Patent ID: 6263402
Filing Date: 2001-07-17
Classification: H04L

Abstract:
A method of dealing with inquiries that concern data-information in a network that includes a plurality of users who ask to be provided with said data-information, a plurality of servers which provide said data-information, and at least one cache active between said servers and users, containing newly used data-information, and wherein said cache includes a plurality of nodes, in which methoda) the user requests the data-information concerned from a first node of said plurality of nodes;b) when the data-information requested is available in said first node, said data-information is sent to said user;c) when said data-information is unavailable in said first node, said first node requests said data-information from said nodes belonging to said cache;d) when step c) is fulfilled and the data-information is available within the cache, the data-information is sent to said user;e) when c) is fulfilled and said data-information is unavailable in said cache, the data-information is fetched from said server and deliver to said cache, whereafter said data-information is sent to said user;wherein subsequent to having been fetched from said server, said data-information is stored in said cache for a given period of time so as to be available for requests and inquiries from further users, wherein the nodes belonging to the cache form a hierarchial tree structure of nodes that includes a plurality of so-called object nodes, a plurality of so-called directory nodes, and a so-called root node, wherein said object nodes are positioned furthest out in said tree structure, wherein said root node forms the root of said tree structure, wherein possible intermediate levels between an object node and said root node are comprised of directory nodes, wherein data-information stored in said tree structure is stored solely in said object nodes, wherein respective directory nodes include a directory that covers all data-information stored in object nodes that are located beneath said directory nodes in said tree structure and in which object nodes respective data-information is stored, wherein said root node includes a directory of all data-information stored in said tree structure and in which object nodes respective data-information is stored, where information that discloses which data-information is available and where said information is available is designated meta-information, in which methodf) the user requests data-information concerned from a first object node of said plurality of object nodes;g) the data-information is sent to said user when said data-information is available in said first object node;h) said first object node requests said data-information from a first directory node that lies directly above said first object node in said tree structure, when said data-information is unavailable in said first object node;wherein the information inquiry procedure isi) when step h) is fulfilled and said data-information is available in a second object node that is located beneath said first directory node in said tree structure, wherein the directory belonging to said first directory node includes data which points to the object node in which said data-information is available, said first directory node orders said second object node, directly or via possible intermediate directory nodes, to send said data-information to said first object node, whereafter said data-information is sent to said user;j) when step h) is fulfilled and said data-information is available in a third object node that lies beneath a second directory node separate in said tree structure from said first directory node, where said directory belonging to said second directory node includes data which points to the object node in which said data-information is available, said first directory node requests said data-information from a further node that lies directly above said first directory node in said tree structure;k) when step j) is fulfilled and said further node is comprised of a third directory node that lies above said second directory node in said tree structure, said third directory node orders said second object node, directly or via possible intermediate directory nodes, to send data-information to said first object node, whereafter said data-information is sent to said user;l) when step j) is fulfilled and said further node is comprised of said root node, the root node orders said second object node, directly or via possible intermediate directory nodes, to send said data-information to said first object node, whereafter said data-information is sent to said user;m) when said data-information is unavailable in the tree structure, the data-information is fetched from said server by said first object node, whereafter said data-information is sent to said user,and that when the requested data-information is available in a plurality of different object nodes, the commanding node decides which object node shall send the data-information, on the basis of the current load on those object nodes that contain the requested data-information.