JP2017169093A - Communication method, communication device and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication method, a communication device, and a communication system that can reproduce streaming contents so that the streaming contents are not discontinued, effectively use the storage area of a relay device, and improve the communication efficiency.SOLUTION: A communication method includes a step of receiving, from each of plural relay devices 14, a next arrival scheduled time representing a time at which each of the plural relay devices 14 next arrives at a first position which enables communications with a gateway device 13 via a first network, a step of receiving an interest packet including the reproduction time of a streaming content from a terminal device 12, a step of selecting the relay device 14 for transmitting the interest packet from the plural relay devices 14 based on the reproduction time and the next arrival scheduled times of the plural relay devices 14, and a step of transmitting the interest packet to the relay device 14.SELECTED DRAWING: Figure 8

Description

  The present disclosure relates to a communication method, a communication apparatus, and a communication system that relay an interest packet requesting content data and a data packet including the content data using a content-oriented network.

  In recent years, there has been proposed a next-generation network architecture capable of acquiring content data by designating the name of the content data itself, not the location where the content exists.

  For example, Patent Literature 1 and Non-Patent Literature 1 disclose a technique called CCN (Content Centric Network). CCN is a content distribution infrastructure network that distributes content based on the name of the content.

  In CCN, a name is assigned in advance to each content to be distributed. A terminal device that acquires content data (hereinafter referred to as “content data”) issues a packet called an interest packet for requesting content data by designating the content name (hereinafter referred to as “content name”).

  The terminal device can acquire the content data specified by the interest packet by sending one or more interest packets corresponding to the content data to the network. When the content provider server that holds the content data requested by the interest packet receives the interest packet, the content provider server sends one or more data packets including the content data to the network to the terminal device that issued the interest packet. To do.

  On the other hand, in Patent Document 2, in an environment where a network connection cannot be established between a terminal device and a content provider server, a relay that can be moved as a means for carrying packets in order to transmit and receive packets between the terminal device and the content provider server A system called a message ferry that uses a device is used. By the relay device functioning as a message ferry, for example, a terminal device arranged in the first network can have a content provider server and a relay device arranged in a second network separated from the first network. It is possible to communicate indirectly.

  Patent Document 3 proposes a method in which a message ferry is applied to a content data distribution service, the load on the network is reduced, and content data is provided by the time reserved by the user. Here, the management server that schedules the distribution of the content data receives a distribution request including information for specifying the distribution completion time from the terminal device, and determines the schedule for distributing the content data.

US Pat. No. 8,386,622 JP 2013-157911 A International Publication No. 2014/142344

Van Jacobson, Diana K. et al. Smetters, James D. Thornton, Michael F. Plus, Nicholas H.M. Briggs, Rebecca L. Brainard, “Networking Named Content”, ACM CoNEXT, 2009

  However, in the above-described conventional technique, further improvement for appropriately selecting and controlling the content data to be transported is required.

  The present disclosure has been made in order to solve the above-described conventional problem, and can play the streaming content without interruption in the terminal device, and can effectively use the storage area of the relay device, An object of the present invention is to provide a communication method, a communication apparatus, and a communication system that can improve communication efficiency.

  A communication method according to an aspect of the present disclosure includes transmitting a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices, and a plurality of data including the streaming content received from the plurality of relay devices. A communication method in a communication device for transmitting a packet to the terminal device, wherein the first location is capable of communicating with the communication device via a first network, and a second network separated from the first network. A next scheduled arrival time indicating a time at which the plurality of relay devices that move between the second location that can communicate with the content providing device that provides the streaming content via the first arrival time at the first location. An interface received from each of the plurality of relay devices and including a playback time of the streaming content A packet is received from the terminal device, and the interest packet is transmitted from the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices. A relay device is selected, and the interest packet is transmitted to the selected relay device.

  According to the present disclosure, a relay device that transmits an interest packet is selected from the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices. The streaming content can be reproduced without interruption. In addition, since content data can be shared and transported by a plurality of relay devices, the storage area of the relay device can be used effectively, and communication efficiency can be improved.

It is a figure which shows an example of a structure of the communication system which concerns on Embodiment 1 of this indication. It is a figure which shows an example of the hardware constitutions of the gateway apparatus in Embodiment 1 of this indication. It is a figure which shows an example of a function structure of the gateway apparatus in Embodiment 1 of this indication. It is a figure which shows an example of the information memorize | stored in the estimated arrival time management part in this Embodiment 1. FIG. It is a figure which shows an example of the information memorize | stored in the streaming content management part in this Embodiment 1. FIG. It is a figure which shows an example of the hardware constitutions of the relay apparatus in Embodiment 1 of this indication. It is a figure which shows an example of a function structure of the relay apparatus in Embodiment 1 of this indication. 7 is a sequence diagram illustrating an example of an operation of the entire communication system according to Embodiment 1 of the present disclosure. FIG. It is a flowchart which shows operation | movement of the interest process part performed when a gateway apparatus receives an interest packet from a terminal device. It is a flowchart which shows the specific operation | movement of the relay apparatus selection process in step S29 of FIG. It is a figure which shows an example of the content name described in the interest packet which requests | requires streaming content. It is a figure which shows an example of the hardware constitutions of the gateway apparatus in Embodiment 2 of this indication. It is a figure which shows an example of a function structure of the gateway apparatus in Embodiment 2 of this indication. It is a figure which shows an example of the information memorize | stored in the prediction free space management part in this Embodiment 2. FIG. It is a flowchart which shows operation | movement of the interest process part performed when a gateway apparatus receives an interest packet from a terminal device. It is a flowchart which shows the specific operation | movement of the interest packet transmission process in FIG.15 S40. It is a figure which shows an example of the hardware constitutions of the gateway apparatus in Embodiment 3 of this indication. It is a figure which shows an example of a function structure of the gateway apparatus in Embodiment 3 of this indication. It is a figure which shows an example of the information memorize | stored in the estimated arrival time management part in this Embodiment 3. FIG.

(Knowledge that became the basis of this disclosure)
Hereinafter, the knowledge that is the basis of the present disclosure will be described.

  CCN is a content distribution infrastructure network that distributes content based on the name of the content.

  In CCN, a name is assigned in advance to each content to be distributed. A terminal device that acquires content data issues a packet called an interest packet for requesting content data by specifying a content name.

  The terminal device can acquire the content data specified by the interest packet by sending one or more interest packets corresponding to the content data to the network. When the content provider server that holds the content data requested by the interest packet receives the interest packet, the content provider server sends one or more data packets including the content data to the network to the terminal device that issued the interest packet. To do.

  A relay device that relays interest packets uses a CS (Content Store) that caches content data, a PIT (Pending Interest Table) that manages interest packets, and an FIB (Forwarding Information Base) that holds route information. Controls transmission and reception of interest packets and data packets.

  Here, when the relay device receives the interest packet, if there is a data packet including the content name described in the interest packet in CS, the interest packet is received without transferring the interest packet to another relay device. Send a data packet from the interface. On the other hand, only when the data packet including the content name described in the received interest packet does not exist in CS and the same content name as the content name described in the interest packet is not stored in the PIT, the relay device Stores the content name described in the interest packet and the information of the interface that received the interest packet in the PIT. Then, the relay device transfers the interest packet to another relay device according to the route information acquired from the FIB. However, when the same content name as the content name described in the interest packet is already stored in the PIT, the relay device does not transfer the interest packet, but stores only the information of the interface that received the interest packet.

  Further, when the relay device receives the data packet, the relay device stores the data packet in CS. However, when there is no area for storing a new data packet in the CS, the relay apparatus deletes the data packet from the CS after a predetermined time has elapsed since it was stored in the CS.

  Then, the relay device duplicates the data packet according to the number of one or more interfaces that have received the plurality of interest packets in which the same content name as the content name of the data packet is described according to the information of the PIT, Forward the duplicated data packet through its one or more interfaces. Thereafter, the relay apparatus deletes the content name of the data packet and the information of the interface that has received the interest packet that matches the content name from the PIT.

  Thus, in CCN, the same content data can be efficiently distributed by making maximum use of PIT and CS in the relay device.

  On the other hand, in Patent Document 2, in an environment in which a network connection cannot be established between a terminal device and a content provider server, a relay that can be moved as a means for transporting packets in order to transmit and receive packets between the terminal device and the content provider server A system called a message ferry that uses a device is used. One relay device out of a plurality of movable relay devices functioning as a message ferry receives information such as the number of shelters, the location of shelters, the number of relay devices, and map information with other relay devices. By sharing and optimizing the range of movement of each relay device, rapid packet transmission is possible.

  However, in Patent Document 2, the content data carried by the relay device is treated uniformly regardless of the content and type of the content data. That is, the relay device receives (records) and transports content data or a packet requesting content data as much as possible in the recording area of the relay device. Therefore, when the capacity of the storage area of the relay device is limited, not all packets to be transported can be recorded in the storage area of the relay device, resulting in transport delay. As a result, there is a possibility that problems such as delay in transport of high priority packets and interruption of playback of streaming content received by the user may occur.

  Patent Document 3 proposes a method in which a message ferry is applied to a content data distribution service, the load on the network is reduced, and content data is provided by the time reserved by the user. Here, when the management server that schedules the distribution of the content data receives a distribution request including information specifying the distribution completion time from the terminal device, the requested content is used using the reservation status of the content data and the load information of the network. The schedule for distributing data and the schedule for the first relay device to relay to the second relay device are determined.

  In other words, in Patent Literature 3, the management server determines all distribution schedules, and in a situation where the network infrastructure is shut off, the distribution schedule cannot be received and processing according to the schedule cannot be performed. . Even in a situation where the network infrastructure is not blocked, communication between a communication device such as a content server or a relay device and a management server, which occurs to determine a content distribution schedule, is inefficient. As a result, there is a possibility that problems such as delay in delivery of high priority packets and interruption of playback of streaming content received by the user may occur.

  In order to solve the above-described problem, a communication method according to an aspect of the present disclosure transmits a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices, and the plurality of relay devices A communication method in a communication device for transmitting a plurality of data packets including the received streaming content to the terminal device, wherein the first position is capable of communicating with the communication device via a first network, and the first The plurality of relay devices that move between a second location that can communicate with the content providing device that provides the streaming content via a second network that is separated from the second network are next to the first location. The next arrival time indicating the arrival time is received from each of the plurality of relay devices, and the streaming code is received. An interest packet including a reproduction time of the content is received from the terminal device, and based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, from among the plurality of relay devices A relay device that transmits the interest packet is selected, and the interest packet is transmitted to the selected relay device.

  According to this configuration, communication with the content providing apparatus that provides the streaming content via the first network that can communicate with the communication apparatus via the first network and the second network separated from the first network is possible. A next scheduled arrival time is received from each of the plurality of relay devices indicating the time at which the plurality of relay devices moving between the possible second positions will arrive at the first position next. An interest packet including the playback time of the streaming content is received from the terminal device. Based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, a relay device that transmits the interest packet is selected from the plurality of relay devices. Then, the interest packet is transmitted to the selected relay device.

  Therefore, since the relay device that transmits the interest packet is selected from the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, the streaming content is transmitted from the terminal device. It can be played back without interruption. In addition, since content data can be shared and transported by a plurality of relay devices, the storage area of the relay device can be used effectively, and communication efficiency can be improved.

  Further, in the above communication method, free capacity of a content cache unit that caches the data packet is obtained from the plurality of relay devices, and the data packet requested by the interest packet from the interest packet received from the terminal device If the acquired data size is larger than the free capacity of the content cache unit of the first relay device selected as the destination of the interest packet among the plurality of relay devices, the first The second relay device different from the relay device or the communication device transmits the interest packet already stored in the first relay device to the second relay device or the communication device, and then receives the interest packet received from the terminal device. May be transmitted to the relay device.

  According to this configuration, the free capacity of the content cache unit that caches data packets is acquired from the plurality of relay devices. The data size of the data packet requested by the interest packet is acquired from the interest packet received from the terminal device. If the acquired data size is larger than the free capacity of the content cache unit of the first relay device selected as the destination of the interest packet among the plurality of relay devices, the second relay different from the first relay device After causing the device or the communication device to transmit the interest packet already stored in the first relay device, the interest packet received from the terminal device is transmitted to the first relay device.

  Therefore, when the data size of the data packet is larger than the free capacity of the content cache unit of the first relay device selected as the transmission destination, the first relay device has already stored in the second relay device or the communication device. Since the interest packet is transmitted, the interest packet can be transmitted to the first relay device selected as the transmission destination, and the streaming content can be continuously reproduced.

  Further, in the above communication method, a priority indicating the degree to which the interest packet is preferentially transmitted is associated with the interest packet, and the interest packet is transmitted based on the acquired priority. It may be judged.

  According to this configuration, the priority indicating the degree to which the interest packet is preferentially transmitted is associated with the interest packet. Then, based on the acquired priority, it is determined whether or not to transmit an interest packet. Therefore, interest packets with high priority can be transmitted with priority.

  Further, in the above communication method, when the priority is lower than a first threshold, the received interest packet is discarded, or the received interest packet is temporarily stored in a memory included in the communication device, When the priority is equal to or higher than the first threshold, a relay device that transmits the interest packet may be selected from the plurality of relay devices.

  According to this configuration, when the priority is lower than the first threshold, the received interest packet is discarded, or the received interest packet is temporarily stored in a memory included in the communication device. When the priority is equal to or higher than the first threshold, a relay device that transmits an interest packet is selected from the plurality of relay devices.

  Therefore, it is possible to prevent the storage area of the relay apparatus from being compressed by the interest packet having a low priority, and the interest packet having a high priority can be preferentially transmitted.

  In the communication method, when the priority is higher than a second threshold value higher than the first threshold value, the received interest packet is duplicated, and the duplicated interest packet is transmitted to the plurality of relay devices. When the priority is between the first threshold and the second threshold, a relay device that transmits the interest packet may be selected from the plurality of relay devices.

  According to this configuration, when the priority is higher than the second threshold value that is higher than the first threshold value, the received interest packet is duplicated, and the duplicated interest packet is transmitted to a plurality of relay devices. When the priority is between the first threshold value and the second threshold value, a relay device that transmits an interest packet is selected from the plurality of relay devices.

  Therefore, since the interest packet having a higher priority is duplicated and transmitted to the plurality of relay apparatuses, the interest packet can be reliably transmitted and the data packet can be reliably received.

  In the above communication method, the relay device arrives at the first location one after another based on the arrival time when the relay device arrived at the first location and the next scheduled arrival time. When predicting a scheduled time and selecting the relay device, the relay device is selected from the plurality of relay devices based on at least one of the reproduction time, the next scheduled arrival time, and the next scheduled arrival time. When a relay device that transmits an interest packet is selected and a destination relay device is selected based on the next scheduled arrival time, the received interest packet is temporarily stored in the memory of the communication device, and the next time When the transmission destination relay device is selected based on the estimated arrival time, the received interest packet may be transmitted to the selected relay device.

  According to this configuration, the next scheduled arrival time at which the relay apparatus arrives at the first position one after another is predicted based on the arrival time at which the relay apparatus arrived at the first position and the next scheduled arrival time. When a relay device is selected, a relay device that transmits an interest packet is selected from a plurality of relay devices based on at least one of the reproduction time, the next arrival time, and the next arrival time. . When the transmission destination relay device is selected based on the estimated arrival time one after another, the received interest packet is temporarily stored in the memory of the communication device. When a transmission destination relay device is selected based on the next scheduled arrival time, the received interest packet is transmitted to the selected relay device.

  Therefore, a relay device as a transmission destination can be selected in advance, and the relay device can distribute a necessary amount of streaming content to a terminal device at a required time. As a result, the amount of streaming content delivered by each relay device is reduced, and the relay device can preferentially deliver content that requires an emergency. In particular, when the number of relay devices is large or when the time for which the relay devices move is short, the communication device can distribute the interest packets to the relay devices more effectively, and the relay device can allocate the storage area more effectively. Can be used.

  Further, in the communication method described above, arrival history information in which the next arrival time is associated with the arrival time is stored for each of the plurality of relay devices, and the next arrival time and the arrival time stored therein are stored. The next scheduled arrival time received from the relay device may be corrected based on the above.

  According to this configuration, the arrival history information in which the next arrival time is associated with the arrival time is stored for each of the plurality of relay apparatuses. Based on the stored next arrival time and arrival time, the next arrival time received from the relay apparatus is corrected.

  Therefore, even when an error occurs in the moving time of the relay device, the communication device can distribute the interest packet requesting the streaming content to the relay device so that the streaming content can be continuously played back by the terminal device.

  A communication device according to another aspect of the present disclosure transmits a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices, and includes a plurality of the streaming contents received from the plurality of relay devices. A communication device for transmitting a data packet to the terminal device, wherein the communication device is configured to communicate with the communication device via a first network, and via a second network separated from the first network. The next arrival time indicating the next arrival time of the plurality of relay devices moving between the content providing device that provides the streaming content and the second location that can communicate with the content providing device. A first receiving unit that receives from each of the relay devices, and an interface including a playback time of the streaming content A second receiving unit that receives a first packet from the terminal device, and based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, from among the plurality of relay devices A selection unit that selects a relay device that transmits the interest packet; and a transmission unit that transmits the interest packet to the selected relay device.

  According to this configuration, communication with the content providing apparatus that provides the streaming content via the first network that can communicate with the communication apparatus via the first network and the second network separated from the first network is possible. A next scheduled arrival time is received from each of the plurality of relay devices indicating the time at which the plurality of relay devices moving between the possible second positions will arrive at the first position next. An interest packet including the playback time of the streaming content is received from the terminal device. Based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, a relay device that transmits the interest packet is selected from the plurality of relay devices. Then, the interest packet is transmitted to the selected relay device.

  Therefore, since the relay device that transmits the interest packet is selected from the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, the streaming content is transmitted from the terminal device. It can be played back without interruption. In addition, since content data can be shared and transported by a plurality of relay devices, the storage area of the relay device can be used effectively, and communication efficiency can be improved.

  A communication system according to another aspect of the present disclosure includes a terminal device, a communication device connected to be communicable with the terminal device, a plurality of relay devices communicably connected to the communication device, and the plurality of relays A communication system comprising a content providing device communicably connected to a device, wherein the terminal device transmits an interest packet including a playback time of the streaming content to the communication device, and the streaming content A receiving unit that receives a data packet including the data packet from the communication device, wherein the communication device is separated from the first network and a first location where the communication device can communicate with the communication device via the first network. A second location capable of communicating with the content providing apparatus that provides the streaming content via the second network A first receiving unit that receives from each of the plurality of relay devices a next arrival time indicating a time at which the plurality of relay devices moving between the first arrival time at the first position; Based on the second receiving unit that receives from the terminal device, the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, the interest packet from among the plurality of relay devices A selection unit that selects a relay device that transmits the packet, a first transmission unit that transmits the interest packet to the selected relay device, and the data packet requested by the transmitted interest packet from the relay device A third receiving unit for receiving, and a second transmitting unit for transmitting the received data packet to the terminal device, Each of the plurality of relay devices includes a first transmission unit that transmits the next scheduled arrival time to the communication device and a first reception unit that receives the interest packet from the communication device at the first position. A second transmission unit that transmits the interest packet to the content providing apparatus after moving from the first position to the second position; and a second transmission unit that receives the data packet from the content providing apparatus. A reception unit; and a third transmission unit that transmits the data packet to the communication device after moving from the second location to the first location. The content providing device transmits the interest packet to the communication device. A receiving unit configured to receive from the relay device; and a transmitting unit configured to transmit the data packet to the relay device.

  According to this configuration, in the terminal device, an interest packet including the streaming content playback time is transmitted to the communication device. A data packet including streaming content is received from the communication device. The communication device can communicate with a content providing device that provides a streaming content via a first network that can communicate with the communication device via a first network and a second network that is separated from the first network. Next scheduled arrival times indicating the time at which the plurality of relay apparatuses moving between the second positions arrive at the first position next are received from each of the plurality of relay apparatuses. An interest packet is received from the terminal device. Based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, a relay device that transmits the interest packet is selected from the plurality of relay devices. An interest packet is transmitted to the selected relay device. A data packet requested by the transmitted interest packet is received from the relay device. The received data packet is transmitted to the terminal device. In each of the plurality of relay apparatuses, the next scheduled arrival time is transmitted to the communication apparatus at the first position. An interest packet is received from the communication device. After moving from the first position to the second position, the interest packet is transmitted to the content providing apparatus. A data packet is received from the content providing apparatus. After moving from the second position to the first position, the data packet is transmitted to the communication device. In the content providing apparatus, the interest packet is received from the relay apparatus, and the data packet is transmitted to the relay apparatus.

  Therefore, since the relay device that transmits the interest packet is selected from the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, the streaming content is transmitted from the terminal device. It can be played back without interruption. In addition, since content data can be shared and transported by a plurality of relay devices, the storage area of the relay device can be used effectively, and communication efficiency can be improved.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiment is an example in which the present disclosure is embodied, and does not limit the technical scope of the present disclosure.

(Embodiment 1)
[System configuration]
FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to Embodiment 1 of the present disclosure.

  The communication system shown in FIG. 1 includes a terminal device 12, a gateway device 13, a plurality of relay devices 14 (relay devices 14A and 14B), a base station 15, and a content provider server 16.

  The terminal device 12 is used, for example, by a user in the refuge 11 and is arranged in the refuge 11. The gateway device 13 is installed in the refuge 11 and is connected to the terminal device 12 and the relay device 14 via a wireless LAN (Local Area Network) 9 so that they can communicate with each other. The relay device 14 moves between the gateway device 13 and the base station 15 and is connected to the gateway device 13 and the base station 15 so as to communicate with each other. The base station 15 is connected to the content provider server 16 via the CCN network 10.

  The CCN network 10 is an example of a content-oriented network.

  The shelter 11 is an example of an area where nearby network infrastructure is blocked by the influence of a disaster such as an earthquake or tsunami. Therefore, the gateway device 13 and the terminal device 12 in the evacuation center 11 are in a state where a network with the content providing source server 16 cannot be established.

  The gateway device 13 transmits a plurality of interest packets requesting streaming content received from the terminal device 12 to the plurality of relay devices 14, and transmits a plurality of data packets including the streaming content received from the plurality of relay devices 14 to the terminal device 12. Send to.

  The gateway device 13 manages the time when the relay device 14 is scheduled to arrive at the evacuation site 11 (hereinafter referred to as “next scheduled arrival time”), and relays the interest packet transferred from the terminal device 12 to the relay device 14. At the same time, the data packet transferred from the relay device 14 is relayed to the terminal device 12. When the gateway device 13 relays the interest packet transmitted by the terminal device 12 to the relay device 14, the gateway device 13 transmits the interest packet based on the information included in the interest packet and the next arrival time of the relay device 14. 14 is selected.

  When the gateway device 13 is originally installed in the refuge 11, the network device operates as a gateway device in the CCN when the network infrastructure is not cut off, and in the situation where the network infrastructure is cut off, the first embodiment Operates as a gateway device in the communication system. Here, the relay device 14 or the terminal device 12 can switch between the operation of the gateway device 13 when the network infrastructure is shut off and the operation of the gateway device 13 when the network infrastructure is not shut off. . Note that the gateway device 13 may automatically detect that the network infrastructure has been shut down and automatically switch the operation setting. On the other hand, when the gateway device 13 is not originally installed in the evacuation center 11, the gateway device 13 is delivered to the evacuation site 11 and installed by a moving body such as an unmanned airplane or a car.

  The relay device 14 temporarily accumulates interest packets transferred from the gateway device 13 in an internal storage area. Then, the relay device 14 physically moves from a position where it can communicate with the gateway device 13 to a position where it can communicate with the base station 15 and then relays the interest packet temporarily stored in the internal storage area to the base station 15. To do. Further, the relay device 14 temporarily accumulates data packets transferred from the base station 15 in an internal storage area. Then, the relay device 14 physically moves from a position where it can communicate with the base station 15 to a position where it can communicate with the gateway device 13, and then relays the data packet temporarily stored in the internal storage area to the gateway device. .

  Further, when the relay device 14 arrives at a place where it can communicate with the gateway device 13, the relay device 14 transmits the next scheduled arrival time to the gateway device 13.

  The terminal device 12 exists in the refuge 11 and transmits an interest packet describing the content name of desired content data to the gateway device 13. Thereafter, the terminal device 12 receives a data packet including content data corresponding to the content name via the gateway device 13. In the first embodiment, as shown in FIG. 1, the terminal device 12 includes a gateway device 13, a relay device 14 that physically moves between the shelter 11 and the base station 15, a base station 15, Interest packets and data packets can be exchanged with the content provider server 16 via the CCN network 10.

  The content provider server 16 provides streaming content. The content provider server 16 receives the interest packet issued by the terminal device 12 via the CCN network 10 and transmits a data packet including content data corresponding to the received interest packet.

  The base station 15 relays the interest packet issued by the terminal device 12 to the CCN network 10 when the relay device 14 is within a communicable range. Further, the base station 15 receives the data packet including the content data issued by the content provider server 16 via the CCN network 10 and relays it to the relay device 14.

  The relay device 14 is an unmanned aerial vehicle, for example. The relay device 14 has a first position where it can communicate with the gateway device 13 via the first network (wireless LAN 9) and a content via the second network (CCN network 10) separated from the first network. It moves between a second location where it can communicate with the provider server 16. Note that both the first network and the second network may be CCN networks. Only the second network may be a CCN network. The relay device 14 may fly autonomously between the first position and the second position, or may be steered by a pilot.

[Hardware configuration of gateway device]
FIG. 2 is a diagram illustrating an example of a hardware configuration of the gateway device according to the first embodiment of the present disclosure.

  The gateway device 13 includes a CPU (Central Processing Unit) 131, a RAM (Random Access Memory) 132, a communication IF (interface) 133, and a communication bus 134. The gateway device 13 may include a storage such as a hard disk drive or a solid state drive.

  The communication IF 133 includes one or more wireless IFs 133A that perform wireless communication. Note that the communication IF 133 may include a wired IF that performs wired communication.

  The RAM 132 includes a CS (Content Store) 132A, a PIT (Pending Interest Table) 132B, a FIB (Forwarding Information Base) 132C, an estimated arrival time management unit 132D, and a streaming content management unit 132E. The CS 132A, the PIT 132B, the FIB 132C, the estimated arrival time management unit 132D, and the streaming content management unit 132E may be included in a storage such as a hard disk drive or a solid state drive.

[Functional configuration of gateway device]
FIG. 3 is a diagram illustrating an example of a functional configuration of the gateway device according to the first embodiment of the present disclosure.

  The gateway device 13 includes one or more wireless IFs 133A, a data processing unit 131A, an interest processing unit 131B, a CS 132A, a PIT 132B, an FIB 132C, an estimated arrival time management unit 132D, and a streaming content management unit 132E. .

  The data processing unit 131A and the interest processing unit 131B are processes executed by the CPU 131.

  The CS 132A stores the data packet received by the data processing unit 131A.

  The PIT 132B stores the content name described in the interest packet received by the interest processing unit 131B, information on the terminal device 12 that has transmitted the interest packet to the gateway device 13, and information on the wireless IF 133A that has received the interest packet. . Here, the information regarding the terminal device 12 is an identifier for identifying the terminal device 12 such as a MAC address.

  The FIB 132C stores path information corresponding to the content name.

  The scheduled arrival time management unit 132D stores the next scheduled arrival time notified by the relay device 14 to the gateway device 13 and information related to the relay device 14 when the relay device 14 arrives at the evacuation center. Here, the information related to the relay device 14 is an identifier for identifying the relay device 14 such as a MAC address.

  FIG. 4 is a diagram illustrating an example of information stored in the estimated arrival time management unit according to the first embodiment. As shown in FIG. 4, the estimated arrival time management unit 132D stores the relay device ID 132D1 and the estimated arrival time 132D2 in association with each other. The relay device ID 132D1 is an identifier for identifying the relay device 14 such as a MAC address. The next scheduled arrival time 132D2 is the time when the relay device 14 is scheduled to arrive at the evacuation site 11 next, which is notified to the gateway device 13 when the relay device 14 arrives at the evacuation site 11.

  The wireless IF 133A has a first position where the wireless IF 133A can communicate with the gateway device 13 via the first network, and a content provider server 16 that provides streaming content via the second network separated from the first network. The next scheduled arrival time indicating the time at which the plurality of relay apparatuses 14 moving between the communicable second positions arrive at the first position next is received from each of the plurality of relay apparatuses 14.

  The next arrival time notified to the gateway device 13 when the relay device 14 arrives at the refuge 11 is described, for example, as “resister_next_arrival_time: / MAC address of the relay device 14 / next arrival time /”. The gateway device 13 is notified of the received packet.

  The streaming content management unit 132E has a playback time (hereinafter referred to as “start playback time”) described in the first interest packet among one or more interest packets requesting a certain streaming content, and the relay selected by the interest processing unit 131B. The next arrival time of the device 14 (hereinafter referred to as “reference arrival time”) and the content name described in the interest packet or a part thereof are stored.

  FIG. 5 is a diagram illustrating an example of information stored in the streaming content management unit according to the first embodiment. As shown in FIG. 5, the streaming content management unit 132E stores a content identification name 132E1, a start reproduction time 132E2, and a reference scheduled arrival time 132E3 in association with each other. The content identification name 132E1 is a content name or a part of the content name described in the interest packet. The start reproduction time 132E2 is a reproduction time described in the first interest packet among one or more interest packets requesting a certain streaming content. The standard estimated arrival time 132E3 is the next scheduled arrival time of the relay device 14 that transfers the first interest packet.

  The interest processing unit 131B receives an interest packet including the playback time of the streaming content from the terminal device 12 via the wireless IF 133A.

  The data processing unit 131A performs processing related to the received data packet. Upon receipt of the data packet, the data processing unit 131A receives the content name described in the received data packet, information on the wireless IF 133A that received the interest packet with the same content name in the past, and the interest with the same content name in the past. Information on the terminal device 12 that has transmitted the packet to the gateway device 13 is acquired from the PIT 132B. Then, the data processing unit 131A transmits the data packet to the terminal device 12 via the wireless IF 133A. The data processing unit 131A may store the data packet in the CS 132A.

  The interest processing unit 131B performs a predetermined process on the received interest packet. The interest processing unit 131B selects the relay device 14 that transmits the interest packet from the plurality of relay devices 14 based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices 14. Details of the operation of the interest processing unit 131B will be described later.

  The interest processing unit 131B transmits the interest packet to the selected relay device 14 via the wireless IF 133A.

[Hardware configuration of relay device]
FIG. 6 is a diagram illustrating an example of a hardware configuration of the relay device according to the first embodiment of the present disclosure.

  The relay device 14 includes a CPU 141, a RAM 142, a communication IF 143, and a communication bus 144. The relay device 14 may include a storage such as a hard disk drive or a solid state drive.

  The communication IF 143 includes one or more wireless IFs 143A that perform wireless communication. Note that the communication IF 143 may include a wired IF that performs wired communication.

  The RAM 142 includes a CS 142A, a PIT 142B, an FIB 142C, and an interest storage unit 142D. Note that the CS 142A, the PIT 142B, the FIB 142C, and the interest storage unit 142D may be included in a storage such as a hard disk drive or a solid state drive.

[Functional configuration of relay device]
FIG. 7 is a diagram illustrating an example of a functional configuration of the relay device according to the first embodiment of the present disclosure.

  The relay device 14 includes one or more wireless IFs 143A, a data processing unit 141A, an interest processing unit 141B, an estimated arrival time notification unit 141C, a CS 142A, a PIT 142B, an FIB 142C, and an interest storage unit 142D.

  The data processing unit 141A, the interest processing unit 141B, and the estimated arrival time notification unit 141C are processes executed by the CPU 141.

  The CS 142A stores the data packet received by the data processing unit 141A.

  The PIT 142B stores the content name described in the interest packet received by the interest processing unit 141B, information on the gateway device 13 that has transmitted the interest packet to the relay device 14, and information on the wireless IF 143A that has received the interest packet. . Here, the information regarding the gateway device 13 is an identifier for identifying the gateway device 13 such as a MAC address.

  The FIB 142C stores route information corresponding to the content name.

  The interest storage unit 142D stores the interest packet received by the interest processing unit 141B.

  The data processing unit 141A receives a data packet from the content provider server 16, and performs processing related to the received data packet and the data packet stored in the CS 142A.

  First, processing relating to the received data packet performed by the data processing unit 141A will be described. When receiving the data packet relayed by the base station 15, the data processing unit 141A stores the data packet in the CS 142A.

  Next, processing related to the data packet stored in the CS 142A performed by the data processing unit 141A will be described. When the relay device 14 reaches a range where the relay device 14 can communicate with the gateway device 13, the data processing unit 141 </ b> A transmits the data packet stored in the CS 142 </ b> A to the gateway device 13. The data processing unit 141A moves the data packet from the second position where the relay device 14 can communicate with the content provider server 16 to the first position where the relay device 14 can communicate with the gateway device 13, and then transfers the data packet to the gateway device 13. Send to.

  The interest processing unit 141B performs processing related to the received interest packet and the interest packet stored in the interest storage unit 142D.

  First, the process regarding the received interest packet performed by the interest processing unit 141B will be described.

  When the interest processing unit 141B receives the interest packet transmitted by the gateway device 13, the interest processing unit 141B confirms whether the data packet corresponding to the content name described in the interest packet is stored in the CS 142A.

  When the data packet corresponding to the content name is stored in the CS 142A, the interest processing unit 141B transmits the data packet to the gateway device 13 that has transmitted the interest packet to the relay device 14, and discards the interest packet.

  On the other hand, when the data packet corresponding to the content name is not stored in the CS 142A, the interest processing unit 141B checks whether the same content name as the content name described in the interest packet is stored in the PIT 142B.

  When the same content name as the content name described in the interest packet is stored in the PIT 142B, the interest processing unit 141B adds the same content name as the content name described in the interest packet to the entry of the PIT 142B. The information regarding the gateway device 13 that transmitted the interest packet to the relay device 14 is added, and the interest packet is discarded.

  On the other hand, when the same content name as the content name described in the interest packet is not stored in the PIT 142B, the interest processing unit 141B includes the content name described in the interest packet and information on the gateway device 13 that transmitted the interest packet. Are stored in the PIT 132B.

  Then, the interest processing unit 141B stores the interest packet in the interest storage unit 142D.

  Next, processing related to interest packets stored in the interest storage unit 142D, which is performed by the interest processing unit 141B, will be described. When the relay apparatus 14 reaches a range where communication with the base station 15 is possible, the interest processing unit 141B transfers the interest packet stored in the interest storage unit 142D to the CCN network 10 via the base station 15. The interest processing unit 141B moves the interest packet from the first position where the relay device 14 can communicate with the gateway device 13 to the second position where the relay device 14 can communicate with the content provider server 16 and then transfers the interest packet to the content provider. Send to server 16.

  When the relay device 14 arrives at the first position where the relay device 14 can communicate with the gateway device 13, the estimated arrival time notification unit 141 </ b> C displays the next arrival time that indicates the next time when the relay device 14 arrives at the first position. The data is transmitted to the gateway device 13 via the IF 143A.

[System-wide operation]
Next, the operation of the entire communication system in the first embodiment will be described with reference to FIG.

  FIG. 8 is a sequence diagram illustrating an example of an operation of the entire communication system according to the first embodiment of the present disclosure.

  First, the terminal device 12 transmits an interest packet to the gateway device 13 (step S101a).

  Next, when the interest processing unit 131B of the gateway device 13 receives the interest packet transmitted by the terminal device 12, the interest processing unit 131B performs a predetermined process on the received interest packet, and sends it to the relay device 14A selected as the transmission destination. Is transmitted (step S102a). Details of the predetermined processing by the interest processing unit 131B will be described later. Here, when the data packet corresponding to the content name described in the interest packet is not stored in the CS 132A and there is no entry corresponding to the content name in the PIT 132B, the interest processing unit 131B transmits the interest packet to the relay device 14A. Send to.

  Next, upon receiving the interest packet, the interest processing unit 141B of the relay device 14A stores the received interest packet in the interest storage unit 142D (step S103a). Here, when the data packet corresponding to the content name described in the interest packet is not stored in the CS 142A and there is no entry corresponding to the content name in the PIT 142B, the interest processing unit 141B transmits the interest packet to the interest storage unit. Store in 142D.

  The process of step S101b, step S102b, and step S103b is the same flow as the process of step S101a, step S102a, and step 103a. The interest packet transmitted by the terminal device 12 is transferred from the gateway device 13 to the relay device 14B. The interest processing unit 141B of the relay device 14B that has received the interest packet stores the received interest packet in the interest storage unit 142D.

  Next, the relay device 14A notifies the gateway device 13 that it moves toward the base station 15 when the current time is the time to leave the shelter 11, and then leaves the shelter 11 and Move to a communicable place (second position) (step S104).

  Next, when the interest processing unit 141B of the relay device 14A arrives at a place where communication with the base station 15 is possible, the interest processing unit 141B transmits the interest packet stored in the interest storage unit 142D to the base station 15 (step S105).

  Next, the base station 15 transmits the interest packet received from the relay device 14A to the content provider server 16 via the CCN network 10 (step S106).

  Next, when receiving the interest packet, the content provider server 16 transmits a data packet including the content data specified by the interest packet to the base station 15 (step S107).

  Next, when receiving the data packet transmitted by the content provider server 16, the base station 15 transmits the received data packet to the relay device 14A (step S108).

  Next, the data processing unit 141A of the relay device 14A receives the data packet issued by the content provider server 16 via the base station 15, and stores the received data packet in the CS 142A (step S109).

  Next, when the exchange of the interest packet and the data packet stored in the interest storage unit 142D ends, the relay device 14A can communicate with the gateway device 13 installed in the shelter 11 (first position). (Step S110).

  Next, when the arrival time notification unit 141C arrives at a location (first position) where communication with the gateway device 13 is possible, the next arrival time is transmitted to the gateway device 13 (step S111).

  Next, when receiving the next scheduled arrival time from the relay device 14A, the wireless IF 133A of the gateway device 13 stores the next scheduled arrival time and information related to the relay device 14A in the scheduled arrival time management unit 132D (step S112).

  Next, the data processing unit 141A of the relay device 14A transmits the data packet stored in the CS 142A to the gateway device 13 (step S113).

  Next, when the data processing unit 131A of the gateway device 13 receives the data packet transmitted by the relay device 14A, the data processing unit 131A transmits the data packet to the terminal device 12 (step S114). The terminal device 12 receives the data packet transmitted by the gateway device 13.

[Operation of Interest Processing Unit of Gateway Device]
Next, a specific operation performed by the interest processing unit 131B of the gateway device 13 will be described using the flowcharts of FIGS.

  FIG. 9 is a flowchart showing the operation of the interest processing unit performed when the gateway device receives an interest packet from the terminal device.

  First, the interest processing unit 131B receives an interest packet (step S21).

  Next, the interest processing unit 131B determines whether a data packet corresponding to the content name described in the interest packet is stored in the CS 132A (step S22).

  If it is determined that the data packet corresponding to the content name is stored in CS 132A (YES in step S22), the interest processing unit 131B sends the CS 132A to the terminal device 12 that has transmitted the interest packet to the gateway device 13. Is transmitted (step S23), and the process is terminated. That is, the interest processing unit 131B reads out the data packet corresponding to the content name from the CS 132A, and transmits the read data packet to the terminal device 12 that is the destination of the interest packet.

  On the other hand, when it is determined that the data packet corresponding to the content name is not stored in CS 132A (NO in step S22), the interest processing unit 131B sets the same content name in the PIT 132B as the content name described in the interest packet. It is determined whether it is stored (step S24).

  When it is determined that the same content name as the content name described in the interest packet is stored in the PIT 132B (YES in step S24), the interest processing unit 131B adds an interest packet to the entry of the PIT 132B corresponding to the content name. Is added to the information related to the terminal device 12 that transmitted the message to the gateway device 13 and the information related to the wireless IF 143A that received the interest packet (step S25), and the process ends.

  On the other hand, when it is determined that the same content name as the content name described in the interest packet is not stored in the PIT 132B (NO in step S24), the interest processing unit 131B includes the content name described in the interest packet, Information regarding the terminal device 12 that has transmitted the interest packet and information regarding the wireless IF 133A that has received the interest packet are stored in the PIT 132B (step S26).

  Next, the interest processing unit 131B determines whether the interest packet is an interest packet for requesting streaming content (step S27). The interest processing unit 131B uses the content name described in the interest packet in order to determine whether the interest packet is an interest packet for requesting streaming content.

  FIG. 11 is a diagram illustrating an example of a content name described in an interest packet requesting streaming content. The content name 30 shown in FIG. 11 includes at least content provider server information 31, a content identifier 32, and a playback time 33. The content provider server information 31 is information about the content provider server 16 that holds the content data. The content identifier 32 represents an identifier for identifying content data such as a moving image or audio such as a file name. The reproduction time 33 is information representing a reproduction position or a frame position based on a time such as a time stamp, for example.

  For example, when the content name described in the interest packet includes the playback time, the interest processing unit 131B determines that the interest packet is an interest packet that requests streaming content.

  If it is determined that the interest packet is not an interest packet that requests streaming content (NO in step S27), the interest processing unit 131B transmits the interest packet from among the plurality of relay devices 14 that can communicate with the gateway device 13. The previous relay device is selected (step S28). Here, the interest processing unit 131B may select the transmission destination relay device 14 based on the next scheduled arrival time of the relay device 14, or may randomly select the transmission destination relay device 14. For example, the interest processing unit 131B may select the relay device having the earliest next arrival time as the transmission destination relay device 14.

  On the other hand, when it is determined that the interest packet is an interest packet that requests streaming content (YES in step S27), the interest processing unit 131B performs relay for selecting the relay device 14 that is the destination of the interest packet that requests streaming content. Device selection processing is performed (step S29).

  Next, the interest processing unit 131B transmits the interest packet to the selected relay device 14 (step S30).

  FIG. 10 is a flowchart showing a specific operation of the relay device selection process in step S29 of FIG.

  First, the interest processing unit 131B acquires the playback time from the content name described in the interest packet (step S291).

  Next, the interest processing unit 131B acquires the next scheduled arrival time of each relay device 14 from the estimated arrival time management unit 132D (step S292).

  Next, the interest processing unit 131B determines whether there is an entry corresponding to the content name described in the interest packet in the streaming content management unit 132E (step S293).

  If it is determined that there is an entry corresponding to the content name described in the interest packet in the streaming content management unit 132E (YES in step S293), the interest processing unit 131B receives the content name from the streaming content management unit 132E. The start reproduction time and the standard estimated arrival time corresponding to are acquired (step S294).

  Next, the interest processing unit 131B selects the relay device 14 that is the destination of the interest packet, based on the reproduction time, the next arrival time, the start reproduction time, and the reference arrival time (step S295).

  Here, a method for selecting the transmission destination relay device 14 will be described. As shown in FIG. 1, there are two relay apparatuses 14 that are transmission destination candidates, that is, the relay apparatus 14A and the relay apparatus 14B, and the next arrival time of the relay apparatus 14A is earlier than the next arrival time of the relay apparatus 14B. To do. At this time, the interest processing unit 131B transmits an interest packet requesting the streaming content to the relay device 14A so that the streaming content is delivered to the terminal device 12 until the relay device 14B arrives at the shelter 11. Then, the interest processing unit 131B transmits, to the relay device 14B, an interest packet for requesting streaming content following the streaming content distributed by the relay device 14A.

  Specifically, when the next arrival scheduled time of the relay device 14A is the reference scheduled time T [s], the next arrival scheduled time of the relay device 14B is t1 [s], and the start reproduction time is S [s], The relay device that is the destination of the interest packet is selected as follows.

  First, when the interest packet is an interest packet requesting streaming content from S [s] to S + t1-T [s] based on the playback time acquired from the interest packet, the interest processing unit 131B sets the relay device 14A. The interest packet is selected as a destination relay device, and the interest packet is transmitted to the relay device 14A. Here, t1-T [s] is the time from the time when the relay device 14A arrives at the evacuation site 11 to the time when the relay device 14B that arrives next after the relay device 14A arrives at the evacuation site 11 next. Represents.

  When the interest packet is an interest packet requesting streaming content from S + t1-T [s], the interest processing unit 131B selects the relay device 14B as a relay device that is the destination of the interest packet, and selects the interest packet as the relay device 14B. Send to.

  Even when there are three or more relay devices 14 as transmission destination candidates, the interest processing unit 131B sets the next arrival time of each relay device 14 and the content name in the same manner as when there are two relay devices 14. Based on the included playback time, start playback time, and reference estimated arrival time, the relay device 14 that is the destination of the interest packet is selected.

  And the relay apparatus selection process of step S29 is complete | finished.

  On the other hand, when it is determined that there is no entry corresponding to the content name described in the interest packet in the streaming content management unit 132E (NO in step S293), the interest processing unit 131B acquires the acquired playback time and the acquired next arrival time. The earliest next arrival time and the content name among the scheduled times are stored in the streaming content management unit 132E (step S296). Here, the stored playback time is the start playback time, and the stored next scheduled arrival time is the reference scheduled arrival time.

  Then, the interest processing unit 131B performs the process of step S295 to select the relay device 14 that is the destination of the interest packet, and ends the relay device selection process of step S29.

  Thus, the terminal device 12 that receives the streaming content can play the streaming content without interruption. Also, other content data can be relayed without using the storage area of the specific relay device 14 for streaming content.

(Embodiment 2)
In addition to the configuration of the gateway device 13 of the first embodiment, the gateway device in the second embodiment includes an interest temporary storage unit that temporarily stores interest packets, a priority management unit that manages the priority of interest packets, The apparatus further includes a predicted free space management unit that manages the predicted free space of the relay apparatus 14 and a data size acquisition unit that acquires the data size of the data packet corresponding to the interest packet. Here, the predicted free space of the relay device 14 is the free space of the CS 142A when it is assumed that the data packet corresponding to the interest packet stored in the relay device 14 is stored in the CS 142A of the relay device 14.

  The configuration of the communication system according to the second embodiment is the same as that of the communication system according to the first embodiment shown in FIG. However, as described below, in the second embodiment, the functional configuration and hardware configuration of the gateway device are different from those in the first embodiment.

[Hardware configuration of gateway device]
FIG. 12 is a diagram illustrating an example of a hardware configuration of the gateway device according to the second embodiment of the present disclosure. In FIG. 12, the same reference numerals as those in FIG. 2 are given to components common to the gateway apparatus in FIG. 2, and detailed description thereof is omitted.

  In the second embodiment, the RAM 432 further includes an interest temporary storage unit 432F, a priority management unit 432G, and a predicted free space management unit 432H. The RAM 432 includes a PIT 432B having a function different from that of the PIT 132B illustrated in FIG. Note that the interest temporary storage unit 432F, the priority management unit 432G, the predicted free space management unit 432H, and the PIT 432B may be included in a storage such as a hard disk drive or a solid state drive.

[Functional configuration of gateway device]
FIG. 13 is a diagram illustrating an example of a functional configuration of the gateway device according to the second embodiment of the present disclosure. In FIG. 13, components common to the gateway device of FIG. 3 are denoted by the same reference numerals as those in FIG. 3, and detailed description thereof is omitted.

  The gateway device 43 shown in FIG. 13 has a data size acquisition unit 431C, an interest temporary storage unit 432F, a priority management unit 432G, and a predicted free space management unit 432H, compared to the configuration of the gateway device 13 shown in FIG. Is further provided. Further, the gateway device 43 includes an interest processing unit 431B and a PIT 432B that are different from those in FIG.

  The interest temporary storage unit 432F temporarily stores the interest packet received by the interest processing unit 431B.

  The priority management unit 432G stores the priority corresponding to the interest packet and the content name or a part of the content name corresponding to the interest packet. The information stored in the priority management unit 432G may be notified by the terminal device 12 or the relay device 14, may be input by directly accessing the gateway device 13 by the user, and is statistically calculated by the gateway device. May be. The priority indicates the degree to which interest packets are preferentially transmitted, and is determined in advance according to the content of the streaming content requested by the interest packets.

  The predicted free space management unit 432H manages the predicted free space of the relay device 14 and information related to the relay device 14. Here, the information related to the relay device 14 is an identifier for identifying the relay device 14 such as a MAC address. The predicted free space management unit 432H stores the free space of the CS 142A transmitted when the relay device 14 arrives at the refuge 11, and information related to the relay device 14 that has transmitted the free space. The interest processing unit 431B updates information stored in the predicted free space management unit 432H based on the interest packet transmitted from the gateway device 13 to the relay device 14.

  FIG. 14 is a diagram illustrating an example of information stored in the predicted free space management unit according to the second embodiment. As illustrated in FIG. 14, the priority management unit 432G stores the content identification name 432G1 and the priority 432G2 in association with each other. The content identification name 432G1 is a content name or a part of the content name described in the interest packet. The priority 432G2 is a priority corresponding to the content identification name 432G1. As described above, the content identification name 432G1 and the priority 432G2 may be notified by the terminal device 12 or the relay device 14, or may be input and set by directly accessing the gateway device 13 by the user. It may be statistically calculated by the device 13.

  The interest processing unit 431B acquires the free capacity of the content cache unit (CS 142A) that caches the data packet from the plurality of relay devices 14.

  The data size acquisition unit 431C is a process executed by the CPU 431. The data size acquisition unit 431C acquires the data size of the data packet corresponding to the interest packet received by the interest processing unit 431B. Note that the data size acquired by the data size acquisition unit 431C may be statistically calculated from the size information of the data packet acquired when the data packet was received in the past, or from the content name described in the interest packet. It may be predicted.

  The data size acquisition unit 431C acquires the size of the data packet requested by the interest packet from the interest packet received from the terminal device 12.

  The PIT 432B includes a content name described in the interest packet received by the interest processing unit 431B, information on the terminal device 12 that has transmitted the interest packet to the gateway device 43, information on the wireless IF 133A that has received the interest packet, and an interest packet. And information related to the relay device of the transmission destination. Here, the information regarding the relay device that is the destination of the interest packet is an identifier for identifying the relay device 14 such as the MAC address of the destination relay device 14.

  The interest processing unit 431B performs predetermined processing on the interest packets stored in the interest temporary storage unit 432F and performs predetermined processing on the received interest packets. The interest processing unit 431B transmits the interest packet stored in the interest temporary storage unit 432F to the relay device 14 when the predicted free space of the relay device 14 that starts moving toward the base station 15 is larger than the predetermined capacity. .

  The interest processing unit 431B has the data packet size acquired by the data size acquisition unit 431C of the content cache unit (CS142A) of the first relay device selected as the destination of the interest packet among the plurality of relay devices 14. When the capacity is larger than the available capacity, the second relay device or gateway device 43 different from the first relay device transmits the interest packet already stored in the first relay device, and then received from the terminal device 12 The interest packet is transmitted to the first relay device.

  The interest processing unit 431B obtains a priority that is associated with the interest packet and indicates the degree to which the interest packet is preferentially transmitted. The interest processing unit 431B determines whether to transmit an interest packet based on the acquired priority.

  When the priority is lower than the threshold (first threshold), the interest processing unit 431B discards the received interest packet or temporarily stores the received interest packet in a memory (interest temporary storage unit 432F) included in the gateway device 43. May be stored. In addition, the interest processing unit 431B may select a relay device that transmits an interest packet from among a plurality of relay devices when the priority is equal to or higher than a threshold value (first threshold value).

[Operation of Interest Processing Unit of Gateway Device]
Next, specific operations performed by the interest processing unit 431B of the gateway device will be described with reference to the flowcharts of FIGS.

  FIG. 15 is a flowchart illustrating the operation of the interest processing unit performed when the gateway device receives an interest packet from the terminal device. In FIG. 15, the processing in steps S31 to S36 is the same as the processing in steps S21 to S26 shown in FIG.

  Next, in step S37, the interest processing unit 431B acquires the priority of the received interest packet. Here, the interest processing unit 431B checks whether or not the content name or part of the content name described in the interest packet is stored in the priority management unit 432G. When the content name or part of the content name described in the interest packet is stored in the priority management unit 432G, the interest processing unit 431B associates with the content name or part of the content name described in the interest packet. The obtained priority is acquired from the priority management unit 432G. On the other hand, when the content name described in the interest packet or a part of the content name is not stored in the priority management unit 432G, the interest processing unit 431B determines the priority of the interest packet to the lowest value. For example, when the priority is expressed in five levels from 1 to 5, where 1 is the lowest priority and the priority increases as the numerical value increases, the interest processing unit 431B determines the priority as 1.

  Next, the interest processing unit 431B determines whether or not the priority of the interest packet acquired in step S37 is lower than a threshold value (step S38). As described above, for example, when the priority is expressed in five levels from 1 to 5, the threshold is set to 3, for example.

  If it is determined that the priority of the interest packet is lower than the threshold (YES in step S38), the interest processing unit 431B temporarily stores the interest packet in the interest temporary storage unit 432F (step S39). In step S39, the interest processing unit 431B may delete the interest packet entry from the PIT 431B and discard the interest packet.

  On the other hand, when it is determined that the priority of the interest packet is equal to or higher than the threshold (NO in step S38), the interest processing unit 431B selects the relay device 14 that is the destination of the interest packet, and the selected relay device 14 receives the interest. An interest packet transmission process for transmitting a packet is performed (step S40).

  In step S38, the interest processing unit 431B may determine whether or not the acquired interest packet has the lowest priority. When it is determined that the priority of the interest packet is the lowest, the interest processing unit 431B may temporarily store the interest packet in the interest temporary storage unit 432F. On the other hand, when it is determined that the priority of the interest packet is not the lowest, the interest processing unit 431B may perform an interest packet transmission process.

  FIG. 16 is a flowchart showing a specific operation of the interest packet transmission process in step S40 of FIG.

  First, the interest processing unit 431B determines whether the interest packet is an interest packet for requesting streaming content (step S401). The process in step S401 is the same as the process in step S27 in FIG.

  If it is determined that the interest packet is not an interest packet requesting streaming content (NO in step S401), the interest processing unit 431B sets the data size of the data packet corresponding to the streaming content requested by the interest packet. Obtained from the data size obtaining unit 431C (step S402).

  Next, the interest processing unit 431B refers to the predicted free space management unit 432H, and determines whether there is a relay device 14 having a predicted free space equal to or larger than the acquired data size among the plurality of relay devices 14. (Step S403).

  Here, when it is determined that there is no relay device 14 whose predicted free space is equal to or larger than the acquired data size (NO in step S403), the interest processing unit 431B temporarily stores the interest packet in the interest temporary storage unit 432F. (Step S404).

  On the other hand, when it is determined that there is a relay device 14 whose predicted free space is greater than or equal to the acquired data size (YES in step S403), the interest processing unit 431B performs relay whose predicted free space is greater than or equal to the acquired data size. The device 14 is selected as a relay device that is the destination of the interest packet (step S405). Note that when there are a plurality of relay apparatuses 14 whose predicted free capacity is equal to or larger than the acquired data size, the interest processing unit 431B selects the relay apparatus 14 as the transmission destination based on the predicted free capacity of the relay apparatus 14 Alternatively, the transmission destination relay device 14 may be selected based on the estimated next arrival time of the relay device 14 whose predicted free space is equal to or larger than the acquired data size, or the transmission destination relay is stochastically performed. The device 14 may be selected.

  Next, the interest processing unit 431B updates the predicted free space of the relay device 14 of the transmission destination managed by the predicted free space management unit 432H (step S406). That is, the interest processing unit 431B adds the acquired data size to the predicted free space.

  Next, the interest processing unit 431B transmits an interest packet to the selected relay device 14 (step S407).

  On the other hand, when it is determined that the interest packet is an interest packet that requests streaming content (YES in step S401), the interest processing unit 431B performs relay for selecting the relay device 14 that is the destination of the interest packet that requests streaming content. Device selection processing is performed (step S408). Note that the relay device selection process in step S408 is the same as the relay device selection process in step S29 of FIG.

  Next, when the interest processing unit 431B selects the relay device 14 that transmits the interest packet, the interest processing unit 431B acquires the data size of the data packet corresponding to the streaming content requested by the interest packet (step S409).

  Next, the interest processing unit 431B refers to the predicted free space management unit 432H, and determines whether or not the predicted free space of the selected relay device 14 is greater than or equal to the acquired data size (step S410).

  If it is determined that the predicted free space of the selected relay device 14 is equal to or larger than the acquired data size (YES in step S410), the interest processing unit 431B manages the predicted free space management unit 432H. The predicted available capacity of the transmission destination relay device 14 is updated (step S406). That is, the interest processing unit 431B adds the acquired data size to the predicted free space.

  Next, the interest processing unit 431B transmits an interest packet to the selected relay device 14 (step S407).

  On the other hand, when it is determined that the predicted free space of the selected relay device 14 is not larger than the acquired data size (NO in step S410), the interest processing unit 431B secures the predicted free space of the selected relay device 14. (Step S411).

  Specifically, when there is another relay device 14 (referred to herein as “second relay device 14”) having a predicted free space equal to or larger than the acquired data size among a plurality of relay devices, The processing unit 431B shifts the interest packet stored in the selected relay device (referred to herein as “first relay device 14”) to the second relay device 14. Here, the interest processing unit 431B refers to the PIT 432B and makes one or more transitions from the first relay device 14 to the second relay device 14 out of the interest packets stored in the first relay device 14. Select the interest packet. The selected interest packet is an interest packet that is sufficient to secure the estimated free space of the first relay device 14 and requests content other than streaming content.

  Note that the selected interest packet may be an interest packet for requesting streaming content only when the next scheduled arrival time of the second relay device 14 is earlier than that of the first relay device 14. Then, the interest processing unit 431B instructs the first relay device 14 to transfer the interest packet from the first relay device 14 to the second relay device 14. The instructed first relay device 14 transfers the interest packet to the second relay device 14 and deletes the entry of the transferred interest packet from the PIT 142B. The first relay device 14 may transfer the interest packet to the second relay device 14 via the gateway device 43, or may transfer the interest packet directly to the second relay device 14. Thereafter, the interest processing unit 431B determines the predicted free space of the first relay device 14 and the predicted free space of the second relay device 14 managed by the predicted free space management unit 432H based on the data size of the transferred interest packet. Update capacity.

  On the other hand, when there is no other relay device 14 whose predicted free space is equal to or larger than the acquired data size, the interest processing unit 431B refers to the PIT 432B, and among the interest packets stored in the first relay device 14 Then, the interest packet requesting content other than the streaming content is transferred to the gateway device 43. When the interest processing unit 431B receives the interest packet transferred from the first relay device 14, the interest processing unit 431B temporarily stores the received interest packet in the interest temporary storage unit 432F. Then, the interest processing unit 431B updates the predicted free space of the first relay device 14 managed by the predicted free space management unit 432H based on the data size of the transferred interest packet.

  When the interest processing unit 431B secures the predicted free space of the first relay device 14, the destination relay device 14 managed by the predicted free space management unit 432H based on the data size acquired from the received interest packet. Is updated (step S406).

  Next, the interest processing unit 431B transmits the received interest packet to the first relay device 14 (step S407).

  In the second embodiment, two types of processing are performed for interest packets with different priorities (processing when the priority of interest packets is lower than the threshold and processing when the priority of interest packets is greater than or equal to the threshold). However, the present disclosure is not particularly limited thereto. When the priority is lower than the first threshold, the interest processing unit 431B discards the received interest packet or temporarily stores the received interest packet in a memory (interest temporary storage unit 432F) provided in the gateway device 43. May be. In addition, when the priority is higher than the second threshold that is higher than the first threshold, the interest processing unit 431B may copy the received interest packet and transmit the plurality of copied interest packets to the plurality of relay devices. . Furthermore, when the priority is between the first threshold value and the second threshold value, the interest processing unit 431B may select a relay device that transmits an interest packet from the plurality of relay devices.

  Note that, when the priority is the highest, the interest processing unit 431B may copy the received interest packet and transmit the plurality of copied interest packets to the plurality of relay devices.

  By distributing the copied plurality of high-priority interest packets to the plurality of relay devices 14, the terminal device 12 can receive the requested content data with a higher probability.

  In the second embodiment, in addition to the configuration of the gateway device 13 of the first embodiment, the gateway device 43 temporarily stores an interest packet, and a priority for managing the priority of the interest packet. The example provided with the management unit 432G, the predicted free space management unit 432H that manages the predicted free space of the relay device 14, and the data size acquisition unit 431C that acquires the size of the data packet corresponding to the interest packet has been described.

  The gateway device 43 according to the second embodiment can select the destination relay device 14 in consideration of the priority of the received interest packet and the data size of the data packet corresponding to the interest packet. Therefore, the storage area of the relay device 14 can be used more effectively without the storage area of the relay device 14 being compressed by content data having a low priority. In particular, when the predicted free space of the relay device 14 is smaller than the data size of the data packet, the gateway device 43 can afford the predicted free space of the relay device 14 by securing the predicted free space of the relay device 14. It is possible to store the interest packet desired by the gateway device 43 in the relay device 14. Accordingly, it is possible to provide streaming content that can be continuously played back to the terminal device 12 even in a situation where there are many interest packets requesting content data from the terminal device 12.

(Embodiment 3)
In addition to the configuration of the gateway device 13 of the first embodiment, the gateway device in the third embodiment includes an interest temporary storage unit that temporarily stores interest packets, an estimated arrival time planning unit that plans next arrival time, And an interest processing unit for transmitting the stored interest packet.

  The configuration of the communication system according to the third embodiment is the same as that of the communication system according to the first embodiment shown in FIG. However, as described below, in the third embodiment, the functional configuration and hardware configuration of the gateway device are different from those in the first embodiment.

[Hardware configuration of gateway device]
FIG. 17 is a diagram illustrating an example of a hardware configuration of the gateway device according to the third embodiment of the present disclosure. In FIG. 17, components common to the gateway device of FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and detailed description thereof is omitted.

  In the third embodiment, the RAM 532 further includes an interest temporary storage unit 532F. The RAM 532 includes an estimated arrival time management unit 532D having a function different from that of the estimated arrival time management unit 132D illustrated in FIG. The interest temporary storage unit 532F and the estimated arrival time management unit 532D may be included in a storage such as a hard disk drive or a solid state drive.

[Functional configuration of gateway device]
FIG. 18 is a diagram illustrating an example of a functional configuration of the gateway device according to the third embodiment of the present disclosure. In FIG. 18, components common to the gateway device of FIG. 3 are assigned the same reference numerals as in FIG. 3, and detailed description thereof is omitted.

  The gateway device 53 illustrated in FIG. 18 further includes an estimated arrival time planning unit 531C and an interest temporary storage unit 532F in addition to the configuration of the gateway device 13 illustrated in FIG. In addition, the gateway device 53 includes an interest processing unit 531B and an expected arrival time management unit 532D that are different from those in FIG.

  The interest temporary storage unit 532F temporarily stores the interest packet received by the interest processing unit 531B and information related to the relay device 14 that is the destination of the interest packet. Here, the information related to the relay device 14 is an identifier for identifying the relay device 14 such as a MAC address.

  The scheduled arrival time management unit 532D determines that the next scheduled arrival time, the time when the relay device 14 arrives at the evacuation site 11 one after another (hereinafter referred to as (the next scheduled arrival time)), and the relay device 14 arrives at the refuge 11 The time (hereinafter referred to as “arrival time”) and information related to the relay device 14 are stored. Here, the information of the relay device 14 is an identifier for identifying the relay device 14 such as a MAC address.

  When the estimated arrival time plan unit 531C receives the estimated next arrival time transmitted by the relay device 14 that has arrived at the evacuation center 11, the received estimated arrival time is an entry corresponding to the relay device 14 of the estimated arrival time management unit 532D. To remember. The scheduled arrival time planning unit 531C sets the next scheduled arrival time stored in the scheduled arrival time management unit 532D, the scheduled next arrival time transmitted by the relay device 14 in the past, and the relay device 14 actually arrives at the evacuation center 11. You may correct | amend based on the difference | error with the measured time.

  That is, the estimated arrival time management unit 532D may store the arrival history information in which the estimated arrival time and the arrival time are associated with each other for each of the plurality of relay apparatuses. Then, the estimated arrival time planning unit 531C may correct the estimated arrival time received from the relay device based on the stored estimated arrival time and arrival time.

  FIG. 19 is a diagram illustrating an example of information stored in the estimated arrival time management unit according to the third embodiment. As shown in FIG. 19, the scheduled arrival time management unit 532D stores the relay device ID 532D1, the arrival time 532D2, the estimated arrival time 532D3, and the next scheduled arrival time 532D4 in association with each other.

  The relay device ID 532D1 is information for identifying the relay device 14 such as a MAC address. The arrival time 532D2 is the time when the relay device 14 arrives at the refuge 11. The next scheduled arrival time 532D3 is the next scheduled arrival time at the evacuation center 11 that notifies the gateway device 13 when the relay device 14 arrives at the evacuation center 11. The next scheduled arrival time 532D3 is based on the estimated next arrival time notified by the relay device 14 in the past and the error between the time when the relay device 14 actually arrived at the refuge 11 and the estimated arrival time planning unit 531C. May be corrected statistically. The next scheduled arrival time 532D4 is the time when the relay device 14 arrives at the evacuation center 11 one after another, predicted by the planned arrival time planning unit 531C based on the arrival time 532D2 and the next scheduled arrival time 532D3.

  The scheduled arrival time management unit 532D does not update the arrival time 532D2 and the next scheduled arrival time 532D3 every time the relay device 14 arrives at the evacuation center 11, but predicts the next scheduled arrival time 532D4 or the next scheduled arrival time. You may hold | maintain as history so that the past information can also be used for correction of time 532D3.

  Further, the estimated arrival time planning unit 531C stores the time when the next estimated arrival time is received as an arrival time in an entry corresponding to information related to the relay device of the estimated arrival time management unit 532D.

  Further, the estimated arrival time planning unit 531C calculates the next scheduled arrival time from the next scheduled arrival time and the arrival time, and the calculated next scheduled arrival time is an entry corresponding to the information related to the relay device of the estimated arrival time management unit 532D. Remember. Here, for the next scheduled arrival time, the difference between the next scheduled arrival time and the arrival time (the time required for the relay device 14 to make a round trip between the shelter 11 and the base station 15) is added to the next scheduled arrival time. Is calculated by

  The estimated arrival time planning unit 531C arrives at the next time when the relay device arrives at the first position one after another based on the arrival time when the relay device arrives at the first position (evacuation shelter 11) and the next scheduled arrival time. Predict the scheduled time. Specifically, when the next scheduled arrival time is t2 [s] and the arrival time is t1 [s], the time required for the relay device 14 to make a round trip between the shelter 11 and the base station 15 is t2- t1 [s], and the estimated arrival time one after another is t2 + t2−t1 [s]. The estimated arrival time planning unit 531C may correct the estimated arrival time one after another based on the error between the scheduled arrival time of the relay device 14 and the arrival time of the relay device 14.

  When selecting the relay device, the interest processing unit 531B transmits the interest packet from the plurality of relay devices based on at least one of the reproduction time, the next scheduled arrival time, and the next scheduled arrival time. Select a device. The interest processing unit 531B temporarily stores the received interest packet in the memory (interest temporary storage unit 532F) of the gateway device 53 when the transmission destination relay device is selected on the basis of the next scheduled arrival time. In addition, when the destination relay device is selected based on the next scheduled arrival time, the interest processing unit 531B transmits the received interest packet to the selected relay device.

  The interest processing unit 531B performs predetermined processing on the interest packets stored in the interest temporary storage unit 532F and performs predetermined processing on the received interest packets.

  Here, a predetermined process performed on the interest packet stored in the interest temporary storage unit 532F in the interest processing unit 531B will be described. The interest processing unit 531B refers to the interest temporary storage unit 532F when the relay device 14 arrives at a place where the relay device 14 can communicate with the gateway device 53. When the interest packet to which the relay device 14 that has arrived is the destination is stored in the interest temporary storage unit 532F, the interest processing unit 531B reads the interest packet from the interest temporary storage unit 532F and transmits it to the relay device 14.

  Next, a predetermined process performed on the received interest packet in the interest processing unit 531B will be described. Note that in the interest processing unit 531B of the third embodiment, detailed description of processing procedures common to the interest processing unit 131B of the first embodiment is omitted. Specifically, description of the processing procedure of step S21 to step S28 shown in FIG. 9 and the processing procedure of step S291 to step S294 and step S296 shown in FIG.

  Here, a process will be described in which the interest processing unit 531B selects the relay device 14 that is the destination of the interest packet requesting the streaming content.

  The interest processing unit 531B refers to the estimated arrival time management unit 532D, and acquires the next arrival scheduled time and the next scheduled arrival time of each relay device 14. The interest processing unit 531B obtains the playback time acquired from the content name described in the interest packet, the next scheduled arrival time and the next scheduled arrival time, the start playback time and the reference scheduled scheduled time acquired from the streaming content management unit 132E. Based on the above, the relay device 14 that is the destination of the interest packet is determined. In the third embodiment, as shown in FIG. 1, it is assumed that there are two transmission destination candidate relay apparatuses 14, that is, a relay apparatus 14 A and a relay apparatus 14 B. Further, the next scheduled arrival time of the relay device 14A is set as a reference scheduled arrival time T [s], the next scheduled arrival time of the relay device 14B is set as t1 [s], and the next scheduled arrival time of the relay device 14A is set as t2 [s]. Assume that the scheduled arrival time of the relay device 14B is t3 [s], and the relationship T <t1 <t2 <t3 holds. Further, the start playback time of the streaming content is S [s].

  At this time, if the interest packet is an interest packet that requests streaming content from S [s] to S + t1-T [s], the interest processing unit 531B determines whether the relay device 14A is based on the acquired reproduction time. The interest packet is selected as a destination relay device, and the interest packet is transmitted to the relay device 14A. Here, t1-T [s] is the time from when the relay device 14A arrives at the evacuation site 11 next to when the relay device 14B that arrives next to the relay device 14A arrives at the evacuation site 11 next. Represents.

  When the interest packet is an interest packet that requests streaming content for a time from S + t1-T [s] to S + t2-t1 [s], the interest processing unit 531B makes the relay device 14B a relay device that is the destination of the interest packet. The interest packet is selected and transmitted to the relay device 14B.

  If the interest packet is an interest packet requesting streaming content from S + t2-t1 [s] to S + t3-t2 [s], the interest processing unit 531B sets the relay device 14A as the interest packet transmission destination relay device. The interest packet and the information regarding the transmission destination relay device 14A are stored in the interest temporary storage unit 532F.

  When the interest packet is an interest packet that requests streaming content for the time from S + t3−t2 [s], the interest processing unit 531B selects the relay device 14B as a relay device that is the destination of the interest packet, and transmits the interest packet and transmission. Information related to the previous relay device 14B is stored in the interest temporary storage unit 532F.

  Even when there are three or more transmission destination candidate relay apparatuses 14, the interest processing unit 531 </ b> B performs the next scheduled arrival time and the next scheduled arrival time of each relay apparatus 14 in the same manner as when there are two relay apparatuses 14. And the destination relay device 14 is selected based on the playback time included in the content name.

  In addition, when the estimated next arrival time of the relay device 14 that has not arrived at the evacuation center 11 is stored in the estimated arrival time management unit 532D, the interest processing unit 531B selects the relay device 14 that has not arrived at the evacuation center 11 It is good also as a transmission destination candidate.

  As described above, by managing the scheduled arrival times one after another by the scheduled arrival time management unit 532D, the gateway device 53 can select in advance the relay device 14 that is the destination of the interest packet requesting the streaming content, The relay device 14 can deliver a necessary amount of streaming content to the terminal device 12 at a required time. As a result, the amount of streaming content delivered by each relay device 14 is reduced, and the relay device 14 can preferentially deliver content that requires an emergency. In particular, when the number of relay devices 14 that move between the refuge 11 and the base station 15 is large, or when the time for the relay device 14 to reciprocate between the refuge 11 and the base station 15 is short, the gateway device 53 can distribute the interest packet to the relay device 14 more effectively, and the relay device 14 can use the storage area more effectively.

  Further, even when an error occurs in the moving time of the relay device 14 by the estimated arrival time planning unit 531C correcting the estimated next arrival time stored in the estimated arrival time management unit 532D based on the history, the gateway device 53 Can distribute the interest packet requesting the streaming content to the relay device 14 so that the terminal device 12 can continuously play the streaming content.

  In addition, although the relay apparatus 14 in this Embodiment 1-3 is an unmanned flight body, this indication is not specifically limited to this, For example, the relay apparatus 14 may be mounted in moving bodies, such as a vehicle.

  The communication method, the communication apparatus, and the communication system according to the present disclosure can reproduce the streaming content without interruption in the terminal apparatus, can effectively use the storage area of the relay apparatus, and improve communication efficiency. A communication method for transmitting a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices and transmitting a plurality of data packets including streaming content received from the plurality of relay devices to the terminal device It is useful as a communication device and a communication system.

9 Wireless LAN
10 CCN network 11 Shelter 12 Terminal device 13, 43, 53 Gateway device 14, 14A, 14B Relay device 15 Base station 16 Content provider server 131, 141, 431, 531 CPU
131A, 141A Data processing unit 131B, 141B, 431B, 531B Interest processing unit 132, 142, 432, 532 RAM
132A, 142A CS
132B, 142B, 432B PIT
132C, 142C FIB
132D, 532D Estimated arrival time management unit 132E Streaming content management unit 133, 143 Communication IF
133A, 143A Wireless IF
134, 144 Communication bus 141C Estimated arrival time notification unit 142D Interest storage unit 431C Data size acquisition unit 432F, 532F Interest temporary storage unit 432G Priority management unit 432H Predicted free capacity management unit 531C Estimated arrival time planning unit

Claims (9)

A communication device that transmits a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices, and transmits a plurality of data packets including the streaming content received from the plurality of relay devices to the terminal device. A communication method,
A first location capable of communicating with the communication device via a first network and a content providing device capable of communicating with the content providing device for providing the streaming content via a second network separated from the first network. Receiving a next scheduled arrival time indicating a time at which the plurality of relay apparatuses moving between two positions arrive at the first position next from each of the plurality of relay apparatuses;
Receiving an interest packet including the playback time of the streaming content from the terminal device;
Based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices, a relay device that transmits the interest packet is selected from the plurality of relay devices,
Transmitting the interest packet to the selected relay device;
Communication method. Obtaining free capacity of the content cache unit that caches the data packet from the plurality of relay devices,
Obtaining the data size of the data packet requested by the interest packet from the interest packet received from the terminal device;
When the acquired data size is larger than the free capacity of the content cache unit of the first relay device selected as the destination of the interest packet among the plurality of relay devices, it is different from the first relay device After causing the second relay device or the communication device to transmit the interest packet already stored in the first relay device, the interest packet received from the terminal device is transmitted to the first relay device. ,
The communication method according to claim 1. A priority level associated with the interest packet and indicating the degree of priority transmission of the interest packet;
Determining whether to transmit the interest packet based on the obtained priority;
The communication method according to claim 1 or 2. If the priority is lower than the first threshold, discard the received interest packet, or temporarily store the received interest packet in a memory included in the communication device;
When the priority is equal to or higher than the first threshold, a relay device that transmits the interest packet is selected from the plurality of relay devices.
The communication method according to claim 3. If the priority is higher than a second threshold higher than the first threshold, the received interest packet is duplicated, and the duplicated interest packet is transmitted to the plurality of relay devices,
When the priority is between the first threshold and the second threshold, a relay device that transmits the interest packet is selected from the plurality of relay devices.
The communication method according to claim 4. Based on the arrival time at which the relay device arrives at the first position and the next scheduled arrival time, predict the next scheduled arrival time at which the relay device arrives at the first location one after another,
Relay for transmitting the interest packet from among the plurality of relay devices based on at least one of the reproduction time, the next scheduled arrival time, and the next scheduled arrival time when selecting the relay device Select the device
When selecting a relay device as a transmission destination based on the next scheduled arrival time, temporarily store the received interest packet in the memory of the communication device,
If the destination relay device is selected based on the next scheduled arrival time, the received interest packet is transmitted to the selected relay device.
The communication method according to any one of claims 1 to 5. Storing arrival history information associating the next arrival time with the arrival time for each of the plurality of relay devices;
Correcting the next scheduled arrival time received from the relay device based on the stored next scheduled arrival time and the arrival time stored;
The communication method according to claim 6. A communication device for transmitting a plurality of interest packets requesting streaming content received from a terminal device to a plurality of relay devices, and transmitting a plurality of data packets including the streaming content received from the plurality of relay devices to the terminal device. There,
A first location capable of communicating with the communication device via a first network and a content providing device capable of communicating with the content providing device for providing the streaming content via a second network separated from the first network. A first receiving unit that receives from each of the plurality of relay devices a next arrival scheduled time indicating a time at which the plurality of relay devices moving between two positions arrive at the first position next;
A second receiving unit for receiving an interest packet including the playback time of the streaming content from the terminal device;
A selection unit that selects a relay device that transmits the interest packet from among the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices;
A transmission unit for transmitting the interest packet to the selected relay device;
A communication device comprising: A terminal device, a communication device communicably connected to the terminal device, a plurality of relay devices communicably connected to the communication device, and a content providing device communicably connected to the plurality of relay devices A communication system comprising:
The terminal device
A transmission unit for transmitting an interest packet including a playback time of the streaming content to the communication device;
A receiving unit for receiving a data packet including the streaming content from the communication device;
With
The communication device
A first location capable of communicating with the communication device via a first network and a content providing device that provides the streaming content via a second network separated from the first network. A first receiving unit that receives from each of the plurality of relay devices a next arrival scheduled time indicating a time at which the plurality of relay devices moving between the second positions arrive at the first position next; ,
A second receiving unit for receiving the interest packet from the terminal device;
A selection unit that selects a relay device that transmits the interest packet from among the plurality of relay devices based on the reproduction time included in the interest packet and the next arrival time of the plurality of relay devices;
A first transmitter that transmits the interest packet to the selected relay device;
A third receiving unit that receives the data packet requested by the transmitted interest packet from the relay device;
A second transmitter for transmitting the received data packet to the terminal device;
With
Each of the plurality of relay devices is
A first transmission unit configured to transmit the next scheduled arrival time to the communication device at the first position;
A first receiving unit for receiving the interest packet from the communication device;
A second transmission unit for transmitting the interest packet to the content providing apparatus after moving from the first position to the second position;
A second receiving unit for receiving the data packet from the content providing device;
A third transmitter that transmits the data packet to the communication device after moving from the second position to the first position;
With
The content providing apparatus includes:
A receiving unit for receiving the interest packet from the relay device;
A transmission unit for transmitting the data packet to the relay device;
A communication system comprising:

Images