JP2019125996A - Multi-point communication system and method, and program - Google Patents

Abstract

To provide a multipoint communication system and method, and program that are small in load on a network and a server and small in delay.SOLUTION: A multipoint communication system includes multipoint control units (MCU) 50 that operate at a plurality of edge servers 40 geographically distributed and deployed in a relay network 30, and an MCU management function 60. The MCU management function 60 selects one or more multipoint connection devices 50 so as to optimize group communication costs on the basis of network configuration information and resource information on the network and the server prior to start of group communication. If there are multiple multipoint connection devices 50, the MCU management function coordinates the multipoint connection devices 50 with each other and controls each of the multipoint connection devices 50 so as to behave themselves such that a terminal device 10 may see as if single group communication is being carried out although the multiple multipoint connection devices are involved.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a multipoint communication system in which group communication is performed between a plurality of terminals by using a multipoint connection function as an AC point.

  In recent years, along with the development of ultra-high-definition camera / display devices such as 4K / 8K and AR (Augmented Reality) / VR (Virtual Reality) technology, telework of each company for the purpose of energy saving and life work balance Demands for video communication services via networks are increasing due to recommended measures and the like.

  A video conference is mentioned as a representative example of a video communication service. A multipoint control unit (MCU: Multipoint Control Unit) is known as a device well-known in configuring a video conference system. The MCU is a device arranged in the network as an exchange point of group communication, and the MCU for the video conference system combines the video of each participant into one screen after receiving video / audio packets from all the user terminals. It is a device that combines and distributes video / audio to all user terminals.

  In multipoint video conferencing using an MCU, there is a problem in that while the terminal load can be reduced compared to multipoint video conferencing in P2P (Peer to Peer), the computational load and network load of the MCU server increase. As an example of a method of reducing the network load of MCUs, a system in which a plurality of MCUs are distributed and distributed geographically is known (see, for example, Patent Document 1). In this system, for example, an MCU in Osaka and a MCU in Tokyo are cascaded while the MCUs accommodating the conference participation terminals are separated in the Osaka area and the Tokyo area. Conference participant images of a plurality of terminals in the Osaka area are sent to the MCU in Tokyo in a state of being combined into one screen in the MCU in Osaka. Similarly, in the reverse direction, conference participant images of a plurality of users in the Tokyo area are sent to the MCU in Osaka in a state where they are combined into one screen in the MCU in Tokyo. Such a system can suppress an increase in the network bandwidth between Tokyo and Osaka.

Patent No. 3457202 JP 2003-69563A

  According to the method described in Patent Document 1 described above, since a plurality of MCUs are cascade-connected, the relay network can be used even when the number of conference participants increases or the video quality rate is made higher. It is expected that the increase of the network load at the interconnections (gateways) with other networks can be prevented. However, the system described in Patent Document 1 requires dedicated hardware to be prepared in advance, and since the MCU can only use a fixedly deployed system, the service subscriber status changes from the initial facility design. There is a problem that the optimality is lost in the case where it has been done.

  Therefore, as described in Patent Document 2, a method of dynamically changing an MCU to be used according to the configuration of a participating terminal from among a group of MCUs distributed geographically and distributed is used each time a conference occurs. Proposed. In this way, it is possible to select the optimal MCU (eg, to minimize the network traffic generated by the conference) each time a conference is held, so participant area configuration without being tied to the initial design This enables effective relay network bandwidth savings. Also, even when a certain MCU fails, another candidate MCU may be selected, so that a conference can be held. Also, as another similar method, a method of calculating the degree of proximity (the sum of inverse numbers of available bands of each section) for each participating terminal, and selecting an MCU with the smallest sum of the degrees of proximity in the meeting is also considered. There is.

  However, the method described in Patent Document 2 or the like is only given a method of selecting a single MCU for each conference, and a plurality of effective ones can be selected according to the regional bias of the conference participation terminals, etc. There is no mention of a method for selecting and cascading MCUs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multipoint communication system, a method, and a program that reduce load and delay of a network and a server.

  In order to achieve the above object, the present invention is a multipoint communication system in which group communication is performed between a plurality of terminals accommodated in a network, in which a plurality of servers geographically distributed in the network are distributed. Based on network configuration information including at least location information of the terminal and location information of the server, and resource information of the network and the server, prior to the start of the group communication and the multipoint connection function that operates, Multipoint connection function selection means for selecting one or more of the multipoint connection functions such that the utilization cost of the network and the server is optimal, and the multipoint connection function selected by the multipoint connection function selection means In the case where there are multiple devices, the multipoint connection function of each other is linked and straddles the multiple point connection functions. Reluctant even from the terminal is characterized in that a multipoint connection function control means for controlling each multipoint connection functions to behave as if a single group communication is being performed.

  According to the present invention, even when the number of terminals participating in group communication increases, it is possible to prevent an increase in the bandwidth of the gateway portion with the network or another network. And since the restriction of the bandwidth of the gateway part with the network and other networks is eased, if the access section between the terminal and the server is a high-speed circuit such as FTTH (Fiber to the Home) or 5G, broadband is It will enable video conferencing with higher definition and higher reality by utilizing it. In addition, even if a failure or a shortage of available resources occurs in a specific server, group communication between multiple points can be performed without using the server.

A diagram for explaining the outline of the present invention System configuration of multipoint communication system System configuration diagram of multipoint conference system according to another example Functional block diagram of MCU management function Functional block diagram of MCU management function according to another example Functional block diagram of MCU management function according to another example Example of flow from conference reservation to conference holding to conference closing in multipoint conference system Example of a flow from conference reservation to conference holding and conference closing in a multipoint conference system (multiple conferences simultaneously) Example of flow of MCU optimal layout calculation processing Detailed flow example of MCU optimal layout calculation processing A diagram for explaining a specific example of the MCU optimum layout calculation process Simple example of cost calculation Simple example of cost calculation Simple example of cost calculation Simple example of cost calculation Simple example of cost calculation Diagram to explain the MCU optimum layout calculation step according to another example Diagram to explain the MCU optimum layout calculation step according to another example Diagram (1/3) explaining the MCU optimal layout calculation step according to another example (simultaneous holding of multiple conferences) Diagram (2/3) explaining the MCU optimum layout calculation step according to another example (simultaneous holding of multiple conferences) Diagram to explain the MCU optimum layout calculation step according to another example (3/3) (simultaneously holding multiple conferences)

  First, the outline of the present invention will be described with reference to FIG. The present invention is a multipoint communication system for performing group communication between a plurality of terminals 1 accommodated in a network, as shown in FIG. The present invention relates to a multipoint communication system in which group communication is performed with the multipoint connection function 3 distributed as described in FIG. Here, the “multipoint connection function” means one that functions as a conventional multipoint control unit (MCU), and its implementation form is irrelevant as described later. In FIG. 1 (b), the multipoint connection function 3 is marked as MCU3. Note that FIG. 1 illustrates a multipoint conference system for realizing a video conference between multiple points as an application example of the multipoint communication system.

  In the prior art shown in FIG. 1A, only one MCU 3 is deployed as a whole, and the images of all the conference participants 1 are combined and distributed to each participant 1. Therefore, there is a problem that video traffic is concentrated on one MCU 3. On the other hand, in the present invention, as shown in FIG. 1B, in each of the distributedly deployed MCUs, primary compilation screen composition is performed for each area, the primary compilation screen is exchanged between the respective MCUs 3, and final composition is performed. It distributes to each participating terminal 1. This has the advantage that the use of the relay network can be achieved with a single screen bandwidth.

  In the present invention, it is optimal according to the network configuration information including the service area of the terminal 1 of the group communication participant, the network resource information such as the available bandwidth of each network section, and the infrastructure information such as the server resource information of the edge server 2 Select edge server 2 for one or more) MCUs (optimal deployment calculation).

  Further, in the present invention, a plurality of MCUs 3 cooperate with each other to control the MCUs 3 so that the terminal 1 of the user looks like the same virtual group communication. As an example of control, a parent MCU and a child MCU are selected from among the determined MCUs 3 and are temporarily connected in cascade.

  The present invention is also characterized in that the above group communication is held based on the reservation information, and the MCU selection calculation is started by back calculation from the time taken for the MCU selection calculation and the MCU instance expansion.

  The present invention provides an MCU management function 4 (or a node / apparatus equipped with the above function) that manages an MCU group in order to realize the above-mentioned group communication. As described above, the MCU management function 4 performs the optimal deployment calculation of the MCU 3 and instructs the MCU 3 to cooperate.

  In FIG. 1, a network accommodating a plurality of edge servers 2 is connected to another network such as the Internet. Therefore, when viewed from the other networks such as the Internet, each edge server 2 appears to be disposed closer to the terminal 1 in the "edge" side of the network, that is, in the entire network including the other networks. Each server in the figure is called an edge server. The same applies to the following description.

  Next, a more specific embodiment of the present invention will be described with reference to FIG. In this embodiment, a multipoint conference system will be described as in FIG. 1 described above. FIG. 2 is a system configuration diagram of the multipoint conference system.

  As shown in FIG. 2, the multipoint conference system includes a plurality of terminals 10, an access network 20, a relay network 30 that spans a plurality of areas, an edge server 40 that is geographically distributed, and the edge server 40. The configuration includes an MCU application 50 deployed on the upper side, and an MCU management function 60 that controls the edge server 40 and the MCU application 50.

  The access network 20 is a network that accommodates the terminal 10 in the relay network 30. In FIG. 2, it does not mean that the plurality of terminals 10 are accommodated in the relay network 30 by one access network 20, but is a logical network showing relative deployment positions of the access network 20 in the network topology. Please note that.

  The relay network 30 is a logical network configured by the interconnection of a plurality of geographically distributed regional networks, and includes a plurality of network devices 35 such as geographically distributed routers. The network topology of the relay network 30 in the present embodiment is assumed to have a tree structure with the network device 35 as a node, as shown in FIG. The relay network 30 is connected to the other network 70 such as the Internet via the top network device 35 of the tree structure. In the following description, between each node in the access network 20 and the relay network 30 will be referred to as a “network section”.

  The edge server 40 is connected to the network device 35 in the vicinity of the network device 35. That is, the edge servers 40 are also distributed and distributed geographically in the relay network 30. The edge server 40 is connected to an arbitrary network device 35 in the relay network 30. In FIG. 2, only the network device 35 to which the edge server 40 is connected is illustrated. Also, a plurality of edge servers 40 may be connected to one network device 35. FIG. 2 shows the case where the number of connected edge servers 40 is one for all the network devices 35.

  The MCU management function 60 may select any one or more of the access network 20, the relay network 30, and the edge server 40 (network topology, location information of the terminal 10, location information of the edge server 40, route cost, Means for acquiring available bandwidth of each network section, available resource of edge server, edge server operating cost, etc.) are provided. In the example of FIG. 2, among the resource information, information related to the network is acquired via the network management node 81, and information related to the server resource is acquired via the server infrastructure management node 82.

  The MCU management function 60 includes means for obtaining conference reservation information (conference start / end time, maximum number of participants, participation terminal list, etc.) from the user. In the example of FIG. 2, the case where the said meeting reservation information is acquired via the meeting reservation system 90 is shown.

  The MCU management function 60 has a function of selecting one or more MCU edge servers 40 most suitable for the area where the conference participant is located, based on the acquired resource information and conference reservation information.

  The MCU management function 60 includes means for instructing the MCU 50 on each edge server 40 to hold / terminate a conference based on the result calculated by the selection function. If the MCU 50 is software that operates on a virtual machine (VM) on a virtual hypervisor, VM creation / deletion / activation / termination also for the virtual hypervisor or VM, activation / termination of the MCU application 50 Etc. are provided. In the example of FIG. 2, the various commands are described using an example in which the server infrastructure management node 82 is used.

  The edge server 40 and the MCU 50 may have various forms. The edge server 40 may be a virtual hypervisor (or virtual host), and the MCU 50 may be software operating on a virtual machine (VM). In addition, the edge server 40 may be a container host, and the MCU application 50 may be provided on the container. Also, the edge server 40 may be a general-purpose server, and the MCU 50 may be application software. In addition, an appliance product in which the edge server 40 and the MCU 50 are integrated can be used.

  The MCU 50 executes the process related to the group communication according to the instruction from the MCU management function 60. When group communication is performed by a plurality of MCUs 50, each MCU 50 cooperates with another MCU 50, and group communication is performed so that the terminal 10 behaves as if a single group communication is performed while straddling the plurality of MCUs 50. Carry out such processing. In the case of the conference system as in the present embodiment, the MCU 50 primarily combines data from each terminal 10 under its control, and transmits the combined data to the other MCU 50. Further, the MCU 50 combines the combined data synthesized by itself and the combined data received from the other MCU 50 to create final combined data, and transmits the final combined data to each terminal 10 under the control of the own. The MCU 50 cooperates with the other MCU 50 to control holding, deletion, and termination of group communication, and halfway participation and withdrawal of the terminal 10, and the like.

  The network management node 81 includes infrastructure resource information (network topology, location information of the terminal 10, location information of the edge server 40, route cost, and the like of any one or more of the access network 20 and the relay network 30). And a means for acquiring the available bandwidth of the network section. The infrastructure resource information is acquired from various network devices and network management devices that configure the access network 20 and the relay network 30. In the example of FIG. 2, a part of infrastructure resource information is acquired from at least each network device 35. Further, the network management node 81 comprises means for notifying the MCU management function 60 of the acquired information.

  The server infrastructure management node 82 includes means for acquiring resource information (available resources (CPU, memory, storage, GPU, etc.) of the edge server 40, operation costs when the server is used, etc.) related to the edge server 40. The server resource information is acquired from the management device directly from the edge server 40 or when there is a management device managing the edge server 40. Further, the server infrastructure management node 82 includes means for notifying the MCU management function 60 of the resource information related to the acquired edge server 40.

  In addition, the server infrastructure management node 82 includes means for performing various operations on the edge server 40 and the MCU 50 based on an instruction from the MCU management function 60. For example, when the edge server 40 is a virtual hypervisor (virtual host server) and the MCU 50 is a software application operating on a VM, the server infrastructure management node 82 transmits a VM image to each edge server 40 or , Create a new VM, delete an existing VM, and have a means to start / stop the VM. Also, a means for creating / deleting a conference room to the MCU application 50, instructing a terminal to make a call, linking a plurality of MCU applications, and executing the same as a virtual conference room is provided.

  The MCU management function 60 such as cooperation, meeting room creation / deletion, call origination, and the like to the MCU 50 directly transmit the instruction from the MCU management function 60 without passing through the server infrastructure management node 82. Also good.

  Further, as shown in FIG. 3, from the MCU management function 60 through the separately provided MCU management node 83, an instruction from the MCU management function 60 to the MCU 50 such as cooperation, meeting room creation / deletion, calling etc. It may be in the form of sending.

  Next, the MCU management function 60 will be described in detail with reference to FIG. FIG. 4 shows a functional block of the MCU management function 60. As shown in FIG. 4, the MCU management function 60 includes a conference reservation information reception unit 61, an infrastructure information reception unit 62, an MCU selection calculation unit 63, and an edge server / application control transmission unit 64.

  The meeting reservation information receiving unit 61 receives meeting holding reservation information from the user. The meeting holding reservation information includes information such as a meeting start / end time, the maximum number of participants, and a list of participating terminals.

  The infrastructure information reception unit 62 includes a network topology, information for specifying the position of each terminal 10, information for specifying the position of each server infrastructure, and resource information such as available bandwidth for each network section. Receive from Further, the server infrastructure management node 82 receives information on resource information (available CPU / memory / GPU / storage, etc.) of each edge server 40 distributed in the area.

  The MCU selection calculation unit 63 optimizes the balance between the network cost, the server infrastructure resource, and the conference quality in holding the meeting based on a part or all of the information on the meeting reservation and the infrastructure resource information. Such one or more MCUs 50 are calculated. Details of the process in the MCU selection calculation unit 63 will be described later.

  The edge server / application control transmission unit 64 links the selected MCU 50 with the other MCU 50 based on the optimal calculation result calculated by the MCU selection calculation unit 63, and a single virtual conference room is held from the user terminal 10. A control instruction is sent to the edge server 40 corresponding to the selected MCU 50 and the MCU 50 so as to make it behave as if it has been done. The control instruction is transmitted to the edge server 40 and the MCU 50 via the server infrastructure management node 82. When the MCU 50 operates as an application on the edge server 40 as a virtual server infrastructure, the edge server / application control transmission unit 64 deploys an instance of an MCU application to each virtual server infrastructure, and the deployed MCUs It instructs collaboration between application instances, creates a virtual conference room, calls a conference participation terminal as soon as the conference opening time, and disconnects at the end of the conference, ends the virtual conference room, deletes unnecessary MCU application instances, etc. Command is sent via the server infrastructure management node 82.

  As described above, in the case of a mode in which the instruction to the MCU 50 among the control instructions is directly transmitted from the MCU management function 60 without passing through the server infrastructure management node 82, as shown in FIG. The server / application control transmission unit 64 includes an edge server control transmission unit 64 a and an application control transmission unit 64 b. Further, as shown in FIG. 6, the instruction to the MCU 50 in the control instruction is the same in the case of transmitting via the MCU management node 83.

  Next, a flow example from conference reservation to conference holding to conference ending in the multipoint conference system according to the present embodiment will be described with reference to FIG. Here, for the sake of simplicity, the procedure for holding a single conference will be described.

  The MCU management function 60 first receives a reservation of a held meeting (step S1). Next, the MCU management function 60 calculates the optimal arrangement of the MCU 50 (step S2). Here, it is assumed that the virtual meeting room can be used at the conference start time immediately before the start of the conference, more specifically, it is calculated back from the time required for the computation and MCU instance deployment. Start at a certain time. The details of the optimal arrangement calculation process will be described later.

  Next, the MCU management function 60 sends out a control instruction to the edge server 40 and the MCU 50 to expand the MCU instance to the MCU position selected in the previous step and link (eg, cascade connection) each MCU (step S3) .

  A meeting is held by the above processing (step S4). At the start of the conference, the MCU 50 makes a call to the participating terminal 10 as needed (call-out). When the conference is over, the MCU 50 disconnects the connected participating terminal 10 and performs a conference ending process (step S5). Further, the MCU management function 60 sends a control instruction to the edge server 40 to delete the MCU instance of the MCU 50 that has held the meeting.

  Next, when there are a plurality of conference reservations scheduled to be held at the same time, an example flow from conference reservation to conference holding to conference termination will be described with reference to FIG. Here, the case where there are n conference reservations scheduled at the same time will be described.

  The MCU management function 60 first receives a reservation of the held meeting (step S11). Next, the MCU management function 60 calculates the optimal arrangement of the MCUs 50 for each of the conferences 1 to n, and stores “cost (described later)” as an evaluation index of the optimal arrangement (step S12).

  Next, the MCU management function 60 performs the same cost calculation based on the information of all the terminals participating in any of the meetings 1 to n (step S13). However, the MCU deployment candidate location is limited to the location selected in the previous step. Then, the MCU management function 60 compares the total cost calculated in the previous step with the cost calculated in this step to determine the final arrangement. In addition, as another example of this step, the method of calculating the optimal deployment after the meeting 2 by subtracting the resources occupied by holding the meeting 1, and temporarily neglecting the resources of other simultaneous meetings at this stage Can be considered.

  Next, the MCU management function 60 sends out a control instruction to the edge server 40 and the MCU 50 to expand the MCU instance to the MCU position selected in the previous step and link (eg, cascade connection) each MCU (step S14) .

  A meeting is held by the above processing (step S15). At the start of the conference, the MCU 50 makes a call to the participating terminal 10 as needed (call-out). When the conference is over, the MCU 50 disconnects the connected participating terminal 10 and performs a conference termination process (step S16). Further, the MCU management function 60 sends a control instruction to the edge server 40 to delete the MCU instance of the MCU 50 that has held the meeting.

  In addition, since the end time changes with meetings even if the meeting holding time is the same, as a variation of the embodiment, a method of performing cost comparison in which time is also considered is considered. In addition, exception processing such as not performing the optimal arrangement calculation may be considered in a meeting of less than 15 minutes.

  Next, the details of the MCU optimum layout calculation process in step S2 and step S12 will be described with reference to FIG. In the present example, it is assumed that the information that is a part of the information necessary for the optimal arrangement calculation process and is not frequently changed is held in advance by the MCU management function 60. Such information may be acquired periodically or in response to an information update trigger at another timing, instead of being requested each time the optimal arrangement calculation is performed. Examples of such information include the network topology, the position of the edge server 40, the route cost of each network section, and the usage cost of each edge server 40.

  As shown in FIG. 9, the MCU management function 60 inquires of the network management node 81 the position of the conference participation terminal 10 (step S21). Here, the network management node 81 is a virtual private network (VPN) identifier (private IP address or E) of the conference participation terminal 10 obtained from the conference reservation information and the conference service component (for example, Gatekeeper in H.323). .164 number) and an identifier on the infrastructure side (in the case of NGN (Next Generation Network), in-network IPv6 address, line number etc., in case of mobile network, terminal identifier or GTP (GPRS Tunneling Protocol) tunnel ID etc.) The position of the conference participation terminal 10 on the network topology is returned to the MCU management function 60 with reference to the correspondence relationship in FIG.

  Next, the MCU management function 60 requests the network management node 81 for available bandwidth information of each network section at that time (step S22).

  Next, the MCU management function 60 requests the server infrastructure management node 82 for available resource information of the edge server 40 at that time (step S23).

  The MCU management function 60 executes the optimum layout calculation process based on the information acquired in the above steps and the information acquired and held in advance (step S24).

  Next, an example of a detailed process of step S24 will be described with reference to FIG. Here, as shown in FIG. 2, it is assumed that the network topology of the relay network 30 has a tree structure in which the other network 70 side is the upper layer and the terminal 10 side is the lower layer.

  The MCU management function 60 performs the following processing for each hierarchy in order from the highest hierarchy (steps S31 to S37). In the process of each layer (layer i), first, the maximum value J of the number (j) of edge servers in the layer i is checked from the network topology information acquired in advance as described above (step S32). Next, the MCU management function 60 makes a list (j = 0 to J) of resources available in the edge server list of the layer i (step S33). Here, when there is no available edge server in the layer i, the process is transferred to the next lower layer (steps S34, S36, and S37).

Next, assuming that the MCU management function 60 places the MCU in all the locations of Node _{i-0 to} Node _{i- J} (which are available),
(A) Sum of path costs from each terminal (Endpoint ₀ to _N ) to the nearest MCU (which can be reached at the shortest when the network topology is traced upstream) (b) Sum of edge server operating costs (However, Edge servers without conference traffic distribution and edge servers with 1 input and 1 output are not counted)
Are calculated taking into account the weights, and summed (step S35). Then, the MCU management function 60 stores the sum value as Cost [i]. Strictly speaking, it is possible to calculate the cost of a plurality of patterns in the same layer, such as which MCU is to be the parent MCU (or one MCU is newly disposed in the upper layer to be the parent MCU). In that case, what has the lowest cost may be substituted into Cost [i] as a representative cost value of the hierarchy. Here, the parent MCU is an MCU that is the center of control in a system (for example, a group of cascade-connected MCUs) in which one virtual conference is held by the cooperation of two or more MCUs. Means When three or more MCUs are cascaded in a tree topology, generally, an MCU located at the root of the tree operates as a parent MCU. (However, although the present embodiment is described using an MCU that performs tree-like cascade connection as an example, it is also possible to consider a system in which a plurality of MCU groups working in cooperation cooperate equally without the concept of a parent MCU / child MCU. Note that the above process is performed in each hierarchy downward (steps S36 and S37).

  Next, when all of the Cost [0] to Cost [I] are null values, the MCU management function 60 adds a service provision impossible error flag and ends the processing (steps S38 and S40). On the other hand, when there is a value in any of the Cost [0] to the Cost [I], the MCU management function 60 determines the MCU layout pattern in the case where the cost is the smallest among the non-null Cost [0] to Cost [I]. Are determined as the optimal arrangement (steps S38 and S39).

  Next, a specific example of the optimal arrangement calculation process described in detail with reference to FIG. 10 will be described. The following is an example of information used for calculation.

・ Network topology ・ Participant location information ・ Edge MCU operation cost (A value is set in advance to match the route cost. The weighting may be different for each layer, “the edge of the area where maintenance operation of maintenance such as remote island takes place The cost of using the server may be high, or "the cost of using an edge server in the vicinity of the area is temporarily set high when a special event is held".
・ Available bandwidth of each network section ・ Available resource information of edge server, Estimated use cost when MCU is operated on an edge server (used to judge availability of edge server)
-Conference terminal band-Inter-MCU band-MCU cascade connection stage number upper limit-MCU number upper limit-Weighting coefficient of path cost of each network section (The higher the rank, the larger the coefficient (higher cost) etc.)
・ The minimum number of users accommodated (For example, since there is no point in operating an MCU that only one terminal is accommodated (one input, one output), etc., set it to "2" or more, etc.)

  In this specific example, in order to simplify the description, the following conditions are assumed.

Network topology: tree structure, four hierarchical levels (i = 0 to 3) (see FIG. 11)
-Participant position information: as shown in FIG. For convenience, the name of the conference participation terminal is terminal 1 to terminal 8-Edge MCU operation cost: for simplicity, weighting is not performed, but it is uniformly "4"-Permissible maximum bandwidth of a specific route: a bottleneck in this example It does not exist.-Available resource information of edge server: It is assumed that sufficient resources are available to all edge servers.-Terminal bandwidth: It is uniformly "1 Mbps". In addition, the path cost when passing through a path without a weighting factor is set to cost “1” per 1 Mbps. • Inter-MCU band: After received video data is synthesized in the MCU, it is uniformly in one-screen (1 Mbps) band It is compressed and distributed to other MCUs and terminals under it.-MCU cascade connection number upper limit: "2"-MCU number upper limit: no upper limit-Path cost weighting factor of each network section: (hierarchy 0 (re-upstream): 4, layer 1: 3, layer 2: 2, layer 3: 1 (see FIG. 11)
· Minimum number of users: "2"

Under the above assumption, the optimal arrangement calculation process described in detail with reference to FIG. 10 is executed. First, cost calculation in hierarchy 0 will be described with reference to FIG. At level 0, since the node is one node of Node _0-0 , the total cost when an MCU is deployed at this position is calculated. As a result, as shown in FIG. 12, Cost [0] is 84.

Next, cost calculation in tier 1 will be described with reference to FIG. At level 1, the total cost when the MCU is deployed at the positions of Node _1-0 and Node _1-1 is calculated. As a result, as shown in FIG. 13, Cost [1] is 64.

Next, cost calculation in tier 2 will be described with reference to FIG. At level 2, the total cost when the MCU is deployed at the positions of Node _{2-0 to} Node _2-3 is calculated. However, since only one conference participation terminal is accommodated in Node- ₂ under the node _2-1 , and the node has one input and one output, there is no point in operating the MCU in the node. Therefore, Node _2-1 is not used. And the participating terminal under Node _2-1 is, in place of Node _2-1 , the other reachable node of the same hierarchy at the shortest reach, in other words, the node of the same hierarchy which can be accommodated at the lowest cost. It will be accommodated in Node _2-0 (see * 1 in FIG. 14).

Further, in FIG. 14, a case is described in which an MCU serving as a core among a plurality of MCUs (referred to as “parent MCU”. MCUs other than that are referred to as “child MCUs”) is Node _2-0 (see FIG. 14). 14 ※ 2). In addition, although description is abbreviate | omitted in this example, the path cost between MCUs in case each of Node _2-2 and Node _2-3 is made into a parent MCU is also calculated strictly, and magnitude comparison is carried out. As a result, as shown in FIG. 14, Cost [2-1] is 70.

Next, in FIG. 15, the participating terminal under Node _2-1 not to be used in Layer ₂ is the node of another higher layer reachable at the shortest, in other words, the smallest in place of Node _2-1. It will be accommodated in Node _1-0 which is another node of the same hierarchy that can be accommodated at cost (see * 1 in FIG. 15). Also, instead of selecting the parent MCU from the MCUs in the same hierarchy, it is separately arranged in Node _1-0 one hierarchy higher (see * 2 in FIG. 15). As a result, as shown in FIG. 15, Cost [2-2] is 68.

Next, in FIG. 16, in tier 2, the participating terminal under Node _2-1 not to be used is the other reachable node in the shortest reach, in other words, the smallest node in place of Node _2-1. It will be accommodated in Node _2-0 which is another node of the same hierarchy that can be accommodated at cost (see * 1 in FIG. 16). Also, instead of selecting the parent MCU from the MCUs in the same hierarchy, it is separately arranged in Node _1-1 one level higher (see * 2 in FIG. 16). As a result, as shown in FIG. 16, Cost [2-3] is 63.

  Since Cost [2-3] is the smallest among Cost [2-1] to Cost [2-3] for Layer 2 by the above processing, 63 is substituted for Cost [2] as a representative cost of Layer 2. Do.

  In this example, the calculation process example for the hierarchy level 3 is omitted. Since Cost [2] is the least cost among the costs Cost [0] to Cost [2] of the hierarchies 0 to 2, the MCU layout configuration at the time of calculating the cost is stored in the memory to finish the calculation.

  Another example of the MCU optimum layout calculation step will be described with reference to FIG. For example, if the MCU expansion cost is set high or the regional bias of the conference participation terminals is large, it is possible to cope with the variation in the best MCU arrangement hierarchy depending on the regional diversification of the participant terminals. It is preferable to do something. That is, it is preferable to look at not only the overall cost but also the partial cost increase / decrease. The example of FIG. 17 shows the case where the conference participation terminals (terminals hatched in the drawing) are biased locally.

in this case,
, Calculation, the hierarchy of the hierarchy 0 1: _{Node 1-1} calculation of subordinate hierarchy 1-2 calculation of subordinate, ..., hierarchy 1-k calculation and hierarchy of subordinate _{2: Node 1-1-1} ~ _1-1 Calculation is performed in the step of confirming whether the path cost between _-l + Node _1-1 and Node _{1-1 -x} has increased. It is preferable to determine that the previous hierarchy is advantageous depending on the MCU expansion cost, and to allow only some branches to return the hierarchy.

  Another example of the MCU optimum layout calculation step will be described with reference to FIG. In this example, it is assumed that MCUs are first deployed at all junctions, and MCU operation locations are gradually excluded to search for an arrangement in which the cost sum is more optimal. The optimum solution differs depending on conditions such as each cost weighting, the upper limit of the number of MCUs, and the upper limit of the number of multi-stage MCUs.

In this example, there can be 2 ¹¹ = 2048 MCU placement patterns in the case of searching in a brute force manner (strictly, each pattern of parent-child MCU relationship also needs to be considered even in the same MCU placement). there,
・ Exclude 1-in-1-out by priority. ・ Exclude unnecessary calculations as much as possible, such as by preferentially excluding MCUs with a small number of storage in the lower layer (low NW cost), and calculate efficiently. More developmentally, it is conceivable to combine machine learning, accumulate the performance information of efficient omission patterns, and reflect to the next calculation.

  Another example of the MCU optimum arrangement calculation step will be described with reference to FIGS. This example is an example in which two meetings are held at the same time. In this case, as shown in FIG. 19, the MCU optimum arrangement is first calculated by the algorithm described in detail with reference to FIG. 11 for the first conference. Similarly, as shown in FIG. 20, the MCU optimum arrangement is calculated by the algorithm detailed with reference to FIG. 11 for the second conference. Next, (A) the first meeting and the second meeting are regarded as one unit and the same cost is calculated, and (B) the MCU installation candidate of the second meeting is limited to the place calculated as a result of the first meeting And try to calculate. And (C) comparing the costs of (A) and (B) to adopt the configuration with the lowest cost. In the example of FIGS. 19 to 21, although the cost is lower in the case of (A), however, depending on the weight of the server operation cost, the total can be achieved by sharing the MCU installation location expected to stand up in another meeting. Costs may be reversed.

  The embodiment of the present invention has been described in detail, but the present invention is not limited to this. For example, in the above embodiment, the conference system has been described as an application example of the multipoint communication system, but the present invention can be applied to other systems. Examples of the application include, for example, a web conference system, a real time video distribution system, and a multicast distribution system for transferring files.

  In the above embodiment, an example of implementation by the MCU management function 60, the network management node 81, the server infrastructure management node 82, and the MCU management node 83 has been described as the management function of the MCU 50. The invention can also be practiced with other implementations such as

  Moreover, although the case where the network topology of the relay network 30 has a tree structure has been described in the above embodiment, the present invention can be practiced even if it is another network topology. In this case, a suitable cost calculation algorithm may be employed according to the network topology.

DESCRIPTION OF SYMBOLS 10 ... Terminal 20 ... Access network 30 ... Relay network 35 ... Relay apparatus 40 ... Edge server 50 ... MCU application 60 ... MCU management function 61 ... Meeting reservation information reception part 62 ... Infrastructure information reception part 63 ... MCU selection calculation part 64 ... Edge Server / application control transmission unit 64a edge server control transmission unit 64b application control transmission unit 70 other network 81 network management node 82 server infrastructure management node 83 MCU management node

Claims (8)

A multipoint communication system for performing group communication between a plurality of terminals accommodated in a network, comprising:
A multipoint connection function operating on a plurality of servers distributed geographically in the network;
Prior to the start of the group communication, use of the network and the server related to the group communication based on network configuration information including at least position information of the terminal and position information of the server and resource information of the network and the server Multipoint connection function selection means for selecting one or more of the multipoint connection functions whose cost is optimum;
When there are multiple multipoint connection functions selected by the multipoint connection function selection means, the multipoint connection functions of each other are linked, and a single group communication is made from the terminal while crossing over the multiple multipoint connection functions. A multipoint communication system comprising: multipoint connection function control means for controlling each multipoint connection function so as to make it behave as if it is implemented. The multipoint communication system according to claim 1, wherein the multipoint connection function is implemented as an application on a virtual machine built on the server. The multipoint communication system according to any one of claims 1 and 2, wherein the multipoint connection function selection unit performs selection processing based on group communication reservation information. Reservation information receiving means for receiving the group communication reservation information including reservation time;
And reservation information storage means for storing the accepted reservation information.
The multipoint connection function selection means is reversely calculated from its own processing time and the processing time of the multipoint connection function control means, and starts its own processing so that the group communication can be started at the reservation time. A multipoint communication system according to claim 3 wherein In the multipoint connection function selection means, when a plurality of group communications are performed in parallel, in the multipoint connection function selection process for each group communication, the network and the server pertaining to the plurality of group communications The multipoint communication system according to any one of claims 1 to 4, wherein one or more of the multipoint connection functions are selected such that the cost of use is optimal. The multipoint connection function selection unit according to any one of claims 1 to 5, wherein the multipoint connection function selection unit calculates the utilization cost of the network as a tree structure in which the network has a relay device as a node. Communication system. A multipoint communication method for performing group communication between a plurality of terminals accommodated in a network, comprising:
Geographically distributed deployment of multiple servers running multipoint connection function in the network;
Prior to the start of the group communication, the multipoint connection function selecting means performs the group communication based on network configuration information including at least position information of the terminal and position information of the server and resource information of the network and the server. Selecting one or more of the multipoint connection functions such that the utilization cost of the network and the server is optimal;
When there are a plurality of multipoint connection functions selected by the multipoint connection function selection means, the multipoint connection function control means makes the multipoint connection functions of each other cooperate and the terminal while straddling the plurality of multipoint connection functions Control each multipoint connection function so that it behaves as if a single group communication is being implemented.   A multipoint communication program characterized by causing a computer to operate as the multipoint connection function selection means and the multipoint connection function control means according to claim 1.

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