node. In addition, since a redundant path can be configured even at the time of multicasting, backup can be performed even if any path is broken. Further, according to the present invention, the detection conditions of the carrier detectors A, F, G and the own node address detectors H, I of the node that has acquired the source node right and the node that has been recognized as the destination node are of a latch / reset type using a specific pattern. By doing so, it is also possible to enable M: N bidirectional multicast communication.

[0020]

As described above, according to the present invention, in a plurality of nodes on a one-way path switching ring network, a center node detector for detecting that the own node is a center node, A center node right acquisition detector that detects the presence of a node that has acquired the center node right in the switching ring network, and monitors a terminal node address sent from the center node, and this terminal node address matches its own node address. A self-node address detector for detecting whether or not to perform the call, a source node, a relay node, and a destination node determined according to the detection results of the center node detector, the center node right acquisition detector, and the self-node address detector. For each node, the selector sets the connection line, drop line, and insertion line prepared for each of these nodes. Since each node in the ring network monitors the source node signal, each node can acquire the source node right, thereby sharing the same transmission path in the ring. M: N multicast communication can be easily realized by dynamically switching the originating nodes by using the multicast node, and the transmission capacity consumption in the ring network can be reduced by using a plurality of multicast communication while sharing the band in the ring. Multicast communication that is minimized and does not depend on the number of terminal nodes can be realized. In particular, the traffic volume generated on the ring network is small, and it is particularly effective for traffic that requires real-time properties after the other party's connection destination is determined. The effect that the transmission path can be established is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a node system of a one-way path switching ring network according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a node in FIG. 1;

FIG. 3 is a sequence diagram showing an operation of the one-way path switching ring network having the node system of the present invention.

FIG. 4 is a block diagram showing details of a source node, a relay node, and a destination node in FIG. 3;

FIG. 5 is an explanatory diagram showing a parallel transmission / reception switching method of a conventional one-way path switching ring network.

FIG. 6 is an explanatory diagram showing a parallel transmission / reception switching method of the one-way path switching ring network of FIG. 5 when a failure occurs.

[Explanation of symbols]

A Carrier detector (center node detector) B, C, D, E selector F, G Carrier detector (center node right acquisition detector, inserted line carrier detector) H, I own node address detector

Continuation of the front page (72) Inventor Takashi Shibamata 2nd Thunder God Yoshioka, Yamato-cho, Kurokawa-gun, Miyagi Prefecture Miyagi NEC Corporation F term (reference) 5K031 CA08 CB12 CB17 DA02 DA12 DB14 EA01 EB05

Claims (7)

[Claims] 1. A plurality of nodes on a one-way path switching ring network, a center node detector for detecting that the own node is a center node, and a center node right acquired in the one-way path switching ring network. A center node right acquisition detector for detecting the presence of a node that has been detected, and a terminal node address for monitoring a terminal node address sent from the center node and detecting whether or not the terminal node address matches the own node address. A detector provided for each of the source node, the relay node, and the destination node determined according to the detection results of the center node detector, the center node right acquisition detector, and the own node address detector. A selector for selecting a line, a dropped line, or an inserted line. Node system countercurrent path switching ring network. 2. The center node right acquisition detector monitors center node right issuance information, and determines that the center node is an insertion line carrier detector that acquires one node on a multicast transmission path with a first-come first-served basis. The node system of a one-way path switching ring network according to claim 1, wherein 3. The node system for a one-way path switching ring network according to claim 1, wherein a self-node address for node selection is defined in advance for each node. 4. The own node address detector monitors a terminal node address sent from the center node, and when the terminal node address matches the own node address, operates the selector as a down line of a multicast transmission path. The node system for a one-way path switching ring network according to claim 1, wherein communication with the center node is established. 5. The self-node address detector monitors a terminal node address sent from the center node, and, if the terminal node address does not match the self-node address, performs multicast transmission on the node as a connection line of a multicast transmission path. The node system for a one-way path switching ring network according to claim 1, wherein the node system operates as a relay node of a path. 6. The communication with the node designated by the center node is terminated by terminating the issuance of the terminal node address and switching the selector with the down line of the multicast transmission path as the connected line. The node system of a one-way path switching ring network according to claim 1, wherein 7. A plurality of nodes on a one-way path switching ring network, using a center node right issue information and a node address, share one transmission path as a time-divisionally available multicast transmission path, An M: N multicast communication method for performing M: N multicast communication in which a transmission path is duplicated.