a session relay apparatus for preventing the packet relay delay by detecting the start and end of the policy settable peer - to - peer communication is disclosed . the session relay apparatus for relay a session control message transmitted and received between communication terminals to control the peer - to - peer communication detects the start and end of the communication from the session control message , and acquires the information for identifying a session and the information on the peer - to - peer communication carried out on the session . upon generation of a policy indicating the packet relay control process by a policy generating unit , edge nodes for passing the packet are searched for and the policy is distributed to the edge nodes . the policy is set in the edge nodes accommodating the communication terminals at the start of communication , and the policy setting is canceled at the end of communication .