Connectionless services in an ATM-LAN provided by a CL-server. An implementation and case study

The paper describes the provision of connectionless services in a local ATM network by a connectionless server CLS, implemented as part of a workstation driver in software. It is described how connectionless service functions, CLSFs, can be provided by changing and enhancing existing workstation drivers, without involving the switch software. This concept should also allow a seamless interconnection of private CLSs with a public CLS. The environment used for the implementation consists of a local ATM switch (ASX100), manufactured by Fore Systems and the modified workstation drivers for the Fore Systems SBA-100 SBus ATM adapter cards for Sun workstations. Throughput measurements are presented for both AAL type 3/4 and AAL type 5 for the CL-data transfer. Issues concerning higher layer protocols like TCP/IP, XTP and ST-II are discussed. A description of the implemented methods and a discussion of the pros and cons of using CLSs in an ATM-LAN is given.