JP2003060678A - Route control system, route control method and program for executing it in computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem wherein alteration of route of an IP network in conventional multicast communication is controlled by a routing protocol where the route can be switched by communicating information between routers upon occurrence of a trouble in the route but the route cannot be altered under specific conditions. SOLUTION: A monitoring means 6 monitors occurrence of a predetermined event for switching the information delivery route to a destination on a network and collects information for deciding the switching of route. Based on the information for deciding the switching of route and predetermined conditions for deciding occurrence of a specific event, a decision means 5 decides alteration of a first route to a second route and a source tunnel router 17 transmits a packet to the second route based on a route decided by the decision means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for delivering information from a transmission source to a plurality of transmission destinations by multicast communication, and when a specific event occurs on a route to the specific transmission destination, the information is transmitted to the specific transmission destination. The present invention relates to a route control system for switching the routes of, and delivering information by unicast communication, a route control method, and a program for causing a computer to execute the route control method.

[0002]

2. Description of the Related Art A conventional IP network route change is
It is controlled by a routing protocol. In the control by the routing protocol, the route can be switched by exchanging information between the routers when the route fails, but the route cannot be changed when a specific event occurs.

Further, in Japanese Patent Laid-Open No. 2000-261488, the satellite line is set to be bidirectional transmission, and when the transmission sensitivity of the transmission system via the satellite line deteriorates, the satellite line is automatically connected to the ground line. A switching satellite router device is disclosed. The technique disclosed in Japanese Patent Laid-Open No. 2000-261488 is UDLR (Uni-Direction).
al Link Routing) is implemented. By operating the routing protocol as if it were bidirectional communication between the satellite line and the terrestrial line, when the satellite line fails, the line is switched to the terrestrial line for transmission.

[0004]

In the conventional multicast communication, the route cannot be switched when a specific event other than the route failure occurs.

Further, in the conventional satellite router device, when a failure occurs in the satellite line, the line is switched to the ground line without considering the ground band and the information is distributed by unicast communication. It sometimes overwhelms the normal communication used.

The present invention has been made to solve the above-mentioned problems, and in a system for delivering information from a transmission source to a plurality of transmission destinations by multicast communication,
An object of the present invention is to obtain a route control system that switches routes when a specific event occurs, a route control method, and a program that causes a computer to execute the route control method.

Further, when a route to a specific destination is switched and information is distributed by unicast communication, a route control system, a route control method and a route control method capable of suppressing pressure on ordinary communication on the switched route are provided to a computer. The purpose is to get a program to run.

[0008]

In the route control system according to the present invention, whether an event predetermined to switch the route of information distribution to the destination occurs in a monitoring target existing on a predetermined network. By monitoring whether or not the route switching determination information, monitoring means for collecting the route switching determination information, based on the route switching determination information and a predetermined determination condition for determining the occurrence of the specific event, the route It is provided with a judging means for judging whether or not the first path is changed to the second path, and a transmission source tunnel router for distributing information to the second path based on the path judged by the judging means. .

Further, the first route is a multicast communication route, the second route is a unicast communication route, and the transmission source tunnel router uses the second route based on the route determined by the determining means. When a packet is transmitted to the above route, the packet to be transmitted is selected and the number of valid unicast routes is limited.

Further, based on the judgment result of the judging means,
A LAN that intercepts packets from the first route when it is determined to change the route, and relays packets from the first route when it is determined that the route is not changed.
It is equipped with a switch.

The control means outputs the determination result of the determination means as control information, and the control means uses the route switching determination information collected by a network management protocol to transmit the source tunnel router or the LAN. It is characterized in that control information based on a network management protocol is passed to the switch.

Further, the judging means has a predetermined judgment threshold value in the judgment conditions, and when the judgment threshold value is exceeded, the path is changed from the first path to the second path.
It is characterized by making a determination to change to the route.

A route control method according to the present invention comprises a steady route router for controlling communication on a multicast communication route, a tunnel router for controlling unicast communication, and a route control means for controlling the steady route router and the tunnel router. A route control method for a communication system comprising: whether a predetermined event that the route control means switches a route of information distribution to a destination has occurred in a monitoring target existing on a predetermined network. By monitoring whether or not the route switching determination information is collected, the route control means based on the route switching determination information and a predetermined determination condition for determining the occurrence of the specific event. A route selection step of selecting a multicast communication route or a unicast communication route as the route, Based on the selection result of the route selection step, when the first route is selected in the route selection step, the route control means blocks the packet from the tunnel router, and the packet from the steady route router. When the second route is selected in the route selection step, the tunnel router regards a packet that matches a predetermined packet type or a band upper limit range as a predetermined valid packet. Relaying within the range of the number of unicast routes to be performed, and the route control means blocking the packet from the steady route router.

A program executed by a computer for the route control method according to the present invention is a steady route router for controlling communication of a multicast communication route, a tunnel router for controlling unicast communication, the steady route router and the tunnel router. Is a program for executing a route control method of a communication system including a route control unit for controlling the route, wherein the route control unit determines a predetermined event that the route of information distribution to the destination is switched, A step of collecting the route switching determination information by monitoring whether or not it has occurred in a monitoring target existing on the network, the route control means confirms the generation of the route switching determination information and the specific event. Multicast communication is set as the route based on a predetermined judgment condition for judgment. A route selection step of selecting a route or a unicast communication route, and based on the selection result of the route selection step, when the first route is selected in the route selection step, the route control means is operated by the tunnel router. Packet is blocked, the packet from the steady route router is relayed, and when the second route is selected in the route selecting step, the tunnel router determines a predetermined packet type or bandwidth upper limit. To relay packets within the range of the number of valid unicast routes determined in advance, and to execute the step of blocking the packets from the steady route router by the route control means. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram for realizing route control in the first embodiment of the present invention. In a system that distributes information from a transmission source to multiple destinations by multicast communication, when a specific event occurs on the route to a specific destination, the route to the specific destination is switched and information is transmitted by unicast communication. About how to deliver
This will be described with reference to FIG. Note that the determination condition is predetermined by the system administrator depending on the line speed, line cost, reliability, communication volume, and the like.

Further, in the present embodiment, a tunneling method is used when information is distributed by unicast communication by switching a route to a specific destination. That is, the number of unicast routes described later means the number of tunnels.

First, the configuration will be described. In FIG. 1, 1 is a route control computer, 2 is a transmission source, and 3 is a transmission destination. Multiple destination networks 1 from source 2
Multicast communication is used when a packet, which is a package of information, is delivered to the destination 3 in the network 3.

Reference numeral 4 is a control means for controlling the path switching, and 5 is a judgment means for judging the path switching, and stores information about a judgment interval and a judgment threshold value which are predetermined by the system administrator. . Reference numeral 6 is a monitoring unit that collects route switching determination information for route switching. The route control computer 1 is an SNMP (Simple Network Management
Protocol) Manager and ICMP (Internet Control M
It is a computer that has a function of essage protocol) and controls path switching, and includes a control unit 4, a determination unit 5, and a monitoring unit 6. The route control means is the route control computer 1. The control procedure in the route control computer 1 will be described later with reference to FIG.

Next, 7 is a first route used as a steady route when a packet is distributed from the source 2 to the destination 3, 8 is a steady route side router for relaying the packet on the first route 7, and 9 is A network group connected to the first route 7. Further, 10 is a second route used when switching from the first route 7, and 11 is a second route 10.
It is a source tunnel router that relays packets in. The transmission source tunnel router 11 determines the type of the packet to be transmitted and the upper limit of the band based on the condition of the second route 10, stores the same, and relays the packet within the range of the number of unicast routes that are valid at the same time. At this time, the band indicates the data transfer rate bit / second (bps) per unit time, and by selecting the upper limit of the band that can be tolerated by the second route 10, the packets to be relayed are selected and the conditions are met. The source tunnel router 11 discards the packet that does not exist. 1
A network group 2 is connected to the second route 10.

Reference numeral 13 denotes a destination network including the destination 3, and 14 denotes the destination 3 when the first route 7 is used.
A stationary destination router that sends packets to the device, 15 is a device to be monitored, which is a predetermined network device or computer for status monitoring, and 16 is a LAN switch having a function to remotely turn on / off the interface via the network. is there. Further, 17 is a destination tunnel router that transmits the packet relayed by the second route 10 to the destination 3. Reference numeral 18 is a third route formed between the route control computer 1 and the destination network 13. The third path 18 is used when turning on / off the LAN switch 16 and when monitoring the state of the monitored device 15.

In this embodiment, information is distributed from a transmission source to a plurality of transmission destinations by multicast communication, so that one transmission source 2 includes a plurality of transmission destination networks 13 including a transmission destination 3. Exists, and packets are simultaneously delivered to a plurality of destination networks 13. That is, there are a plurality of destination networks 13 shown in FIG.

The first route 7 is a physically constructed route. The second route 10 is a logical route configured as a point-to-point (one-to-one) unicast route between the source tunnel router 11 and the destination network 13. Furthermore, the third path 18 is
It is a physically constructed route. At this time, the second path 10 can be logically constructed on the third path 18.

FIG. 2 is a block diagram showing an example of the interface of the source tunnel router 11. Reference numeral 21 is an interface serving as an entrance of the transmitted packet. 22 is a LAN relay interface, LAN
It is assumed to have four interfaces 1 to LAN4.
Reference numeral 23 denotes a WAN relay interface, which is a WA
It has an N1 interface. Reference numeral 24 denotes a unicast route relay interface, which is TUN1 to TU.
It is assumed that the second route 10 having an N3 interface and configured as a unicast route is connected.

Further, in this example, since the unicast route relay interfaces 24 are TUN1 to TUN3, the number of unicast routes that are valid at the same time is three. That is, the number of unicast routes that are valid at the same time is the same as the number of unicast route relay interfaces 24.

The interface 21 serving as an entrance can receive a unicast packet and a multicast packet. When a unicast packet is transmitted from a transmission source (not shown) other than the transmission source 2, the LAN1 to LAN4 of the LAN relay interface 22 or the interface of WAN1 of the WAN relay interface 23 according to the address specified in the packet. Relay the packet from.

When a multicast packet is transmitted from the transmission source 2, the unicast route relay interface 24 relays it to the second route 10 from the interfaces TUN1 to TUN3. At this time, the interfaces of TUN1 to TUN3 of the unicast route relay interface 24 are turned on / off according to the control information output by the control means 4.

Table 1 is a table 41 showing an example of a combination of a packet type 42 and a band 43 used by the packet. The transmission source 2 sets a band 43 to be used for each packet type 42, and controls so that the upper limit of the band 43 used by the packet transmitted from the transmission source 2 is not exceeded.

[0029]

[Table 1]

Further, the source tunnel router 11 uses the second
Based on the conditions of the route 10 of
The upper limit of the band is defined and stored. Table 2 is a storage table 51 stored in the source tunnel router 11 and showing an example of a combination of the type 52 of a packet to be transmitted and the band 53.

[0031]

[Table 2]

For example, it is assumed that the second route 10 is a route having a transmission rate of 10 Mbps, and 1 Mbps is a band which can be used when the route is switched from the first route 7. The source tunnel router 11 defines a packet type 52 and a band 53 to be used so that the packet can be transmitted with an upper limit of 1 Mbps, and stores it in the storage table 51. At this time, as shown in FIG. 2, since the unicast route relay interface 24 is TUN1 to TUN3, even if all the interfaces of TUN1 to TUN3 are in the ON state and all the packets are transmitted at the same time, it is 1 Mbps. Define so that the upper limit is not exceeded. That is, in the storage table 51, the packet type 52
3 types of text 1, text 2 and still image are defined in, but when 3 types are transmitted to the interfaces of TUN1 to TUN3 at the same time, the bandwidth to be used is calculated as 0.9 Mbps as follows, and the upper limit is set. Specified not to exceed 1 Mbps. 0.1 Mbps × 3 + 0.1 Mbps × 3 + 0.1 Mbps × 3 =
0.9 Mbps In this way, the transmission source tunnel router 11 turns on / off the unicast route relay interface 24 according to the control information output from the control means 4, and when the unicast route relay interface 24 is turned on, the storage table A packet that can be transmitted within the upper limit 53 of the type 52 and the bandwidth stored as 51 is stored in the second route 1
Send to 0. That is, the transmission source tunnel router 11 has a function of validating the relay to the specific transmission destination 3 and switching the multicast communication to the unicast communication within the range of the number of unicast routes that are simultaneously effective.

Regarding the operation, first, a method of delivering a packet by normal multicast communication will be described.
In FIG. 1, since the packet distributed from the transmission source 2 is a multicast packet, the regular route side router 8
And broadcast to the source tunnel router 11. Normally, when the first route 7 is a steady route, the unicast route relay interface 24 of the transmission source tunnel router 11 is kept in the OFF state, so that the packet is not delivered from the transmission source tunnel router 11 and It is delivered from the route side router 8 to the destination network 13.

The packet delivered to the destination network 13 reaches the destination network 13 by relaying the network group 9 from the steady route router 8 shown in FIG. 1, and reaches the destination network 13 from the steady destination router 14 to the LAN switch 16. It is delivered to the destination 3 via. Normally, the interface on the steady transmission destination router 14 side of the LAN switch 16 is in the ON state, and therefore the route is as described above.

Next, a specific event occurs on the route to the specific destination 3, the route to the specific destination 3 is switched based on a predetermined determination condition, and the packet is distributed by unicast communication. A method for doing so will be described with reference to FIG. The packet distributed from the transmission source 2 includes the transmission source tunnel router 11, the second route 10 and the network group 12.
Via the LAN switch 16 from the destination tunnel router 17
It is delivered to the destination 3. At the same time, a packet transmitted to the steady route router 8 may also reach the destination network 13 through the network group 9 and be delivered from the steady destination router 14 to the LAN switch 16. Since the interface on the side of the 16 regular transmission destination routers 14 is in the OFF state, the packet is not delivered before that. That is, at this time, the packet is distributed from the transmission source 2 to the specific transmission destination 3 using the second route 10.

When the second route 10 is a terrestrial line and the communication is steadily relayed, if the packet relayed by the first route 7 is switched to the second route 10 as it is,
The normal communication of the second route 10 may be overwhelmed. FIG. 3 is a configuration diagram showing the system configuration diagram shown in FIG. 1 focusing on the transmission source 2 and a plurality of transmission destination networks 13. A method of switching the route without compressing the normal communication of the second route 10 will be described with reference to FIGS. 2 and 3.

In FIG. 3, since the packet distributed from the transmission source 2 is a multicast packet, it is broadcast to the steady route side router 8 and the transmission source tunnel router 11. Normally, when the first route 7 is a steady route, the unicast route relay interface 2 of the source tunnel router 11 is controlled by the control information output by the control means 4.
4, TUN1 to TUN3 are turned off. Therefore, the source tunnel router 11 does not deliver the packet, but the steady route side router 8 delivers the packet to the four sites A, B, C, and D of the destination network 13.

Next, when the transmission path to the specific destination network 13 is switched from the first path 7 to the second path 10, the control information output from the control means 4 causes L
The interface on the steady destination router 14 side of the AN switch 16 is turned off. At this time, the control information output by the control means 4 is transferred to the LAN switch 16 using the third path 18.

After that, the source tunnel router 11 obtains the address of the base of the destination network 13 to be delivered from the control information output by the control means 4, and the unicast route relay interface 24, TUN1 to TUN3.
Either of them is turned on. After that, the transmission source tunnel router 11 transmits the stored packet type 52 and the packet that can be transmitted within the band 53 based on the address of the base of the transmission destination network 13 described above, A, B, C of the transmission destination network 13. Deliver to any of D bases. That is, when the source tunnel router 11 turns on the unicast route relay interface 24,
Using the address of the base of the destination network 13, it operates to validate the second route 10, which is a unicast route.

As described above, the number of unicast routes that are valid at the same time is determined by the number of unicast route relay interfaces 24. Therefore, the source tunnel router 11 controls so as to deliver packets within that range. . Therefore, it is possible to prevent the normal communication of the second route 10 from being overwhelmed.

As an example, A of the destination network 13
The operation when switching the distribution to A and C among the four bases B, C, and D to the second route 10 will be described. The number of unicast routes that are valid at the same time is defined to be 2 or more, and the number of currently operating unicast routes is 0.
If so, the distribution to A and C is switched to the second route 10. The number of unicast routes that are valid at the same time is defined as 2, and the number of currently operating unicast routes is 2.
If so, neither of the distributions to A and C can be switched to the second route 10. Further, if the number of unicast routes that are valid at the same time is defined to be 1 and the number of unicast routes currently operating is 0, only one of A and C is switched to the second route 10. That is, the distribution to either A or C is not relayed from the source tunnel router 11 depending on the number of unicast routes that are valid at the same time.

By the control described above, the packet delivered from the transmission source 2 is transmitted to the specific transmission destination 3 where the specific event occurs.
Is delivered by unicast communication via the second route 10 based on the condition of the second route 10.

Next, the control procedure in the route control computer 1 and the transmission source tunnel router 11 will be described with reference to FIG. Starting from step S0, in step S1, the monitoring means 6 monitors the state of the monitoring target device 15 and collects the path switching determination information in order to collect the monitoring target device 1
5 SNMP get request and ICMP Echo (pin
g) is sent. The route switching determination information is, for example, the amount of received packets per unit time.

After that, in step S2, the route switching determination information collected from the monitored device 15 by the SNMP GET response and the ICMP Echo reply is passed to the determination means 5. When the Trap transmission function of the monitored device 15 causes the Trap transmission according to the preset transmission requirement, the route switching determination information is collected in step S3. The Trap transmission function of the monitored device 15 will be described later with reference to FIG.

In step S4, the determination means 5 makes a determination for switching the route. The determination means 5 stores information of a determination interval and a determination threshold value which are predetermined by the system administrator as a determination condition. Depending on the determination interval, it is determined whether or not to switch the route by comparing the information about the determination threshold value with the route switching determination information passed from the monitoring means 6. When it is necessary to switch the route, the determination result is passed to the control means 4. If it is determined that it is not necessary to switch the route, the process returns to step S0. As described above, the determination condition is predetermined by the system administrator according to the line speed, reliability, communication amount, line cost, or the like. As an example, when the monitoring target device 15 is a router that constantly receives packets, the amount of received packets per unit time is measured, and a certain value is set as the determination threshold value. It is conceivable that the received packet amount is measured at the determination interval, and if the determination threshold is not reached, the route is determined to be unavailable and the route is switched.

Then, in step S5, in order to switch to the second route 10, the control means 4 controls the source tunnel router 11 and the LAN switch 16 based on the judgment of the judgment means 5. Specifically, when switching from the first route 7 to the second route 10, first, the number of currently operating unicast routes is confirmed. When the number is within the range of the unicast route stored in the source tunnel router 11 that is valid at the same time, the unicast route relay interface 24 of the source tunnel router 11 is turned on. At the same time, the control information is transferred to the LAN switch 16 using the third path 18, and the interface on the steady transmission destination router 14 side of the LAN switch 16 is turned off.

At this time, the control means 4 passes the address of the base of the destination network 13 which delivers the packet from the second route 10 to the source tunnel router 11 as control information. When the number of currently operating unicast routes is the same as the number of simultaneously valid unicast routes, the unicast route relay interface 24 of the source tunnel router 11 is not turned on. Also, the second route 10
When the value obtained by adding the number of destination networks 13 to be switched to the number exceeds the number of valid unicast routes at the same time, it is relayed to the destination network 13 within the range. The details are as described above.

When switching from the second route 10 to the first route 7, the unicast route relay interface 24 of the source tunnel router 11 is turned off,
After that, the interface on the steady transmission destination router 14 side of the LAN switch 16 is turned on. At this time, the third path 18 is used.

In step S5, the control means 4
When the unicast route relay interface 24 of the source tunnel router 11 is turned on / off,
Based on the number of addresses of the bases of the destination network 13 passed as control information, TUN1 to TUN3 are set to 0.
N / OFF state.

Next, in step S6, the transmission source tunnel router 11 relays only the packets that meet the conditions defined in the storage table 51, and discards the packets that do not meet the conditions. As a result, only packets that match the conditions can be relayed without affecting normal communication on the second route 10. The process ends in step S7.

As described above, the source tunnel router 11 stores the type and band of the packet to be relayed in the storage table 51, so that the packet can be sorted and the priority of the packet can be given.

Although FIG. 5 shows the route control by monitoring the combination of SNMP and ICMP, the route switching determination information of the monitored device 15 and the network management protocol supported by the monitored device 15 are optimal. It is also possible to control the route by monitoring only SNMP or only ICMP by selecting a proper collection method.

Next, the operation of the monitored device 15 will be described. The monitored device 15 is the route control computer 1
It's a network management client. In other words, from the routing computer 1 which is a server
In response to the SNMP GET request, the monitored device 15, which is a network management client, returns an SNMP GET response, and returns an ICMP Echo reply to the ICMP Echo. In addition, if the SNMP Trap transmission function is set in advance in the monitored device 15, the route switching determination information can be collected by Trap when a transmission requirement occurs on the network management client side.

SNMP in the monitored device 15 with reference to FIG.
The processing procedure of the Trap transmission function will be described. Starting from step S10, the Trap transmission function is initialized in step S11. The contents to be set are the item to be monitored, the judgment threshold, the detection period, and the destination of the Trap.
The destination of the Trap is defined as the route control computer 1. The item to be monitored becomes the route switching determination information, and as one example, there is the communication amount of the route to which the monitored device 15 is connected, the physical state, and the number of route error detections.

Thereafter, in step S12, the monitoring target device 15 monitors the route connected to the monitoring target device 15 itself at the set detection cycle or reporting cycle.
As a result of monitoring in step S13, when it is determined that a Trap transmission requirement has occurred, the process moves to Step S14, the requirement is described in Trap, and Trap is transmitted to the route control computer 1. If there is no Trap transmission requirement in step S13, the process returns to step S12 and monitoring is performed according to the detection cycle.

The network management protocol for collecting the route switching determination information described with reference to FIGS. 4 and 5 is transmitted / received using the first route 7 and the third route 18. Specifically, the ICMP Echo and the ICMP Echo reply to the ICMP Echo use the first route 7. The third path 18 is used for the SNMP GET request, the SNMP GET response to the SNMP GET request, and the Trap transmission function.

As described above, the monitoring means 6 can monitor the state of the network group that can be logically reached even if there is no adjacency by monitoring the network device or the computer as the monitored device 15 in advance. it can.

As described above, in the present embodiment, the line speed,
When a normal route is defined as the first route in the first route and the second route which are different in reliability, communication volume, line cost, etc., and a route failure or an event that meets a predetermined determination condition occurs. , A system for switching to the second path can be provided.

When switching to the second route, the conditions of the second route are taken into consideration, the type of packet to be delivered, the upper limit of the bandwidth, and the number of unicast routes that are valid at the same time are determined, and the range is met. Since the packet to be transmitted is distributed, it is possible to suppress the pressure on the normal communication on the second route.

Furthermore, when the route control computer 1 collects the route switching determination information from the monitored device 15, since SNMP and ICMP are used, it can be constructed by a general-purpose network management protocol.

In this embodiment, the tunneling method is used when the information is distributed by the unicast communication by switching the route to the specific destination, but the method is not limited to this.

Embodiment 2. The system configuration diagram in the second embodiment is the same as FIG. 1 shown in the first embodiment.

In the present embodiment, when the judging means 5 makes a judgment for switching a route, the system manager sets a certain value as a judgment threshold value according to the line speed, and the judging means 5 makes the judgment. Remember the conditions. As an example, when a router that constantly receives packets is set as the monitoring target device 15, the monitoring unit 6 monitors the line speed of the route to which the router is connected, and when the determination threshold is not reached, The judging means 5 judges that the route cannot be used.

Similarly, when reliability, line cost, etc. are set as the judgment conditions, if a certain value is used as the judgment threshold and the judgment threshold is not satisfied, the judgment means 5 cannot use the route. It is possible to make a decision to switch the route.

[0065]

Since the present invention is constructed as described above, it has the following effects.

In the route control system of the present invention, it is possible to switch the information delivery route to the destination by monitoring whether or not a predetermined event has occurred in the monitoring target existing on the predetermined network. A monitoring unit that collects route switching determination information, the route is changed from the first route to the second route based on the route switching determination information and a predetermined determination condition for determining the occurrence of a specific event. Since the determination means for determining whether or not to carry out and the transmission source tunnel router for distributing the information to the second route based on the route determined by this determination means are provided, the route can be switched when a specific event occurs. .

Further, the first route is a multicast communication route, the second route is a unicast communication route, and the transmission source tunnel router sends a packet to the second route based on the route judged by the judging means. When sending, to select the packets to send and to limit the number of valid unicast routes, switch the route to a specific destination. The pressure on normal communication can be suppressed.

Further, based on the determination result of the determination means, when it is determined that the route is changed, the packet from the first route is blocked, and when it is determined that the route is not changed, the packet from the first route is changed. Since the LAN switch for relaying the packet is provided, it is possible to suppress the packet transmission from the first route when switching to the second route.

The control means outputs the determination result of the determination means as control information, and the control means performs network management on the transmission source tunnel router or LAN switch based on the route switching determination information collected by the network management protocol. Since the control information by the protocol is passed, it can be constructed by a general-purpose network management protocol.

Further, the judging means judges that the route is changed from the first route to the second route when the judgment condition has a predetermined judgment threshold value and exceeds the judgment threshold value. Therefore, the determination threshold value can be set and changed according to the condition of the second route.

In the route control method of the present invention, whether or not a predetermined event that the route control means switches the route of information distribution to the destination has occurred in the monitoring target existing on the predetermined network. By monitoring the route switching determination information by the route control means, the route control means based on the route switching determination information and a predetermined determination condition for determining the occurrence of a specific event, and the multicast communication route as the route. Alternatively, when the first route is selected in the route selection step based on the route selection step of selecting the unicast communication route and the selection result of the route selection step, the route control means cuts off the packet from the tunnel router. , When the packet from the steady route router is relayed and the second route is selected in the route selection step, The tunnel router relays a packet matching the predetermined packet type or the upper limit range of the band within the predetermined number of valid unicast routes, and the route control means from the steady route router. Since the step of blocking the packet is included, the route can be switched when a specific event occurs.

In the program for causing the computer to execute the route control method of the present invention, the event that the route control means switches the route of the information distribution to the transmission destination is preset on the predetermined network. A step of collecting route switching determination information by monitoring whether or not it occurs in the target, the route control means provides route switching determination information and a predetermined determination condition for determining the occurrence of a specific event. On the basis of the route selection step of selecting a multicast communication route or a unicast communication route as a route based on the selection result of the route selection step, the route control means selects a tunnel when the first route is selected. Block the packets from the router, relay the packets from the steady route router, and When the second route is selected in the selection step, the tunnel router determines the range of the number of unicast routes for which the packet that matches the predetermined type of packet or the upper limit range of the bandwidth is determined to be valid. Since there is a step of relaying the packet within the router and blocking the packet from the steady route router, the route can be switched when a specific event occurs.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a functional block diagram showing a source tunnel router 11 according to the first embodiment of the present invention.

FIG. 3 is a functional block diagram showing the system according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a control process of the route control computer 1 according to the first embodiment of the present invention.

FIG. 5 is a monitoring target device 1 according to the first embodiment of the present invention.
6 is a flowchart showing an SNMP Trap transmission process in 5.

[Explanation of symbols]

3 destination, 4 control means, 5 determination means, 6 monitoring means, 7 first route, 10 second route, 11 source tunnel router, 16 LAN switch.

Claims (7)

[Claims] 1. A route switching determination is performed by monitoring whether or not a predetermined event of switching a route of information distribution to a destination occurs in a monitoring target existing on a predetermined network. Monitoring means for collecting information, whether to change the route from the first route to the second route based on the route switching determination information and a predetermined determination condition for determining the occurrence of the specific event A route control system comprising: a determining unit that determines whether or not there is a source tunnel router that distributes information to the second route based on the route determined by the determining unit. 2. The first route is a multicast communication route, the second route is a unicast communication route, and the source tunnel router is the second route based on the route determined by the determining means. The route control system according to claim 1, wherein when a packet is transmitted to the route, the packet to be transmitted is selected and the number of valid unicast routes is limited. 3. Based on the determination result of the determining means, when it is determined that the route is changed, the packet from the first route is blocked, and when it is determined that the route is not changed, the first route is changed. The routing control system according to claim 1, further comprising a LAN switch that relays a packet from the route. 4. A control unit for outputting the determination result of the determination unit as control information, the control unit according to the route switching determination information collected by a network management protocol, the source tunnel router or the LAN. The routing control system according to any one of claims 1 to 3, wherein control information based on a network management protocol is passed to the switch. 5. The determination means has a predetermined determination threshold value in the determination conditions, and when the determination threshold value is exceeded, changes the route from the first route to the second route. The determination to change to (1) is made.
The route control system according to any one of 1 to 4. 6. A route of a communication system comprising a steady route router for controlling communication of a multicast communication route, a tunnel router for controlling unicast communication, and a route control means for controlling the steady route router and the tunnel router. A control method, wherein the route control means monitors whether or not a predetermined event that the route of information distribution to the destination is switched occurs in a monitoring target existing on a predetermined network. Collecting the route switching determination information, the route control means based on the route switching determination information and a predetermined determination condition for determining the occurrence of the specific event, the multicast communication route as the route. Or a route selection step of selecting a unicast communication route, selection result of the route selection step Based on the above, when the first route is selected in the route selection step, the route control means cuts off the packet from the tunnel router, relays the packet from the steady route router, and When the second route is selected in the selecting step, the number of unicast routes for which the tunnel router makes a packet matching a predetermined packet type or a band upper limit range predetermined And a step of causing the route control means to block the packet from the steady route router. 7. A communication comprising: a computer, a steady route router for controlling communication of a multicast communication route, a tunnel router for controlling unicast communication, and a route control means for controlling the steady route router and the tunnel router. A program for executing a system route control method, wherein a predetermined event that the route control means switches a route of information delivery to a destination occurs in a monitoring target existing on a predetermined network. Collecting the route switching determination information by monitoring whether or not the route switching means has the route switching determination information and a predetermined determination condition for determining the occurrence of the specific event. A route for selecting a multicast communication route or a unicast communication route as the route based on Selection step, based on the selection result of the route selection step, when the first route is selected in the route selection step, the route control means blocks the packet from the tunnel router and When the packet from the router is relayed and the second route is selected in the route selecting step, the tunnel router predefines a packet that matches a predetermined packet type or a band upper limit range. A program for relaying within the range of the number of valid unicast routes, and for causing the route control means to block the packet from the steady route router.