Cisco Systems Cisco Systems Cisco Systems Cisco Systems Cisco Systems Ennovate Networks Cisco Systems A Multi Protocol Label Switching architecture is described in [1]. Label Switching enables the use of ATM Switches as Label Switching Routers. The ATM Switches run network layer routing algorithms (such as OSPF, IS-IS, etc.), and their data forwarding is based on the results of these routing algorithms. No ATM-specific routing or addressing is needed. This document describes how the label switching architecture is applied to ATM switches.