Peter Newman, Greg Minshall, and Tom Lyon.
IP traffic on the Internet and private enterprise networks has been growing exponentially for some time. This growth is beginning to stress the traditional, processor based design of current day routers. Switching technology offers much higher aggregate bandwidth but presently only offers a layer-2 bridging solution. Various proposals are under way to support IP routing over an ATM network. However, these proposals hide the real network topology from the IP layer by treating the data-link layer as a large, opaque, network cloud. We argue that this leads to complexity, inefficiency and duplication of functionality in the resulting network.
We propose an alternative in which we discard the end-to-end ATM connection and integrate fast ATM hardware directly with IP, preserving the connectionless nature of IP. We use soft-state in the ATM hardware to cache the IP forwarding decision. This enables further traffic on the same IP flow to be switched by the ATM hardware rather than forwarded by IP software. We claim that this approach combines the simplicity, scalability, and robustness of IP with the speed, capacity, and multiservice traffic capabilities of ATM.