Caching in Mobile Networks

A cache manager for controlling distribution of content stored in caches in a cache domain in a packet data network, the cache manager comprising:

• an object monitor configured to receive notifications from caches in the cache domain about data objects requested at those caches;
• an object database configured to collate and store object information about the requested data objects, the object information including information about the caches at which the data objects have been requested and frequency with which the requests have been made;
• an object distributor configured to:
• identify objects for distribution on the basis of the object information and instruct the caches in the cache domain to distribute data objects stored in those caches between themselves;
• wherein the object information includes a popularity parameter for each object, and the object distributor is configured to classify the objects into one of at least three classes, the classes including:
• a high popularity class comprising objects which should be distributed to all caches in the cache domain;
• a medium popularity class comprising objects which should be distributed to one or more subsets of the caches in the cache domain;
• and
• a low popularity class comprising objects which should not be distributed.

A method for optimizing distribution of data objects between caches in a cache domain of a resource limited network, the method comprising:

• receiving user requests for data objects at caches in the cache domain;
• sending a notification from the cache at which a request is received to a cache manager, the notification reporting the user request and identifying the requested data object;
• at the cache manager, collating and storing object information including the request frequency of each requested data object and the locations of the caches at which the requests were received;
• at the cache manager, identifying objects for distribution within the cache domain on the basis of the object information;
• sending instructions from the cache manager to the caches to distribute data objects stored in those caches between themselves;
• and
• distributing the data objects between the caches by an object distributor;
• wherein the object information includes a popularity parameter for the object, and the object distributor is configured to classify the object into one of at least three classes, the classes including:
• a high popularity class comprising objects which should be distributed to all caches in the cache domain;
• a medium popularity class comprising objects which should be distributed to one or more subsets of the caches in the cache domain;
• and
• a low popularity class comprising objects which should not be distributed.

A computer program product stored in a non-transitory computer readable medium for controlling a cache manager in a resource limited network, the computer program product comprising software instructions which, when run on the cache manager, causes the cache manager to:

• retrieve notifications from caches in a cache domain controlled by the cache manager, the notifications including details of data objects recently requested at those caches;
• collate and store object information about the requested data objects, the object information including the location and popularity of requested data objects;
• identify objects for distribution on the basis of the object information;
• instruct the caches in the network to distribute data objects stored in those caches between themselves;
• wherein the object information includes a popularity parameter for each object, and the objects are classified into one of at least three classes, the classes including:
• a high popularity class comprising objects which should be distributed to all caches in the cache domain;
• a medium popularity class comprising objects which should be distributed to one or more subsets of the caches in the cache domain;
• and
• a low popularity class comprising objects which should not be distributed.