JP2023112290A - Switching method and IP retransmission device - Google Patents

Abstract

To provide stable content reproduction on a reproduction device with simple constitution while an IP retransmission device retransmitting contents is configured to be switched.SOLUTION: There is provided a switching method of an IP retransmission system comprising a plurality of IP retransmission devices which receive repeating IP packets including a broadcasted content and retransmit the content, included in the received repeating IP packets, in retransmitting IP packets, and the switching method includes the steps of: determining switching timing based upon information included in the repeating IP packets and changing in value according to transmission time of the repeating IP packets; and switching, at the switching timing, the retransmission of the content from an IP retransmission device of an in-operation system to an IP retransmission device of a standby system.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a switching method and an IP retransmission device.

Conventionally, a system has been developed for retransmitting IP packets containing content to be broadcast.

For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2020-10199) discloses the following IP retransmission device. That is, the IP retransmission device is an IP retransmission device used in an IP retransmission system for retransmitting digital broadcast signals of multiple channels received from an antenna to a plurality of receivers via an IP multicast network, SI information is extracted from a digital broadcast signal, the SI information is stored in a packet having an SI identification value added to part of header information, and the packet is sent to the IP multicast network together with the broadcast stream or separately from the broadcast stream. Send out.

JP 2020-10199 A

Stations of digital broadcasting distributors such as cable television are often provided with backup IP retransmission devices in addition to active IP retransmission devices.

Here, when retransmission by the IP retransmission device is stopped for maintenance replacement of the active IP retransmission device, and retransmission is switched to the backup IP retransmission device, the content can be reproduced satisfactorily. is desired.

The present disclosure has been made to solve the above-mentioned problems, and its object is to enable stable content reproduction in a playback device with a simple configuration in a configuration that allows switching of IP retransmission devices that retransmit content. It is to provide a switching method and an IP retransmission device that can be implemented.

A switching method according to the present disclosure includes a plurality of IP retransmitting devices that receive relay IP packets containing content to be broadcast, include the content contained in the received relay IP packets, and retransmit the retransmission IP packets. A switching method for switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device, wherein the active IP retransmission device receives causing the standby IP retransmission device to start receiving the same packet as the relay IP packet; determining a switching timing based on information included in the relay IP packet, the value of which varies depending on the transmission time of the relay IP packet; and in the switching timing, and switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device.

An IP retransmission apparatus according to the present disclosure receives a relay IP packet containing content to be broadcast, and includes the content included in the received relay IP packet in the retransmission IP packet for retransmission. is an IP retransmission device according to claim 1, wherein a receiving unit for receiving the relay IP packet, a transmitting unit for transmitting the retransmitting IP packet, and switching between start and stop of transmission of the retransmitting IP packet by the transmitting unit an acquisition unit configured to acquire switching timing, which is the timing to switch, based on information included in the relay IP packet received by the reception unit, the value of which varies depending on the transmission time of the relay IP packet; a switching unit that switches between starting and stopping transmission of the IP packet for retransmission by the transmitting unit when it is detected that the switching timing acquired by the unit has arrived.

One aspect of the present disclosure can be implemented not only as an IP retransmission device including such a characteristic processing unit, but also as an IP retransmission method including such characteristic processing steps, or , a semiconductor integrated circuit that implements part or all of the IP retransmission device, or an IP retransmission system including the IP retransmission device.

Advantageous Effects of Invention According to the present disclosure, it is possible to realize stable content reproduction in a reproduction device with a simple configuration in a configuration that allows switching of IP retransmission devices that retransmit content.

FIG. 1 is a diagram showing the configuration of an IP retransmission system according to an embodiment of the present disclosure. FIG. 2 is a diagram showing the configuration of an IP retransmission device according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example of an IP packet received by an IP receiver of the IP retransmission device according to the embodiment of the present disclosure; FIG. 4 is a diagram illustrating an example of a switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 5 is a diagram showing another example of the switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 6 is a diagram showing another example of the switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 7 is a diagram illustrating another example of a switching process sequence in the IP retransmission system according to the embodiment of the present disclosure.

First, the contents of the embodiments of the present disclosure will be listed and described.

(1) A switching method according to an embodiment of the present disclosure receives a relay IP packet containing content to be broadcast, and includes the content included in the received relay IP packet in a retransmission IP packet for retransmission. A switching method for switching retransmission of the content from the active IP retransmitting device to the standby IP retransmitting device in an IP retransmitting system comprising a plurality of transmitting IP retransmitting devices, the method comprising: a step of causing the standby IP retransmission device to start receiving the same packet as the relay IP packet received by the IP retransmission device of the above; determining the switching timing based on the step of adjusting to the setting contents related to retransmission of the IP retransmitting device of the system; and switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device at the switching timing.

In this way, a method of switching retransmission of content from an active IP retransmission device to a standby IP retransmission device at the switching timing determined based on the information whose value changes according to the transmission time of the relay IP packet. As a result, it is possible to match the timing of switching content retransmission in the active IP retransmitting device and the standby IP retransmitting device with a simple configuration. When switching from the standby system to the standby system, the content can be seamlessly reproduced in the reproduction device. For example, even in a time period during which content should be retransmitted, that is, while the IP retransmission device is in operation, the playback device can seamlessly reproduce the content when the IP retransmission device that retransmits the content switches from the active system to the standby system. It can be performed. Therefore, it is possible to achieve stable content reproduction in the reproduction device with a simple configuration.

(2) The IP retransmission system further includes a control device, and the switching method further includes: The step of creating a switching plan for retransmission of the content in the device and the standby IP retransmission device may be included.

With such a method, content retransmission switching can be systematically performed based on, for example, the operating state of the active IP retransmission device.

(3) An IP retransmission device according to an embodiment of the present disclosure receives a relay IP packet including content to be broadcast, and includes the content included in the received relay IP packet in the retransmission IP packet. An IP retransmission device in an IP retransmission system that retransmits the relay IP packet, comprising: a receiving unit for receiving the IP packet for relay; a transmitting unit for transmitting the IP packet for retransmission; and the IP packet for retransmission by the transmitting unit. and a value corresponding to the transmission time of the relay IP packet included in the relay IP packet received by the receiving unit. a switching unit that switches between starting and stopping transmission of the IP packet for retransmission by the transmitting unit when the arrival of the switching timing acquired by the acquiring unit is detected based on changed information.

In this way, the arrival of the switching timing is detected based on the information whose value changes according to the transmission time of the IP packet for relay, and the start and stop of transmission of the IP packet for retransmission are switched. In the IP retransmitting device and the standby IP retransmitting device, the timing for switching content retransmission can be matched with a simple configuration, so that the IP retransmitting device that retransmits content is switched from the active system to the standby system. In this case, the content can be seamlessly played back on the playback device. For example, even in a time period during which content should be retransmitted, that is, while the IP retransmission device is in operation, the playback device can seamlessly reproduce the content when the IP retransmission device that retransmits the content switches from the active system to the standby system. It can be performed. Therefore, it is possible to achieve stable content reproduction in the reproduction device with a simple configuration.

Embodiments of the present disclosure will be described below with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Moreover, at least part of the embodiments described below may be combined arbitrarily.

[Configuration and basic operation]
<IP retransmission system>
FIG. 1 is a diagram showing the configuration of an IP retransmission system according to an embodiment of the present disclosure. Referring to FIG. 1, IP retransmission system 401 includes a plurality of IP retransmission devices 101, a plurality of IP retransmission devices 111, control devices 201 and 211, a headend device 221, and an EWS transmission device 251. , and an SI sending device 261 . IP retransmission devices 101 and 111, control devices 201 and 211, head end device 221, EWS transmission device 251 and SI transmission device 261 are provided, for example, in a cable TV station building. The cable television station is capable of IP multicast broadcasting of multiple independent channels.

As an example, the IP retransmission system 401 includes N active IP retransmission devices 101, one standby IP retransmission device 101, M active IP retransmission devices 111, and a standby IP retransmission device 111 . N and M are integers of 1 or more, and may be the same value or different values. The standby IP retransmission device 101 is a backup device for backing up the active IP retransmission device 101 . Standby IP retransmission device 111 is a backup device for backup of active IP retransmission device 111 . IP retransmission system 401 may be configured to include a plurality of standby IP retransmission devices 101 or may be configured to include a plurality of standby IP retransmission devices 111 .

The head-end device 221 transmits a stream containing a plurality of self-broadcast contents to the IP retransmission device 101 . The content includes, for example, audio information, video information, PSI (Program Specific Information) information, SI information, caption information, and the like. The headend device 221 generates a plurality of TS packets containing information obtained by dividing the content into a plurality of pieces. The headend device 221 generates an IP packet Pcon in which, for example, seven TS packets are stored in the payload, and transmits the generated IP packet Pcon to each IP retransmission device 101 . For example, IP packet Pcon is an IPv4 packet. The IP packet Pcon is an example of a relay IP packet.

The IP retransmitting device 101 receives an IP packet Pcon including content to be broadcast from the headend device 221 via a HUB (not shown), includes the content included in the received IP packet Pcon in the IP packet, and retransmits the IP packet.

More specifically, each of the N active IP retransmitting apparatuses 101 is assigned, for example, one channel different from each other. The active IP retransmission device 101 receives the IP packet Pcon containing the content belonging to the assigned channel, and acquires the TS packet from the received IP packet Pcon. The active IP retransmission device 101 generates an IP packet Prt1 in which the obtained seven TS packets are stored in the payload, and sends the generated IP packet Prt1 to the STB (Set Top Box) at the subscriber's home via the IP network 151. ) 301 . For example, IP packet Prt1 is an IPv6 packet. IP packet Prt1 is an example of a retransmission IP packet. In an IP network (CDN: Content Delivery Network) 151, IP packets are transmitted, for example, according to the IP protocol.

Further, the active IP retransmitting device 101 extracts a TS packet containing SI information from among the acquired TS packets, generates an IP packet Psi1 in which the extracted TS packet is stored in the payload, and generates an IP packet Psi1. Psi1 is sent to the SI sending device 261 . For example, IP packet Psi1 is an IPv4 packet. IP packet Psi1 is an example of a retransmission IP packet.

The IP retransmitting device 111 receives broadcast waves of terrestrial digital broadcasting, BS digital broadcasting, or advanced BS digital broadcasting, and retransmits IP packets containing content included in the received broadcast waves. The content includes, for example, audio information, video information, PSI information, SI information, caption information, EWS information, and the like.

More specifically, each of the M active IP retransmission devices 111 is assigned, for example, one channel different from each other. The active IP retransmitting device 111 acquires content belonging to the assigned channel from the received broadcast wave, and generates a plurality of TS packets containing information obtained by dividing the acquired content into a plurality of pieces. The active IP retransmission device 111 generates an IP packet Prt2 in which seven TS packets are stored in the payload, and transmits the generated IP packet Prt2 to the STB 301 via the IP network 151 . For example, IP packet Prt2 is an IPv6 packet.

In addition, the active IP retransmitting device 111 acquires the EWS information and the SI information from the received broadcast wave, and the IP packet Pews in which the TS packet containing the EWS information is stored in the payload and the TS packet containing the SI information is stored in the payload. generates an IP packet Psi2 stored in . The active IP retransmission device 111 transmits the generated IP packet Pews to the EWS transmission device 251 and transmits the generated IP packet Psi2 to the SI transmission device 261 . For example, IP packet Pews, Psi2 is an IPv4 packet.

The EWS transmission device 251 receives the IP packet Pews from the active IP retransmission device 111 and rewrites the header information of the received IP packet Pews to generate the IP packet PE to the STB 301 via the IP network 151. Send. For example, IP packet PE is an IPv6 packet.

The SI transmission device 261 receives IP packets Psi1 and si2 from the active IP retransmission device 101 and the active IP retransmission device 111, respectively, and rewrites the header information of the received IP packets Psi1 and si2. The IP packet PS generated by is transmitted to the STB 301 via the IP network 151 . For example, IP packet PS is an IPv6 packet.

The control device 201 is connected to each IP retransmission device 101 via a HUB (not shown) via a LAN (Local Area Network). The control device 201 controls and monitors each IP retransmission device 101 .

After starting the IP retransmitting device 101, the control device 201 sends communication setting information Ccm indicating an IP address for communication with the control device 201, and indicating whether the IP retransmitting device 101 is an active system or a standby system. Initial setting information Cin and retransmission setting information Crt regarding retransmission are transmitted to the IP retransmission apparatus 101 .

The control device 211 is LAN-connected to each IP retransmission device 111 via a HUB (not shown). A controller 211 controls and monitors each IP retransmitter 111 .

<IP retransmission device>
FIG. 2 is a diagram showing the configuration of an IP retransmission device according to an embodiment of the present disclosure. Referring to FIG. 2, IP retransmitting device 101 includes IP receiving unit 11, communication unit 12, TS acquiring unit 13, time information extracting unit 14, processing unit 15, and PID (Packet ID) filter 16. , IP transmission units 17A and 17B, and a storage unit 18 . IP receiver 11 is an example of a receiver. The IP transmitters 17A and 17B are examples of transmitters. The processing unit 15 is an example of an acquisition unit and an example of a switching unit.

The communication unit 12 can transmit and receive various information to and from the control device 201 using IP packets.

The IP receiver 11 receives IP packets Pcon from the headend device 221 via a HUB (not shown). The IP receiver 11 outputs the received IP packet Pcon to the TS acquirer 13 each time it receives an IP packet Pcon from the headend device 221 .

FIG. 3 is a diagram illustrating an example of an IP packet received by an IP receiver of the IP retransmission device according to the embodiment of the present disclosure; Referring to FIG. 3, IP packet Pcon includes an IP header, a UDP (User Datagram Protocol) header, an RTP (Real-time Transport Protocol) header and a payload.

The RTP header includes fields of Version, Padding, Extension, CSIC (Contributing Source Identifiers Count), Marker, Payload Type, Sequence Number, Timestamp, and SSRC (Synchronization Source).

For example, the timestamp field stores the clock count value Ccnt in the headend device 221 . For example, the sequence number field stores a sequence value Cnmb indicating the order in which the IP packets Pcon are transmitted by the headend device 221 . The count value Ccnt and the sequence value Cnmb are examples of transmission time information whose values change according to the transmission time of the IP packet Pcon by the headend device 221 .

Referring to FIG. 2 again, TS acquisition unit 13 receives IP packet Pcon from IP reception unit 11, acquires seven TS packets from the payload of the received IP packet Pcon, and supplies IP transmission unit 17A and the PID filter. 16. The TS acquisition unit 13 also outputs the RTP information stored in the RTP header of the IP packet Pcon to the time information extraction unit 14 .

For example, the time information extraction unit 14 receives the RTP information from the TS acquisition unit 13, extracts the time stamp and the sequence number from the received RTP information, and extracts the count value Ccnt indicated by the time stamp and the sequence value Cnmb indicated by the sequence number. Output to the processing unit 15 .

Based on a plurality of sequence values Cnmb received from the time information extraction unit 14 in a period of a predetermined length, the processing unit 15 calculates a unit increase amount that is an increase amount of the sequence value Cnmb per unit time, and calculates the calculated unit increase. The amount is saved in the storage unit 18 .

The PID filter 16 receives the TS packets from the TS acquisition unit 13 and outputs the TS packets containing the SI information among the received TS packets to the IP transmission unit 17B. The SI information includes table information such as NIT (Network Information Table), SDT (Service Description Table), EIT (Event Information Table), BIT (Broadcaster Information Table) and CDT (Common Data Table). The PID filter 16 refers to the PID of the TS packet received from the TS acquisition unit 13 to extract a TS packet containing SI information from among the received TS packets. The PID filter 16 outputs the extracted TS packet to the IP transmitter 17B.

The IP transmission unit 17A receives the TS packet from the TS acquisition unit 13 and generates an IP packet Prt1 in which seven TS packets are stored in the payload. The IP transmission unit 17A transmits the generated IP packet Prt1 to the IP network 151. FIG. The IP transmission unit 17A can switch between a transmission-on state in which IP flows can be transmitted and a transmission-off state in which IP flows are not transmitted. For example, IP transmission unit 17A is set to a transmission off state when IP retransmission device 101 is activated.

The IP transmitter 17B receives the TS packets from the PID filter 16 and generates an IP packet Psi1 in which seven TS packets are stored in the payload. The IP transmission unit 17B transmits the generated IP packet Psi1 to the SI transmission device 261. FIG. The IP transmission unit 17B can switch between a transmission-on state in which IP flows can be transmitted and a transmission-off state in which IP flows are not transmitted. For example, IP transmission section 17B is set to a transmission off state when IP retransmission device 101 is activated.

(Initial setting)
After starting the IP retransmission device 101, the communication unit 12 receives the communication setting information Ccm from the control device 201, and communicates with the control device 201 using the IP address indicated by the received communication setting information Ccm.

The communication unit 12 also receives initial setting information Cin and retransmission setting information Crt from the control device 201 . As described above, the initial setting information Cin is information indicating whether the IP retransmitting apparatus 101 is the active system or the standby system.

For example, communication unit 12 in active IP retransmission device 101 receives reception setting information C1, transmission setting information C2, and SI extraction information C3 as retransmission setting information Crt. The reception setting information C1 is information indicating the IP address and port number of the IP packet Pcon to be received by the active IP retransmission device 101 . The transmission setting information C2 is information indicating the IP address and port number of the IP packet Prt1 to be transmitted by the active IP retransmission device 101 . The SI extraction information C3 is information indicating the PID of the TS packet that the active IP retransmitting device 101 should store in the IP packet Psi1.

Further, for example, the communication unit 12 in the standby IP retransmission device 101 receives the correspondence information RE1, RE2, and RE3 as the retransmission setting information Crt. The correspondence information RE1 is information indicating the correspondence relationship between the ID of the active IP retransmission device 101 and the reception setting information C1 in the IP retransmission device 101 concerned. The correspondence information RE2 is information indicating the correspondence relationship between the ID of the active IP retransmission device 101 and the transmission setting information C2 in the IP retransmission device 101 concerned. The correspondence information RE3 is information indicating the correspondence relationship between the ID of the active IP retransmission device 101 and the SI extraction information C3 in the IP retransmission device 101 concerned.

The communication unit 12 outputs the received initial setting information Cin and retransmission setting information Crt to the processing unit 15 .

The processing unit 15 receives the initial setting information Cin and the retransmission setting information Crt from the communication unit 12 and stores the received initial setting information Cin and retransmission setting information Crt in the storage unit 18 .

When the processing unit 15 receives the initial setting information Cin indicating that the IP retransmitting device 101 is a standby system, the processing unit 15 maintains the transmission off state of the IP transmitting units 17A and 17B. On the other hand, when processing unit 15 receives initial setting information Cin indicating that IP retransmitting device 101 is the active system, processing unit 15 outputs an operation instruction to IP transmitting units 17A and 17B, thereby disabling IP transmitting units 17A and 17B. Switch to transmission on state.

Processing unit 15 in active IP retransmission device 101 outputs reception setting information C<b>1 to IP reception unit 11 . Further, the processing unit 15 in the active IP retransmission device 101 outputs the transmission setting information C2 to the IP transmission units 17A and 17B. Also, the processing unit 15 in the active IP retransmission device 101 outputs the SI extraction information C3 to the PID filter 16 .

In the active IP retransmission device 101 , the IP receiver 11 starts receiving IP packets Pcon from the headend device 221 according to the reception setting information C 1 received from the processor 15 . Also, the IP transmission units 17A and 17B start generating and transmitting IP packets Prt1 and Psi1 according to the transmission setting information C2 received from the processing unit 15. FIG. Further, according to the SI extraction information C3 received from the processing unit 15, the PID filter 16 extracts the TS packets including the PID indicated by the SI extraction information C3 from among the TS packets received from the TS acquisition unit 13, 17B.

In the standby IP retransmission device 101, the IP receiver 11 waits for the start of reception of the IP packet Pcon. Also, the IP transmission units 17A and 17B wait for start of generation and start of transmission of IP packets Prt1 and Psi1.

(Example 1 of switching method)
For example, the control device 201 creates a content retransmission switching plan between the active IP retransmitting device 101 and the standby IP retransmitting device 101 based on the monitoring result of the active IP retransmitting device 101. .

More specifically, the communication unit 12 of the active IP retransmission device 101 regularly or irregularly indicates the operation state of the power supply unit, the fan operation state, version information, etc. of the IP retransmission device 101. State information is sent to the controller 201 .

Based on the state information received from the N active IP retransmitting devices 101, the control device 201 determines which of the N active IP retransmitting devices 101 should stop retransmitting content. A switching plan is created that includes the transmission device 101 and the start timing for starting the switching process. Hereinafter, the IP retransmitting device 101 that should stop retransmitting content will also be referred to as a "switching target IP retransmitting device 101".

In the switching process, the IP retransmission system 401 causes the standby IP retransmission apparatus 101 to start receiving the same IP packet Pcon received by the switching target IP retransmission apparatus 101 . Also, the setting contents regarding retransmission of the standby IP retransmitting apparatus 101 are matched with the setting contents regarding retransmission of the switching target IP retransmitting apparatus 101 .

More specifically, when the start timing arrives, control device 201 transmits switching announcement SW1 including the ID of IP retransmission device 101 to be switched to standby IP retransmission device 101 .

When the processing unit 15 in the standby IP retransmission device 101 receives the switching notice SW1 from the control device 201 via the communication unit 12, the switching notice SW1 is included in the switching notice SW1 from the correspondence information RE1, RE2, RE3 in the storage unit 18. Acquire reception setting information C1, transmission setting information C2, and SI extraction information C3 corresponding to the ID. The processing unit 15 outputs the acquired reception setting information C1 to the IP reception unit 11, outputs the acquired transmission setting information C2 to the IP transmission units 17A and 17B, and outputs the acquired SI extraction information C3 to the PID filter 16. .

In the standby IP retransmission device 101 , the IP reception unit 11 starts receiving the IP packet Pcon from the headend device 221 according to the reception setting information C 1 received from the processing unit 15 . That is, the IP receiving unit 11 starts receiving an IP packet Pcon having the same content as the IP packet Pcon received by the IP retransmitting device 101 to be switched. Further, the IP transmission units 17A and 17B hold the transmission setting information C2 received from the processing unit 15 and wait for operation instructions from the processing unit 15. FIG. Further, according to the SI extraction information C3 received from the processing unit 15, the PID filter 16 extracts the TS packets including the PID indicated by the SI extraction information C3 from among the TS packets received from the TS acquisition unit 13, 17B.

In addition, the control device 201 transmits the switching notice SW2 to the IP retransmission device 101 to be switched.

When the processing unit 15 in the active IP retransmission device 101 receives the switching notice SW2 from the control device 201 via the communication unit 12, the processing unit 15 recognizes that the IP retransmission device 101 is the IP retransmission device 101 to be switched. do. Then, processing unit 15 transmits, for example, timing information including the latest count value Ccnt received from time information extracting unit 14 to control device 201 via communication unit 12 .

The control device 201 receives the timing information from the IP retransmission device 101 to be switched, and retransmits the content from the IP retransmission device 101 to be switched to the standby IP retransmission device 101 based on the received timing information. Determines when to switch to

For example, the control device 201 determines switching timing based on the count value Ccnt included in the timing information. More specifically, the control device 201 holds frequency information indicating the frequency of the clock in the headend device 221 . Based on the frequency information, the control device 201 calculates a count value SWcnt by adding, for example, a count value for 5 seconds to the count value Ccnt included in the timing information. The control device 201 determines the timing at which the IP packet Pcon, in which the count value Ccnt that is the same as the count value SWcnt is stored in the timestamp field, arrives at the IP retransmission device 101 as the switching timing.

The control device 201 generates switching information including the calculated count value SWcnt, and transmits the generated switching information to the switching target IP retransmitting device 101 and the standby IP retransmitting device 101 .

The processing unit 15 in the switching target IP retransmission device 101 receives the switching information from the control device 201 via the communication unit 12 and stores the received switching information in the storage unit 18 .

Also, the processing unit 15 in the standby IP retransmission device 101 receives switching information from the control device 201 via the communication unit 12 and stores the received switching information in the storage unit 18 .

Based on the count value Ccnt received from the time information extraction unit 14, the processing unit 15 in the switching target IP retransmission device 101 and the processing unit 15 in the standby IP retransmission device 101 detect that the switching timing has arrived. , the start and stop of transmission of IP packets Prt1 and Psi1 by the IP transmission units 17A and 17B are switched.

More specifically, in the switching target IP retransmission device 101, each time the processing unit 15 receives the count value Ccnt from the time information extraction unit 14, the processing unit 15 compares the received count value Ccnt and the count value SWcnt indicated by the switching information. match. When the received count value Ccnt matches the count value SWcnt, the processing unit 15 determines that the switching timing has arrived, and outputs a stop instruction to the IP transmission units 17A and 17B, thereby transmitting the IP transmission units 17A and 17B. Switch to off state. When switched to the transmission off state, the IP transmission units 17A and 17B stop generating and transmitting IP packets Prt1 and Psi1. Also, the processing unit 15 outputs a stop instruction to the IP receiving unit 11 . Upon receiving the stop instruction from the processing unit 15 , the IP receiving unit 11 stops receiving IP packets Pcon from the headend device 221 .

For example, when the switching of the IP transmission units 17A and 17B to the transmission off state is completed, the processing unit 15 in the switching target IP retransmission device 101 sends a completion notification indicating that the switching is completed to the control unit 101 via the communication unit 12. 201.

In the standby IP retransmission device 101, each time a time stamp is received from the time information extraction unit 14, the processing unit 15 collates the count value indicated by the received time stamp with the count value SWcnt indicated by the switching information. When the received count value Ccnt matches the count value SWcnt, the processing unit 15 determines that the switching timing has arrived, and outputs an operation instruction to the IP transmission units 17A and 17B, thereby transmitting the IP transmission units 17A and 17B. Switch to ON state. When the IP transmission units 17A and 17B are switched to the transmission ON state, they start generating and transmitting IP packets Prt1 and Psi1 according to the transmission setting information C2 they hold.

For example, when the switching of the IP transmission units 17A and 17B to the transmission ON state is completed, the processing unit 15 in the standby IP retransmission device 101 sends a completion notification indicating that the switching has been completed to the control unit 101 via the communication unit 12. 201.

Processing unit 15 in IP retransmission device 101 to be switched may further transmit a stop notification indicating that the active system has stopped to control device 201 in addition to the completion notification. More specifically, the processing unit 15 transmits a completion notification to the control device 201 via the communication unit 12 when the switching of the IP transmission units 17A and 17B to the transmission off state is completed. After that, when the reception of the IP packet Pcon by the IP receiver 11 is stopped and the switching target IP retransmission device 101 can be removed from the IP retransmission system 401, the processing unit 15 sends the stop notification to the communication unit 12. It transmits to the control device 201 via. As a result, in addition to the completion of content retransmission switching, it is possible to notify the control device 201 that the IP retransmission device 101 that has been switched from the active system to the standby system can be replaced for maintenance. In other words, switching to retransmission of content and subsequent maintenance replacement of the device can be handled separately.

Further, instead of the processing unit 15 in the active IP retransmission device 101, the processing unit 15 in the standby IP retransmission device 101 transmits the timing information to the control device 201 via the communication unit 12. good too. More specifically, when the processing unit 15 in the standby IP retransmission device 101 receives the switching notice SW1 from the control device 201 via the communication unit 12, the IP reception unit 11 starts receiving the IP packet Pcon. After that, timing information including the latest count value Ccnt received from time information extraction unit 14 is transmitted to control device 201 via communication unit 12 . The control device 201 receives the timing information from the standby IP retransmission device 101 and determines the switching timing based on the count value Ccnt included in the received timing information.

(Example 2 of switching method)
In the switching method example 1 described above, the control device 201 is configured to determine the switching timing based on the count value Ccnt of the IP packet Pcon, but the present invention is not limited to this. In example 2 of the switching method, the control device 201 determines the switching timing based on the sequence value Cnmb of the IP packet Pcon.

More specifically, when the processing unit 15 in the active IP retransmitting device 101 receives the switching notice SW2 from the control device 201 via the communication unit 12, the IP retransmitting device 101 becomes the switching target IP retransmitting device. 101. Then, the processing unit 15 transmits timing information including the latest sequence value Cnmb and the unit increment received from the time information extraction unit 14 to the control device 201 via the communication unit 12 .

The control device 201 receives the timing information from the switching target IP retransmission device 101, and calculates the increment of the sequence value Cnmb for, for example, 5 seconds based on the unit increment included in the received timing information. The control device 201 calculates a sequence value SWnmb by adding the calculated increment to the sequence value Cnmb included in the timing information. The control device 201 determines the timing at which the IP packet Pcon, in which the sequence value Cnmb having the same value as the sequence value SWnmb is stored in the sequence number field, arrives at the IP retransmission device 101 as the switching timing.

The control device 201 generates switching information including the calculated sequence value SWnmb, and transmits the generated switching information to the switching target IP retransmitting device 101 and the standby IP retransmitting device 101 .

The processing unit 15 in the switching target IP retransmission device 101 receives the switching information from the control device 201 via the communication unit 12 and stores the received switching information in the storage unit 18 .

Also, the processing unit 15 in the standby IP retransmission device 101 receives switching information from the control device 201 via the communication unit 12 and stores the received switching information in the storage unit 18 .

Based on the sequence value Cnmb received from the time information extraction unit 14, the processing unit 15 in the switching target IP retransmission device 101 and the processing unit 15 in the standby IP retransmission device 101 detect that the switching timing has arrived. , the start and stop of transmission of IP packets Prt1 and Psi1 by the IP transmission units 17A and 17B are switched.

More specifically, in the switching target IP retransmission device 101, each time the processing unit 15 receives the sequence value Cnmb from the time information extraction unit 14, the received sequence value Cnmb and the sequence value SWnmb indicated by the switching information are match. When the received sequence value Cnmb matches the sequence value SWnmb, the processing unit 15 determines that the switching timing has arrived, and outputs a stop instruction to the IP transmitting units 17A and 17B, thereby transmitting the IP transmitting units 17A and 17B. Switch to off state. When switched to the transmission off state, the IP transmission units 17A and 17B stop generating and transmitting IP packets Prt1 and Psi1. Also, the processing unit 15 outputs a stop instruction to the IP receiving unit 11 . Upon receiving the stop instruction from the processing unit 15 , the IP receiving unit 11 stops receiving IP packets Pcon from the headend device 221 .

For example, when the switching of the IP transmission units 17A and 17B to the transmission off state is completed, the processing unit 15 in the switching target IP retransmission device 101 sends a completion notification indicating that the switching is completed to the control unit 101 via the communication unit 12. 201.

In the standby IP retransmission device 101, each time the processing unit 15 receives the sequence value Cnmb from the time information extraction unit 14, it collates the received sequence value Cnmb with the sequence value SWnmb indicated by the switching information. When the received sequence value Cnmb matches the sequence value SWnmb, the processing unit 15 determines that the switching timing has arrived, and outputs operation instructions to the IP transmitting units 17A and 17B, thereby transmitting the IP transmitting units 17A and 17B. Switch to ON state. When the IP transmission units 17A and 17B are switched to the transmission ON state, they start generating and transmitting IP packets Prt1 and Psi1 according to the transmission setting information C2 they hold.

For example, when the switching of the IP transmission units 17A and 17B to the transmission ON state is completed, the processing unit 15 in the standby IP retransmission device 101 sends a completion notification indicating that the switching has been completed to the control unit 101 via the communication unit 12. 201.

Note that instead of the processing unit 15 in the active IP retransmission device 101, the processing unit 15 in the standby IP retransmission device 101 is configured to transmit the timing information to the control device 201 via the communication unit 12. good too. More specifically, when the processing unit 15 in the standby IP retransmission device 101 receives the switching notice SW1 from the control device 201 via the communication unit 12, the IP reception unit 11 starts receiving the IP packet Pcon. After that, for example, the timing information including the latest sequence value Cnmb received from the time information extraction unit 14 is transmitted to the control device 201 via the communication unit 12 . The control device 201 receives the timing information from the standby IP retransmission device 101 and determines the switching timing based on the sequence value Cnmb included in the received timing information.

(Example 3 of switching method)
In Examples 1 and 2 of the switching method described above, the configuration is such that the control device 201 determines the switching timing, but the present invention is not limited to this. In example 3 of the switching method, instead of the control device 201, the processing unit 15 in the IP retransmission device 101 determines the switching timing.

More specifically, when the processing unit 15 in the active IP retransmitting device 101 receives the switching notice SW2 from the control device 201 via the communication unit 12, the IP retransmitting device 101 becomes the switching target IP retransmitting device. 101. Then, the processing unit 15 calculates a count value SWcnt by adding, for example, the count value for 5 seconds to the latest count value Ccnt received from the time information extraction unit 14, for example. The processing unit 15 determines the timing at which the IP packet Pcon, in which the count value Ccnt that is the same as the count value SWcnt is stored in the timestamp field, arrives at the IP retransmitting device 101 as the switching timing.

The processing unit 15 in the active IP retransmission device 101 generates calculation information including the calculated count value SWcnt, and transmits the generated calculation information to the control device 201 via the communication unit 12 .

The control device 201 receives the calculation information from the switching target IP retransmission device 101 and acquires the count value SWcnt from the received calculation information. The control device 201 generates switching information including the count value SWcnt, and transmits the generated switching information to the standby IP retransmission device 101 .

Instead of processing unit 15 in active IP retransmitting device 101, processing unit 15 in standby IP retransmitting device 101 may determine the switching timing. More specifically, when processing unit 15 in standby IP retransmission device 101 receives switching notice SW1 from control device 201 via communication unit 12, processing unit 15 calculates count value SWcnt. The processing unit 15 determines the timing at which the IP packet Pcon, in which the count value Ccnt that is the same as the count value SWcnt is stored in the timestamp field, arrives at the IP retransmitting device 101 as the switching timing.

Further, the processing unit 15 in the active IP retransmission device 101 or the processing unit 15 in the standby IP retransmission device 101 generates calculation information including the sequence value SWnmb instead of the count value SWcnt, and the generated calculation Information may be transmitted to the control device 201 via the communication unit 12 .

(Example 4 of switching method)
In Example 1 of the switching method described above, the configuration is such that the control device 201 creates a switching plan, but the present invention is not limited to this. In switching method example 4, instead of the controller 201 creating a switching plan, one of the devices in the IP retransmission system 401 receives a switching instruction including a switching plan from the administrator of the IP retransmission system 401 .

More specifically, IP retransmission system 401 further comprises a console device (not shown). For example, control device 201 receives a switching instruction including a switching plan from an administrator of IP retransmission system 401 via the console device.

When the start timing indicated by the received switching plan arrives, the control device 201 transmits the switching notice SW1 to the standby IP retransmitting device 101 and the switching notice SW2 to the switching target IP retransmitting device 101 .

Instead of the control device 201, the IP retransmission device 101 may receive a switching instruction including a switching plan from the administrator of the IP retransmission system 401 via a console device. For example, standby IP retransmission device 101 or IP retransmission device 101 to be switched receives a switching instruction from an administrator of IP retransmission system 401 via a console device. The processing unit 15 in the IP retransmission device 101 receives the switching instruction and transmits the received switching instruction to the control device 201 via the communication unit 12 .

(Example 5 of switching method)
In Examples 1 to 4 of the switching method described above, the switching process is performed using the control device 201, but the present invention is not limited to this. In example 5 of the switching method, switching processing is performed without using the control device 201 . In this case, for example, the active IP retransmitting device 101 and the standby IP retransmitting device 101 are LAN-connected via a HUB (not shown).

For example, IP retransmission device 101 to be switched receives a switching instruction including a switching plan from an administrator of IP retransmission system 401 via a console device.

When the start timing indicated by the received switching plan arrives, the processing unit 15 in the IP retransmitting device 101 to be switched transmits the switching notice SW1 including the ID of the IP retransmitting device 101 to the standby IP retransmitting device 101. do.

In addition, the processing unit 15 in the switching target IP retransmission device 101 determines switching timing based on the count value Ccnt or the sequence value Cnmb. Then, the processing unit 15 generates switching information including the count value SWcnt or the sequence value SWnmb, and transmits the generated switching information to the standby IP retransmission device 101 via the communication unit 12 .

Note that IP retransmission system 401 may perform switching processing by combining some or all of Examples 1 to 5 of the switching methods described above.

[Flow of operation]
Each device in the IP retransmission system according to the embodiment of the present disclosure includes a computer including a memory, and an arithmetic processing unit such as a CPU in the computer includes part or all of the steps of the following flowcharts and sequences. The program is read from the memory and executed. Programs for these multiple devices can each be installed from the outside. Programs for these devices are distributed in a state of being stored in recording media or via communication lines.

FIG. 4 is a diagram illustrating an example of a switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. In FIG. 4, as an example of the IP retransmission device 101, active IP retransmission devices 101A and 101B and a standby IP retransmission device 101C are shown. FIG. 4 shows the sequence of Example 1 of the switching method described above.

Referring to FIG. 4, after IP retransmitting devices 101A, 101B, and 101C are activated, control device 201 transmits communication setting information Ccm, initial setting information Cin, and retransmission setting information Crt to IP retransmitting devices 101A, 101B. , 101C (step S11).

Next, the IP retransmission devices 101A and 101B switch the IP transmission units 17A and 17B to the transmission ON state, and start generating and transmitting IP packets Prt1 and Psi1 (step S12).

Next, the control device 201 creates a switching plan based on the operating states of the power supply units, the operating states of the fans, version information, and the like in the IP retransmitting devices 101A and 101B. As an example, the control device 201 creates a switching plan indicating that retransmission of content by the IP retransmission device 101A should be stopped (step S13).

Next, the IP retransmission system 401 causes the IP retransmission device 101C to start receiving the same IP packet Pcon received by the switching target IP retransmission device 101A. Also, the setting contents regarding retransmission of the IP retransmitting device 101C are matched with the setting contents regarding retransmission of the IP retransmitting device 101A. More specifically, control device 201 transmits switching notice SW1 including the ID of IP retransmitting device 101A to IP retransmitting device 101C when it is time to start switching processing (step S14).

Next, IP retransmitting device 101C acquires reception setting information C1, transmission setting information C2 and SI extraction information C3 corresponding to the ID of IP retransmitting device 101A, and according to reception setting information C1, Reception of the IP packet Pcon is started (step S15).

Next, the control device 201 transmits the switching notice SW2 to the IP retransmission device 101A (step S16).

Next, after receiving the switching notice SW2 from the control device 201, the IP retransmission device 101A receives timing information including the latest count value Ccnt stored in the timestamp field of the IP packet Pcon received from the headend device 221. to the control device 201 (step S17).

Next, the control device 201 determines switching timing based on the count value Ccnt included in the timing information received from the IP retransmission device 101A. More specifically, the control device 201 calculates a count value SWcnt by adding a count value for 5 seconds to the count value Ccnt (step S18).

Next, control device 201 transmits switching information including count value SWcnt to IP retransmission devices 101A and 101C (step S19).

Next, at the switching timing determined by the control device 201, retransmission of the content is switched from the IP retransmission device 101A to the IP retransmission device 101C. More specifically, when the count value Ccnt stored in the time stamp field of the received IP packet Pcon matches the count value SWcnt, the IP retransmission device 101A determines that the switching timing has arrived, and the IP transmission unit 101A 17A and 17B are switched to the transmission off state, and generation and transmission of IP packets Prt1 and Psi1 are stopped (step S20).

When the count value Ccnt stored in the time stamp field of the received IP packet Pcon matches the count value SWcnt, the IP retransmission device 101C determines that the switching timing has arrived, and IP transmission units 17A and 17B to the transmission ON state, and start generating and transmitting IP packets Prt1 and Psi1 (step S21).

In step S17, the IP retransmitting device 101A sends timing information including the latest sequence value Cnmb and the unit increment stored in the sequence number field of the IP packet Pcon received from the headend device 221 to the control device 201. You may send. In this case, in step S18, the control device 201 determines the switching timing based on the sequence value Cnmb included in the timing information received from the IP retransmission device 101A. More specifically, the control device 201 calculates the sequence value SWnmb by adding the increase amount of the sequence value Cnmb in 5 seconds to the sequence value Cnmb. Then, in step S19, the control device 201 transmits switching information including the sequence value SWnmb to the IP retransmitting devices 101A and 101C.

FIG. 5 is a diagram showing another example of the switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 5 shows the sequence of Example 3 of the switching method described above.

Referring to FIG. 5, control device 201 and IP retransmission devices 101A, 101B, and 101C first perform steps S31 to S36, which are the same as steps S11 to S16 in the sequence of FIG.

Next, after receiving the switching notice SW2 from the control device 201, the IP retransmission device 101A uses the latest count value Ccnt stored in the timestamp field of the IP packet Pcon received from the headend device 221 as a reference, Decide when to switch. More specifically, the IP retransmission device 101A calculates a count value SWcnt by adding a count value for 5 seconds to the count value Ccnt (step S37).

Next, IP retransmission device 101A transmits calculation information including count value SWcnt to control device 201 (step S38).

Next, the control device 201 acquires the count value SWcnt from the calculation information received from the IP retransmission device 101A, and transmits switching information including the count value SWcnt to the IP retransmission device 101C (step S39).

Next, at the switching timing determined by the IP retransmission device 101A, retransmission of the content is switched from the IP retransmission device 101A to the IP retransmission device 101C. More specifically, when the count value Ccnt stored in the timestamp field of the received IP packet Pcon matches the calculated count value SWcnt, the IP retransmission device 101A determines that the switching timing has arrived, The IP transmission units 17A and 17B are switched to the transmission off state, and generation and transmission of IP packets Prt1 and Psi1 are stopped (step S40).

When the count value Ccnt stored in the time stamp field of the received IP packet Pcon matches the count value SWcnt, the IP retransmission device 101C determines that the switching timing has arrived, and IP transmission units 17A and 17B is switched to the transmission ON state, and generation and transmission of IP packets Prt1 and Psi1 are started (step S41).

FIG. 6 is a diagram showing another example of the switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 6 shows the sequence of Example 4 of the switching method described above.

Referring to FIG. 6, control device 201 and IP retransmission devices 101A, 101B, and 101C first perform steps S51 to S52, which are the same as steps S11 to S12 in the sequence of FIG.

Next, control device 201 receives a switching instruction including a switching plan from the administrator of IP retransmission system 401 via the console device (step S53).

Next, control device 201 and IP retransmitting devices 101A and 101C perform the same processing as steps S14 to S21 in the sequence of FIG. 4 as steps S54 to S61.

FIG. 7 is a diagram illustrating another example of a switching process sequence in the IP retransmission system according to the embodiment of the present disclosure. FIG. 7 shows, as an example of the IP retransmission device 101, an active IP retransmission device 101A and a standby IP retransmission device 101C. FIG. 7 shows the sequence of Example 5 of the switching method described above.

Referring to FIG. 7, first, control device 201 and IP retransmission devices 101A and 101C perform the same processing as steps S11 to S12 in the sequence of FIG. 4 as steps S71 to S72.

Next, IP retransmission device 101A receives a switching instruction including a switching plan from the administrator of IP retransmission system 401 via the console device (step S73).

Next, when the start timing indicated by the accepted switching plan arrives, IP retransmitting device 101A transmits switching notice SW1 including the ID of IP retransmitting device 101A to IP retransmitting device 101C (step S74).

Next, IP retransmitting device 101C acquires reception setting information C1, transmission setting information C2 and SI extraction information C3 corresponding to the ID of IP retransmitting device 101A, and according to reception setting information C1, Reception of the IP packet Pcon is started (step S75).

Next, the IP retransmission device 101A determines switching timing based on the latest count value Ccnt stored in the timestamp field of the IP packet Pcon received from the headend device 221 . More specifically, the IP retransmission device 101A calculates a count value SWcnt by adding a count value for 5 seconds to the count value Ccnt (step S76).

Next, IP retransmitting device 101A transmits switching information including count value SWcnt to IP retransmitting device 101C (step S77).

Next, at the switching timing determined by the IP retransmission device 101A, retransmission of the content is switched from the IP retransmission device 101A to the IP retransmission device 101C. More specifically, when the count value Ccnt stored in the timestamp field of the received IP packet Pcon matches the calculated count value SWcnt, the IP retransmission device 101A determines that the switching timing has arrived, The IP transmission units 17A and 17B are switched to the transmission off state, and generation and transmission of IP packets Prt1 and Psi1 are stopped (step S78).

When the count value Ccnt stored in the time stamp field of the received IP packet Pcon matches the count value SWcnt, the IP retransmission device 101C determines that the switching timing has arrived, and IP transmission units 17A and 17B is switched to the transmission ON state, and generation and transmission of IP packets Prt1 and Psi1 are started (step S79).

By the way, in a configuration in which IP retransmission devices that retransmit content can be switched, there is a demand for a technology that can realize stable content playback in a playback device with a simple configuration.

In contrast, the switching method according to the embodiment of the present disclosure receives an IP packet Pcon including content to be broadcast, includes the content included in the received IP packet Pcon in IP packets Prt1 and Psi1, and retransmits the content. This is a switching method for switching retransmission of content from the active IP retransmission device 101 to the standby IP retransmission device 101 in an IP retransmission system 401 having a plurality of IP retransmission devices 101 that are connected to each other. In this switching method, first, the IP retransmitting device 101 of the standby system starts receiving the same IP packet Pcon as the IP packet Pcon received by the IP retransmitting device 101 of the active system. Next, the setting contents regarding retransmission of the IP retransmitting device 101 of the standby system are matched with the setting contents regarding retransmission of the IP retransmitting device 101 of the active system. The switching timing is determined based on the information included in the IP packet Pcon, the value of which changes according to the transmission time of the IP packet Pcon. Next, at the switching timing, content retransmission is switched from the active IP retransmission device 101 to the standby IP retransmission device 101 .

In this way, at the switching timing determined based on the information whose value changes according to the transmission time of the IP packet Pcon, the content retransmission is switched from the active IP retransmitting device to the standby IP retransmitting device. In the IP retransmitting device of the active system and the IP retransmitting device of the standby system, the switching timing of content retransmission can be matched with a simple configuration. When switching to the standby system, the content can be seamlessly reproduced in the reproduction device. In addition, even during the time period when the content should be retransmitted, that is, during the operation of the IP retransmission device, the content can be seamlessly reproduced by the reproduction device when the IP retransmission device that retransmits the content is switched from the active system to the standby system. It can be performed. Therefore, it is possible to achieve stable content reproduction in the reproduction device with a simple configuration.

Further, by determining the switching timing using, for example, the count value Ccnt and the sequence value Cnmb stored in the RTP header of the IP packet Pcon as information whose value changes according to the transmission time of the IP packet Pcon, the active IP In the retransmitting device and the standby IP retransmitting device, arrival of timing for switching content retransmission can be detected without analyzing the TS packet stored in the payload of the IP packet Pcon.

The above-described embodiments should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

The above description includes the features appended below.
[Appendix 1]
An IP retransmission system comprising a plurality of IP retransmission devices that receive relay IP packets containing content to be broadcast, and retransmit the content contained in the received relay IP packets in the retransmission IP packets a switching method for switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device,
causing the standby IP retransmission device to start receiving the same packet as the relay IP packet received by the active IP retransmission device;
a step of matching the settings regarding retransmission of the standby IP retransmission device to the settings regarding retransmission of the active IP retransmission device;
determining switching timing based on information included in the relay IP packet, the value of which changes according to the transmission time of the relay IP packet;
at the switching timing, switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device;
The switching method according to claim 1, wherein, in the step of determining the switching timing, the switching timing is determined based on information stored in an RTP header of the relay IP packet.

11 IP receiver 12 communication unit 13 TS acquisition unit 14 time information extraction unit 15 processing unit 16 PID filter 17A, 17B IP transmission unit 18 storage unit 101 IP retransmission device 111 IP retransmission device 151 IP network 201 control device 211 control device 221 Headend Device 251 EWS Sending Device 261 SI Sending Device 301 STB
401 IP retransmission system

Claims (3)

An IP retransmission system comprising a plurality of IP retransmission devices that receive relay IP packets containing content to be broadcast, and retransmit the content contained in the received relay IP packets in the retransmission IP packets a switching method for switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device,
causing the standby IP retransmission device to start receiving the same packet as the relay IP packet received by the active IP retransmission device;
a step of matching the settings regarding retransmission of the standby IP retransmission device to the settings regarding retransmission of the active IP retransmission device;
determining switching timing based on information included in the relay IP packet, the value of which changes according to the transmission time of the relay IP packet;
and switching retransmission of the content from the active IP retransmission device to the standby IP retransmission device at the switching timing. The IP retransmission system further comprises a controller,
The switching method further comprises:
a step in which the control device creates a switching plan for retransmission of the content in the active IP retransmission device and the standby IP retransmission device based on the monitoring result of the active IP retransmission device; 2. The switching method of claim 1, comprising: An IP retransmission apparatus in an IP retransmission system that receives a relay IP packet containing content to be broadcast, and retransmits the content included in the received relay IP packet in the retransmission IP packet,
a receiving unit that receives the relay IP packet;
a transmission unit that transmits the IP packet for retransmission;
an acquisition unit that acquires switching timing, which is timing at which to switch between starting and stopping transmission of the IP packet for retransmission by the transmission unit;
The arrival of the switching timing obtained by the obtaining unit is based on information included in the relay IP packet received by the receiving unit, the value of which changes according to the transmission time of the relay IP packet. and a switching unit that switches between starting and stopping transmission of the IP packet for retransmission by the transmitting unit when it is detected.

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