Abstract: Disclosed are a method and an apparatus for calculating a distance in a contents delivery network.

Abstract: Protection against unauthorized copying of digital media content is achieved by receiving information from a client device related to its storing function used to store digital media content that is to be sent to the client device; and performing a procedure to protect against unauthorized copying of the digital media content if the client device is able to store the digital media content using its storing function.

Abstract: Disclosed are a method and an apparatus for calculating a distance in a contents delivery network.

Abstract: The present invention relates to a file system, an apparatus in the file system thereof, and a method of providing and managing content in the file system thereof. According to the present invention, it may be possible to minimize data loss caused by server failure and to provide the convenience of data (content) management by (1) grouping overall data nodes (servers) to manage with a network server group including several data nodes (servers), (2) defining content management information, (3) storing and duplicating contents in each network server group using the defined content management information to maintain and manage the contents, (4) and maintaining and managing the contents in a file unit without using file chunks.

Abstract: Provided are a method and apparatus for selecting an optimal transport protocol. According to an exemplary embodiment of the present invention, there is provided a method for selecting a transport protocol, the method including: detecting a network state with another node connected to a node; and selecting a transport protocol between the node and the other node using the network state, the selected transport protocol being a modified transport protocol'. According to the present invention, the modified transport protocol' may be used even in varying network circumstances, and the modified transport protocol' may be widely used in a shared communication network.

Abstract: A method of determining the type of communication network. The method comprises measuring latency between the content server and a device that made a content transmission request, determining whether the measured latency is longer than a predetermined reference, and determining the content transmission request to be for over the mobile communication network if the measured latency is longer than the predetermined reference. Content can be provided through the mobile communication network and the Internet communication network by operating a single content server while distinguishing between the mobile communication network and the Internet communication network, without requesting content by installing an additional program by the client or operating an additional content server for the mobile communication network. Content can be provided more quickly by distinguishing between the mobile communication network and the Internet communication network.

Abstract: Disclosed are a method and an apparatus for measuring distances between nodes. According to an exemplary embodiment of the present invention, N or more nodes among a plurality of nodes located in a network are randomly selected, n-dimensions (where N>n and n?1) are formed by using the randomly selected N or more nodes, coordinates of other nodes are determined in the formed n-dimensional spaces by using distances between the randomly selected N or more nodes and other nodes, and distances between the plurality of nodes located in the network are calculated by using the determined coordinates. According to the present invention, the distance between nodes located in a network may be more effectively measured.

Abstract: Method and apparatus for providing content according to the type of communication network. IP address included in received content provision request is extracted, it is determined whether the extracted IP address is private IP address. Content transmission request is determined to be via mobile communication network when the extracted IP address is private IP address, and requested content is transmitted to the extracted IP address. Content server replies to content transmission request even from a private IP address. Mobile communication network requests content transmission from content server without involving a NAT device. Content is provided through mobile communication network and Internet communication network by operating a single content server while distinguishing between such two networks. Content is provided more quickly by distinguishing between the mobile communication network and the Internet communication network.

Abstract: A distributed data cache included in a content delivery network expedites retrieval of data for application execution by a server in a content delivery network. The distributed data cache is distributed across computer-readable storage media included in a plurality of servers in the content delivery network. When an application generates a query for data, a server in the content delivery network determines whether the distributed data cache includes data associated with the query. If data associated with the query is stored in the distributed data cache, the data is retrieved from the distributed data cache. If the distributed data cache does not include data associated with the query, the data is retrieved from a database and the query and associated data are stored in the distributed data cache to expedite subsequent retrieval of the data when the application issues the same query.

Abstract: Disclosed are a method for setting a plurality of sessions and a method for transmitting/receiving data using the same. According to an exemplary embodiment of the present invention, at least some of the data including attribute information of the data are received through initial sessions, the number of additional sessions for receiving the data is calculated by using the attribute information of the data, and the additional sessions are set as many as the calculated number of additional sessions. According to the exemplary embodiments of the present invention, various and complicated states of the communication network can be reflected to session setting as the configuration of the communication network becomes more and more complicated and the sessions depending on the state of the communication network can be set, thereby transmitting data more effectively.

Abstract: Round-trip time (RTT) for communication between an edge point of presence (POP) in a content delivery network (CDN) and a local domain name server (LDNS) is determined by resolution of a canonical name (CNAME) record. A first server in a first edge POP in a CDN receives a request to resolve a domain name from a LDNS and transmits a CNAME record including a timestamp indicating when the CNAME record was transmitted to the LDNS. The first server subsequently receives a request from the LDNS to resolve the CNAME record and determines a RTT time indicating the time needed for round-trip transmission between the LDNS and the first server based on the time when the request to resolve the CNAME request was received by the first server and the time indicated by the timestamp.

Abstract: A method for providing one or more contents to a client is disclosed. The method comprise receiving a request for one or more specific contents from the client; transmitting, to the client, a contents reproducer, which allows a user of the client to define at least one new command and to define an external appearance of the contents reproducer, wherein the external appearance includes an object to be represented as the new command; and transmitting, to the client, the requested contents thereby to be reproduced using the contents reproducer.

Abstract: Data access time in content delivery networks is improved by storing files in cache servers as file bundles. A cache server determines that multiple files are requested by the same client based on information available in the request including the IP address of the client, a URL of a webpage referring to the file, and/or a cookie stored at a client. The cache server stores multiple files requested by the same client on the hard drive as a file bundle with meta data associating the files with one another, such that they can be accessed together. A future request from the client for a file in a file bundle results in multiple files from the file bundle being loaded in the memory. If the client requests another file from the file bundle, the file is accessed directly from the memory instead of the hard drive, resulting in improved performance.

Abstract: Disclosed are a method and an apparatus for measuring distances between nodes. According to an exemplary embodiment of the present invention, N or more nodes among a plurality of nodes located in a network are randomly selected, n-dimensions (where N>n and n?1) are formed by using the randomly selected N or more nodes, coordinates of other nodes are determined in the formed n-dimensional spaces by using distances between the randomly selected N or more nodes and other nodes, and distances between the plurality of nodes located in the network are calculated by using the determined coordinates. According to the present invention, the distance between nodes located in a network may be more effectively measured.

Abstract: Disclosed are a method for setting a plurality of sessions and a method for transmitting/receiving data using the same. According to an exemplary embodiment of the present invention, at least some of the data including attribute information of the data are received through initial sessions, the number of additional sessions for receiving the data is calculated by using the attribute information of the data, and the additional sessions are set as many as the calculated number of additional sessions. According to the exemplary embodiments of the present invention, various and complicated states of the communication network can be reflected to session setting as the configuration of the communication network becomes more and more complicated and the sessions depending on the state of the communication network can be set, thereby transmitting data more effectively.

Abstract: Provided are a method and apparatus for selecting an optimal transport protocol. According to an exemplary embodiment of the present invention, there is provided a method for selecting a transport protocol, the method including: detecting a network state with another node connected to a node; and selecting a transport protocol between the node and the other node using the network state, the selected transport protocol being a modified transport protocol'. According to the present invention, the modified transport protocol' may be used even in varying network circumstances, and the modified transport protocol' may be widely used in a shared communication network.

Abstract: According to an embodiment of the present invention, the present invention includes: providing advertisement providing condition information which is previously set and receiving advertisement providing request information corresponding to the advertisement providing condition information; calculating an advertisement providing rate for the multiple web sites using the advertisement providing condition information and the advertisement providing request information; and transmitting advertisement data to the client in accordance with the advertisement providing rate when the advertisement data transmitting request is received from the client.

Abstract: Disclosed is the parallel download for a file, which calculates availability values of each block by using node operation rates of each node having blocks constituting a file, and preferentially downloads a block having a minimum availability value among the calculated availabilities, thereby increasing probability to access the file and each block constituting the file, thus to perform file downloading more accurately and rapidly.

Abstract: Round-trip time (RTT) for communication between an edge point of presence (POP) in a content delivery network (CDN) and a local domain name server (LDNS) is determined by resolution of a canonical name (CNAME) record. A first server in a first edge POP in a CDN receives a request to resolve a domain name from a LDNS and transmits a CNAME record including a timestamp indicating when the CNAME record was transmitted to the LDNS. The first server subsequently receives a request from the LDNS to resolve the CNAME record and determines a RTT time indicating the time needed for round-trip transmission between the LDNS and the first server based on the time when the request to resolve the CNAME request was received by the first server and the time indicated by the timestamp.

Abstract: A distributed data cache included in a content delivery network expedites retrieval of data for application execution by a server in a content delivery network. The distributed data cache is distributed across computer-readable storage media included in a plurality of servers in the content delivery network. When an application generates a query for data, a server in the content delivery network determines whether the distributed data cache includes data associated with the query. If data associated with the query is stored in the distributed data cache, the data is retrieved from the distributed data cache. If the distributed data cache does not include data associated with the query, the data is retrieved from a database and the query and associated data are stored in the distributed data cache to expedite subsequent retrieval of the data when the application issues the same query.