The lightweight protocol CLIC on Gigabit Ethernet

In Gigabit class networks, the physical transmission time is small compared to the time required to process the TCP/IP protocol stack. Thus, the usefulness of lightweight protocols that reduce the communication software overhead is even higher, as the performance demands shift to the network interface hardware and/or software. The communication protocol CLIC has recently been proposed for efficient communication in clusters using the Linux operating system. It uses an approach to optimize the communication performance in a cluster of computers different from that of providing a user-level interface that removes the operating system (OS) mediation in the communication path. Thus, besides reducing the latencies and increasing the bandwidth figures even for short messages, CLIC meets other requirements such as multiprogramming, portability, protection against corrupted programs, reliable message delivery, direct access to the network for all applications, etc., by providing an optimized OS support to reliable and efficient network software, that avoids the TCP/IP protocol stack. In this paper we show how new facilities and improved performance of network interface cards (NICs) have been incorporated to CLIC in order to take advantage of the gigabit network technology.