The operation of IP and address resolution over the ATM LAN interworking unit

This paper introduces an ATM LAN switching system which has been devised to construct our prototyping ATM LAN. "Classical IP over ATM" based on IETF RFC1577 is applied to provide existing IP services to ATM LAN subscribers. Furthermore, this switching system supports interworking between existing LANs and ATM LANs. To do this, a special interworking unit has been developed. It allows existing LAN subscribers to connect directly to our switch. Therefore, existing LAN subscribers may look upon this switch as a proxy. We describe the hardware structure of the interworking unit and how it handles ARP and IP packets to provide seamless IP services on ATM LAN. We show some message flows between hosts via the interworking units and the routers on the ATM LAN to resolve the address resolution problems. We also address the ATM LAN router briefly. Based on IP over ATM, existing routing protocols can be used without any modification.