Interfaces Gateways

  Gateway - software/hardware access between two networks or sub-nets.
    Connects systems of dis-similar architectures and/or domain/sub-domain id. 

    Uses logical protocol to identify packet destinations such as TCP/IP

    Performs protocol changes between networks.

    The gateway machine/card has a unique id public to local network.
   
    Often physically implemented on a switch or router.

    Routers are gateway devices with additional functions and database features.