METHOD AND NODE ENTITY FOR ENHANCING CONTENT DELIVERY NETWORK

The present invention prdvides a method and a caching node entity for ensuring at least a predetermined number of a content object to be kept stored in a network, comprising a plurality of cache nodes for storing copies of content objects. The present invention makes use of ranking states values, deletable or non-deletable, which when assigned to copies of content objects are indicating whether a copy is either deletable or non-deletable. At least one copy of each content object is assigned the value non-deletable The value for a copy of a content object changing from deletable to non-deletable in one cache node of the network, said copy being a candidate for the value non-deletable, if a certain condition is fulfilled.