Efficient support for IP over ATM

With the explosive growth and pervasive reach of the Internet, it is becoming the de facto standard user network interface. The vast majority of new networking applications assume this interface. Consequently, ATM technology is increasingly used to carry IP datagrams. So far however, the control and signaling model of ATM has not been adequately optimized for this use. Moreover, the incompatibility of the quality of service models increase complexity as IP level RSVP reservations are translated into (close to) equivalent ATM QoS requests. UNITE is a lightweight signaling protocol for ATM, that substantially reduces the cost of connection setup, while providing flexible support for quality of service. In particular, UNITE does not incur an end-to-end setup delay, but instead makes the connection available for transmission almost immediately. In addition, the connection setup cost is sufficiently low to be amortized even for the shortest flows (one or two datagrams). UNITE´s service model is generic, and thus is equally suitable to support either the ATM service model, or the RSVP service model or both. We describe how UNITE enables IP flows to better exploit the high forwarding performance of ATM switches, and avoids the complexities caused by service model mismatch