JP3013832B2 - ATM multicast system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ATM multicast system for performing multicast in a selective broadcast format, and more particularly to a multicast transfer path having a multicast node and a plurality of edge nodes as a source and a destination, respectively. The present invention relates to an ATM multicast system constructed for each user group to reduce a processing load on a relay node.

[0002]

2. Description of the Related Art In recent years, an Asynchronous Transfer Mode (ATM) switching system for dividing information into fixed-length cell units for transmission and reception has attracted attention as a broadband communication technology. However, a communication device using such an ATM switching system has to set up a connection prior to communication, and is required to perform data packet communication represented by a local area network (LAN) or the like. For a connectionless network in which information transfer based on destination information in each information packet is performed, the procedure of communication setting is greatly different, so that the network cannot be accommodated as it is. Therefore, a semi-fixed path is set in advance between the end terminals so that such a communication apparatus of the ATM switching system can be provided in a connectionless network.

In such an ATM connectionless network, a plurality of edge nodes accommodating a user network are physically separated and distributed. In order to perform broadcast in the form of a broadcast notification from an arbitrary network of the distributed user networks to all other networks constituting the same user network, another same user network is transmitted from an edge node accommodating the network. The transfer in the ATM connectionless network is performed to the accommodating edge node. An edge node accommodating a user network has performed multicast, which is a broadcast selection notification format, to a plurality of edge nodes accommodating other user networks.

FIG. 17 shows such a conventionally proposed ATM.
1 shows an outline of a configuration of a multicast system. In this ATM multicast system, a plurality of edge nodes 151, 152, 153, 154, and 155 are distributed in an ATM connectionless network 150, and each accommodates a user network forming a user group (not shown). In order to transfer information between these edge nodes, the relay nodes 156, 15
7, 158, and 159 are arranged, and a plurality of network paths can be formed when transferring networks forming the same user group. Such a path is called a multicast tree. Edge node 15
Assuming that the network constituting this user group is not accommodated in the multicast tree 160, the multicast tree 160
3,154 is a multicast tree. Therefore, when a broadcast is performed from the user network accommodated in the edge node 151, the multicast tree 160 is transmitted to the edge nodes 153 and 154.
Will be performed along the route.

[0005] Similarly, the multicast tree 161 is a multicast tree from the edge node 153 to the edge nodes 151 and 154. When a broadcast is performed from the network accommodated in the edge node 153, the multicast tree 161 is connected to the relay nodes 157 and 156. The relay node 157, a path to the edge node 161 via the
Multicasting is performed along the paths to the edge node 154 via the 159 in order. Similarly, the multicast tree 162 is multicast from the edge node 154 to the edge nodes 151 and 153.

In such an ATM multicast system, a multicast tree indicating a transfer route from a source edge node to a destination edge node in order to perform multicast accommodates user networks constituting a distributed user group. Only the number corresponding to the number of edge nodes is required. That is, since it is necessary to set a corresponding path for each user group, the management of the entire network is very complicated.

For the purpose of solving such a problem, a group communication server is provided in a network, and when a broadcast is executed from a user network, an edge node accommodating the user network once transfers the broadcast to the group communication server. A to do
A TM multicast system has been proposed. In such an ATM multicast system, a table is provided in a group communication server, and a virtual communication from the group communication server to a plurality of user networks included in each group communication is provided in accordance with an identifier for group communication used in connectionless communication. Along with the path, a virtual path for broadcasting from the group communication server to all nodes is set in advance. When a broadcast is executed from a certain user network, the edge node accommodating the user network temporarily transfers the broadcast to the group communication server as described above. In the group communication server, when a virtual path corresponding to the group communication identifier set at the time of performing the broadcast in the user network is set, the transfer packet is transmitted according to the virtual path. When the corresponding virtual path is not set, the data is transferred to all relay nodes according to the virtual path for broadcast. The edge node has an accommodation list of the end terminal of the group communication accommodated by itself, and the transfer packet transferred from the group communication server receives the group communication of the group communication accommodated by the own edge node according to the accommodation list. If it is a transfer packet, it is transferred to this user network. However, a transfer packet of a group communication that is not accommodated by the own edge node is discarded.

An ATM for providing such a group communication server, preliminarily setting a virtual path and a virtual path for broadcast for each group communication, and discarding the transfer packet according to a user network accommodating the transfer packet at an edge node. Techniques related to the multicast system are disclosed in, for example, JP-A-5-219095 and JP-A-5-219096.

[0009]

SUMMARY OF THE INVENTION FIG.
In the ATM multicast system, each relay node needs to create a forwarding table for the multicast tree and hold it. When the scale of the network increases and the user network is distributed, not only does the size of such a table increase accordingly, but also the load on the relay nodes that perform processing based on this table increases. There is a problem.

In each relay node, the creation of a transfer table for a multicast tree is performed by a remote operation by a network management device, or statically set by a local terminal provided for each relay node. . As a result, the management of these tables is very complicated, making it difficult to cope with a failure, and there is also a problem with the maintainability of the system.

Further, for example, in an ATM multicast system using a "group communication system in an ATM switching system" disclosed in Japanese Patent Application Laid-Open No. H5-219095, a virtual path for each group communication from a group communication server and a virtual path for each group communication from a group communication server. It is necessary to set a broadcast virtual path to all nodes in the group communication server in advance. For example, the initial setting by the network management device and the collective management of the multicast tree by the group communication server are performed. However, when the multicast tree is not set in the group communication server, the multicast tree is always transferred by the virtual path for broadcast, and is not transmitted to the network. When a load is imposed, and the scale of the network is increased, the throughput of the network becomes a serious problem. In addition, each time the network configuration changes, it is necessary to reconfigure the multicast tree with the optimal load and reset the list for routing.

[0012] For example, a "group communication system in an ATM switching system" disclosed in JP-A-5-219095 and JP-A-5-219096, respectively.
In an ATM multicast system using, an edge node receiving a packet multicasted from a group communication server checks whether the destination is addressed to a user network accommodated in its own edge node, and a user accommodated in its own edge node. When the packet is not addressed to the network, the multicast packet is discarded. Until the list for routing the multicast tree of the group communication server is newly set by the network management device or the like in this way, each time a group communication of an identifier not set in this group communication server is performed, a virtual virtual machine for broadcast is used. The path broadcasts to all nodes and places a heavy load on the network each time.

It is an object of the present invention to provide an ATM multicast system which reduces the load on each node in an ATM connectionless network and facilitates management for generating a multicast tree.

[0014]

According to the first aspect of the present invention, (a) identification information for identifying networks accommodating a plurality of users and identification information of a relay node which is a transmission / reception destination of a broadcast packet of these networks. And an edge node table storing a multicast address for performing a multicast in a broadcast selection notification format corresponding to the identification information, and (b) receiving a broadcast packet from the user, storing the packet in the edge node table. An edge node transmitting means for assigning a multicast address corresponding to the broadcast packet to the packet and transferring the packet based on the identification information of the relay node in the edge node table, and (c) identifying an input interface to which the transfer packet is input A relay node table for storing identification information for identifying the transfer packet, a multicast address assigned to the transfer packet, and identification information for identifying an output interface to which a transfer packet corresponding to the identification information and the multicast address is output; D) From the output interface corresponding to the multicast address of the transfer packet and the output interface identification information stored in the relay node table based on the input interface identification information as the identification information of the input interface to which the transfer packet is input, the transfer packet (E) a multicast node table storing the multicast address and the identification information of the relay node that is the destination of the multicast corresponding to the multicast address; And a multicast node for the broadcast selection notification as multicast packets based on the identification information of the relay relay node node stored in the multicast node table from the multicast address of the transfer packet transferred from the relay from (g) multicast node Through the node
Multicast of multicast packets transmitted by
Host address is registered in the edge node table
Multicast address determining means for determining whether or not
(H) The multicast address determination means
When it is determined that the multicast address is registered
Kiniwa and the edge node transfer means for transferring only the network corresponding to the identification information of the user network corresponding to the multicast address is registered in the edge node table of the multicast packet, (i) Ma
Multicast by multicast address discriminating means
Relay when it is determined that the address is not registered
The data of this multicast address is
First transfer stop message for sending transfer stop message
(G) sending the first transfer stop message.
Receive a transfer stop message sent by
Stops the transfer stored in the relay node table.
Output interface corresponding to the multicast address
Relay node transfer stop setting means for invalidating source identification information
And (ル) transfer is stopped by the transfer stop message
Multicast address in relay node table
All stored output interface identification information is invalid
If the multicast packet is
Send a further stop message to the sender of the packet
Second transfer stop message transmitting means for performing ()
Sent by the second transfer stop message sending means
When a transfer message is received, the multicast node data
The multicast address stored in the
Multicast that invalidates stored information corresponding to a dress
Node table invalidation means and (W) relay node table
Registered for each multicast address registered in the
For output interfaces that have been unregistered after being recorded
Confirmation message to send a transfer confirmation message periodically.
Message transmission means, and (f) transmission of this transfer confirmation message.
Multicast to the edge node table
When updating the registration information corresponding to the dress,
Transfer request message that sends a transfer request message to the
Message transmission means, and (Y) transmission of the transfer request message.
The transfer request message sent by the
Multicast of the relay node table that sent the message
Registration information to update the registration information corresponding to the
New means are provided for the ATM multicast system.

That is, in the first aspect of the present invention, the edge node table for storing the user network identification information, the relay node identification information, and the multicast address is provided for each edge node accommodating the user network. In addition, a relay node table for storing input interface identification information, output interface information, and multicast address to which a transfer packet is input / output is provided for each relay node that relays between the edge nodes. The multicast server node has a multicast node table for storing a multicast address and relay node identification information of the multicast destination. When a broadcast is executed from the user network accommodated by the edge node, a multicast address is added from the edge node table, transferred to the multicast server node via each relay node once, and added from the multicast server node to the edge node. Multicast is performed based on the multicast address.
Each relay node determines the next transfer destination based on the multicast address and the input interface identification information from the relay node table. The edge node identifies the multicast address of the received multicast packet from the edge node table, and transfers the multicast packet only to the user network accommodated in the edge node. In addition, the keys registered in the relay node table
For each multicast address, the corresponding output
The interface was unregistered after being registered
A transfer confirmation message is periodically sent to the output interface.
Sent to the transfer request message from the edge node.
Output interface corresponding to relay node table
The output interface from which the registration has been deleted.
Check if transfer is possible to the interface again.
And

[0016]

[0017]

[0018] In the second aspect of the present invention, an ATM multicast system according to claim 1, the identification information and these networks for identifying a user of the network when the multicast address of the transfer packet to the edge node table is not registered And an edge node initial setting unit for setting, in an edge node table, identification information of relay nodes that are transfer destinations of the broadcast packet and a multicast address corresponding to the identification information.

That is, according to the second aspect of the invention, when the multicast address of the transfer packet is not registered in the edge node table, the multicast address is set in the edge node table according to the user network to be accommodated. did.

[0020] In the third aspect of the present invention, an ATM multicast system according to claim 1, identifying for when the multicast address of the transfer packet to the relay node table is not registered to identify the input interface transfer packet is input A relay node setting unit for registering, in a relay node table, information, a multicast address given to the transfer packet, and identification information of all output interfaces other than the output interface of the pair with the input interface. I have.

That is, according to the third aspect of the present invention, for the multicast address first received in the relay node table, the relay node table is broadcasted to an output interface other than the transmission source of the transfer packet. Added output interface identification information.

[0022] In the present invention of claim 4, wherein, in ATM multicast system according to claim 1, the identification of the multicast address and the total output interface in the multicast node table when the multicast address of the transfer packet to the multicast node table is not registered A multicast address setting unit for registering information.

In other words, according to the fourth aspect of the present invention, the multicast address first received in the multicast node table is registered in the multicast server node table so as to broadcast to all output interfaces.

[0024]

[0025]

[0026]

[0027]

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

[0029]

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

FIG. 1 shows an outline of the configuration of an ATM multicast system according to an embodiment of the present invention. In the ATM multicast system, edge nodes 11, 12, 1 and 2 each accommodating a plurality of user networks are provided in an ATM connectionless network 10.
3, 14, and 15 and A are relayed between these edge nodes.
Relay nodes 16, 17, 18, 1 connected by TM
9.

The multicast server node 20 is connected to the relay node 19, and when executing a broadcast from the user network, a semi-fixed path is set from each edge node accommodating this user network to the multicast server node 20. I have. In addition, the multicast server node 20 has a multicast server node table in which, when receiving a broadcast packet from each user network, a path to an edge node to be transferred according to the user network that transmitted the broadcast packet is registered. Therefore, when the broadcast is executed from the user network, the edge node accommodating the user network detects the broadcast and transfers the broadcast to the multicast server node 20 once. The received broadcast packet is transferred to the corresponding relay node or edge node based on the multicast server node table.

The relay nodes 16, 17, 18, and 19 are also adapted to transfer to the next-stage relay node or edge node in response to a multicast from a multicast server node or a broadcast from a user network.

FIG. 2 shows a configuration of an interface of an edge node accommodating a user network in such an ATM connectionless network.
The edge node 21 has a user interface 23, and transmits and receives transfer data to and from the relay interface 22 based on registration information in the edge node table according to a packet to be transferred and an input / output direction. .

FIG. 3 shows the structure of the edge node table. The edge node table 24 includes a multicast address 25, a user interface ID (ID) 26 which is also an identifier of a user network accommodated by the edge node, and a relay interface ID 27 which is also an identifier of a relay node connecting the edge nodes. Each is registered.

According to the registration information in the edge node table 24, for example, a user network having a user interface ID 26 of "1" is a user interface "1", and a relay node having a relay interface ID 27 of "1" is a relay interface " Assuming that the broadcast is executed from the user interface “1”, the edge node detects the multicast address “www.xxx.yyy.zzz” from the user network as the multicast address “www.xxx.yyy.zzz”. It is designed to forward broadcast packets. When a multicast packet having a multicast address “ppp.qqq.rrr.sss” is transferred from the multicast server node 20 via the relay interface “2”, the multicast packet is transmitted to the user network of the user interface “2”. It is designed to transfer multicast packets.

Next, the details of processing performed by the edge node on transfer data will be described.

FIG. 4 shows the processing contents when receiving a broadcast from a user network accommodated in such an edge node. In this edge node, for the multicast address received for the first time such as at the start of operation, the interface to which the contained user network is connected is set as the user interface ID 26 in the edge node table 24, and the transfer destination is set as the relay interface 27. , The corresponding multicast address 25 is set. When a broadcast packet such as an Ethernet (Ethernet) is received from the user network (step S41: Y), an edge node table provided for each edge node is searched (step S42), and preset corresponding to each user network. The relay interface ID and the multicast address are taken out. Then, this multicast address is assigned to the received broadcast packet and transferred to the multicast server node 20 (step S43), and a series of processing ends.

FIG. 5 shows the processing contents when the edge node receives a multicast packet for the accommodating user network from the multicast server node 20. When the edge node receives the transfer data from the multicast server node 20 via the relay nodes distributed as a multicast tree (step S52: Y), it identifies the multicast address of the received data based on the edge node table, and It is determined whether or not the packet is addressed to the user network accommodated by the edge node (step S53). If it is determined that the packet is addressed to the user network accommodated by the own edge node (step S53: Y), the multicast address, the relay interface ID which is the input interface of the transfer data, and the user which is the output interface of the transfer data are stored in the edge node table. The interface ID is registered (step S54), the broadcast is transferred to the interface to which the corresponding user network is connected (step S55), and a series of processing is completed.

If it is determined that the packet is not addressed to the user network accommodated by the own edge node (step S5)
3: N), the transfer data is discarded because there is no transfer destination to transfer (step S56), and a transfer stop message for the data of the multicast address is sent to the upstream relay node, which is the input side of the transfer data. After transmission (step S57), a series of processing is completed.

Next, a description will be given of a relay node for relaying the above-described edge nodes.

FIG. 6 shows the structure of the interface of the relay node. The relay node 61 has input / output interfaces 62 and 63, and the input / output interface 62 and the input / output interface 63 are functionally the same. Transmission and reception of data to and from these input / output interfaces is performed based on registration information in a relay node table provided for each relay node.

FIG. 7 shows the structure of the relay node table. The relay node table 71 includes a multicast address 72 and an input interface ID for identifying an interface input to this relay node.
73 and an output interface ID 74 for identifying an interface output from the relay node are registered.

According to the registration information of the relay node table 71, for example, the input interface ID 73 is "1"
When a multicast packet with a multicast address 72 of “www.xxx.yyy.zzz” is input from the input interface “1” of the output interface “1”, the output interface “71” of which the output interface ID 71 is “2”, “3”, “4” 2 ”and output interface“ 3 ”,
The received multicast packet is transferred to the output interface “4”. Similarly, the transfer packet of the multicast address “sss.tttt.uuu.vvv” is transferred from the input interface “1” to the output interface “3” and the output interface “4”.

Next, the contents of processing performed by the relay node on transfer data will be described in detail.

FIG. 8 shows the processing contents when such a relay node receives transfer data from another node. Upon receiving the transfer data (step S81: Y), the relay node determines whether the multicast address of the transfer data is registered in the relay node table (step S82). When the transfer data is registered in the relay node table (step S82: Y), the transfer data is sent to the output interface registered in the relay node table from the input interface from which the transfer node is input and the multicast address of the transfer data. Transfer the transfer data (step S83),
A series of processes is terminated.

The multicast address of the transfer data is not registered in the relay node (step S82:
N) Sometimes, as a new multicast group,
The output interface ID is registered in the relay node table together with the input interface ID and the new multicast address (step S84), and a series of processing is completed. The output interface ID registered here registers all except the output interface ID paired with the input interface ID. That is, the data of the multicast address received for the first time is registered so as to be transferred to all the nodes other than the node that has transferred the data.

As described above, when the destination of the multicast packet is not to the user network accommodated by the own edge node, the edge node transmits a transfer stop message to the upstream side (step S57 in FIG. 5).
However, the relay node receives the multicast address for which the transfer is stopped together with the transfer stop message from the edge node.

FIG. 9 shows the processing contents when the relay node receives such a transfer stop message. When this relay node receives the transfer stop message (step S91: Y), when the relay node receives the transfer stop message from all output interface IDs corresponding to the multicast address to be deleted from the relay node table (step S92: Y), it further proceeds. A transfer stop message is transmitted to the upper-level relay node (step S93),
A series of processes is completed. That is, when a transfer stop message is received from all output interface IDs, all output interfaces to be output have been deleted, so that a transfer stop message to the upper side is transmitted to avoid unnecessary traffic. . If the output interface ID deleted by the received transfer stop message still exists, the output interface ID corresponding to the node that transmitted the transfer stop message is deleted (step S94), and the transfer to the node is stopped (step S94). S95), and a series of processes is completed.

As described above, when the relay node receives the transfer stop message from the edge node or another relay node, it searches the relay node table for a multicast address at which transfer is to be stopped, and corresponds to the node that has transmitted the transfer stop message. Only the output interface ID is deleted. By deleting only the output interface ID corresponding to the node that has transmitted the transfer stop message, the transfer packet will not be retransmitted even if the next multicast packet of this multicast address is received.

There may be a plurality of output interface IDs registered in the relay node table for one multicast address as shown in FIG.
Only the output interface ID corresponding to the output interface ID by the transfer stop message is deleted, and the remaining registered output interface ID is not affected at all. For example, the multicast address 72 in FIG. 7 is "www.xxx.yyy.zzz".
When a transfer stop message is received from the node whose output interface ID 71 is “3” for the transfer data of
The output interface ID “3” is deleted from the output interface ID 71 “2, 3, 4”, and the registration information is updated so that the output interface ID 71 becomes “2, 4”.

Next, a multicast server node that transfers such a multicast packet to an edge node via each relay node will be described.

FIG. 10 shows the configuration of the interface of the multicast server node. The multicast server node 96 is connected to the input / output interface 9
7 ₁ , 97 ₂ and the input / output interface 97 ₁
Output interface 97 ₂ are those functionally identical. Thus, the multicast server node 96
Has basically the same interface configuration as the relay node. The multicast server node has a multicast server node, and transfer path information on which relay node to transfer to in accordance with the broadcast packet transferred from the edge node via the relay node is registered. .

FIG. 11 shows the structure of the multicast server node table. In the multicast server node table 98, a multicast address 99, an input interface ID 100 for identifying an input interface input to the multicast server node, and an output interface ID 101 for identifying an output interface to be output as a multicast packet are registered. It has become so.

According to the registration information of the multicast server node 98, for example, the input interface ID 10
The multicast address 99 is “www.xxx.yyy.zzz” from the input interface where “0” is “2”.
Is received from the edge node via the relay node, the output interface “1” whose output interface ID 98 is “1” and the output interface ID
This multicast packet is transferred to the output interface “2” whose 98 is “2” and the output interface “3” whose output interface ID 98 is “3”. Then, the relay node corresponding to each output interface relays the transfer packets one after another based on the above-described relay node table.

Next, the contents of processing performed by the multicast server node on transfer data will be described in detail.

FIG. 12 shows the processing contents when such a multicast server node receives the transfer data. When the multicast server node receives the transfer message (step S102), it determines whether or not the message is a transfer stop message as described above (step S103). When it is determined that the received transfer message is a transfer stop message (step S103: Y), the multicast of the multicast address to which the transfer stop is transmitted to the corresponding output interface is stopped based on the multicast server node table, As in the case of the registration information deletion in the relay node table, the corresponding output interface ID in the multicast server node table is deleted to update the table (step S104), and a series of processing ends.

When it is determined that the received transfer message is not a transfer stop message (step S10).
3: N), it is determined whether or not the multicast address of the transfer data is registered in the multicast server node (step S105). When it is determined that the multicast address corresponding to the multicast server node is registered (step S105:
Y), it is transferred to the output interface of the registered output interface ID (step S106), and a series of processing ends. When it is determined that the corresponding multicast address has not been registered (step S105: N), this multicast address is newly registered and transferred to all output interfaces (step S107), and a series of processing ends. I do.

Next, an AT composed of such an edge node, a relay node, and a multicast server node
The operation of configuring a multicast tree in an M connectionless network will be described.

FIG. 13 is a first explanatory diagram for explaining the operation when the broadcast is executed in the user network accommodated by the edge node 11 in the ATM connectionless network. 13, the same elements as those of FIG. 1 are denoted by the same reference numerals, and the description will be appropriately omitted. In the following, it is assumed that the user networks are distributed and accommodated in the edge nodes 11, 13, and 14. When a broadcast is executed from one end terminal of the user network accommodated by the edge node 11, the edge node 11 detects this. As described above, the multicast address set in the edge node table at the start of operation is added to this broadcast packet, and the broadcast packet is transferred to the relay node 16 identified by the relay interface ID. Relay node 16
Then, based on the input interface ID to which the transfer packet is input from the relay node table and the multicast address given by the edge node 11, the transfer packet is transferred to the output interface indicated by the obtained output interface ID. In this manner, as indicated by the transfer path 110, the broadcast packet of the user network is transferred to the multicast server node 20 via the relay node 19.

FIG. 14 is a second explanatory diagram for explaining the operation when the broadcast is executed in the user network accommodated by the edge node 11 in the ATM connectionless network. 14, the same elements as those of FIG. 1 are denoted by the same reference numerals, and the description thereof will not be repeated. In the multicast server node 20, if the multicast address of the transferred packet is registered from the registration information of the multicast server node table, the packet is transferred from the output interface corresponding to the multicast address as the transfer destination of the transferred packet. In the following, it is assumed that all output interfaces have been registered at the start of operation as described above, corresponding to this multicast address. That is, the transfer path 120
, To the edge nodes 11 and 12 via the relay nodes 19 and 16, to the edge node 13 via the relay nodes 19 and 17, and to the edge nodes 14 and 15 via the relay nodes 19 and 18. , Respectively. In each relay node, a multicast address of a transfer packet transferred on the transfer path 120, an input interface ID for identifying an input interface, and an output interface ID for identifying an output interface are registered. Thus, at the start of operation, the broadcast is broadcast to all edge nodes.

FIG. 15 is a third explanatory diagram for explaining the operation when the broadcast is executed in the user network accommodated by the edge node 11 in the ATM connectionless network. In FIG. 15, the same elements as those in FIG. At the edge node receiving the transfer packet transferred from the multicast server node 20 via each relay node, each edge node determines the multicast address and the relay interface ID of the transfer packet based on the edge node table of each edge node. A user interface ID for identifying a destination user network is obtained. If the multicast address of the received packet is registered in the edge node table as described above, the transfer packet is transferred to the user interface corresponding to the obtained user interface ID, and the broadcast is performed. If the multicast address of the received packet is not registered in the edge node table, the transfer packet is discarded, and a transfer stop message is transmitted to the upper node that transmitted the transfer packet. . Hereinafter, it is assumed that the multicast address assigned by the edge node 11 is not registered in the edge node tables of the edge nodes 12 and 15.

Since the multicast addresses of the received packets are not registered in the respective edge node tables at the edge nodes 12 and 15, the received packets are discarded and the relay node 1 which is the upper node is
6 and 18, a transfer stop message 131,
132 is transmitted. The relay nodes 16 and 18, which have received the transfer stop message, stop the transfer by deleting the output interface ID corresponding to the multicast address from the relay node table in each relay node and corresponding to the edge nodes 12 and 15, respectively. Therefore, unnecessary traffic is prevented from being generated at the next multicast.

At this time, a higher-level transfer stop message is transmitted to the multicast address for which there is no more transferable output interface due to the deletion of the output interface ID at the relay node. For example, when there is no more output interface corresponding to this multicast address due to the transfer stop message 132, the relay node 19
A transmission stop message is transmitted to the multicast server node. In this embodiment, since the relay node 18 has an output interface indicating that the transfer should be made to the edge node 14, the transfer stop message is not transmitted any more.

FIG. 16 is a fourth explanatory diagram for explaining the operation when the broadcast is executed in the user network accommodated by the edge node 11 in the ATM connectionless network. In FIG. 16, the same elements as those in FIG. 1 are denoted by the same reference numerals, and the description will be appropriately omitted. In this manner, the multicast tree shown in the transfer path 140 corresponding to the multicast address is formed by the registration information in the multicast node table, the relay node table, and the edge node table as shown in FIGS. It has become.

In each relay node, the node corresponding to the output interface deleted from the registration information is
If a transfer confirmation message is periodically transmitted to an output interface that is not registered in the relay node table for each multicast address, it is possible to confirm again whether transfer is necessary. As described above, the data of the multicast address received for the first time is paired with the input interface ID corresponding to the transfer source node as an output interface ID so that the data is transferred to all but the transfer source node. Everything other than the output interface ID is registered. After the provisional table is configured as described above, when the transfer request message responding to the transfer confirmation message is received from the edge node, the transfer request message is registered in the relay node table, and when the transfer unnecessary message is received, the registration is not performed. Can also. Further, even if the data of the corresponding multicast address is not regularly transferred to an output interface that is not registered, instead of the transfer confirmation message, the retransmission can be performed similarly.

If the multicast server node 20 is provided with a command for executing a broadcast by designating a multicast address, a multicast tree can be easily created as described above even if the configuration of the user network changes. be able to. For example, when a new user network is accommodated in the edge nodes 12 and 15, the multicast tree can be easily formed by executing the broadcast execution command after registering the corresponding information in the edge node table. Furthermore, for example, to delete the user network edge node 14 is accommodated, after deleting the relevant information of the edge node table, it is possible to reconstruct the multicast tree also by executing the broadcast command. In addition, by transmitting a transfer stop message to the relay node on the upper side simultaneously with the deletion of the corresponding information from the edge node table, unnecessary multicast trees can be easily deleted.

[0067]

As described above, according to the first aspect of the present invention, the edge node table accommodating the edge node accommodating the user network, the relay node relaying between these edge nodes, and the multicast server node are respectively provided. A relay node table and a multicast server node table are provided, and multicast is performed based on these tables . Edge nodes
Multicast packet multicasting
To determine whether the multicast address is registered
To the user network when registered
To transfer. Also, when not registered
Discard this multicast packet at the edge node
And the source of this multicast packet.
Send a transfer stop message to the upper node that is
The upper node requests the edge node to stop forwarding.
Do not forward the forwarding packet of the multicast address
I did it. The output to be forwarded in the relay node table
Multi when all force interfaces are disabled
Multicast to stop forwarding cast addresses
Send a transfer stop message to the strike server node
So that it will not be forwarded the next time.
This greatly reduces the size of the relay node table
And reduce the load.
You. Also, the transfer stop message is sequentially sent to the upper
Sent to the node to update each table information
Can easily configure a multicast tree
Will be able to do it. In other words, the network configuration
Easy reconfiguration of multicast tree when changes occur
Operation load can be greatly reduced.
You. In addition, the multicast registered in the relay node table
Output address corresponding to each multicast address.
Output interface that is not registered
Send a transfer confirmation message to the
Relay node message by the transfer request message from the
Table update. As a result, once deleted
Output interface that has been
Can update the relay node table every time
Allows you to perform flexible processing according to network conditions.
Swell.

[0068]

Further, according to the invention described in claims 2 to 4 ,
By updating the registration information of each table for the multicast address received for the first time, it is possible to respond flexibly to changes in the user network configuration without performing complicated network management and maintainability of the system. Can be increased.

[0070]

[0071]

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of a configuration of an ATM multicast system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an interface of an edge node according to an embodiment of the present invention.

FIG. 3 is a table configuration diagram showing storage information of an edge node table in one embodiment of the present invention.

FIG. 4 is a flowchart showing the processing content of an edge node that has received a broadcast in one embodiment of the present invention.

FIG. 5 is a flowchart showing the processing contents of an edge node receiving a multicast packet in one embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a configuration of an interface of a relay node in one embodiment of the present invention.

FIG. 7 is a table configuration diagram showing storage information of a relay node table in one embodiment of the present invention.

FIG. 8 is a flowchart showing the processing content of the relay node receiving the transfer data in one embodiment of the present invention.

FIG. 9 is a flowchart showing the processing contents of the relay node which has received the transfer stop message in one embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a configuration of an interface of a multicast server node in one embodiment of the present invention.

FIG. 11 is a table configuration diagram showing storage information of a multicast server node table in one embodiment of the present invention.

FIG. 12 is an explanatory diagram showing processing contents of a multicast server node which has received transfer data in one embodiment of the present invention.

FIG. 13 is a first explanatory diagram illustrating the principle of the multicast tree configuration operation of the ATM connectionless network in one embodiment of the present invention.

FIG. 14 is a second explanatory diagram illustrating the principle of the multicast tree configuration operation of the ATM connectionless network in one embodiment of the present invention.

FIG. 15 is a third explanatory diagram illustrating the principle of the multicast tree configuration operation of the ATM connectionless network in one embodiment of the present invention.

FIG. 16 is a fourth explanatory diagram illustrating the principle of the multicast tree configuration operation of the ATM connectionless network in one embodiment of the present invention.

FIG. 17 is a block diagram showing an outline of a configuration of a conventionally proposed ATM multicast system.

[Explanation of symbols]

 Reference Signs List 10 ATM connectionless network 11-15 Edge node 12-19 Relay node 20 Multicast server node

Claims (4)

(57) [Claims] 1. An identification information for identifying a network accommodating a plurality of users, identification information of a relay node to which a broadcast packet of these networks is transmitted / received, and multicast which is a broadcast selection notification format corresponding to the identification information. An edge node table storing a multicast address for performing the operation, and upon receiving a broadcast packet from the user, assigning a multicast address corresponding to the broadcast packet stored in the edge node table to the packet and adding the packet to the packet Edge node transmitting means for transferring based on the identification information of the relay node in the edge node table; identification information for identifying an input interface to which the transfer packet is input; A relay node table for storing a cast address, identification information, and identification information for identifying an output interface to which a transfer packet corresponding to the multicast address is output; and a multicast address of the transfer packet and the transfer packet being input. A relay node that transfers the transfer packet from an output interface corresponding to the output interface identification information stored in the relay node table based on the input interface identification information as the input interface identification information; A multicast node table storing identification information of a relay node which is a corresponding multicast destination; and a multicast address of a transfer packet transferred from the relay node. And a multicast node for the broadcast selection notification as multicast packets based on the identification information of the relay node stored less than in the multicast node table, via the relay node from the multicast node
Multicast of forwarded multicast packets
Is not registered in the edge node table.
Address judging means for judging whether or not
And the multicast address discriminating means.
When it is determined that a multicast address has been registered
And the edge node transfer means for transferring only the network corresponding to the identification information of the user of the network that is registered corresponding to the multicast address of the multicast packet to the edge node table in the circle by the multicast address discrimination means
That the multicast address has not been registered
The multicast address to the relay node.
The first transfer that sends a data transfer stop message
Transmission stop message transmitting means and the first transfer stop message transmitting means.
When the received transfer stop message is received, the relay node
Multicast that stops this transfer stored in the
No output interface identification information corresponding to the address
A relay node transfer stop setting means to be activated, and a multi- unit for stopping transfer by the transfer stop message.
The cast address is stored in the relay node table.
All output interface identification information is invalid.
In some cases, this multicast packet that stops transmission is
Send a forwarding stop message to the sender of the
Second transfer stop message transmitting means, and the second transfer stop message transmitting means.
When the received transfer message is received, the multicast
Multi-key for stopping this transfer stored in the load table
Multi that invalidates the storage information corresponding to the
A cast node table invalidating means, and a multicast registered in the relay node table.
For each email address, the
Transfer confirmation message periodically for the input interface
Transfer confirmation message transmitting means for transmitting the edge no.
Entry corresponding to the multicast address in the
When updating the recording information, the relay node
The sender of the transfer request message that sends the transmission request message
And the transfer request message transmitted by the transfer request message transmitting means.
Said relay that transmitted a transfer confirmation message by message
Noboru that correspond to the multicast address of the node table
An ATM multicast system comprising: a registration information updating unit for updating recording information . 2. A transfer packet is stored in the edge node table.
When the multicast address of the port is not registered
Is identification information for identifying the user's network
And transmission of broadcast packets on these networks
The identification information of the relay node that is the recipient and the identification information
Set the corresponding multicast address to the edge node.
Edge node initial setting unit for the
2. The ATM multi-function device according to claim 1, further comprising:
Cast system. 3. A transfer packet stored in the relay node table.
When no multicast address is registered
Identify the input interface to which the forwarding packet is input
Identification information for the
Output of a pair with a multicast address and the input interface.
Identification information of all output interfaces other than the power interface
Relay node for registering information in the relay node table.
2. The device according to claim 1, further comprising:
ATM multicast system. 4. The transfer to the multicast node table.
The multicast address of the transmitted packet is not registered
This multicast node table
Multicast address and identification information of all output interfaces
And a multicast address setting unit for registering information.
The ATM multicast according to claim 1, wherein:
System.