JP7084365B2 - Transporters and programs for content distribution systems - Google Patents

Description

The present disclosure relates to a transfer device and a program of a content distribution system that performs routing based on a content name.

A content distribution system that requests and distributes content based on a content name indicating the content has been proposed. Patent Document 1 discloses a content-centric network (CCN), which is one such system.

In the CCN, the server device that publishes the content divides the content into one or more chunks, and the client device acquires the content in units of the divided chunks. Further, in the CCN, the communication device (hereinafter referred to as a transfer device) that has transferred the chunk can store (cache) the chunk. When the transfer device receives an interest packet (request packet) requesting a chunk cached by the own device from the client device, the transfer device caches the interest packet without forwarding the interest packet to the server device. The chunk can be sent to the client device that is the source of the interest packet.

An example of the operation of the transfer device will be described below. The transfer device manages CS (Contents Store), FIB (Forward Information Base), and PIT (PIT: Ending Interest Table). CS is information indicating chunks cached by the own device. The FIB is information indicating the relationship between the chunk requested by the interest packet and the interface to which the interest packet should be forwarded. The PIT is information indicating the relationship between the chunk requested by the transferred interest packet and the interface that received the transferred interest packet.

Upon receiving the interest packet, the transfer device searches the CS and determines whether or not the chunk requested by the interest packet (hereinafter referred to as the requested chunk) is cached. When the request chunk is cached, the data packet including the request chunk cached by the own device is transmitted to the client device that is the source of the interest packet. The interface for transmitting the data packet is the interface for receiving the interest packet. On the other hand, if the request chunk is not cached, the transfer device searches the PIT to forward another interest packet requesting the request chunk and determines whether the request chunk is waiting to be received. When in the reception wait state, the transfer device does not forward the received interest packet and adds the reception interface of the interest packet to the entry of the request chunk of the PIT. On the other hand, when the request chunk is not in the reception waiting state, the transfer device transfers the interest packet from the interface determined based on the FIB, and adds the request chunk entry to the PIT. This entry shows information indicating the request chunk and information indicating the interface on which the interest packet was received. Further, when the transfer device receives the data packet including the chunk, the transfer destination interface of the chunk is determined based on the PIT and transferred, and the entry of the chunk is deleted from the PIT. The transfer destination interface is an interface that has received an interest packet requesting the chunk. Further, the transfer device updates the CS when it caches the received and transferred chunks.

Thus, in the CCN, the data packet containing the chunk is transmitted to the interface that received the interest packet requesting the chunk. Therefore, the chunk is forwarded in the reverse direction on the same route as the interest packet requesting the chunk, and is delivered to the client device requesting the chunk. The interest packet contains information indicating a request chunk (chunk name), but does not include information for identifying the client device that is the source of the interest packet. Therefore, the server device or transfer device that distributes the stored chunk cannot recognize in which region or network the client device that requested the chunk is located. That is, the server device and the transfer device cannot limit the area or network to which the content is delivered.

Patent Document 1 discloses a configuration that restricts the distribution of a predetermined content to a predetermined area or network. According to Patent Document 1, the FIB of the transfer device located in the predetermined area or network is not provided with an entry for an interest packet requesting a chunk of the predetermined content. With this configuration, the transfer device located in the predetermined area or network discards the interest packet requesting the chunk of the predetermined content, so that the predetermined content is not delivered to the predetermined area or network. ..

Japanese Unexamined Patent Publication No. 2018-49474

In the FIB, the chunk name prefix is used to reduce the number of entries. For example, there is content with a content name "/ Tokyo / Olympic / soccer" divided into 20000 chunks, and the chunk name is "/ Tokyo / Olympic / soccer / 1" to "/ Tokyo / Olympic / soccer / 20000". And. When all the transfer destination interfaces of these 20000 chunks are the same, instead of providing 20000 entries in the FIB, each of which indicates the same transfer destination interface, only one entry of "/ Tokyo / Olympic / soccer" is set in the FIB. It can be configured to be provided in.

Furthermore, there is content with a content name "/ Tokyo / Olympic / basketball" divided into 10,000 chunks, and the chunk name is "/ Tokyo / Olympic / basketball / 1" to "/ Tokyo / Olympic / basketball / 10000". And. If the transfer destination interface of the 10,000 chunks is the same as the 20,000 chunks of the content name "/ Tokyo / Olympic / soccer", instead of providing an entry for each of the 30,000 chunks in the FIB, "/". It is also possible to provide the FIB with only one entry of "Tokyo / Olympic".

Here, for example, as shown in FIG. 1, it is assumed that there is a network in which the content "/ Tokyo / Olympic / soccer" can be distributed, but the content "/ Tokyo / Olympic / basketball" cannot be distributed. The transfer device of this network provides the entry of "/ Tokyo / Olympic / soccer" in the FIB and does not provide the entry of "/ Tokyo / Olympic / basketball" in the FIB, so that the content "/ Tokyo / Olympic / basketball" It is possible to prevent chunks from being delivered to the network. However, when the transfer device of the network provides the entry of "/ Tokyo / Olympic" in the FIB as shown in FIG. 1, the packet requesting the chunk of "/ Tokyo / Olympic / basketball" is also directed to the server device. It will be forwarded and therefore delivery cannot be restricted.

The present invention provides a mechanism capable of controlling the distribution destination of a content in a content distribution system that routes the content based on the content name.

According to one aspect of the present invention, the transfer device of the content distribution system that transfers the request packet including the content name of the content for which distribution is requested based on the content name is a plurality of communications for connecting to a plurality of other devices. A storage means for storing the interface, attribute information indicating the attributes of each of the plurality of communication interfaces, and restriction information indicating the content name and one or more attributes associated with the content name, and the request packet. Upon reception, the first attribute of the communication interface that received the request packet is determined based on the attribute information, and whether or not the first content name included in the request packet is associated with the first attribute in the restriction information. It is characterized by comprising a processing means for performing a process of determining whether or not to discard the received request packet according to the above.

According to the present invention, it is possible to control the distribution destination of the content in the content distribution system that routes the content based on the content name.

Explanatory diagram of the task. Explanatory drawing of one embodiment. The figure which shows the information which the transfer apparatus by one Embodiment holds. A flowchart of processing performed when the transfer device according to the embodiment receives an interest packet. The block diagram of the transfer apparatus by one Embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar configuration will be given the same reference number, and duplicated explanations will be omitted.

Hereinafter, the present embodiment will be described assuming that the content distribution network is CCN. However, the present invention can be applied to any content distribution network that routes based on the content name. In particular, in the following, the present embodiment will be described in the form of distributing the content in units of pieces of content called chunks according to the distribution of the content by CCN, but the present invention also applies to a network that distributes the content without dividing the content. Can be applied. Therefore, the chunks and chunk names in the following description can be replaced with content and content names.

FIG. 2 shows a part of a content distribution network for explaining the present embodiment. The transfer device 20 is connected to the transfer device 23 by IF # 2, is connected to the transfer device 22 by IF # 3, and is connected to the transfer device 21 by IF # 4. In this embodiment, attribute information is given to each transfer device. The attribute information indicates, for example, the area or network in which the transfer device is located. In FIG. 2, the transfer devices 20, 21 and 22 are given the attribute information "Tokyo", and the transfer device 23 is given the attribute information "Osaka".

FIG. 3A shows the FIB of the transfer device 20. The chunk name field of the FIB and the restriction information in each figure may indicate a prefix common to the chunk names in addition to the chunk names themselves. According to FIG. 3A, an interest packet requesting a chunk with an arbitrary chunk name prefixed with "/ Tokyo / Olympic" is forwarded to IF # 4, that is, to the transfer device 21. FIG. 3B shows the interface attribute information stored in the transfer device 20. The interface attribute information indicates the attributes of each interface of the transfer device 20, and the attributes of the interface are the same as the attribute information of the transfer destination connected by the interface, as shown in FIG. Each transfer device receives the attribute information of the transfer device from the transfer device connected by the interface, and stores this as the attribute information of the interface. FIG. 3C shows the restriction information stored in the transfer device 20. In FIG. 3C, an interest packet or a data packet relating to a chunk with an arbitrary chunk name having "/ Tokyo / Olympic / basketball" as a prefix is a transfer to which the attribute information "Tokyo" is added. It has been shown that it can only be transferred to the device. In other words, it is shown that interest packets and data packets related to chunks with arbitrary chunk names prefixed with "/ Tokyo / Olympic / basketball" cannot be transferred to the transfer device to which the attribute information "Osaka" is attached. Has been done.

FIG. 4 is a flowchart of the process executed by the transfer device 20 when the interest packet is received. In S10, it is determined whether or not the entry of the chunk (hereinafter referred to as the request chunk) requested by the received interest packet is in the restriction information. In the case of the restriction information of FIG. 3C, if the chunk name of the request chunk is "/ Tokyo / Olympic / basketball" as a prefix, the processing of S10 is Yes. On the other hand, when the chunk name of the request chunk is "/ Tokyo / Olympic / soccer" as a prefix, the process of S10 is No. When S10 is Yes, the transfer device 20 determines in S11 whether the attribute of the interface that received the interest packet is included in the entry determined in S10. In the case of the restriction information of FIG. 3C, since the attribute information "Tokyo" is shown in the entry of "/ Tokyo / Olympic / basketball", the interface that received the interest packet is IF # 3. , S11 is Yes, and if it is IF # 2, S11 is No. If S11 is No, the transfer device 20 discards the received interest packet in S12 and ends the process.

On the other hand, in the case of No in S10 or Yes in S11, the transfer device 20 does not discard the received interest packet, but performs the usual processing necessary for transmitting the request chunk to the source of the interest packet. .. That is, it is determined whether the request chunk is cached, and if it is cached, the cached request chunk is transmitted from the receiving interface of the interest packet. If the request chunk is not cached, the PIT is searched to determine whether the request chunk is in the reception waiting state. When waiting for a request chunk to be received, the interface for receiving the interest packet is added to the entry of the request chunk of the PIT. Therefore, when a request chunk is received, the request chunk is transmitted from the receiving interface of the interest packet. Further, if the request chunk is not in the reception waiting state, the interest packet is transferred based on the FIB, and the request chunk entry is added to the PIT. Therefore, when a request chunk is received, the request chunk is transmitted from the receiving interface of the interest packet.

For example, if the request chunk of the received interest packet is "/ Tokyo / Olympic / soccer / 1", the result is No in S10, so that the request is made regardless of which transfer device the interest packet is received from. Chunks are transmitted to the transfer device that sent the interest packet. On the other hand, when the request chunk is "/ Tokyo / Olympic / basketball / 1", but the receiving interface of the interest packet is IF # 3, it becomes Yes in S11, so that the request chunk transmits the interest packet. It is transmitted to the transfer device 22. However, if the request chunk is "/ Tokyo / Olympic / basketball / 1" and the reception interface of the interest packet is IF # 2, S11 is No, so the request chunk is transmitted to the transfer device 23. Not done.

With the above configuration, it is possible to limit the distribution of predetermined content to a predetermined area or network.

In FIG. 4, when the interest packet is received, the interest packet is discarded based on the restriction information, thereby restricting the distribution of the predetermined content to the predetermined area or network. However, when the interest packet is received, normal processing can be performed, and the data packet including the request chunk can be restricted when being transmitted. That is, before transmitting a chunk from a certain interface, it is determined whether the chunk can be transmitted from the interface based on the restriction information, and the chunk is transmitted from the interface only when it is determined that the chunk can be transmitted. You can also do it.

For example, when the chunk to be transmitted is "/ Tokyo / Olympic / soccer / 1", the transfer device 20 can transmit at any interface because there is no entry for the chunk in the restriction information. .. On the other hand, when the chunk to be transmitted is "/ Tokyo / Olympic / basketball / 1", it can be transmitted from IF # 3 having Tokyo as an attribute shown in the attribute information, but Osaka not shown in the attribute information is used as an attribute. It cannot be sent from IF # 2.

Further, although the restriction information of the present embodiment indicates an attribute that is not restricted, it may indicate an attribute that restricts. For example, in the case of restricting the distribution of "/ Tokyo / Olympic / basketball" to the transfer device 23, Osaka may be set in the attribute information of FIG. 3C. In this case, in the case of Yes in S11 of FIG. 4, the process of S12 is performed. It should be noted that, regardless of whether the attribute indicated by the restriction information is an attribute that is restricted or an attribute that is not restricted, a plurality of attributes can be set in one entry of the restriction information.

FIG. 5 is a configuration diagram of a transfer device according to the present embodiment. The communication unit 30 has a plurality of communication interfaces and transmits / receives interest packets and request packets. The storage unit 32 stores interface attribute information and restriction information in addition to the FIB, PIT, and CS. The interface information can be acquired from the transfer information of the connection destination via, for example, each communication interface. Further, the restriction information is set by, for example, an operator of the content distribution network.

When the delivery destination of the content is restricted by discarding the request packet, the processing unit 31 uses the restriction information that the first content name (first chunk name) included in the received interest packet determines the interest packet. It is determined whether to discard the interest packet depending on whether or not it is associated with the first attribute of the received communication interface. For example, when the attribute information indicates an attribute that cannot be delivered, the processing unit 31 considers that the restricted information has a first content name and the restricted information has the first content name associated with the first attribute. Determine to discard the packet. On the other hand, when the attribute information indicates an attribute that can be delivered, the processing unit 31 has the interest packet when the restriction information has the first content name but the first content name is not associated with the first attribute in the restriction information. Is determined to be discarded. In other cases, the processing unit 31 performs normal processing necessary for delivering the content.

On the other hand, when the distribution destination of the content is restricted by discarding the data packet, the processing unit 31 transmits the data packet including the content (or a fragment thereof) of the first content name from the communication interface of the first attribute. Whether to discard or to discard is determined by whether or not the first content name is associated with the first attribute in the restriction information. For example, when the attribute information indicates an attribute that cannot be delivered, the processing unit 31 indicates a data packet when the restriction information has a first content name and the first content name is associated with the first attribute in the restriction information. Cannot be sent and is determined to be discarded. On the other hand, when the attribute information indicates an attribute that can be delivered, the processing unit 31 sends a data packet when the restriction information has the first content name but the first content name is not associated with the first attribute in the restriction information. It is judged that it cannot be sent and is discarded. Otherwise, the processing unit 31 transmits the data packet from the communication interface.

The transfer device according to the present invention can be realized by a program that operates the computer as the transfer device. These computer programs are stored in a computer-readable storage medium or can be distributed over a network.

The invention is not limited to the above embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

32: Storage unit, 31: Processing unit

Claims (7)

A transfer device of a content distribution system that transfers a request packet including the content name of the content for which distribution is requested based on the content name.
Multiple communication interfaces for connecting to multiple other devices,
A storage means for storing attribute information indicating the attributes of each of the plurality of communication interfaces and restriction information indicating the content name and one or more attributes associated with the content name.
When the request packet is received, the first attribute of the communication interface that received the request packet is determined based on the attribute information, and the first content name included in the request packet is associated with the first attribute in the restriction information. A processing means that performs a process of determining whether or not to discard the received request packet depending on whether or not the packet is received.
A transfer device characterized by being equipped with. When the restriction information has the first content name and the first content name is associated with the first attribute in the restriction information, the processing means determines to discard the received request packet. The transfer device according to claim 1. The processing means determines that the received request packet is discarded when the restriction information includes the first content name but the first content name is not associated with the first attribute in the restriction information. The transfer device according to claim 1. It has multiple communication interfaces for connecting to a plurality of other devices, and receives a data packet containing the content as a response to receiving a request packet containing the content name of the content requested to be delivered. It is a transfer device of the content distribution system that transmits from the communication interface.
A storage means for storing attribute information indicating the attributes of each of the plurality of communication interfaces and restriction information indicating the content name and one or more attributes associated with the content name.
Whether or not a data packet containing the content of the first content name can be transmitted from the communication interface of the first attribute is determined by whether or not the first content name is associated with the first attribute in the restriction information. Processing means to perform processing and
A transfer device characterized by being equipped with. When the restriction information has the first content name and the first content name is associated with the first attribute in the restriction information, the processing means sets the data packet as the first attribute. The transfer device according to claim 4, wherein it is determined that transmission cannot be performed from the communication interface. When the processing means has the first content name in the restriction information, but the first content name is not associated with the first attribute in the restriction information, the data packet is communicated with the first attribute. The transfer device according to claim 4, wherein it is determined that transmission cannot be performed from the interface. A program according to any one of claims 1 to 6, wherein the computer functions as the transfer device.

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