JP2001230776A - Exchange, differential information collection device, and communication network system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication network system that can reduce traffic of an entire network by reducing the quantity of a routing message exchanged by a routing protocol. SOLUTION: Each of the exchanges being components of a communication network system is provided with a periodic notice timer that generates topology state periodic notice timing specific to the exchange outputting periodically timing of calculating a connection setting path and topology information able to be directly measured, a path generating section that simultaneously calculates a connection setting path with other exchanges according to the topology information and the path calculation timing, a topology information management section that manages the topology information, and a routing function section that exchanges a routing message including the topology information with other exchange according to topology state periodic notice timing specific to the exchange.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network system comprising, for example, a plurality of communication nodes (switching devices) and links (communication lines). Switching device), a difference information collecting device that collects the state of the network (topology information) autonomously exchanged between communication nodes, and attempts to set up a call based on a route calculated from the collected topology information (routing protocol The present invention relates to a communication network and a communication method capable of reducing the amount of information exchanged by a routing protocol.

[0002]

2. Description of the Related Art A conventional communication network system will be described below. For example, as a conventional technology for realizing a routing protocol that attempts to set up a call based on a route calculated from topology information, for example, "PNNI 1.0 (Private Neighborhood)" in "The ATM Forum"
twork-Network Interface Specification Version1.
0) "and JP-A-10-135980.

FIG. 11 is a diagram showing a configuration of a conventional notification network system, and is an example of a state change notification called “flooding” of a routing protocol called “link state type” in PNNI. FIG.
1, 111, 112, 113, 114, 11
5, 116, 117 are communication nodes, 121 is a failure, and 131 is a communication network. When the failure 121 occurs between the communication nodes 112 and 116 in the communication network 131, for example, the communication node 116 that has detected the failure
7 is notified of the occurrence of the failure 121, and the communication node 117 that has received the notification of the occurrence of the failure notifies the adjacent communication nodes 114 and 115 of the occurrence of the failure 121.

The communication nodes 114 and 115
Notifies the communication node 113 of the occurrence of the failure 121, and then notifies the communication nodes 111 and 112 of the occurrence of the failure 121 in the same manner (this communication method is referred to as flooding). Call). Thus, all the communication nodes in the communication network 131 recognize the occurrence of the failure 121. In addition, flooding is performed in the same procedure from the communication node 112 on the opposite side.

[0005] Such status notification called "flooding" is not limited to the occurrence of a fault, but includes, for example, a change in the status of a communication node and a communication link (a decrease in the available bandwidth in the communication link, a cost value via the communication link). , Etc.). Accordingly, each communication node in the communication network 131 can reflect the content of the state change occurrence notification on the topology information stored therein.

FIG. 12 shows a routing message (topology information) in a conventional communication network system.
FIG. 6 is a diagram showing an example of a sequence of notification timing and calculation timing. The routing message includes topology status periodic notifications 211, 212, 213,
And state change occurrence notifications 221 and 22 of the topology state
There are two types, 2,223,224,225, which are notified by flooding at the timing shown. Further, the regular route calculation interval in the communication node (1) is calculated based on the timing of the route calculation times 231 and 234, while the communication node (2) and the communication node (3) have different timings (route calculation times). Times 232, 233) are calculated.

[0007] Information elements of the routing message in the PNNI include, for example, a node IG (Information Group) indicating a state of a communication node, a horizontal link IG indicating a link state, and an uplink IG. These IGs are called PTSEs and are included in a PTSP including a plurality of PTSEs. For example, when a state change occurs or when a notification is made periodically, as shown in FIG. Perform flooding.

FIG. 13 is a diagram showing a configuration of a conventional communication node. In FIG. 13, reference numeral 311 denotes a routing function unit that collects topology information (corresponding to the IG) received by flooding, 312 denotes a topology information management unit that manages the collected topology information,
Reference numeral 313 denotes a route generation unit that calculates a route based on topology information, and 314 denotes a periodic notification timer that notifies a route calculation timing.

On the other hand, in the system described in Japanese Patent Application Laid-Open No. 10-135980, for example, when line quality deterioration information, line disconnection information, or a crankback (call setup failure) message is received, the information is attached to the topology table. Start a timer to perform a call setup request.
It is determined whether it is within a predetermined time from the reception time of the message. If it is within a certain time, call setting is performed based on the route calculation, and if after a certain time, call setting is performed based on a route in the route candidate table calculated in advance. That is, in this system, a bypass route is selected when a failure occurs based on the time from the occurrence of the failure.

[0010]

SUMMARY OF THE INVENTION However,
In a conventional communication network system (PNNI), when calculating a route based on a detailed link state, a large amount of calculation time is required. When a call setting request is made, an attribute parameter (maximum) required for each call is required. Since the transfer delay (MaxCTD), delay variation (CTDV), average bandwidth (SCR), peak bandwidth (PCR), maximum burst size (MBS), etc. are different, it is necessary to calculate the route periodically before calling. Is common.

In a conventional communication network system (PNNI), when an attribute parameter of a link state changes, a routing message is issued,
It is specified that a state change is notified.

Therefore, when the network is represented by detailed link state parameters, even if the state change is a minute difference, the state change is notified to an adjacent communication node in the network every time the state changes. There was a problem that there was no. Further, in a case where change information is frequently notified, for example, due to cost reduction, a communication node that does not have the ability to perform route calculation based on a detailed link state may transmit the received state change notification. There was a problem that it could not be used for route calculation.

In a conventional communication network system (Japanese Patent Laid-Open Publication No. Hei 10-135980), a timer is started by line deterioration, line disconnection, and reception of a crankback message on a relay link. Therefore, there is a problem that, for example, a change when the line quality is improved is not supported because the route is acquired. In addition, there is a problem that unnecessary topology information that cannot be used for route calculation is notified by flooding during normal times (other than when a failure occurs).

The present invention has been made in view of the above, and it is possible to reduce the amount of traffic of the entire network by reducing the amount of routing messages exchanged by the routing protocol, that is, a route notified by flooding. It is an object of the present invention to provide a communication network system, a switching device, and a difference information collecting device capable of reducing the amount of unnecessary topology information that cannot be used for calculation.

[0015]

Means for Solving the Problems To solve the above-mentioned problems,
In order to achieve the object, a switching device according to the present invention operates in a communication network system in a state where synchronization is established, and further calculates a timing for calculating a connection setting path and a topology that can be directly measured. Timer means (corresponding to a periodic notification timer 11 in an embodiment described later) for generating a device-specific topology state periodic notification timing for periodically outputting information, and connection setting according to the topology information and the route calculation timing. A route calculation unit (corresponding to a route generation unit 12) for calculating a route together with another switching device, a topology information management unit (corresponding to a topology information management unit 13) for managing the topology information, and a topology state unique to the device. A rule containing the topology information according to the periodic notification timing Routing means for the coating message, exchanged with other exchanging device (routing function unit 1
4).

In the switching device according to the next invention, the timer means generates a unique topology state periodic notification timing so that each communication device is shifted from each other at a certain interval unit. I do.

In the switching device according to the next invention, when a topology state changes due to a failure that interferes with the connection setting path, the routing means does not wait for the topology state periodic notification, but instead issues a routing message including the failure information. Is exchanged with another exchange device.

In the exchange device according to the next invention,
When the topology state changes, difference data corresponding to the change in the topology information is generated, and the difference data is
A differential data generating / transmitting unit (corresponding to the topology information differential data generating unit 15 and the topology information differential data pp transmitting unit 16) for transmitting to a differential information collecting device that manages topology information of the entire network; If the connection setup route requested by the client cannot be found for any reason other than a failure that prevents
A difference information request message for requesting the latest difference data is generated, the message is transmitted to the difference information collection device, and then the difference data included in the difference information response message from the difference information collection device is generated. Requesting / collecting difference data to be collected (topology information difference data collection unit 25, topology information difference data pp reception unit 2)
6), wherein the route calculation means recalculates the connection setting route according to the topology information reflecting the difference data.

In the difference information collecting apparatus according to the next invention, a communication network system is formed together with a plurality of switching apparatuses operating in a state where synchronization is established, and a topology state periodic notification of each of the switching apparatuses is provided. Is stored, and the difference information request message for requesting the latest difference data includes the desired difference data. And a topology information / difference data management unit (corresponding to the topology information difference data storage unit 31 and the topology information difference data transmission / reception unit 32) for returning the received difference information response message.

In the difference information collecting apparatus according to the next invention, when the latest topology information is notified by the topology state periodic notification from the switching apparatus, the topology information previously notified by the switching apparatus is further provided. And a difference information erasing unit (corresponding to the difference information erasing processing unit 84) for erasing the difference data from the topology information / difference data managing unit.

In the difference information collecting apparatus according to the next invention, when the difference data is notified by the topology change information notification notified when the topology state changes, the difference data is stored in the topology information. / A difference information registration unit (corresponding to the difference information registration processing unit 83) for registering in the difference data management unit.

In the difference information collecting apparatus according to the next invention, when a difference information request message for requesting the latest difference data is received, desired difference data is sent from the topology information / difference data management means. A difference information notifying unit (corresponding to the difference information notification processing unit 85) for reading and notifying the requesting switching device of a difference information response message including the difference data is provided.

In the communication network system according to the next invention, the communication network system comprises a plurality of switching devices operating in a state where synchronization is established, and a difference information collecting device for managing topology information and difference information of the entire network. Timer means for generating a timing at which each switching device calculates a connection setting path, and a device-specific topology state periodic notification timing that periodically outputs directly measurable topology information, and the topology information and the topology information. Route calculation means for calculating a connection setting route together with another switching device according to the route calculation timing; topology information management means for managing the topology information; and the topology information according to the device-specific topology status periodic notification timing. Routines that contain A routing unit for exchanging a message with another switching device, and a difference for generating difference data corresponding to a change in the topology information when the topology state changes, and transmitting the difference data to the difference information collecting device. A data generation / transmission unit, and a difference information request message for requesting the latest difference data when a connection setting route requested by the client cannot be found for a reason other than a failure that obstructs the connection setting route; To the difference information collection device, and thereafter, a difference data request / collection unit that collects difference data included in a difference information response message from the difference information collection device. , Topology information notified by the topology state periodic notification, and the topology state There difference data to be notified when changes in advance to accumulate, the difference information in response to the request message, the topology information / differential data management means for returning the difference information response message,
It is characterized by having.

[0024] In the communication network system according to the next invention, the difference information collection device may further include a notification device that, when the latest topology information is notified by the topology status periodic notification from the switching device, the switching device previously notifies the difference information. A difference information erasing unit for erasing the topology information and the difference data obtained from the topology information / difference data management unit, and a difference change notification that is notified when the topology state has changed. A difference information registering means for registering the difference data in the topology information / difference data management means, and, upon receiving the difference information request message, reading desired difference data from the topology information / difference data management means; Of the difference information response message containing the And the difference information notification means for notifying the apparatus, characterized in that it comprises a.

In the communication method according to the next invention,
The processing by each switching device generates a timing for calculating a connection setting route, and a device-specific topology state periodic notification timing for periodically outputting directly measurable topology information, and a timing generation step of generating the topology information and the topology information. A route calculation step of calculating a connection setting route together with another switching device according to the route calculation timing, a topology information management step of managing the topology information, and the topology information according to the device-specific topology status periodic notification timing. A routing message for exchanging a routing message containing
A difference data generation / transmission step of generating difference data corresponding to a change in the topology information when the topology state has changed, and transmitting the difference data to the difference information collection device; If a connection setting path requested by the client cannot be found for a reason other than the above, a difference information request message for requesting the latest difference data is generated, and the message is transmitted to the difference information collection device. A difference data request / collection step of collecting difference data included in a difference information response message from the difference information collection device, wherein the processing by the difference information collection device is notified by the topology status periodic notification; And difference data notified when the topology state changes. And advance, in correspondence with the difference information request message, characterized in that it comprises a topology information / differential data management step for returning the difference information response message.

In the communication method according to the next invention,
The processing by the difference information collecting apparatus further includes, when the latest topology information is notified by the topology state periodic notification from the switching apparatus, the topology information and the difference data previously notified by the switching apparatus, the topology information A difference information erasing step of erasing from the difference data management means, and, when the difference data is notified by the topology change information notification notified when the topology state has changed, the difference data is stored in the topology information / difference data management means. Registering the difference information, and when receiving the difference information request message, reads desired difference data from the topology information / difference data management means, and sends a difference information response message including the difference data to the request source. A difference information notification step of notifying the exchange device of Characterized in that it contains.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configuration of an exchange apparatus, a difference information collecting apparatus, and a communication network system according to the present invention. The present invention is not limited by the embodiment.

Embodiment 1 FIG. 1 is a diagram showing a configuration of a communication network system according to the present invention. In FIG. 1, reference numerals 1, 2, 3, 4, 5, 6, and 7 are communication nodes (exchange devices) according to the present invention, 8 is a difference information collection device, and 9 generates a time notification timing signal 10. It is a time synchronization device. The communication nodes 1 to 7 are connected by a communication link and constitute a communication network. Also,
The difference information collecting device 8 and the time synchronizing device 9 are connected to any of the communication nodes or included in any of the communication nodes. Note that the difference information collection device 8 and the time synchronization device 9 may exist in the same communication node.

Further, these communication nodes receive a timing notification from a timer that generates a periodic timing, and receive a topology state (for example, a state of the own node, a state of a link connected to the own node) that can be directly measured by the own node. And the like) are notified to other communication nodes by a routing message, and in particular, the route calculation is executed in a state where synchronization is established between the communication nodes.

FIG. 2 is a diagram showing a configuration of a communication node and a difference information collecting device according to the present invention. Here, as an example of transmission and reception of a change (difference information) of the topology information, for example, a communication node 1 on the difference information notification side, a difference information collection device 8, a communication node 2 on the difference information request side,
Assume a communication network composed of The communication nodes referred to here are communication nodes 1 to 1 in FIG.
7, and each communication node has both the function of the difference information notification side and the function of the difference information request side.

In the communication node 1 of FIG. 2, reference numeral 11 denotes a periodic notification timer for notifying the timing of the route calculation and the timing of the periodic status notification, and 12 denotes a route generation unit for calculating a connection setting route based on the topology information. , 13 are topology information management units for managing topology information (connection relationship between communication nodes and communication links, failure status, usable bandwidth of communication links, line quality, etc.) required for route calculation, and 14 is a communication node. It is a routing function unit for exchanging routing messages including topology information between them. Communication node 2
, 21 is a periodic notification timer, 22 is a route generation unit, 23 is a topology information management unit, and
Is a routing function unit, and each communication node includes these parts as common function parts on the difference information notification side and the difference information request side.

In the communication node 1, reference numeral 15 denotes a topology information difference data generator for generating topology state change difference information, and 16 denotes topology information difference data p for notifying the topology information change difference information to the difference information collecting device 8. -P transmission unit, and the communication node 1 includes these parts as a difference information notification function. On the other hand, in the communication node 2, reference numeral 25 denotes a topology information difference data collection unit that collects topology state change difference information;
Is a topology information difference data pp receiving unit that receives topology state change difference information from the difference information collection device 8, and the communication node 2 has these parts as a difference information request function.

In the difference information collecting device 8 of FIG. 2, reference numeral 31 denotes a topology information difference data storage unit for storing topology state change difference information, and 32 denotes a topology information difference data transmission / reception unit for transmitting / receiving topology state change difference information. It is.

Here, the operation of the communication network system configured as described above will be described with reference to the drawings.
Note that here, a method for establishing the synchronization of the route calculation time and a method for periodically notifying the topology information are described.
This will be described in detail.

First, in order to establish time synchronization between communication nodes, the time synchronization device 9 notifies the communication node 7 of an appropriate time notification timing signal. Then, the communication node 7 that has received the timing signal further transmits the communication nodes 1 to 6 in the communication network system.
, A routing message (hereinafter, referred to as a time synchronization message) including the current time and the regular route calculation interval is notified by flooding (hereinafter, this flooding is referred to as time synchronization flooding). Thus, synchronization of the route calculation time between the communication nodes is established.

In the communication nodes that have received the time synchronization message by flooding, for example, the communication nodes 1 and 2 in FIG. 2, the time synchronization messages are received by the routing function units 14 and 24, respectively. In the routing function units 14 and 24, the periodic route calculation intervals included in the received time synchronization message are set in the periodic notification timers 11 and 21, respectively. A route calculation instruction is issued to the route generation units 12 and 22, respectively.

FIG. 3 is a diagram showing the timing of the route calculation in each communication node. For example, when the current time 1:00 is received and the regular route calculation interval 10 [min] is received by the time synchronous flooding, the route generation unit of each communication node executes the route calculation at the time 1:10. Then, in each communication node, a topology state periodic notification is performed a predetermined time before the route calculation is performed at the same time. That is, a topology state that can be directly measured by the own node (corresponding to, for example, the state of the own node, the state of a link connected to the own node, and the like) is notified to another communication node by a routing message. Thereby, each communication node always keeps the topology information in the latest state.

As described above, since the synchronization of the route calculation is established, and the regular notification of the topology state is specified a predetermined time before the route calculation, the number of times of transmission of the routing message can be reduced. That is, the number of times of unnecessary topology information notification that cannot be used for route calculation can be reduced, so that the traffic volume of the entire communication network can be significantly reduced.

FIG. 4 is a diagram showing the timing of the periodic status notification. For example, by establishing synchronization as described above, each communication node as shown in FIG. 3 executes a route calculation at a regular route calculation interval 47 at the same time (corresponding to the route calculation times 41 and 42), Further, between the route calculation time 41 at which the synchronization is established and the next route calculation time 42, at a predetermined timing before the route calculation, the topology status periodic notification (corresponding to the topology status periodic notifications 43, 44, and 45 shown in the figure). )I do. In this case, the predetermined timing refers to a timing before the route calculation time and such that the communication nodes are shifted from each other by the unit of the status periodic notification flood interval 46 units.

As described above, in order to set the flooding interval so as to be executed before the route calculation time 42 and not to overlap the time of the topology state periodic notification, for example, an appropriate time different for each communication node is calculated. Then, the timing obtained by subtracting the calculated time from the route calculation time 42 is set in the above-described periodic notification timers 11 and 21 as the topology state periodic notification time of the communication node.

As described above, by shifting the timing of the periodic status notification between the communication nodes at regular intervals, transmission of routing messages due to flooding is concentrated and the load on the communication network temporarily increases. Can be prevented.

Next, a description will be given of a process of setting a call by bypassing the route when a failure occurs in a communication link. FIG. 5 is a diagram illustrating a detour route when a failure occurs.
In FIG. 5, reference numeral 51 denotes a normal route from the communication node 3 to the communication node 6, and reference numeral 52 denotes a detour route when a failure occurs.

For example, if a failure occurs between the communication node 2 and the communication node 6 when the normal route 51 is selected, each communication node 2 and the communication node 6 will operate as described in the related art. Notify the adjacent communication node that a failure has occurred. That is, information on the failure is asynchronously notified to the communication nodes in the communication network as a routing message by flooding.

More specifically, for example, the communication node 2
When a failure occurs between the communication node 6 and the communication node 6, the communication node 2 shown in FIG. 5 notifies a routing message as follows. FIG. 6 is a diagram in which a configuration related to an operation at the time of occurrence of a failure is extracted from the configuration of the communication node illustrated in FIG. In FIG. 6, the same components as those described above are denoted by the same reference numerals and description thereof will be omitted.

The routing function unit 24 of the communication node 2 transmits the routing message 53 including the failure information without waiting for the topology state periodic notification so that the communication node 1 recognizes the occurrence of the failure. The routing function unit 14 receives the routing message 53.

When the routing function unit 14 of the communication node 1 that has received the routing message 53 recognizes the occurrence of the failure, the routing function unit 14 notifies the upper-level topology information management unit 13 of the occurrence of the failure, and receives the notification. At 13, the failure function is immediately instructed to the routing function unit 13.

In the present embodiment, the process of confirming the failure state may be performed at all times by exchanging a survival confirmation message between the routing function units. That is, the routing function units 14 and 24
By transmitting and receiving the survival confirmation messages 53 and 54 to each other at regular intervals, the occurrence / non-occurrence of a failure can be confirmed.
In the present embodiment, the present invention is not limited to the above. For example, in the case where a survival confirmation message cannot be received from an adjacent communication node for some reason, the occurrence of a failure may be recognized at a timeout occurrence timing after a predetermined time. Is also good.

When the failure information reaches the communication node 3 shown in FIG. 5 by the flooding, the communication node 3 switches the route from the normal route 51 passing through the failure location to the bypass route 52 not passing through the failure location. . At this time, the switching of the route may be performed by calculating the route again, or by calculating the second route in advance and switching to the route.

As described above, according to the present embodiment, when a failure occurs in a communication link, all communication nodes in the communication network are asynchronously flooded with the failure information without waiting for the periodic notification of the topology state. , It is possible to prevent call setting via a faulty part from being performed. In other words, by selecting a route that bypasses the failure location, the difference information collection device 8 can be reliably established.
Can be notified of the topology information.

Next, a description will be given of a case where the topology information managed by each communication node changes between the route calculation time 41 at which the synchronization is established and the next route calculation time. FIG. 7 is a diagram showing a notification / accumulation process of changed topology information and a request / notification process of difference information. Here, for convenience of explanation, a case where the topology information managed by the communication node 1 changes and a case where a difference of the topology information is requested by the communication node 3 will be described as an example. Note that the detailed configuration of the communication network will be described using the configuration shown in FIG. 2 and replacing the illustrated communication node 2 with the communication node 3.

For example, from the route calculation time 41 (1:00) at which the synchronization is established, the next route calculation time 42
Until (1:10), specifically, time 1: 0
When the topology information managed by the communication node 1 changes to 2, the communication node 1 sets the topology change information 55
Is notified to the difference information collection device 8, and the difference information collection device 8 that has received the notification stores the contents of the change (see FIG. 7).

On the other hand, for example, at time 1:07, when a call setting request is generated in the communication node 3 and the route calculation is performed based on the detailed topology state, the communication node 3 sends the difference information request message 56 It issues an inquiry to the information collection device 8 to determine whether there is difference information.
Then, when there is difference information, the difference information collection device 8 issues a difference information response message 57 to the communication node 3 and notifies the communication node 3 of the difference information (see FIG. 7).

Here, the topology change information 55,
The transmission process of the difference information request message 56 and the difference information response message 57 will be described in detail with reference to FIGS. FIG. 7 shows the topology change information 55,
FIG. 9 is a diagram illustrating timings at which a difference request message 56 and a difference information response message 57 are generated.

First, at time 1:02, when the topology information managed by the topology information management unit 13 inside the communication node 1 changes, the topology information management unit 13 sends a topology change to the topology information difference data generation unit 15. Request creation of information.

The topology information difference data generator 15 generates a change in the topology information as topology change information (difference information) 55 and notifies the topology information difference data pp transmitter 16 of the change. Then, in the topology information difference data pp transmission unit 16,
The received topology change information 55 is transferred to the difference information collection device 8.

After that, in the difference information collecting device 8, the topology change information 55 is received by the topology information difference data transmitting / receiving section 32 and is stored in the topology information difference data storage section 31.

On the other hand, if the route requested by the client (not shown) does not satisfy the available bandwidth, or if there is no route satisfying the requested end-to-end transfer delay, the client request may be caused by a reason other than the route failure. If the route to be found cannot be found, the route generation unit 22 requests the topology information management unit 23 to update the topology information.

The topology information management unit 23 requests the topology information difference data collection unit 25 to collect the topology information difference data. Here, the topology information difference data collection unit 25 requests the topology information difference data p-p.
A difference information request message 56 is notified to the difference information collection device 8 via the p receiving unit 26 to request transmission of difference information.

For example, when the difference information request message 56 is notified at the time 1:07, the difference information collecting device 8 receives the difference information request message 56 by the topology information difference data transmitting / receiving unit 32 and stores the topology information difference data storage unit. 31 is notified that there is a request for difference information. At this time, the topology information difference data accumulating unit 31 stores the stored difference information as a difference information response message 57 via the topology information difference data transmitting / receiving unit 32 and the topology information difference data pp.
Notify the receiving unit 26.

Topology information difference data pp receiving section 2
In step 6, the received difference information response message 57 is notified to the topology information difference data collection unit 25, and the topology information difference data collection unit 25 merges the received difference information with the topology information management unit 23.

After the merge of the difference information, the topology information management unit 23 notifies the route generation unit 22 of the completion of the merge, and finally, the route generation unit 22 executes the route calculation again.

As described above, in the present embodiment, the communication node whose topology information managed by itself has changed notifies the difference information collecting device 8 of the topology change information 55 as needed, and collects the difference information. The device 8 stores it. Then, the communication node desiring to recalculate the route based on the latest topology information notifies the difference information collecting device 8 of the difference request message 56, and the response of the difference information response message 57 from the difference information collecting device 8 is sent. Wait and then perform route calculation. This makes it possible to execute a recalculation of the route based on the latest topology information as needed.

Embodiment 2 FIG. 9 is a diagram illustrating a configuration of the difference information collecting apparatus according to the second embodiment of the present invention.
In FIG. 9, reference numeral 8a denotes a difference information collecting apparatus of the present embodiment, 81 denotes a message receiving unit, 82 denotes a message analyzing unit, 83 denotes a difference information registration processing unit,
84 is a difference information erasure processing unit, 85 is a difference information notification processing unit, 86 is a topology difference information management unit, 87 is a difference information counter, 88 is a notified difference information management unit, 89 Is a message transmission unit, and 9
1 is a reception link, and 92 is a transmission link.

FIG. 10 is a diagram showing a detailed configuration of the topology difference information management unit 86, the difference information counter 87, and the notified difference information management unit 88. In the topology difference information management unit 86, reference numeral 93 denotes a topology information difference table.
Reference numeral 4 denotes a counter table, and a notified difference information management unit 8
In FIG. 8, reference numeral 95 denotes a notified difference information table.

Note that the overall configuration of the communication network system in the present embodiment uses FIG. 1 in the first embodiment, and in this case, the above-described difference information collecting device 8 is replaced with a difference information collecting device 8a. It shall be.

The processing of the difference information collecting device 8a is described below with reference to FIG.
This will be described with reference to FIG. First, the reception link 91
Are received by the message receiving unit 81, and then notified to the message analyzing unit 82. Then, in accordance with the content type of the received message, the message analysis unit 82 notifies the content to one of the difference information registration processing unit 83, the difference information deletion processing unit 84, and the difference information notification processing unit 85.

For example, when the type of the received message is the above-described topology change information notification 55, the message is notified to the difference information registration processing unit 83. Then, the difference information registration processing unit 83 additionally registers the received difference information in the topology information difference table 93 inside the topology difference information management unit 86. In this case, the difference information registration processing unit 83 registers the information number and the difference information content as a pair in the topology information difference table 93.
The counter table 94 counts the number of pieces of information currently registered as differences.

When the type of the received message is the above-mentioned regular topology status notification 43, 44, 45, the message is notified to the difference information deletion processing unit 84. Then, the difference information deletion processing unit 84 deletes all the topology information and the difference data from the corresponding communication node, which are currently stored in the topology information difference table 93 inside the topology difference information management unit 86.

Further, when the type of the received message is the above-described difference information request message 56, the message is notified to the difference information notification processing unit 85. And
The difference information notification processing unit 85 acquires the difference information stored in the topology information difference table 93 inside the topology difference information management unit 86 by a predetermined method, and sends the acquired difference information to the requesting communication node via the message transmission unit 89. Then, the difference information is notified. In this case, the topology difference information management unit 86 obtains a notified information number corresponding to the requesting communication node from the notified difference information table 95 from the counter table 94 based on the node identifier unique to the communication node included in the message. The current information numbers are obtained, and the difference between the notified information number and the current information number is generated as the difference information for the not-yet-notified information. Notify.

More specifically, for example, when the identifier of the communication node that has requested the difference information is A, the notified information number corresponding to A up to the previous time is 2, and at this time, the current information number counter Is 5, the topology difference information management unit 86 notifies difference information corresponding to the information numbers 3, 4, and 5.

As described above, in the present embodiment, the function of deleting the difference information managed by the topology difference information management unit 86 in accordance with the instruction of the difference information erasure processing unit 84 is provided, so that after the network operation is started, Since there is no need to store all state changes, the storage capacity can be significantly reduced. Furthermore, even if for some reason a difference occurs between the state in which the difference information is added by the topology state periodic notification and the actual topology state (including a case where part of the difference information is lost), Incorrect information can be cleared every time the topology status is notified,
The state mismatch can be resolved.

Also, in the present embodiment, the topology difference information management unit 86
By having the function to register the difference information, the communication node that sent the difference information does not need to transmit the topology information that has been notified up to the previous time. Becomes possible. As a result, the amount of information can be significantly reduced, so that the traffic amount of the entire network can be significantly reduced.

Also, in the present embodiment, the topology difference information management unit 86
Has the function of notifying the difference information request source communication node of the difference information acquired from the communication node, so that the difference information request source communication node can omit the process of detecting the overlapping part in the plurality of pieces of information received up to the previous time. Becomes possible. As a result, the amount of information can be significantly reduced, so that the traffic amount of the entire network can be significantly reduced.

[0074]

As described above, according to the present invention, according to the present invention, the synchronization of the route calculation is established, and the periodic status notification of the topology is defined a predetermined time before the route calculation, so that the number of times of transmission of the routing message can be reduced. Since it is possible to reduce the number of times that unnecessary topology information that cannot be used for route calculation can be reduced, the traffic amount of the entire communication network can be significantly reduced. There is an effect that an exchange device can be obtained.

According to the next invention, the transmission of the routing message by flooding is concentrated by shifting the timing of the periodic notification of the topology state between the respective switching devices at regular intervals, and the load on the communication network temporarily increases. It is possible to obtain an exchange device capable of preventing such a situation.

According to the next invention, when a failure occurs in the communication link, the failure information is notified to all the switching devices in the communication network by flooding without waiting for the periodic notification of the topology status. There is an effect that it is possible to obtain a switching device capable of selecting a route bypassing a location and reliably notifying the difference information collecting device of the topology information.

According to the next invention, the switching device in which the topology information has changed notifies the difference information collecting device of the topology change information as needed, and the difference information collecting device stores it. Then, the switching device that wants to recalculate the route based on the latest topology information notifies the difference information collecting device of a difference request message, and waits for a response of the difference information response message from the difference information collecting device. As a result, there is an effect that a switching device capable of executing a recalculation of a route based on the latest topology information as needed can be obtained.

According to the next invention, the difference information collecting device stores the topology change information from the switching device whose topology information has changed as needed. Then, the difference information collection device receives the difference request message from the switching device that desires the recalculation of the route, and returns a difference information response message. As a result, it is possible to obtain a difference information collecting device capable of causing the switching device to recalculate a route based on the latest topology information.

According to the next invention, by having the function of deleting the difference data according to the instruction of the difference information erasing means, it is not necessary to store all state changes after the start of network operation, so that the storage capacity is greatly increased. This provides an effect that a difference information collecting device that can be reduced to a minimum can be obtained. Also, even if for some reason a difference occurs between the state where the difference data is added by the topology state periodic notification and the actual topology state,
Since the erroneous information can be cleared every time the topology status is periodically notified, an effect is obtained that a difference information collection device that can eliminate the status mismatch can be obtained.

According to the next invention, by having the function of registering the difference data in accordance with the instruction of the difference information registering means, it is necessary for the exchange apparatus which is the notification source of the difference information to transmit the topology information which has been notified up to the previous time. Then, only the difference data newly accumulated is notified. This allows
Since the amount of information can be significantly reduced, it is possible to obtain a differential information collecting device capable of significantly reducing the traffic amount of the entire network.

According to the next invention, the difference information obtained from the topology information / difference data management means by the instruction of the difference information notifying means is provided to the switching apparatus which has requested the difference information, thereby providing a function of notifying the difference data. It becomes possible for the switching device of the information request source to omit the process of detecting a duplicate portion in the plurality of pieces of information received up to the previous time. As a result, since the amount of information can be significantly reduced, it is possible to obtain a difference information collecting device capable of greatly reducing the traffic amount of the entire network.

According to the next invention, the amount of traffic of the entire network can be reduced by reducing the amount of routing messages exchanged by the routing protocol. That is, there is an effect that it is possible to obtain a communication network system capable of greatly reducing the amount of unnecessary topology information that cannot be used for route calculation notified by flooding.

According to the next invention, since it is not necessary to store all state changes after the start of network operation, it is possible to obtain a communication network system capable of greatly reducing storage capacity. To play. Also, for some reason, even if a difference occurs between the state in which the difference data is added by the periodic topology status notification and the actual topology status, incorrect information can be cleared for each topology status periodic notification. Thus, it is possible to obtain a communication network system capable of eliminating a state mismatch. Furthermore, since the amount of information can be significantly reduced, there is an effect that a communication network system that can significantly reduce the traffic amount of the entire network can be obtained.

According to the next invention, by reducing the amount of routing messages exchanged by the routing protocol, the traffic amount of the entire network can be reduced. That is, there is an effect that it is possible to obtain a communication method capable of greatly reducing the amount of unnecessary topology information that cannot be used for the route calculation notified by flooding.

According to the next invention, it is not necessary to store all state changes after the start of network operation, so that a communication method capable of greatly reducing the storage capacity can be obtained. Play. Also, for some reason, even if a difference occurs between the state in which the difference data is added by the periodic topology status notification and the actual topology status, incorrect information can be cleared for each topology status periodic notification. Thus, it is possible to obtain a communication method capable of eliminating the state mismatch. Further, since the amount of information can be significantly reduced, it is possible to obtain a communication method capable of significantly reducing the traffic amount of the entire network.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a communication network system according to the present invention.

FIG. 2 is a diagram showing a configuration of a communication node and a difference information collecting device according to the present invention.

FIG. 3 is a diagram illustrating timing of route calculation in each communication node.

FIG. 4 is a diagram showing the timing of a periodic status notification.

FIG. 5 is a diagram illustrating a detour route when a failure occurs.

FIG. 6 is a diagram in which a configuration related to an operation at the time of occurrence of a failure is extracted from the configuration of the communication node illustrated in FIG. 2;

FIG. 7 is a diagram illustrating notification / accumulation processing of changed topology information and request / notification processing of difference information.

FIG. 8 shows topology change information, a difference request message,
FIG. 9 is a diagram illustrating the timing of occurrence of a difference information response message.

FIG. 9 is a diagram showing a configuration of a difference information collecting apparatus according to a second embodiment of the present invention.

FIG. 10 is a diagram illustrating a detailed configuration of a topology difference information management unit, a difference information counter, and a notified difference information management unit.

FIG. 11 is a diagram showing a configuration of a conventional notification network system.

FIG. 12 is a diagram showing an example of a notification timing and a calculation timing of a routing message in a conventional communication network system.

FIG. 13 is a diagram showing a configuration of a conventional communication node.

[Explanation of symbols]

1,2,3,4,5,6,7 communication node, 8,8a
Difference information collection device, 9 time synchronization device, 10 time notification timing signal, 11, 21 periodic notification timer, 12, 2
2 route generation unit, 13, 23 topology information management unit,
14, 24 routing function unit, 15 topology information difference data generation unit, 16 topology information difference data p
-P transmission unit, 25 topology information difference data collection unit,
26 topology information difference data pp receiving unit, 31 topology information difference data storage unit, 32 topology information difference data transmitting / receiving unit, 81 message receiving unit, 82
Message analysis unit, 83 Difference information registration processing unit, 84
Difference information deletion processing unit, 85 Difference information notification processing unit, 86
Topology difference information management unit, 87 difference information counter, 88 notified difference information management unit, 89 message transmission unit, 91 reception link, 92 transmission link, 93 topology information difference table, 94 counter table,
95 Notification difference information table.

Claims (12)

[Claims] In a communication network system, in a plurality of switching devices that operate in a state where synchronization is established, a timing for calculating a connection setting route and a device specific output device for periodically outputting directly measurable topology information are provided. Timer means for generating a topology status periodic notification timing; path calculation means for calculating a connection setting path together with another switching device according to the topology information and the path calculation timing; topology information management for managing the topology information And a routing unit for exchanging a routing message containing the topology information with another switching device in accordance with the topology status periodic notification timing unique to the device. 2. The timer unit according to claim 1, wherein the timer means generates a unique topology state periodic notification timing so that each communication device is shifted from each other by a predetermined interval unit. Exchange equipment. 3. When a topology state changes due to a failure that interferes with the connection setting path, the routing means transmits a routing message including the failure information to another switching device without waiting for the topology state periodic notification. The exchange device according to claim 1, wherein the exchange device is exchanged. 4. A difference for generating difference data corresponding to a change in topology information when the topology state changes, and transmitting the difference data to a difference information collection device that manages topology information of the entire network. A data generation / transmission unit, and a difference information request message for requesting the latest difference data when a connection setting route requested by the client cannot be found for a reason other than a failure that obstructs the connection setting route; To the difference information collection device, and thereafter, a difference data request / collection unit that collects difference data included in a difference information response message from the difference information collection device. Recalculate the connection setting route according to the topology information reflecting the difference data The switching device according to claim 1, 2 or 3, wherein: 5. A difference information collection device constituting a communication network system, together with a plurality of switching devices operating in a state where synchronization is established, a topology information notified by a topology status periodic notification of each switching device, and a topology. The difference data notified when the status changes is accumulated, and a difference information response message including desired difference data is returned to the difference information request message for requesting the latest difference data. A difference information collecting device, comprising: topology information / difference data management means. 6. When the latest topology information is notified by the topology status periodic notification from the switching device, the topology information and the difference data previously notified by the switching device are combined with the topology information / difference data management. The difference information collection device according to claim 5, further comprising: a difference information deletion unit that deletes the difference information from the unit. 7. Difference information registration means for registering the difference data in the topology information / difference data management means when the difference data is notified by the topology change information notification notified when the topology state changes. The difference information collection device according to claim 5, comprising: 8. When a difference information request message for requesting the latest difference data is received, desired difference data is read from the topology information / difference data management means, and a difference information response including the difference data is received. 8. The difference information collecting device according to claim 5, further comprising: a difference information notifying unit that notifies a message to a requesting switching device. 9. A communication network system comprising: a plurality of switching devices operating in a state in which synchronization is established; and a difference information collecting device for managing topology information and difference information of the entire network. A timer means for generating a timing for calculating a connection setting path, and a periodic state notification timing for a device-specific topology that periodically outputs directly measurable topology information, and according to the topology information and the path calculation timing, A route calculating means for calculating a connection setting path together with another switching device; a topology information managing means for managing the topology information; and a routing message including the topology information according to the topology status periodic notification timing unique to the device. , Routing means for exchanging with the switching device of the above, and, when the topology state changes, generating difference data corresponding to a change in the topology information and transmitting the difference data to the difference information collecting device Means for generating a difference information request message for requesting the latest difference data when a connection setting path requested by a client cannot be found for a reason other than a failure that obstructs the connection setting path, and A difference data requesting / collecting unit for transmitting to the collection device, and thereafter collecting difference data included in a difference information response message from the difference information collection device, wherein the difference information collection device has the topology state Topology information notified by periodic notification, and when the topology status changes A difference information notified in such a case, and topology information / difference data management means for returning the difference information response message in response to the difference information request message. . 10. The difference information collection device, further, when the latest topology information is notified by the topology state periodic notification from the switching device, the topology information and the difference data previously notified by the switching device, A difference information erasing means for erasing from the topology information / difference data management means, and, when the difference data is notified by the topology change information notification notified when the topology state has changed, the difference data is deleted from the topology information / difference information. A difference information registering means for registering in the data management means; and a difference information response message including, when the difference information request message is received, a desired difference data read from the topology information / difference data management means and including the difference data. And a difference information notifying means for notifying the requesting switching device of Communication network system according to claim 9, characterized in Rukoto. 11. A communication method between a plurality of switching devices operating in a state in which synchronization is established and a difference information collecting device for managing topology information and difference information of the entire network, wherein the processing by each switching device includes connection setting. A timing generation step of generating a timing for calculating a route, and a periodic status notification timing of a device-specific topology that periodically outputs directly measurable topology information, and a connection setting route according to the topology information and the route calculation timing. A route calculation step of calculating together with other switching devices, a topology information management step of managing the topology information, and a routing message including the topology information according to the device-specific topology state periodic notification timing. Routing step for exchanging with a switching device of the same type, and generating / transmitting difference data for generating difference data corresponding to a change in topology information when the topology state changes, and transmitting the difference data to the difference information collecting device. Generating a difference information request message for requesting the latest difference data when a connection setting route requested by the client cannot be found for a reason other than a failure that obstructs the connection setting route; A difference data request / collection step of transmitting to the collection device, and then collecting difference data included in a difference information response message from the difference information collection device, wherein the processing by the difference information collection device includes: Topology information notified by periodic topology status notification; Topology information / difference data management step of storing difference data notified when the status has changed, and returning the difference information response message in response to the difference information request message. Communication method. 12. The processing by the difference information collecting device,
Further, when the latest topology information is notified by the periodic status notification from the switching device, the topology information and the difference data previously notified by the switching device are deleted from the topology information / difference data management means. An information erasing step; a difference information registering step of registering the difference data in the topology information / difference data management means when the difference data is notified by the topology change information notification notified when the topology state changes; Upon receiving the difference information request message, the difference information for reading the desired difference data from the topology information / difference data management means and notifying the requesting switching device of a difference information response message including the difference data. 12. An information notification step, comprising: Communication method described in.