Method and node entity for enhancing content delivery network

A caching node entity for ensuring at least a predetermined number of copies of a content object to be kept stored in a network comprising a plurality of cache nodes for storing copies of content objects, the entity comprising:

• assigning means adapted to assign each of a plurality of copies of content objects a value of a ranking state, wherein the value of the ranking state indicates whether the copy is deletable or non-deletable, and wherein at least one copy of each content object is assigned with the value non-deletable;
• and
• changing means configured to change the ranking state value for at least one copy of at least one content object from non-deletable to deletable in a cache node, said at least one copy being eligible for the value deletable only if a deletable copy of said at least one content object in another cache node is eligible for the value non-deletable.