Moip control device and program

Abstract

To enable control utilizing the advantage of multicast in an IP system of MoIP for transmitting a media signal by using multicast in an IP network.SOLUTION: A virtual receiver which does not receive the media signal receives reception control, and a virtual sender which does not transmit the media signal discloses the information on the basis of the received information, and / or performs reception control to other receivers. Also, the sender information of a sender which does not correspond to SMPTEST2022 - 7 is altered to make it look like a sender which corresponds to SMPTEST2022 - 7.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is directed to a MoIP (Media Over IP) environment using multicast in an IP network. control device and regarding the program. [Background technology]

[0002] The technology for transmitting media content (e.g., video, audio, auxiliary data; hereinafter referred to as media signals) using an IP network is called MoIP, and in this regard, SMPTE specifies in the SMPTE ST2022-10 standard (see Non-Patent Document 1), SMPTE ST2110-6 standard (see Non-Patent Document 2), and related standards that media signals be transmitted in RTP packets using unicast or multicast. When multicast is used, a sender sends a packet to a multicast address, which can be received by multiple receivers via a network switch.

[0003] Sender and receiver devices are called nodes, and AMWA NMOS IS-04 (see Non-Patent Document 4) has been published as a standard for discovering and registering nodes and obtaining node information on a network. Also, AMWA NMOS IS-05 (see Non-Patent Document 5) has been published as a standard for controlling transmission to nodes.

[0004] The SMPTE ST2110-10 standard, the SMPTE ST2022-6 standard, and their related standards stipulate that parameters such as the format of the signal to be transmitted be described in the Session Description Protocol (SDP) (see Non-Patent Documents 6, 7, and 8). AMWA NMOS IS-05 provides a means for a receiver to obtain information described in SDP.

[0005] The SMPTE ST2022-7 standard (see Non-Patent Document 3) specifies measures to deal with packet loss by multiplexing the network path from the sender to the receiver. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent 7401097 [Non-patent literature]

[0007] [Non-Patent Document 1] SMPTE ST2110-10 [Non-patent document 2] SMPTE ST2022-6 [Non-patent document 3] SMPTE ST2022-7 [Non-patent document 4] AMWA NMOS IS-04 Discovery and Registration Specification [Non-patent document 5] AMWA NMOS IS-05 Connection Management [Non-patent document 6] RFC 4566 [Non-Patent Document 7] RFC 5888 [Non-patent document 8] RFC 7104 Summary of the Invention [Problem to be solved by the invention]

[0008] With conventional SDI (Serial Digital Interface), the signal sending and receiving sides are separate, and bidirectional communication is not possible. In broadcasting facilities using SDI, when sending and receiving video signals between multiple facilities, the sending side sends the appropriate signal. When selectively specifying a transmitter from multiple transmitters or switching video signals due to equipment failure or maintenance, the sending side does this, and the receiving side does not need to be aware of it. In addition, the video signal sent by the sending side can be distributed and used as desired on the receiving side, and the sending side does not need to be aware of this. The boundary between facilities is clearly defined by the output and input of the SDI signal.

[0009] MoIP, which transmits media signals using multicast over IP networks, requires receivers to control which senders they receive. In broadcasting equipment using MoIP (hereafter referred to as IP systems), when media signals are sent and received between multiple IP systems, if the sending IP system wants to switch senders, it must cross-system boundaries to control the receivers in the receiving IP system. However, the sending IP system may not know which receivers are receiving which senders in the receiving IP system. Furthermore, because each IP system node is registered in its own Registration & Discovery System (RDS) and controlled by its own system's controller, cross-system control is difficult. Cross-system control also poses the problem of system independence being compromised.

[0010] Therefore, when a sending IP system needs to switch senders, measures such as interfacing with SDI, IP retransmission, multicast NAT (Network Address Translation), and information sharing between multiple RDSs are used.

[0011] The SDI interfacing method involves converting the IP packets of the media signal into SDI in the sending IP system, and then converting the SDI back into IP packets in the receiving IP system. This allows for operation in the same way as before, but it has significant disadvantages, such as not being able to take advantage of the benefits of IP networks and multicast, and increasing costs, delays, and points of failure.

[0012] The IP retransmission method receives IP packets of media signals from a local system and retransmits them to other systems as media signals with a different fixed multicast address. Because the receiving side of the other system only needs to receive a fixed multicast address, it can be operated in a similar manner to the SDI method mentioned above. However, it has problems such as an increased load on the IP network, which makes it difficult to take advantage of the advantages of multicast, increased costs, and the inability to handle breakdowns in the IP retransmission device itself.

[0013] The multicast NAT mentioned above is a method that uses the network switch's functions to convert and fix the multicast address of media signals sent from one system to another. With this method, the receiving side only needs to always receive a fixed multicast address, so it takes advantage of the benefits of multicast and allows for operation similar to the aforementioned SDI. However, because the control method differs depending on the network switch product, individual control must be performed depending on the network switch product used, and there is a high possibility of shocks in the video and audio when switching, which in the case of broadcast stations, could cause problems such as damage to the broadcast.

[0014] The method for sharing information between multiple RDSs involves installing an RDS shared server that obtains sender information from the RDS of the sending IP system and registers that information in the RDS of the receiving IP system. This allows the sender of the sending IP system to appear as the sender of its own system on the receiving IP system, enabling it to receive media signals from senders of other systems. This method takes advantage of multicast and enables so-called resource sharing. However, in the event of an emergency switchover, such as when the sender of the sending IP system fails, even if the RDS information in the sending IP system is updated, the RDS shared server cannot immediately detect the information update in the RDS of the sending IP system, and there is no guarantee that the controller of the receiving IP system will detect the information update in its own RDS and immediately switch the receiver's destination. Therefore, this method is not suitable for emergency switchover.

[0015] Furthermore, when multicast packets of a media signal sent from a sender that does not support SMPTE ST2022-7 are received by a receiver that supports SMPTE ST2022-7, even if the network route along the way is multiplexed, the packets only pass through one of the networks, so the benefits of multicast are not fully utilized.

[0016] The present invention was made in consideration of the above-mentioned problems, and while taking advantage of the benefits of multicast, clarifies the boundary of the interface between IP systems, allowing the sending IP system to switch senders at any time, similar to SDI operation. The receiving IP system can arbitrarily distribute the media signals received from the sending IP system, increasing or decreasing the number of receivers.

[0017] In addition, when a multicast packet sent from a sender that does not support SMPTE ST2022-7 is received by an SMPTE ST2022-7 compatible receiver, the packet can pass through each of the multiplexed network paths along the way. [Means for solving the problem]

[0018] In order to solve the above problem, one embodiment of the present invention provides a method for transmitting media signals by multicast in an MoIP environment, comprising: Multicast address, port number and source address of Information included a storage unit that stores the The above information of Receive the original Receive control, a receiving-side control interface that stores the information in the storage unit; of function of a first function which is a function of a transmission side control interface that has the control destination information and publishes information held by the storage unit, and a second function which is a function of a control controller that has control destination information and controls reception so that a receiver set in the control destination information receives based on the information held by the storage unit, or both of the first function and the second function. Equipped with Characterized by It states that:

[0019] One embodiment of the present invention comprises: The device is characterized by having a plurality of functional assemblies in any combination of a set of functional assemblies having the function of the receiving control interface, the first function and the second function, a set of functional assemblies having the function of the receiving control interface and the first function, and a set of functional assemblies having the function of the receiving control interface and the second function.

[0020] One embodiment of the present invention comprises: Functions of two or more of said receiving control interfaces By linking these, one Functions of the receiver control interface but Reception is performed based on the above information When receiving control, the device compares the information in its own storage unit with that of the other device, and if they are identical, adds itself to the other device's control destination information, and if they are not identical, deletes itself from the other device's control destination information. It is characterized by .

[0021] One embodiment of the present invention comprises: the storage unit It has the function of modifying the information held by the above to multiplex the SMPTE ST2022-7. It is characterized by the following.

[0022] A general-purpose computer may be configured to have the above functions.

[0023] In the following, the function of the receiving side control interface will be referred to as a "virtual receiver," the first function as a "virtual sender," and the second function as a "control controller," and a set of functions comprising a virtual receiver and one or both of a virtual sender and a control controller will be referred to as a "virtual node." [Effects of the Invention]

[0024] According to this invention, in MoIP, which transmits media signals using multicast over an IP network, it is possible to clearly define the boundaries of interfaces between IP systems while taking advantage of the benefits of multicast. That is, a sending IP system can switch senders at any time, and a receiving IP system can receive multicast packets sent from the sending IP system at any receiver. A single device can establish interfaces with multiple other systems, which also offers significant cost benefits.

[0025] In addition, by taking advantage of the benefits of multicast, senders that do not support SMPTE ST2022-7 can be treated as if they were SMPTE ST2022-7 compatible senders, making it possible to configure an IP system while taking costs into consideration. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a block diagram illustrating a functional configuration of a virtual node according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an example of a configuration in which a virtual node according to an embodiment of the present invention is used as a virtual receiver and controller. [Figure 3] FIG. 10 is a configuration diagram of an example in which a virtual node of an embodiment of the present invention is used as both a virtual receiver and a virtual sender. [Figure 4] FIG. 10 is a block diagram illustrating an example of a functional configuration for combining two or more virtual nodes according to an embodiment of the present invention and dynamically updating control destination information. [Figure 5a] FIG. 1 is a first diagram of an example of cooperation between two IP systems to which a virtual node according to an embodiment of the present invention is applied. [Figure 5b] FIG. 10 is a second diagram of an example of cooperation between two IP systems to which a virtual node according to one embodiment of the present invention is applied. [Figure 5c] FIG. 10 is a third diagram of an example of cooperation between two IP systems to which a virtual node according to one embodiment of the present invention is applied. [Figure 5d]FIG. 4 is a fourth diagram of an example of cooperation between two IP systems to which a virtual node according to one embodiment of the present invention is applied. [Figure 6] FIG. 10 is a diagram illustrating an example of modifying a non-multiplexed SDP into an SDP that supports multiplexing, according to one embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating an example of modifying parameters of a non-multiplexed NMOS staged API to parameters corresponding to multiplexing, according to an embodiment of the present invention. [Figure 8] 1 is a diagram illustrating an example of a multicast packet passing from a non-SMPTE ST2110-7 compliant sender to an SMPTE ST2110-7 compliant receiver via both multiplexed networks in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same elements are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, the following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to only these embodiments. Furthermore, the present invention can be modified in various ways without departing from the gist of the invention.

[0028] FIG. 1 is a block diagram showing the functional configuration of a virtual node 1 to which an embodiment of the present invention can be applied. The virtual node 1 includes the functional blocks of a virtual receiver 10, a virtual sender 20, and a controller 30.

[0029] The virtual receiver 10 comprises a receiving side control interface 11 that receives reception control, and a storage unit 12 that stores the received reception control information. The virtual sender 20 includes a sender control interface 21 . The receiving control interface 11 and the transmitting control interface 21 may be configured by, for example, AMWA NMOS IS-04 and IS-05 interfaces. The control controller 30 includes a control interface 31 and control destination information 32. The control interface 31 may be configured by, for example, an AMWA NMOS IS-05 interface. The apparatus according to the embodiment of the present invention may be configured as a dedicated apparatus, or a general-purpose computer may be configured to have the functions of the apparatus according to the embodiment of the present invention.

[0030] The receiver control interface 11 behaves as a normal receiver in terms of control. That is, when configured with AMWA NMOS IS-04 and IS-05, it has a unique ID as a node and can be optionally discovered by DNS-SD (DNS-Based Service Discovery) or registered in RDS. When it receives reception control as a receiver, it stores that information in the memory unit 12 and behaves as if it has started receiving.

[0031] The information stored in the storage unit 12 includes a multicast address, a port number, and a source address, and may further include an SDP (hereinafter, this information will be referred to as sender information).

[0032] The sender control interface 21 behaves as a normal sender in terms of control. That is, when configured with AMWA NMOS IS-04 and IS-05, it has a unique ID as a node and can be discovered by DNS-SD or registered with RDS. It then behaves as if it is transmitting multicast based on the information stored in the memory unit 12. However, while a normal sender can be controlled to change the destination multicast address or stop or start transmission, if it receives such control, it returns an error or ignores the control.

[0033] When the information in the storage unit 12 changes, the control interface 31 promptly performs reception control on the receivers set in the control destination information 32 described below. A retry may be performed for receivers that could not be controlled at this time. When information in the control destination information 32 is added or changed, reception control may be performed on the added or changed receiver based on the information in the storage unit 12.

[0034] The control destination information 32 is assumed to be preset with information about the receiver that will perform reception control. That is, if the control controller 30 is configured with AMWA NMOS IS-05, it is configured to include information about the receiver ID, the address of the NMOS API (Application Programming Interface), and the port. There may be zero or multiple pieces of control destination information. If there is zero control destination information, no control will be performed.

[0035] The flow of operations according to one embodiment of the present invention will be specifically described with reference to the drawings. Figure 2 shows an example of using virtual node 1 as a virtual receiver and controller.

[0036] In this example, the network is configured to include a control network 50 that controls the transmission and reception of media signals, a media network 51 that transmits and receives media signals by multicast, a control controller 60 that controls reception for receivers, a sender 70 that transmits media signals, a receiver 80 that receives media signals, and a virtual node 1. A control controller 60, a sender 70, a receiver 80, and a virtual node 1 are connected to the control network 50, and the sender 70 and the receiver 80 are connected to the media network 51.

[0037] The control network 50, the media network 51, the controller 60, the sender 70, and the receiver 80 are devices configured using existing technology. A single network may be used as both the control network 50 and the media network 51. A plurality of senders 70 and receivers 80 may be present.

[0038] It is assumed that a media signal is being transmitted by multicast from the sender 70, but there are no receivers to receive it yet.

[0039] The control flow will be explained in alphabetical order in parentheses in the diagram. The controller 60 in this example acquires sender information from the sender 70 (A), and performs reception control for the virtual node 1 based on the sender information (B). As a result, the sender information of the sender 70 is registered in the storage unit 12. The receiver 80 is registered in advance in the control destination information 32 of the virtual node 1, and the virtual node 1 that has received reception control performs reception control on the receiver 80 based on the sender information in the storage unit 12 (C). The receiver 80 begins receiving the multicast media signal from the sender 70 (D).

[0040] As a result, the receiver 80 can receive a media signal from the sender 70 without being directly controlled by the controller 60 .

[0041] By applying the above, it is possible to quickly control reception of a sender selected from multiple senders in one IP system to a receiver in another IP system.

[0042] FIG. 3 shows an example in which virtual node 1 is used as both a virtual receiver and a virtual sender.

[0043] In this example, the network is composed of a control network 50 that controls the transmission and reception of media signals, a media network 51 that transmits and receives media signals by multicast, a control controller 60, another control controller 61, a sender 70 that transmits media signals, a receiver 80 that receives media signals, and a virtual node 1. The control network 50 is connected to a control controller 60, a control controller 61, a sender 70, a receiver 80, and a virtual node 1, and the media network 51 is connected to the sender 70 and the receiver 80.

[0044] The control network 50, the media network 51, the control controller 60, the control controller 61, the sender 70, and the receiver 80 are devices configured using existing technology. A single network may be used as both the control network 50 and the media network 51. A plurality of senders 70 and receivers 80 may be present.

[0045] It is assumed that a media signal is being transmitted by multicast from the sender 70, but there are no receivers to receive it yet.

[0046] The control flow will be explained in alphabetical order in parentheses in the diagram. The control controller 61 performs reception control so that the virtual node 1 receives the sender 70 (A). As a result, the sender information of the sender 70 is registered in the storage unit 12. Nothing is registered in the control destination information 32, and no particular control is performed. The controller 60 acquires sender information from the virtual node 1 (B), and performs reception control on the receiver 80 based on the sender information (C). The receiver 80 begins receiving the multicast media signal from the sender 70 (D).

[0047] As a result of the above, the control controller 60 can control the receiver 80 to receive a media signal from the sender 70 without having any direct relationship with the sender 70, and the control controller 61 can control the receiver 80 to receive a media signal from the sender 70 without having any direct relationship with the receiver 80.

[0048] By applying the above, a sender selected from multiple senders in one IP system can be registered in a virtual node in the other IP system, and the other IP system can treat the virtual node as if it were a sender in its own IP system, making so-called resource sharing possible.

[0049] 4 is an example block diagram showing a functional configuration according to an embodiment of the present invention in which two or more virtual nodes 1 are combined and control destination information 32 is dynamically updated. There may be multiple source virtual nodes 1 and multiple destination virtual nodes 1. Details within each virtual node 1 are omitted, and only the necessary parts are shown. Each virtual node 1 may be in a separate housing or in the same housing. If they are in the same housing, a single node may be configured with multiple virtual receivers and virtual senders. The device according to the embodiment of the present invention may be configured as a dedicated device, or a general-purpose computer may be configured to have the functions of the device according to the embodiment of the present invention.

[0050] When a control signal arrives from outside and the information in its own memory unit 12 changes, the source virtual node 1 compares the information in its own memory unit 12 with the information in the memory unit 12 of the destination virtual node 1. If they match, the source virtual node 1 is added to the control destination information 32 of the destination virtual node 1. However, if the source virtual node 1 already exists in the control destination information 32 of the destination virtual node 1, no action is taken. If they do not match, the source virtual node 1 is deleted from the control destination information 32 of the destination virtual node 1. However, if the source virtual node 1 does not exist in the control destination information 32 of the destination virtual node 1, no action is taken.

[0051] The flow of operations according to one embodiment of the present invention will be specifically described with reference to the drawings. 5a, 5b, 5c, and 5d show an example of cooperation between a receiving IP system 100 and a sending IP system 101. Each is connected to a media network and a control network as necessary, but these are omitted from the drawings.

[0052] The IP system 100 is an example configured to include a controller 60, one or more senders 70, one or more receivers 80, and a plurality of virtual nodes 1. The IP system 101 is an example configured to include a controller 61, a plurality of senders 70, and a virtual node 1.

[0053] The solid arrows in the figure represent the control destination information of each virtual node that has been set in advance. In the virtual node A1, the receiver A80 is registered as control destination information. In the virtual node B1, the receiver B80 is registered as control destination information. In the virtual node C1, a receiver C80 is registered as control destination information. Virtual node Y1 has virtual node X1 registered as control destination information.

[0054] The dotted arrows in the figure (arrows painted white) represent the pre-set relationship between the addition source virtual node and the addition destination virtual node. Virtual node A1 is the source virtual node, and virtual node X1 is registered as the destination virtual node. Virtual node B1 is the source virtual node, and virtual node X1 is registered as the destination virtual node. Virtual node C1 is the source virtual node, and virtual node X1 is registered as the destination virtual node.

[0055] The flow of Figure 5a will be explained in alphabetical order in parentheses. The control controller 61 acquires sender information from sender S70 and controls virtual node Y1 to receive sender S70 (A). Virtual node Y1, which has received the control, controls virtual node X1 to receive (B). As a result, the sender information of sender S70 is registered in the storage unit 12 of virtual node X1. At this point, there is no registration in the control destination information 32 of virtual node X1, so no further control is performed.

[0056] Next, the flow of FIG. 5b will be explained in alphabetical order in parentheses. Assume that controller 60 acquires sender information from virtual node X1 (C) and applies reception control to virtual nodes A1 and C1 (D). Having received reception control, virtual nodes A1 and C1 then apply reception control to receivers A80 and C80, respectively (E). At this point, receivers A80 and C80 begin receiving media signals from sender S70. At the same time, virtual nodes A1 and C1 compare the information they received reception control from with the information in storage unit 12 of virtual node X1. Since they match, virtual nodes A1 and C1 are added to control destination information 32 of virtual node X1 (F).

[0057] Next, the flow of FIG. 5c will be explained in alphabetical order in parentheses. Assume that the IP system 100 switches the media signal being received by the receiver C80 to the media signal from the sender U70 of its own system. The controller 60 acquires sender information from the sender U70 and applies reception control to the virtual node C1 based on the sender information (G). The virtual node C1, which has received reception control, then applies reception control to the receiver C80 (H). At this point, the receiver C80 switches to receiving media signals from the sender U70. At the same time, the virtual node C1 compares the information it has received reception control with the information in the memory unit 12 of the virtual node X1, and since they do not match, it deletes the virtual node C1 from the control destination information 32 of the virtual node X1 (I).

[0058] Next, the flow of FIG. 5d will be explained in alphabetical order in parentheses. Assume that IP system 101 needs to switch the source of the media signal being sent to IP system 100 from sender S70 to sender T70. Controller 61 acquires sender information from sender T70 and controls virtual node Y1 to receive from sender T70 (J). Virtual node Y1, which has received the reception control, controls virtual node X1 to receive (K). As a result, sender information for sender T70 is registered in storage unit 12 of virtual node X1. Because virtual node A1 was registered in the control destination information of virtual node X1 in step (I), virtual node X1 controls virtual node A1 to receive (L). Virtual node A1 controls receiver A80 to receive (M). At this point, receiver A80 switches to receiving media signals from sender T70.

[0059] As a result, when the sender on the IP system 101 side is changed, the IP system 100 receiving the media signal from the IP system 101 can quickly switch the receiving mode for each receiver 80 that is currently receiving the media signal from the IP system 101.

[0060] Each virtual node 1 is contained within its own IP system, and the control controller 60 and the control controller 61 do not need to control beyond their own system. This is because each virtual node 1 serves as an interface boundary, which clarifies the interface boundary between systems.

[0061] In one embodiment of the present invention, the present invention has a function of modifying sender information that does not support path multiplexing defined in the SMPTE ST2022-7 standard, thereby realizing path multiplexing.

[0062] FIG. 6 shows an example in which, when an SDP is included in the sender information, a non-multiplexed SDP 200 is changed to an SDP 201 that supports multiplexing (duplexing in this example).

[0063] The specific processing contents will be explained.

[0064] The non-multiplexed SDP200 is divided into string group 1 and string group 2 from the beginning, using the line beginning with "m=" as a separator.

[0065] Create an empty string variable. The string group 1 is output to the string variable, and then "a=group:DUP identifier 1 identifier 2" is output to indicate that multiplexing is occurring. Identifier 1 and identifier 2 can be any unique alphanumeric string ("primary" and "secondary" in the example of Figure 6). If multiplexing is to occur, the number of identifiers can be listed accordingly. The character string group 2 is output to the character string variable, and "a=mid:identifier 1" is output to indicate that this is the first media in a dual system. Again, the character string group 2 is output to the character string variable, and "a=mid:identifier 2" is output, indicating that this is the second media in the duplex system.

[0066] The character string variable generated as described above is referred to as the modified SDP 201.

[0067] Figure 7 shows an example of changing the multicast address, port number, and source address included in the sender information from non-multiplexed parameters 300 to parameters 301 corresponding to multiplexing (duplication in this example) when expressed in JSON (JavaScript Object Notation) of the staged API of AMWA NMOS IS-05.

[0068] The specific processing will be explained. Prepare an empty JSON object variable. The first object in the array of the value of the "transport_params" key of the non-multiplexing parameters 300 is extracted, a "transport_params" key is generated in the JSON object variable, and two identical objects are placed in the array with that value. All other keys and values ​​are copied as is.

[0069] The JSON object variable generated as described above is used as the parameter 301 corresponding to the modified multiplexing.

[0070] The sender information modified as described above is recognized as sender information that complies with the SMPTE ST2110-7 standard. As a result, when combined with virtual node 1, it can be treated as a normal sender that complies with the SMPTE ST2110-7 standard. Similar operations can also be achieved by incorporating this sender information modification function into a conventional controller.

[0071] As a result, a sender that does not support route multiplexing can be made to operate as if it supports route multiplexing. Receivers that support SMPTE ST2022-7 multiplexing and have undergone reception control using modified sender information will use Internet Group Management Protocol (IGMP) JOIN control to ensure that they receive the same multicast address from their respective network interfaces. As such, by configuring a network configuration such as the example shown in Figure 8, whereby non-multiplexed multicast packets output from senders that do not support SMPTE ST2110-7 can be transferred via a network switch to each of the multiplexed networks, it is possible to take advantage of the benefits of multicast and actually multiplex the routes after the network switch.

[0072] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be embodied in various other forms without departing from the spirit and scope of the present invention. Therefore, the above embodiment is merely illustrative in all respects and should not be interpreted as limiting. For example, a control protocol other than NMOS may be used. Furthermore, with regard to SMPTE ST2022-7 multiplexing, sender information may be modified so that a device compatible with duplexing becomes a device compatible with triplexing. [Explanation of symbols]

[0073] 1 Virtual Node 10 Virtual Receiver Function Block 11 Receiver Control Interface 12 Storage section 20 Virtual Sender Function Block 21 Sender Control Interface 30 Controller Function Block 31 Control Interface 32 Control destination information 50 Control Network 51 Media Network 60 Controller 61 Controller 70 Sender 80 Receiver 100 Example of a receiving IP system 101 Example of a sending IP system 200 Non-multiplexed SDP example 201 An example of a modified SDP that supports multiplexing 300 An example of a non-multiplexed NMOS staged API 301 An example of modified NMOS staged API for multiplexing

Claims

1. A virtual node that behaves as a receiver in terms of control in an MoIP (Media Over IP) environment using multicast, has a memory unit that stores parameters subject to reception control, and has a virtual receiver that behaves as if it is receiving.

2. 2. The virtual node according to claim 1, which acts as a sender in terms of control and also has a function as a virtual sender that publishes information held in said storage unit.

3. The virtual node according to claim 1 , further comprising control destination information and also functioning as a controller that performs reception control on a receiver set in the control destination information using the information stored in the storage unit.

4. 4. The virtual node according to claim 3, wherein a plurality of virtual nodes according to claim 3 are linked together, and when one virtual node receives reception control, the virtual node compares the information in its own memory unit with the information in the other memory unit, and if the information is identical, adds itself to the control destination information of the other virtual node, and if the information is not identical, deletes itself from the control destination information of the other virtual node.

5. A method for modifying sender information including a multicast address, a port number, and a source address to multiplex SMPTE ST2022-7.

6. 6. The virtual node according to claim 1, wherein the information held in the storage unit is modified by the method of claim 5.

7. A program that causes a computer to function as the virtual node according to any one of claims 1 to 4.

8. A program that causes a computer to function as the virtual node according to claim 6.

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