JP6406671B2 - Content cache method and apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for caching content on a network, and more particularly, to a content cache method and apparatus that can efficiently download content between node devices.

  A content-oriented network that caches content on the network and enables users to download content from the network as one of the methods to solve the problems in the server-client model network with IP addresses as identifiers Is underway.

  Non-Patent Document 1 shows a content-oriented network that routes content request messages and download content using content identifiers based on hierarchical naming. Also shown is a content-oriented network in which each node device has a content cache and the content request message is routed to the nearest content cache holding the desired content.

G. Xylomennos, et al., "A Survey of Information-Centric Networking Research," IEEE Communication Surveys and Tutorials, vol. 16, no. 2, pp. 1024-1049, 2014.

  FIG. 4 is a diagram showing a network configuration for explaining a conventional content cache method. The connection between the node devices N1, N3, and N4 and the connection between the node devices N2, N3, and N5 are all in one hop. Yes, the connection between the node devices N1 and N4 and the node devices N2 and N5 is two hops that relay the node device N3.

  FIG. 4A shows an initial cache state, in which content A is cached in the node device N1, and content B is cached in the node device N2.

  Here, when the maximum allowable number of hops of the content request message is limited to one hop, if any of the node devices N3, N4, and N5 requests the download of the content A and B, the node device N4 only sends the content A to the node Downloadable from device N1. The node device N5 can download only the content B from the node device N2.

  The node device N3 can download both the contents A and B from the node devices N1 and N2, respectively. However, if the cache capacity of the node device N3 is one content, the contents A and B cannot be cached simultaneously. Therefore, if the content download order is A, B, only the content B remains in the node device N3 as shown in FIG. As a result, as shown in FIG. 5C, the node device N4 can download the content B, but the node device N5 cannot download the content A.

  As described above, in the conventional content cache method, if the cache capacity of the node device is small, the content that can be downloaded by the peripheral node device is limited, and thus the desired content cannot be downloaded.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described technical problem, a content cache method and a node device on a network that can cache various contents with a small cache capacity, and that peripheral node devices can download desired content with a sufficient probability. To provide a device.

  In order to achieve the above object, the present invention is characterized in that a content cache apparatus that caches content on a network has the following configuration.

  (1) Generate a coded content by network-coding at least one cached content relevant to the new content and a means for judging the relationship between the downloaded new content and at least one cached content And means for caching the encoded content instead of the cached content.

  (2) A content identifier based on hierarchical naming is set for each content, and the means for judging the relevance judges the relevance between the contents based on the similarity of the content identifiers.

According to the present invention, the following effects are achieved.
(1) Since node devices on the network encode and cache contents that are similar or related to each other, even a node device with a small cache capacity has a high possibility of being requested to download at the same time. Content can be cached together.

  (2) Since similar or related contents are network-encoded, a user who desires one of these contents already has the remaining contents or can easily download from other node devices. There is a high possibility of being in an environment and situation. Therefore, even if the content to be downloaded is network-encoded, it can be easily decoded, and the desired content can be acquired in the same manner as when the content that has not been encoded is downloaded.

  (3) Since an identifier based on hierarchical naming is set for each content, the similarity or relevance of each content can be easily and accurately determined based on the matching length of the identifier.

It is the block diagram which showed the structure of the principal part of the content cache apparatus 1 which concerns on one Embodiment of this invention. 5 is a flowchart illustrating an operation of the content cache device according to the embodiment of the present invention. It is the figure which expressed typically the download method and the cache method of the content to which this invention is applied. It is the figure which expressed typically the download method and the cache method of the content by a prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a main part of a content cache device 1 according to an embodiment of the present invention. An application (program) for realizing each function described later on a computer or a server configuring a network node device. ) Can be configured. Alternatively, a part of the application may be configured as a dedicated machine or a single-function machine in which hardware or ROM is implemented.

  The content acquisition unit 101 downloads content from other node devices, content servers, or user terminals (hereinafter collectively referred to as node devices N) via the network. The relevance determining unit 102 determines whether content similar to or related to the downloaded new content has been cached in the cache memory 100.

  In the present embodiment, content identifiers based on hierarchical naming are used for all content, and content having a content identifier matching length longer than a predetermined reference value is determined to be similar or related content.

  The cache control unit 103 includes a network encoding unit 104. When content similar or related to new content is cached in the cache memory 100, these are collectively network encoded, and encoded content is cached content. Instead, it is cached in the cache memory 100. That is, all the cached content that has been network-encoded is deleted, and the encoded content is cached instead.

  The content request reception unit 105 receives a content request from another node device N via the network. The content selection unit 106 selects content that responds to the content request from the cache memory 100. In the present embodiment, if the requested content is cached alone without being network encoded with other content, the single content is preferentially selected. On the other hand, if the requested content is network-encoded together with other content, the encoded content is selected.

  The content distribution unit 107 distributes the selected single content or encoded content to the request source of the content. The cache information publicizing unit 108 publicizes information on contents cached in the cache memory 100 on the network. At this time, a group of contents that are network-encoded are advertised in association with the group of contents.

  FIG. 2 is a flowchart showing the operation of the content cache device 1. When new content is downloaded by the content acquisition unit 101 in step S1, the cached content similar to the new content is displayed in step S2. The relevancy determination unit 102 searches the cache memory 100.

  In the present embodiment, the identifier of the new content and the identifier of the cached content are compared by the relevance determination unit 102, and all cached content whose content identifier match length exceeds a predetermined threshold is searched.

  If it is determined in step S3 that the content similar to the new content has been cached in the cache memory 100, the process proceeds to step S4, and the cached content having the maximum content identifier match length is selected from among the content.

  In step S5, the selected cached content and new content are network encoded by the network encoding unit 104 to generate encoded content. In step S6, the encoded content is replaced with the selected cached content. That is, the encoded content is cached in the cache memory 100 instead of the cached content.

  On the other hand, when a content request via the network is received by the content request receiving unit 105 in step S8, it is determined whether or not the requested content has been cached in the cache memory 100 in step S9. If it has not been cached, the process ends. If it has been cached, the process proceeds to step S10.

  In step S10, the requested content is selected from the cache memory 100 by the content selection unit 106 and distributed to the request source by the content distribution unit 107.

  FIG. 3 is a diagram schematically showing a content download method and a cache method to which the present invention is applied. The connection between the node devices N1, N3, and N4 and the connection between the node devices N2, N3, and N5 are all shown. The connection between the node devices N1 and N4 and the node devices N2 and N5 is 2 hops.

  The maximum allowable hop count of the content request message is limited to one hop, and the cache capacity of the node device N3 (content cache device 1) according to an embodiment of the present invention is one content. Therefore, in order for each node device N to cache a plurality of types of content at the same time, it is necessary to network-encode these contents.

  FIG. 5A shows an initial cache state, in which the content A is held in the node device N1 and the content B is held in the node device N2. The contents A and B are similar or related, and the content identifiers of both contents are sufficiently long.

  Here, when the node devices N3, N4, and N5 all request download of the contents A and B, the node device N4 can download only the content A from the node device N1. The node device N5 can download only the content B from the node device N2. The node device N3 can download both the contents A and B from the node devices N1 and N2, respectively. However, since the cache capacity of the node device N3 is one content, the contents A and B cannot be cached simultaneously.

  Therefore, if the content download order is A and B, when the node device N3 downloads the content B after the content A is downloaded, the relevance determining unit 102 caches content similar to or related to the content B. It is determined whether or not it has been completed.

  Here, since it is determined that the content A is similar to the content B, the content A and B are network-encoded by the network encoding unit 104, and as shown in FIG. Instead, the encoded content [A + B] is cached.

  When the node device N3 publicizes the fact that the encoded contents [A + B] of the contents A and B are cached from the cache information publicizing unit 108 onto the network, the node device N4 requests the content B from the node device N3.

  Since the node device N3 responds with the encoded content [A + B] in response to the content request, the node device N4 decodes the encoded content (A + B) using the content A already possessed. Content B can be acquired.

  Similarly, when the node device N5 requests the content A from the node device N3, the node device N3 responds with the encoded content [A + B] in response to the content request. The node device N5 can acquire the content A by decoding the encoded content (A + B) using the content B already possessed.

  According to the present embodiment, since the node device N on the network encodes and caches contents similar to or related to each other, even a node device with a small cache capacity can be requested to download at the same time in relation to it. It is possible to cache multiple contents with high characteristics.

  In addition, in order to decode the encoded content, a part of the content must be possessed. In the present embodiment, content similar to or related to each other is network-encoded. There is a high possibility that a user who desires one content already has all the remaining content or is in an environment and situation where it can be easily downloaded from another node device.

  Therefore, even if the content to be downloaded is network-encoded, it can be easily decoded, and the desired content can be acquired in the same manner as when content that has not been encoded is downloaded. .

  Furthermore, according to the present embodiment, related contents are not discarded even if the cache capacity is insufficient, and are continuously cached as encoded contents. Therefore, it is possible to increase a hit rate at which a node device can find a desired content by searching.

  Furthermore, according to the present embodiment, since an identifier based on hierarchical naming is set for each content, the similarity or relevance of each content can be easily and accurately determined based on the matching length of the identifier. .

  DESCRIPTION OF SYMBOLS 100 ... Cache memory, 101 ... Content acquisition part, 102 ... Relevance judgment part, 103 ... Cache control part, 104 ... Network encoding part, 105 ... Content request reception part, 106 ... Content selection part, 107 ... Content distribution part, 108… Cash Information Public Relations Department

Claims (8)

In a content cache device that caches content on a network,
Means for determining the relevance between the downloaded new content and at least one cached content;
Means for network-encoding at least one cached content associated with the new content to generate encoded content;
Means for caching the encoded content in place of the cached content ,
Each content has a content identifier based on hierarchical naming,
The content cache apparatus characterized in that the means for determining the relevance determines relevance between contents based on the similarity of content identifiers .   In a content cache device that caches content on a network,
  Means for determining the relevance between the downloaded new content and at least one cached content;
  Means for network-encoding at least one cached content associated with the new content to generate encoded content;
  Means for caching the encoded content instead of the cached content;
  Means for publicizing the cached content on a network;
  A content cache apparatus characterized in that the means for publicizing relates to a group of contents that are network-encoded together in relation to the encoded contents. Each content has a content identifier based on hierarchical naming,
3. The content cache apparatus according to claim 2 , wherein the means for determining relevance determines relevance between contents based on a similarity of content identifiers.   3. The content cache apparatus according to claim 1, further comprising means for responding the encoded content to a request for any of the network-encoded content. The content cache apparatus according to claim 1 , further comprising means for publicizing the cached content on a network. 6. The content cache apparatus according to claim 5 , wherein the publicizing means publicizes a group of contents that are network-encoded together with respect to the encoded content. In a content caching method for caching content on a network,
A procedure for determining the relevance between the downloaded new content and at least one cached content;
Network encoded encoding of at least one cached content associated with the new content to generate encoded content;
Look contains a procedure to cache instead of the encoded content to the cached content,
Each content has a content identifier based on hierarchical naming,
In the procedure of determining the relevance , the content cache method is characterized in that the relevance between the contents is determined based on the similarity of the content identifiers .   In a content caching method for caching content on a network,
  A procedure for determining the relevance between the downloaded new content and at least one cached content;
  Network encoded encoding of at least one cached content associated with the new content to generate encoded content;
  Caching the encoded content instead of the cached content;
  Publicizing the cached content on a network,
  In the publicity procedure, the content cache method is characterized in that a group of contents that are both network-encoded are associated and publicized with respect to the encoded content.