JP2001257718A - Multicast method and its execution device, and recording medium recording its processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that can reduce a time from revision of a group configuration associated with participation or retirement of a multicast group member until revision of relay contents of a concerned multicast relay router. SOLUTION: The multicast method to send data to a member belonging to a specific group includes a step where revision contents of group information denoting a group conducted by multicast communication are reported, a step where a relay path of a distribution tree denoting a relay path of a multicast packet is revised depending on revision contents of the group information, a step where a relay instruction to instruct start or end of relay of the multicast packet is transmitted depending on the revision of the relay path, and a step where the relay of the multicast packet is started or finished depending on the contents of a relay instruction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicast system for transmitting data to members belonging to a specific group, and more particularly to a technique effective when applied to a multicast system for managing information indicating a multicast group for performing IP multicast communication. It is about.

[0002]

2. Description of the Related Art Conventionally, when transmitting the same data to a plurality of computers belonging to a specific group among a plurality of computers connected to a network, multicast communication has been used. This multicast communication is based on IP (Internet Protocol) transmitted by one computer to the group.
col) relays the datagram to all of the computers belonging to the group. This group
It is a communication unit where multicast communication is performed,
The multicast router has a plurality of relay interfaces for one group.

As a conventional protocol for performing this multicast communication, for example, DVMRP (Distance Vector M)
ulticast Routing Protocol), basically this DVM
In multicast communication using RP, a delivery tree with the sender at the top is created in order to deliver a multicast packet from the source network to all group members, and the datagram is a necessary branch of this delivery tree. Only copied as packets.

[0004] In multicast communication, a destination group address is stored in a destination address field of an IP datagram header. As the destination group address, a class D address is used for coexistence and distinction with the existing IP destination address. In multicast communication, a source address is stored in a source address field of an IP datagram header, and a multicast group address is stored in a destination address field of an IP datagram header.

When performing multicast communication, first,
It checks whether there is a multicast-capable router nearby by sending a confirmation message. The response message to the confirmation message includes information on the neighboring router that has received the confirmation message, and it is possible to dynamically detect a neighboring router capable of multicast communication by transmitting the confirmation message.

[0006] The multicast router registers the interface to which the detected neighboring router belongs in the distribution tree, and sends a multicast group membership information transmission request message to the interface where there is no neighboring router, and sends the computer belonging to each multicast group. Investigate the presence or absence of If there is a computer belonging to the multicast group, the multicast router adds the interface as a leaf network to the multicast relay interface.

[0007] In preparation for a case in which a computer belonging to each multicast group fluctuates, the multicast router periodically transmits a group membership information transmission request message to the leaf network, and confirms a response from each computer. I do. If there is a response message, the multicast relay interface is not updated. If there is no response message, the interface is deleted from the multicast relay interface.

[0008] When the multicast router receives the multicast packet and there is no member receiving the multicast packet sent from the transmission source among the nodes connected to the multicast router, the multicast packet is sent to the multicast router. A pruning request message indicating that there is no need to transmit the packet is sent back to the multicast router of the transmission source. The multicast router that has received the pruning request message deletes the interface from the multicast communication interface, and transmits a pruning request message to the multicast router of the previous hop.

A multicast system and method for multicasting to a specific object group on a network with a small amount of traffic, and a network actor and a node actor for the system are described in JP-A-11-21940. Have been.

[0010]

In the above prior art, when the configuration of the multicast distribution tree is changed, the content of the configuration change is transmitted to the entire network by sequentially transferring the content to each multicast router. For this reason, when multicast communication is to be realized in a large-scale network, there is a problem that sufficient time is required for the contents of the configuration change accompanying the joining or leaving of the multicast group member to be transmitted to the entire network.

In the multicast method using the network actor and the node actor, the network actor receiving the message including the designation of the destination domain performs the multicast by distributing the message to all the node actors. There is a problem that multicast is performed even to a node that does not include the transmission destination domain.

An object of the present invention is to solve the above-mentioned problem and to provide a technique capable of shortening the time required from the change of the group configuration due to the joining or leaving of a multicast group member to the change of the relay contents of the related multicast relay router. To provide.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a multicast system for transmitting data to members belonging to a specific group, wherein a multicast packet is relayed according to an instruction from an area management router for centrally managing a delivery tree. It is.

[0014] The multicast relay router of the present invention is a region management system for centrally managing a delivery tree when a connected computer joins or leaves a multicast group and changes group information indicating a group in which multicast communication is performed. Notifies the router of the change in group information.

[0015] The area management router changes a relay route in a distribution tree indicating a relay route of the multicast packet according to the content of the change of the group information, and starts or stops the relay of the multicast packet according to the change of the relay route. A relay instruction for instructing termination is transmitted to the associated multicast relay router. The multicast relay router receiving the relay instruction starts or ends the relay of the multicast packet according to the contents.

As described above, according to the multicast system of the present invention, a multicast packet is relayed according to an instruction from an area management router that centrally manages a distribution tree of the multicast packet. It is possible to reduce the time required from the change of the configuration to the change of the relay contents of the related multicast relay router.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multicast system according to an embodiment for transmitting data to members belonging to a specific group will be described below.

FIG. 1 is a diagram showing an outline of a multicast system according to this embodiment. In the present embodiment, when joining a multicast group, a join message is transmitted to a previously designated area management router using a unicast routing table, and a response message is received. Determine the area management router for each. At this time, a plurality of area management routers to be registered can be set for each area.

Here, the multicast area is an area indicating a set of multicast relay routers set under a certain policy. The area management router is a router that is adjacent to other multicast areas as well as the multicast area managed by itself. A plurality of routers that are candidates for the area management router can be installed, but in this case, at the stage of joining the multicast group, negotiation is performed between the candidate routers to determine the master / slave. Not be. The area management router integrally manages the multicast information to which the multicast node of the area belongs and distance information to the multicast receiving node.

FIG. 2 shows an area management router 100 according to this embodiment.
It is a figure which shows schematic structure of. As shown in FIG. 2, the area management router 100 according to the present embodiment includes a CPU 201, a RAM 2
02, ROM 203, memory card interface 204, relay module 205, and delivery tree information 2
06.

The CPU 201 is a device for controlling the operation of the entire area management router 100. The RAM 202 is a storage device for loading various processing programs and data for controlling the operation of the entire area management router 100.

The ROM 203 is a storage device for storing the various processing programs and data. The memory card interface 204 is an interface for reading the contents of the memory card on which the various processing programs are recorded.

The relay module 205 is a module for transmitting a multicast group change notification, a multicast packet relay instruction, and a multicast packet. The delivery tree information 206 is tree information for centrally managing a relay route of a multicast packet in a specific area.

The area management router 100 has a delivery tree change processing unit 210 and a relay instruction processing unit 211.

The distribution tree change processing unit 210 is a processing unit that changes the relay route in the distribution tree indicating the relay route of the multicast packet in accordance with the change of the multicast group information indicating the group in which the multicast communication is performed. The relay instruction processing unit 211 is a processing unit that transmits a relay instruction for instructing start or end of the relay of the multicast packet according to the change of the relay route.

A program for causing the area management router 100 to function as the delivery tree change processing unit 210 and the relay instruction processing unit 211 is recorded on a recording medium such as a memory card and executed. The recording medium for recording the program may be a recording medium other than a memory card.

In this embodiment, the area management router 1
It is assumed that the area management router 110 other than 00 has the same configuration as the area management router 100.

FIG. 3 is a diagram showing a schematic configuration of the multicast relay router 101 of the present embodiment. As shown in FIG. 3, the multicast relay router 101 of this embodiment
U301, RAM 302, ROM 303, memory card interface 304, relay module 305
, Group information 306, and relay information 307.

The CPU 301 is a device for controlling the operation of the entire multicast relay router 101. RAM30
Reference numeral 2 denotes a storage device for loading various processing programs and data for controlling the operation of the entire multicast relay router 101.

The ROM 303 is a storage device for storing the various processing programs and data. The memory card interface 304 is an interface for reading the contents of the memory card on which the various processing programs are recorded.

The relay module 305 is a module for transmitting a multicast group change notification, a multicast packet relay instruction, and a multicast packet. The group information 306 is information indicating a multicast group in which a node connected to the multicast relay router 101 is participating. The relay information 307 is information indicating a relay destination of the multicast packet.

Also, the multicast relay router 101
Change notification processing unit 310 and relay information change processing unit 311
And a relay processing unit 312.

The change notification processing section 310 is a processing section for notifying change contents of group information indicating a group in which multicast communication is performed. Relay information change processing unit 311
Is a processing unit that changes the relay information 307 according to the content of a relay instruction for instructing start or end of multicast packet relay. The relay processing unit 312 outputs the relay information 30
7 is a processing unit for starting or ending the relay of the multicast packet in accordance with the contents of No. 7.

A program for causing the multicast relay router 101 to function as the change notification processing unit 310, the relay information change processing unit 311 and the relay processing unit 312 is a ROM.
Etc., and are executed. The recording medium for recording the program may be a recording medium other than the ROM.

In this embodiment, the multicast relay routers 102 other than the multicast relay router 101
It is assumed that routers such as to 104 have the same configuration as the multicast relay router 101. The area management router 100 according to the present embodiment also operates as a multicast relay router, and has the same function as the multicast relay router 101.

FIG. 4 is a flowchart showing a processing procedure of the multicast group change notification processing of this embodiment. FIG. 4 shows a process of notifying the area management router 100 of the change of the multicast group in which the members connected to the multicast relay router participate.
Note that routers such as the multicast relay routers 102 to 104 perform the same processing as the multicast relay router 101.

In step 401, the change notification processing unit 310 of the multicast relay router 101 checks whether or not the node 105 connected to the multicast relay router 101 has joined a new multicast group by referring to the group information 306. If it has joined a new multicast group, it proceeds to step 402, and if it has not joined a new multicast group, it proceeds to step 403.

At step 402, the newly joined multicast group is registered in the group information 306, and the node 10 connected to the multicast relay router 101 is registered.
5 transmits to the area management router 100 a join message indicating that it has joined the new multicast group.

In step 403, the node 105 connected to the multicast relay router 101 leaves the multicast group and
In the node connected to No. 1, it is checked whether or not the member participating in the multicast group no longer exists with reference to the group information 306. If the member participating in the multicast group no longer exists, the step is performed. Proceeding to 404, the process returns to step 401 if there are still nodes participating in the multicast group.

In step 404, the multicast group whose participating members no longer exist is deleted from the group information 306, and the multicast relay router 10
Then, the node management server 100 transmits a leave message indicating that there is no longer any member participating in the multicast group at the node connected to the area management router 100.

FIG. 5 is a flowchart showing the processing procedure of the delivery tree change processing and the relay instruction processing of this embodiment. FIG. 5 shows processing contents when the area management router 100 receives a join message or a leave message from the multicast relay routers 101 to 104.

In step 501, the distribution tree change processing unit 210 of the area management router 100 checks whether a participation message indicating that it has joined a new multicast group has been received from the multicast relay routers 101 to 104, and has received the participation message. In this case, the process proceeds to step 502, and if the participation message has not been received, the process proceeds to step 504.

In step 502, information indicating a relay route to the newly joined multicast group is added to the distribution tree information 206.

In step 503, the relay instruction processing unit 211
Transmits a relay start instruction for instructing a router on the relay route added to the distribution tree information 206 among the multicast relay routers 101 to 104 and the area management router 110 to start multicast relay. In this embodiment, since the area management router 100 also serves as a multicast relay router, if the area management router 100 is on the relay route added to the distribution tree information 206, the area management router 100 also starts relaying itself. To instruct.

In step 504, the delivery tree change processing unit 2
10 checks whether a leave message indicating that there are no more members participating in the specific multicast group has been received from the multicast relay routers 101 to 104, and if a leave message has been received, proceeds to step 505. If no withdrawal message has been received, the process returns to step 501.

In step 505, information indicating a relay route to the multicast group in which the participating members no longer exist is deleted from the distribution tree information 206.

In step 506, the relay instruction processing unit 211
Transmits a relay end instruction for instructing a router on the relay path deleted from the distribution tree information 206 among the multicast relay routers 101 to 104 and the area management router 110 to end multicast relay. In this embodiment, since the area management router 100 also serves as a multicast relay router, if the area management router 100 is on the relay route added to the distribution tree information 206, the relay end is also sent to the area management router 100 itself. To instruct.

FIG. 6 is a flowchart showing a processing procedure of the relay information change processing of the present embodiment. In FIG. 6, the multicast relay routers 101 to 104 are connected to the area management router 10.
0 indicates a processing content when a relay instruction is received.

In step 601, the relay information change processing unit 311 of the multicast relay routers 101 to 104 checks whether or not a relay start instruction for instructing the start of multicast relay has been received from the area management router 100, and has received the relay start instruction. In this case, the process proceeds to step 602, and if no relay start instruction has been received, the process proceeds to step 603.

In step 602, a relay destination corresponding to the received relay start instruction is added to the relay information 307.

In step 603, a relay end instruction for instructing the end of the multicast relay is sent to the area management router 100.
It is checked whether or not a relay end instruction has been received. If a relay end instruction has been received, the process proceeds to step 604. If no relay end instruction has been received, the process returns to step 601.

In step 604, the relay destination corresponding to the received relay end instruction is deleted from the relay information 307.

FIG. 7 is a flowchart showing the processing procedure of the delivery tree change processing and the relay instruction processing of this embodiment. In FIG. 7, the area management router 110 is the area management router 1
12 shows the processing contents when a relay instruction is received from 00.

In step 701, the distribution tree change processing unit 210 of the area management router 110 checks whether or not a relay start instruction for instructing to start multicast relay has been received from the area management router 100. Proceeds to step 702, and proceeds to step 704 if a relay start instruction has not been received.

In step 702, information indicating the relay route to the multicast group instructed to start the relay is added to the distribution tree information 206.

At step 703, the relay instruction processing unit 211
Transmits a relay start instruction for instructing a router on the relay route added to the distribution tree information 206 among the multicast relay routers 111 to 114 to start multicast relay. In this embodiment, since the area management router 110 also functions as a multicast relay router, if the area management router 110 is on the relay path added to the distribution tree information 206, the area management router 110 also starts relaying itself. To instruct.

In step 704, the delivery tree change processing unit 2
10 checks whether or not a relay end instruction for instructing the end of the multicast relay has been received from the area management router 100. If the relay end instruction has been received, the process proceeds to step 705. If the relay end instruction has not been received, Returns to step 701.

In step 705, information indicating a relay route to the multicast group instructed to end the relay is deleted from the delivery tree information 206.

At step 706, the relay instruction processing unit 211
Transmits a relay end instruction for instructing a router on the relay path deleted from the distribution tree information 206 among the multicast relay routers 111 to 114 to end multicast relay. In this embodiment, since the area management router 110 also serves as a multicast relay router,
If the area management router 110 is on the relay route added to the delivery tree information 206, the area management router 110 instructs itself to end the relay.

FIG. 8 is a flowchart showing a processing procedure of the relay processing of this embodiment. In step 801, the relay processing unit 312 of the multicast relay routers 101 to 104
Checks whether a multicast packet has been received. If a multicast packet has been received, the process proceeds to step 802. If a multicast packet has not been received, the device waits for a multicast packet.

In step 802, the group information 306
And the relay information 307, a destination of a port different from the port that received the multicast packet is determined as a destination of the multicast packet.

In step 803, if there are a plurality of the determined destinations, the multicast packet is copied and the multicast packet is sent to the destination.

FIG. 9 is a diagram showing an example of a multicast group change notification according to this embodiment. FIG. 9 shows a process of notifying the area management router 100 that the node 105 connected to the multicast relay router 101 has joined the multicast group G1.

IGMP (Internet Group Management Protocol)
According to l), the node 105 sets the multicast group G1
4, the change notification processing unit 310 of the multicast relay router 101 detects that the node 105 has joined the new multicast group in the processing of step 401 in FIG. It registers with the group information 900 and transmits to the area management router 100 a join message 901 indicating that the node 105 connected to the multicast relay router 101 has joined the new multicast group G1.

FIG. 10 is a diagram showing an example of the relay route generation according to the present embodiment. FIG. 10 shows a relay route generated by the area management router 100 that has received the participation message 901 from the multicast relay router 101.

When the distribution tree change processing unit 210 of the area management router 100 detects from the multicast relay router 101 that the participation message 901 indicating that it has joined the new multicast group G1 is detected in the processing of step 501 in FIG. Go to 502.

In step 502, information indicating a relay route to the newly joined multicast group G 1 is generated in the distribution tree information 206. That is, the information indicating the connection state between the multicast relay routers 101 to 104 in the multicast area managed by the area management router 100 and the area management router 110 connected to the area management router 100 is referred to, and among them, Relay routes 1001 to 1005 from the router located at the end to the multicast relay router 101 are generated and stored in the distribution tree information 206.

In step 503, the relay instruction processing unit 211
Instructs the multicast relay routers 102 to 104, the area management router 100 itself, and the area management router 110 on the relay path stored in the distribution tree information 206 to start multicast relay.

FIG. 11 is a diagram showing an example of a relay instruction according to the present embodiment. In FIG. 11, the multicast relay router 10
1 shows the relay information generated by the multicast relay routers 102 to 104 and the area management router 100 in accordance with the relay instruction transmitted by the area management router 100 that has received the participation message 901 from No. 1.

The relay information change processing unit 3 of the multicast relay routers 102 to 104 in the processing of step 601 in FIG.
11 detects that a relay start instruction for instructing the start of multicast relay has been received from the area management router 100, and proceeds to step 602.

In step 602, the relay destination corresponding to the received relay start instruction is set to the relay information 1102-1104.
To store. That is, the multicast relay router 10
2 receives a relay instruction instructing the start of the relay of the multicast packet having the destination of G1 to the area management router 100, and stores this information in the relay information 1102. Similarly, the multicast relay router 103 transmits the multicast packet of the destination G1 to the multicast relay router 10.
The multicast relay router 104 stores information for relaying the multicast packet of the destination G1 to the area management router 100 in the relay information 1103. Area management router 1
00 itself stores information for relaying the multicast packet of the destination G1 to the multicast relay router 101 in the relay information 1100.

In the processing of step 701 in FIG. 7, the distribution tree change processing unit 210 of the area management router 110 detects that the relay start instruction for instructing the start of the multicast relay has been received from the area management router 100, and then proceeds to step 7
Go to 02. The area management router 100 receives the participation message 9
01, the delivery tree information 2
06, and transmits a relay start instruction to the multicast relay routers 111 to 114 on the relay route to start multicast relay.

FIG. 12 is a diagram showing an example of the relay processing of the present embodiment. FIG. 12 shows a relay process when the node 106 transmits a multicast packet to the multicast group G1 after the node 107 also joins the multicast group G1 in the same manner as the above-described process.

The relay processing unit 312 of the multicast relay router 103 executes the processing of step 801 in FIG.
It is detected from step 06 that the multicast packet of the destination G1 has been received, and the process proceeds to step 802.

Then, the relay processing unit 312 of the multicast relay router 103 determines in step 802 that the relay information 110
3, the multicast relay router 102, which is a relay destination connected to a port different from the port that received the multicast packet, is read from the relay information 1103, and is determined as the relay destination of the multicast packet. In step 803, the multicast packet of the destination G1 is relayed to the determined relay destination, and similarly, the relay processing unit 312 of the multicast relay router 102
The multicast packet of the destination G1 is transmitted to the area management router 1
Relay to 00.

The area management router 100 also serving as the multicast relay router operates here as a multicast relay router, and in step 803, copies the multicast packet of the destination G1 and relays it to the multicast relay routers 101 and 104.

The relay processing unit 312 of the multicast relay router 101 determines the group information 9
00, a port P01 different from the port that received the multicast packet is determined as the destination of the multicast packet. In step 803, the multicast packet of the destination G1 is transmitted to the node 105 connected to the determined destination port P01.

The relay processing unit 312 of the multicast relay router 104 refers to the group information 1202 in the processing of step 802, and determines a port P42 different from the port that received the multicast packet as a destination of the multicast packet. And step 80
In step 3, the multicast packet of the destination G1 is transmitted to the node 107 connected to the determined destination port P42.

As described above, according to the multicast system of the present embodiment, multicast packets are relayed according to an instruction from the area management router that centrally manages the distribution tree of the multicast packets. It is possible to reduce the time required from the accompanying change in the group configuration to the change in the relay contents of the related multicast relay router.

[0080]

According to the present invention, a multicast packet is relayed according to an instruction from an area management router that centrally manages a distribution tree of the multicast packet. Therefore, the present invention relates to a change in the group configuration due to the joining or leaving of a multicast group member. It is possible to reduce the time required for changing the relay contents of the multicast relay router.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overview of a multicast system according to an embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of an area management router 100 according to the present embodiment.

FIG. 3 shows a multicast relay router 101 according to the embodiment.
It is a figure which shows schematic structure of.

FIG. 4 is a flowchart illustrating a processing procedure of a multicast group change notification process according to the embodiment.

FIG. 5 is a flowchart illustrating a processing procedure of a delivery tree change process and a relay instruction process according to the embodiment.

FIG. 6 is a flowchart illustrating a procedure of a relay information change process according to the embodiment;

FIG. 7 is a flowchart illustrating a processing procedure of a delivery tree change process and a relay instruction process according to the embodiment;

FIG. 8 is a flowchart illustrating a procedure of a relay process according to the embodiment;

FIG. 9 is a diagram illustrating an example of a multicast group change notification according to the embodiment;

FIG. 10 is a diagram illustrating an example of a relay route generation according to the present embodiment.

FIG. 11 is a diagram illustrating an example of a relay instruction according to the embodiment;

FIG. 12 is a diagram illustrating an example of a relay process according to the embodiment;

[Explanation of symbols]

100 area management router, 101-104 multicast relay router, 105-107 node, 110 area management router, 111-114 multicast relay router, 115-117 node, 201 CPU, 20
2 RAM, 203 ROM, 204 memory card interface, 205 relay module, 206 delivery tree information, 210 delivery tree change processing unit, 211
Relay instruction processing unit, 301 ... CPU, 302 ... RAM, 3
03: ROM, 304: memory card interface,
305: relay module, 306: group information, 30
7 relay information, 310 change notification processing unit, 311 relay information change processing unit, 312 relay processing unit, 900 group information, 901 participation message, 1001 to 1005
... Relay route, 1100 ... Relay information, 1102-1104
... relay information, 1201 ... relay information, 1202 ... group information.

Claims (5)

[Claims] 1. A multicasting method for transmitting data to members belonging to a specific group, comprising: a step of notifying a change in group information indicating a group in which multicast communication is performed; Changing a relay route in a distribution tree indicating a relay route of a multicast packet, transmitting a relay instruction for instructing start or end of relay of the multicast packet in accordance with the change of the relay route, Starting or ending the relay of the multicast packet according to the content of the multicast packet. 2. An area management router for transmitting data to members belonging to a specific group, comprising: a distribution tree indicating a relay route of a multicast packet according to a change in group information indicating a group in which multicast communication is performed. A distribution tree change processing unit for changing a relay path of the packet, and a relay instruction processing unit for transmitting a relay instruction for instructing start or end of the relay of the multicast packet according to the change of the relay path. Management router. 3. A multicast relay router for delivering a multicast packet according to group information indicating a group on which multicast communication is performed, a change notification processing unit for notifying a change in group information indicating a group on which multicast communication is performed, and a multicast packet. And a relay processing unit for starting or ending the relay of the multicast packet in accordance with the contents of the relay instruction for instructing the start or end of the relay. 4. Group information indicating a group in which a multicast communication is performed on a computer-readable recording medium storing a program for causing a computer to function as an area management router for transmitting data to members belonging to a specific group. A delivery tree change processing unit that changes a relay route in a delivery tree indicating a relay route of a multicast packet according to the change content of the multicast packet, and a relay that instructs start or end of the relay of the multicast packet according to the change of the relay route A recording medium on which a program for causing a computer to function as a relay instruction processing unit for transmitting an instruction is recorded. 5. A computer-readable recording medium storing a program for causing a computer to function as a multicast relay router for delivering a multicast packet in accordance with group information indicating a group in which multicast communication is performed. The computer functions as a change notification processing unit that notifies a change content of the indicated group information and a relay processing unit that starts or ends the relay of the multicast packet in accordance with the content of the relay instruction that instructs start or end of the relay of the multicast packet. Recording medium for recording a program for recording.