In communications systems operations, the geographical path that is followed by a call or message over the circuits that are used in establishing a chain of connections. 2. To determine the path that a message or call is to take in a communications network. Note: In a Transmission Control Protocol/Internet Protocol (TCP/IP) internet, each IP datagram is routed separately. The route a datagram follows may include many gateways and many physical networks. 3. To construct the path that a call or message is to take in a communications network in going from one station to another or from a source user end instrument to a destination user end instrument.