JPH07321780A - Multi-cast communication system - Google Patents

Abstract

PURPOSE:To confirm the algorithm to relieve a total traffic in a network by allowing a caller exchange node to copy a setup request signal and transferring a multi-cast call ID and a multi-cast sub-call ID depending definitely on a multi- cast call into a network based on the request signal. CONSTITUTION:In the setup phase, a caller terminal equipment 1-1 sends a multi-cast setup request signal with destination of each called terminal equipment added to a caller node 5-1. The caller node 5-1 copies the signal by the number of incoming terminal equipments and provides a multi-cast call ID used to identify definitely the multi-cast call in a network and a multi-cast sub-call ID included in the multi-cast call to identify each called terminal equipment into each setup request signal to be generated. When a called terminal equipment is accommodated in its own node, the signal is sent to the called terminal equipment and when a called terminal equipment is accommodated in other node, the signal is sent to a relay node 5-6. The relay node 5-6 makes routing leading to the called terminal equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a plurality of switching nodes and a plurality of terminals, which transmits a call setting request signal from a calling terminal to a called terminal and returns a call setting response signal from the called terminal to the calling terminal. The present invention relates to a multicast communication method for performing multicast communication between a plurality of terminals in a communication network in which a call route is set and data is transferred by the route.

[0002]

2. Description of the Related Art In the prior art, when performing multicast communication, a processing method for sending one data signal sent from a calling terminal to a plurality of called terminals is generally There are two methods shown below.

First of all, the first method is that there is one data signal generating node outside the data network, in which the data signal from the calling terminal is duplicated and the signal is sent to a plurality of destination terminals. And a process for performing. A brief description will be given below with reference to FIG. In FIG. 1, 1-1 is a calling side terminal, and 1-2 to 1-5 are called side terminals, respectively. It is assumed that multicast communication is performed between these terminals. Further, 5 is a data signal generation node, 7 is a data exchange network, and 8-1 to 8-4 are data exchange nodes.

When the exchange node 8-1 receives the data signal to be multicast from the originating terminal 1-1, it relays the signal to the data signal generating node 5. The data signal generation node duplicates the data signal from the calling subscriber for a plurality of destination terminals, and adds relay information to the destination terminals so that the data signal can be relayed. Send to the switching node. In switching nodes 8-3 and 8-4,
The data signal is transmitted to each designated destination terminal by the relay information.

In the first method, there is one data signal generation node 5 outside the data network, and the data signal from the source terminal is duplicated by the node for the destination side terminal and relayed in the network. As a result, there arises a problem that intra-network traffic increases in proportion to the number of destination terminals.

The second method is, as shown in FIG. 2, a plurality of data signal generating nodes 5-1 to 5-4 in a data switching network.
There is a method in which the node duplicates the data signal from the calling terminal and transmits the signal to a plurality of called terminals. The second method is more advantageous than the first method in terms of traffic distribution because the data signal generation nodes are distributed in the network, but specifically how to duplicate the data signal and relay it. Since a clear algorithm has not been established as to whether to perform it, it cannot be said that it is superior to the first method in reducing the total traffic volume in the network.

[0007]

As described above in the description of the prior art, in the multicast communication between a plurality of terminals, the data signal sent by the calling terminal is duplicated for the called terminal, so that the final result is Intranet traffic will increase. As used herein, "finally increases intra-traffic traffic" means that the data signal itself is copied to the destination terminal on a one-to-one basis.
Since it is transmitted, the number of traffic of the data signal between the switching node immediately before reaching the destination terminal, that is, the switching node accommodating the destination terminal and the terminal is, in the case of multicast communication, naturally the source terminal. It means that the number of incoming terminals is increased more than the data signal transmitted by.

In other words, in multicast communication, the closer the position where the data signal to be transmitted to the destination terminal is duplicated is to the switching node in which the originating terminal is accommodated, the total traffic in the network due to the relayed data signal. The amount increases. An increase in the total traffic amount leads to a reduction in the processing capacity of the switching node in the network, and eventually causes a deterioration in the service quality of the network as a whole such as a data signal transfer delay. In multicast communication, a method of reducing intra-network traffic by using a duplicated data signal has become a major issue, and this is an issue to be solved by the present invention.

As described above, an object of the present invention is to perform a relay process by duplicating a data signal by a plurality of data signal generating nodes in a data exchange network when performing multicast communication between a plurality of terminals. In the method of 2,
It is to establish an algorithm of the multicast communication method for reducing the total traffic volume in the network.

[0010]

To achieve the above object, according to the present invention, an exchange node accommodating a calling terminal receives a multicast call setting request signal from a calling terminal during a call setting phase. After that, the call setup request signal for the other terminal is duplicated, and in each of the generated call setup request signals, the multicast call ID that can uniquely identify the multicast call in the network and the multicast call ID that belongs to the multicast call. A multicast call sub-ID for identifying each called terminal is set, and these are included and transmitted to each called terminal.

Each relay switching node and / or destination switching node through which the multicast call goes through has its ID,
The sub ID is detected, and when the call setup response signal from the destination terminal is received, the switching node close to the destination terminal is determined as the data signal generation node for the call. In the data transfer phase, when the data signal generating node determined in the call setting phase receives the data signal transmitted by the calling terminal, the data signal generating node duplicates the data signal for the call in charge. Send to the destination terminal.

In the call setup phase, if the call setup response signal to the multicast call setup request signal is not returned from the receiving side terminal within a certain period of time,
The originating / switching node accommodating the originating terminal transmits a call release signal for disconnecting the multicast sub-call for the terminating terminal, and each relay switching node and / or the terminating / switching node sends a multicast sub-call in charge of data generation. Delete the multicast sub-call addressed to the called terminal from among the above.

When another terminal is added to or deleted from a multicast communication that is already in communication, the data generation node of the terminal is determined by the multicast call ID and the multicast call sub ID, and the data generation node determines the data generation node. Add / delete communication of.

[0014]

In the multicast communication in which the signal transmitted from one calling terminal is duplicated in the network and delivered to a plurality of called terminals,
In the call setup / release phase, the call setup request signal is duplicated at the originating switching node, and this signal uniquely determines the multicast call ID and one of the plurality of destination terminals belonging to the multicast call. By transferring the multicast sub-call IDs assigned to each of them in the network, there is no high-performance node, and by adding a function based on public intra-network routing, in the switching node as close as possible to the destination terminal in the data transfer phase. The data signal from the calling terminal can be duplicated to suppress an increase in intra-network traffic due to the multicast call.

Further, the present invention can realize the processing in the case where no response is returned from all the terminals, and the operation in the case where the terminal is added to the multicast call or is disconnected from the multicast call on the way. The present invention is also applicable to multicast communication in frame relay or ATM exchange as well as packet exchange.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. In FIG. 3, 1-1 is a calling side terminal and 1-2 to 1-5 are receiving side terminals. Further, reference numeral 2 denotes a multicast communication group for performing the multicast communication which is the premise of this description. 3-1 to 3-5 are multicast call setup request signals, and 4-1 to 4-4 are call setup response signals to the call setup request signals. 5-1 to 5-3 indicate switching nodes accommodating each terminal, and 5-4 to 5-7 indicate relay switching nodes, respectively. Here, terminal 1-1
The data generation node determination method in the call setup phase will be described based on an example in which multicast communication between 1 to 5 is performed.

The calling terminal 1-1 transmits to the calling node 5-1 a multicast call setting request signal 3-1 to which the destination of each called terminal is added. At the source node, the signal is duplicated for each destination terminal, and at the same time, a multicast call ID (11 in FIG. 4) that uniquely identifies the multicast call in the network is included in each generated call setup request signal. A multicast sub-call ID (Fig. 4-12) that belongs to the multicast call and identifies each called terminal is assigned.

When the destination terminal is accommodated in the own node, the signal 3-2 is transmitted to the destination terminal, and when accommodated in another node, the relay node 5-6 is notified to the relay node 5-6. Send a signal. The relay node relays the signals 3-3 to 3-5, respectively, and performs routing to the destination terminal. At this time, each node detects the multicast call ID and the multicast sub-call ID respectively, and recognizes that the multicast call has passed through its own node.

The switch node responds to the plurality of multicast sub-calls from each destination terminal by call setup response signals 4-1 to 4-4.
When a message is received, a data signal generation node display indicating that the node becomes a data signal generation node for the plurality of multicast sub-calls from each relay switching node and / or destination switching node to the calling side (Fig. 21 of 5)
Is transmitted on the call setting response signal (22 in FIG. 5). The relay node and / or the originating switching node which received the data signal generation node indication are set so as not to generate data for the multicast sub-call.

In the data transfer phase, when the data signal generating node determined in the call setting phase receives the data signal transmitted by the calling terminal, the data signal generating node is in charge of the data corresponding to the multicast sub-call. A signal is generated and transmitted to the destination terminal. According to the above procedure, in the example of FIG. 3, the switching node 5-1 duplicates two data signals, the data signal to the destination terminal 1-2 and the data signal to the destination terminals 1-3 to 1-5. , Switching node 5-6
In the switching node 5-3, the data signal to the destination terminal 1-3 and the data signal to the destination terminals 1-4 and 1-5 are duplicated.
It is set as a data signal generation node that replicates the data signal for 1-4 and the data signal for the destination terminal 1-5.

FIG. 4 shows the structure of a multicast call setup request signal generated at the originating node, where 11 is a multicast call ID and 12 is a multicast subcall ID.
Reference numeral 13 denotes the main body of the call setting request signal from the calling terminal. FIG. 5 shows the structure of the multicast call setup response signal generated in the data signal generation node, 21 indicates the data signal generation node display, and 22 indicates the main body of the multicast call setup response signal from the destination terminal. ing.

Next, the disconnection process in the case where the call setup response signal of the destination terminal is not returned within a fixed time in response to the multicast call setup request signal will be described in detail with reference to FIG. The originating switching node 5-1 accommodating the originating terminal 1-1 sends a call setup request signal 3-2 to each destination terminal 1-2 to 1-5 based on the multicast call setup request signal 3-1 from the originating terminal. Through 3-5
The timer T is started when is transmitted.

In the example of FIG. 6, the call setup response signals 4-1 to 4-3 from the destination terminals 1-2 to 1-4 arrive at the originating switching node before the value of the timer T reaches a certain value. When the call setup response signal from the destination terminal 1-5 is not returned to the source node before the value of the timer T reaches a certain value, a call for disconnecting the multicast sub call for the destination terminal The relay switching node and / or the destination switching node 5-3, 5-6, 5-7 which transmits the call release signal 6 and receives the call release signal releases the call and the data generation node of the multicast sub-call. Relay switching node or destination switching node 5-3 that was set as
Then, the multicast sub-call addressed to the called terminal is deleted from the multicast sub-calls in charge of data generation.

Next, referring to FIG. 7, in the data transfer phase of the multicast communication from the source terminal to the plurality of destination terminals via one or more data generation nodes,
A method for soliciting participation in the multicast data communication from the calling terminal to the other terminal will be described in detail.
In FIG. 7, 1-1 is a calling side terminal and 1-2 to 1-5 are receiving side terminals. Furthermore, 2 has shown the multicast communication group which has already performed the multicast communication. (In the example of FIG. 7, terminals 1-1 to 1-4 are included.)

In the calling terminal 1-1, in the data transfer phase of the multicast communication, the invitation signal for participation in the multicast data communication is sent to the other terminal (1-5 in FIG. 7) not participating in the multicast communication. Send 3-1 of 7). The participation invitation signal includes the already set multicast call ID and the new multicast sub-call ID belonging to the multicast call. Relay switching node and / or destination switching node 5-2 which receives the participation invitation signal
At 5-7, the presence / absence of a set call belonging to the multicast call or the presence / absence of a setting of the multicast call as a data generation node is detected.

When the relay exchange node or the destination exchange node has detected a set call belonging to the multicast call and receives a participation confirmation signal 3-2 from the other destination terminal, the relay exchange node Alternatively, a data signal generation node indicating from the destination switching node 5-3 to the originating side that the own node becomes a data signal generation node for the set multicast subcall and a new multicast subcall for another destination terminal. The display is transmitted along with the participation confirmation signal. The relay node and / or the originating switching node 5-1,5,4,5-6,5-7 which received the data signal generating node indication are set so as not to generate data for the multicast sub-call.

When the relay exchange node or the destination exchange node receives the invitation signal to the other destination terminal and detects the setting as the data generating node of the multicast call, the other destination terminal When the participation confirmation signal is received, the node from the relay switching node or the destination switching node to the originating side transmits data to the data signal generation node for the plurality of set multicast sub-calls and new multicast sub-calls for other terminals. A data signal generation node display that indicates that the participation confirmation signal is transmitted.
The relay node and / or the originating switching node receiving the data signal generation node indication are set so as not to generate data for the multicast sub-call. By the above procedure, after the data generation node corresponding to the multicast sub call addressed to the other terminal is determined, the data transfer to the other terminal is added.

Next, referring to FIG. 8, in the data transfer phase of the multicast communication from the calling terminal to the plurality of destination terminals via one or more data generating nodes,
A method of making a request for participation in the multicast data communication from the other-arrival terminal to the originating terminal will be described in detail. In FIG. 8, 1-1 is a calling side terminal, and 1-2 to 1-5 are receiving side terminals. Furthermore, 2 has shown the multicast communication group which has already performed the multicast communication. (In the example of FIG. 8, terminals 1-1 to 1-4 are included.)

In the other terminal (1-5 in FIG. 8) not participating in the multicast communication, in the data transfer phase of the multicast communication, the originating terminal 1-1 and the participation request signal 4-1 for the multicast data communication are sent. Send. A multicast call ID already set in the participation request signal and a new multicast sub-call ID belonging to the multicast call
Is included in the multicast call at the destination switching node 5-3 and / or the relay switching node 5-4,5-6,5-7 and / or the originating switching node 5-1 which receives the participation request signal. The presence / absence of a set call to which it belongs or the presence / absence of a setting as a data generation node of the multicast call is detected.

When it is detected that the set call or the setting as the data generation node is detected, the fact is included in the participation request signal and sent to the calling side, and the relay switching node that has received the participation request signal and The origination / switching node is set so as not to be the data generation node of the new multicast subcall. As a result, the relay switching node or the destination switching node 5-3 set as the data generation node of the new multicast sub-call receives the participation confirmation signal 3-1 for the participation request signal transmitted from the calling terminal, Is transmitted to the other destination terminal, and then data transfer to the other destination terminal is added.

Next, referring to FIG. 9, in the data transfer phase of the multicast communication from the source terminal to the plurality of destination terminals via one or more data generation nodes, a specific multicast sub belonging to the multicast call is transmitted. The method of releasing the call will be described in detail. A multicast sub-call release signal 3-1 for releasing a specific multicast sub-call belonging to the multicast call,
It is transmitted from the calling terminal 1-1 or the called terminal 1-5 corresponding to the multicast subcall.

The originating switching node 5-1 and / or the relay switching node 5-4, which receives the multicast sub-call release signal,
The 5-6, 5-7 and / or the destination switching node 5-3 releases the multicast sub-call. Further, when the originating switching node, the relay switching node, or the destination switching node is set as the data generating node for the multicast subcall (5-3 in the example of FIG. 9), the transfer to the destination terminal is canceled. , The communication of other multicast sub-calls belonging to the multicast call is continued.

[0033]

According to the present invention, in multicast communication in which a signal transmitted from one calling terminal is duplicated in a network and delivered to a plurality of called terminals, a call setting request is made at a calling switching node in a call setting / release phase. Copying a signal, and transferring a multicast call ID uniquely determined by the signal to the multicast call and a multicast sub-call ID that belongs to the multicast call and is assigned to each of the plurality of destination terminals to the network. As a result, it becomes possible to easily realize multicast communication without a high-performance node and by adding a function based on the public network routing.

Further, in the present invention, the data signal from the calling terminal can be duplicated in the switching node as close as possible to the called terminal in the data transfer phase, and the increase of intra-network traffic due to the multicast call can be suppressed.
Further, the present invention can also realize the processing in the case where no response is returned from all the destination terminals, and the operation in the case of joining the multicast call from the middle or leaving from the multicast call on the way. The present invention is also applicable to multicast communication in frame relay or ATM exchange as well as packet exchange.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a conventional multicast communication method.

FIG. 2 is a diagram illustrating a conventional multicast communication system.

FIG. 3 is a diagram illustrating a method of determining a data signal generation node according to the first aspect of the present invention.

FIG. 4 is a diagram showing a configuration of a multicast call setup request signal generated by a calling-side node.

FIG. 5 is a diagram showing a structure of a multicast call setup response signal generated by a data signal generation node.

FIG. 6 is a diagram for explaining a cancellation method when the called terminal has not responded in the second aspect of the present invention.

FIG. 7 is a diagram illustrating a method of soliciting from another terminal to participate in multicast communication of another terminal according to the third aspect of the present invention.

FIG. 8 is a diagram illustrating a method in which another terminal participates in multicast communication according to the fourth aspect of the present invention.

FIG. 9 is a diagram illustrating a method for releasing a specific terminal from multicast communication according to the fifth aspect of the present invention.

[Explanation of symbols]

1-1 Originating terminal 1-2 -1-5 Destination terminal 2 Multicast communication group 3-1-3-5 Request signal 4-1-4-4 Response signal 5 Data signal generating node 5-1-5-7 Switching node 6 Call release signal 7 Data switching network 8-1 -8-4 Switching node 11 Multicast call ID 12 Multicast sub call ID 13 Main body of multicast call setup request signal sent by the calling terminal 21 Data signal generation display 22 Sended by the called terminal Multicast call setup response signal body

Claims (5)

[Claims] 1. A call route is configured by comprising a plurality of switching nodes and a plurality of terminals, transmitting a call setting request signal from a calling terminal to a called terminal and returning a call setting response signal from the called terminal to the calling terminal. Then, in the communication network that transfers data by that route, in the call setting phase, the calling terminal sends a multicast call setting request signal for requesting call setting to a plurality of called terminals, and the calling switch that accommodates the calling terminal. After the node receives the multicast call setup request signal, it generates a call setup request signal for the other terminal, and uses each call setup request signal to uniquely identify the multicast call in the network. Each including the multicast call ID and the multicast sub-call ID that belongs to the multicast call and identifies each called terminal, and transmits to each called terminal The relay switching node and / or the destination switching node detects that a plurality of multicast sub-calls having the same multicast call ID and different multicast sub-call IDs pass through the relay switching node and / or the destination switching node. However, after receiving a call setup response signal corresponding to the plurality of multicast sub-calls from each called terminal, the node from the relay switching node and / or the called switching node toward the calling side sends the plurality of multicast sub-calls. To the multicast switching sub-call, the relay node and / or the originating switching node which has transmitted the data signal generation node indication indicating that it will become a data signal generation node for Is set not to generate data for the When the data signal generation node determined in the call setup phase receives the data signal transmitted by the calling terminal, the data signal generation node generates the data signal for the number of multicast sub-calls for which the data signal generation node is in charge A multicast communication method characterized by transmitting. 2. An originating switching node accommodating an originating terminal starts a timer T when transmitting a call establishment request signal to each destination terminal based on a multicast call establishment request signal from the originating terminal, and sets a value of T. If the call setup response signal does not come back from the specific destination terminal before the number reaches a certain value, the call release signal for disconnecting the multicast sub call for the destination terminal is transmitted and the call release signal is received. The relay switching node and / or the destination switching node releases the call, and at the relay switching node or the destination switching node set as the data generation node of the multicast sub call, from the multicast sub call in charge of data generation, First, characterized in that a multicast sub-call addressed to the destination terminal is deleted
Multicast communication method described in section. 3. In a data transfer phase of a multicast communication from an originating terminal to a plurality of destination terminals via one or more data generation nodes, participation in the multicast data communication from the originating terminal to other destination terminals. The invitation signal is transmitted, and the participation invitation signal includes the already set multicast call ID and the new multicast sub-call ID belonging to the multicast call, and the relay switching node and / or the relay switching node that receives the participation invitation signal. The destination switching node detects the presence or absence of a set call belonging to the multicast call or the setting of the multicast call as a data generation node, and the relay switching node or the destination switching node sets a set call belonging to the multicast call. If the participation confirmation signal is received from the other terminal when the A data signal generation node display indicating that the node becomes a data signal generation node for the set multicast sub call and a new multicast sub call for another destination terminal from the destination or destination switching node to the originating side. The relay node and / or the originating switching node which have transmitted the participation confirmation signal and received the data signal generating node indication are set so as not to generate data for the multicast sub-call, and the relay switching node or the destination switching node When the exchange node receives the invitation signal to join the other terminal, when it detects the setting as the data generation node of the multicast call, when it receives the join confirmation signal from the other terminal, From the relay switching node or destination switching node to the originating side, the local node sends a plurality of multicast sub-calls already set and other A data signal generating node display indicating that the data signal generating node for a new multicast sub-call for a terminal is displayed on the participation confirmation signal and transmitted, and the relay node and / or the call originator receiving the data signal generating node display. The switching node is set so as not to generate data for the multicast sub-call, so that after the data generation node corresponding to the multicast sub-call addressed to the other terminal is determined,
The multicast communication system according to claim 1, wherein data transfer to the other terminal is added. 4. In a data transfer phase of multicast communication from an originating terminal to a plurality of destination terminals via one or more data generating nodes, participation in the multicast data communication from another destination terminal to the originating terminal. A request signal is transmitted, and the participation request signal includes the already set multicast call ID and a new multicast sub-call ID belonging to the multicast call, and the destination switching node and / or the node that receives the participation request signal. The relay switching node and / or the originating switching node detects the presence / absence of a set call belonging to the multicast call or the presence / absence of a setting of the multicast call as a data generation node, and detects whether the set call or the data generation node is set. If the setting is detected, the fact is included in the participation request signal and sent to the calling side. The relay switching node and / or the originating switching node that received the participation request signal are set so as not to become the data generating node of the new multicast subcall, and as a result, the relay switching set as the data generating node of the new multicast subcall. That the node or the destination switching node receives a participation confirmation signal for the participation request signal transmitted from the originating terminal, transmits it to the other destination terminal, and then adds data transfer to the other destination terminal. The multicast communication system according to item 1, which is characterized. 5. A multicast for releasing a specific multicast sub-call belonging to the multicast call in a data transfer phase of multicast communication from an originating terminal to a plurality of destination terminals via one or more data generating nodes. At the originating switching node and / or the relay switching node and / or the destination switching node that transmits the sub call release signal from the calling terminal or the called terminal corresponding to the multicast sub call and receives the multicast sub call release signal, When the call is released, or when the originating switching node, the relay switching node, or the destination switching node is set as the data generation node for the multicast subcall, the transfer to the destination terminal is released and the multicast call is added. Communication of other multicast sub-calls to which it belongs continues The multicast communication system according to item 1, characterized in that