Abstract: We examine two key aspects of the ATM deployment in the TCP/IP environment-logical IP sub-networks (LISs) and address mapping servers, with a specific emphasis on how different alternatives for LISs and address mapping servers enable efficient exploration of all the capabilities that ATM promises to deliver. We propose an approach for ATM deployment in the TCP/IP environment that leverages the existing technologies (e.g. DNS, routing protocols), minimizes new development, imposes no new requirements on ATM, allows for small, incremental changes with immediate payoffs, while at the same time retains backward compatibility with the existing schemes, such as LAN Emulation and "classical" IP over ATM. The proposed approach combines a switch-based infrastructure with router-based overlay and uses each for that which it is best suited: switch-based infrastructure for applications that can justify an SVC establishment; router-based overlay for all other applications.