Design issues and performance comparisons in supporting the sockets interface over user-level communication architecture

Since user-level communication (ULC) architecture provides only primitive operations for application programmers, there have been several researches to build a portable and standard communication interface, such as sockets, on top of ULC architecture. Basically there are three different approaches to supporting the sockets interface over ULC architecture: LAN emulation, a user-level sockets, and a kernel-level sockets. The primary objective of this paper is to compare these approaches in terms of their design, implementation, and performance. We have developed and implemented a kernel-level sockets layer over ULC architecture, since there is currently no available implementation. We also present different design and implementation decisions on data receiving, data sending, connection management, etc. in the three approaches. Through the performance comparison, we show that LAN emulation approach exhibits the worst performance both in latency and bandwidth. Our experiments also show that a user-level sockets is useful for latency-sensitive applications and a kernel-level sockets is effective for applications which require high bandwidth and full compatibility with the legacy sockets interface.