ATM and fast Ethernet network interfaces for user-level communication

Fast Ethernet and ATM are two attractive network technologies for interconnecting workstation clusters for parallel and distributed computing. This paper compares network interfaces with and without programmable co-processors for the two types of networks using the U-Net communication architecture to provide low-latency and high-bandwidth communication. U-Net provides protected, user-level access to the network interface and offers application-level round-trip latencies as low as 60 /spl mu/sec over Fast Ethernet and 90 /spl mu/sec over ATM. The design of the network interface and the underlying network fabric have a large bearing on the U-Net design and performance. Network interfaces with programmable co-processors can transfer data directly to and from user space while others require aid from the operating system kernel. The paper provides detailed performance analysis of U-Net for Fast Ethernet and ATM, including application-level performance on a set of Split-C parallel benchmarks. These results show that high-performance computing is possible on a network of PCs connected via Fast Ethernet.