Before revision:  In this paper we focus on the LRU cache where requests for distinct contents are described by independent stationary and ergodic processes.
After revision: The modeling and analysis of an LRU cache is extremely challenging as exact results for the main performance metrics (e.g. hit rate) are either lacking or cannot be used because of their high computational complexity for large caches. As a result, various approximations have been proposed. The state-of-the-art method is the so-called TTL approximation, first proposed and shown to be asymptotically exact for IRM requests by Fagin. It has been applied to various other workload models and numerically demonstrated to be accurate but without theoretical justification. In this paper we focus on the LRU cache where requests for distinct contents are described by independent stationary and ergodic processes.