1. A caching system functionally associated with a network, said system comprising: a content characterization module comprising processing circuitry adapted to computationally derive, from one or more data segments of a first content item received from an external content source, a derived identifier of the first content item, as the first content item enters said network through a gateway node of the network; two or more network caching units, each: physically connected by wire or cable to a different base station of the network, adapted to provide caching service to the respective base station of the network and comprising: a cache repository to cache multiple content items along with corresponding derived identifiers of the cached content items; and a communication module comprising communication circuitry adapted to provide inter-caching communication between said caching units; wherein said caching units are configured to deliver content items to client devices of the network, through the base stations; and a cache management comprising control circuitry configured to actively select a given network caching unit, of said two or more network caching units, to cache a given content item entering the gateway, based on a load balancing algorithm.