This project involves the problem of supporting connectionless service in an ATM network. The urgency of this problem stems from the need to interconnect LANs and MANs (typically, operated in a connectionless mode) to the connection oriented ATM. The problem is quite challenging because the ATM network requires that users set up connections and declare in advance the expected traffic on each connection. The network then uses this information to allocate bandwidth to individual users. Connectionless sources, on the other hand, are by their nature unpredictable, thus eluding  the ATM bandwidth allocation strategy, and potentially compromising  network efficiency. In this project, a scheme - the Connectionless Server (CLS) overlay network - is investigated. This scheme permits efficient handling of connectionless traffic in ATM.  Various design options (topology connectivity, bandwidth allocation, buffer management, etc.) are examined, and performance  models and criteria for their selection are developed. The CLS scheme will be compared with other connectionless support schemes (Bandwidth Reservation and On-the-Fly Transmission) and the respective pros and cons will be evaluated. Finally, a hybrid scheme combining features of al of the schemes will be examined in an attempt to combine their benefits while avoiding their pitfalls.