The SIP server can be comprised of an engine tier and a state tier distributed on a cluster network environment. The engine tier can send, receive and process various messages. The state tier can maintain in-memory state data associated with various SIP sessions. A near cache can be residing on the engine tier in order to maintain a local copy of a portion of the state data contained in the state tier. Various engines in the engine tier can determine whether the near cache contains a current version of the state needed to process a message before retrieving the state data from the state tier. Accessing the state from the near cache can save on various latency costs such as serialization, transport and deserialization of state to and from the state tier. Furthermore, the near cache and JVM can be tuned to further improve performance of the SIP server.