1. An integrated multiport network switch for interfacing with a data network to permit data communication among a plurality of remote stations coupled to said data network, said switch having a logic chip comprising: a plurality of ports for transmitting data frames to and receiving data frames from said data network; media access control (MAC) circuitry for controlling the flow of data frames at each of said ports, said MAC circuitry being coupled in common to each of said ports on a time shared basis, said MAC circuitry comprising logic circuit means for performing media access functions and state memory means for storing media access states of the said plurality of ports; at least one input receive first-in-first-out (FIFO) buffer at each port for temporarily holding data frames received from the network at the respective port; and at least one transmit FIFO buffer at each port for temporarily holding data frames to be transmitted to the network at the respective port, each said FIFO buffer being coupled to said logic circuit means.