Demultiplexed architectures: a solution for efficient STREAMS-based communication stacks

This article analyzes the efficiency of various high-performance implementation techniques for the communication system of UNIX workstations. Using an open system implies that a certain compatibility level is required from the protocol, user interface, and implementation framework. These constraints limit the opportunities to design a high-performance communication system. The authors have designed an experimental platform around the TCP/IP protocol suite, using the STREAMS environment. A BSD TCP/IP stack and a classic STREAMS-based TCP/IP stack serve as reference implementations for performance comparisons. The article explains why the efficiency of some high-performance implementation techniques the authors have applied to this platform is limited. The impacts of the hardware architecture, operating system, and communication stack architecture on performances are analyzed. It is shown that the efficiency of data transmission would benefit from more simplicity and more synchronism in the communication environment, direct data paths between the applications and the device drivers, and a limited ILP integration.