ATM switch routers for combined connection-oriented and connectionless transport

This paper demonstrates the need for an ATM network to support both connection-oriented and connectionless networking in order to be an effective integrated services network. It identifies two key properties for an efficient solution that offers both networking modes: the use of a common addressing scheme and a common routing protocol for both modes. To enhance PNNI (private network-to-network interface) based ATM networks to support both networking modes, we propose a datagram protocol called CL-ATM (connectionless ATM) that uses the same addressing scheme and routing protocol as connection-oriented ATM. ATM switches with CL-ATM packet forwarding modules are referred to as ATM switch routers. This paper also addresses the problem of how two different integrated services networks, each supporting both networking modes, can interwork. Specifically, it shows how a network based on IP interworks with a network of ATM switch routers.