TigerSwitch: a case study in embedded computing system design

The paper describes and analyzes the design of TigerSwitch, a PC-based private branch exchange (PBX) designed at Princeton University. Building TigerSwitch required creating custom hardware and software designed to fit onto a standard IBM PC-compatible platform. The authors´ design experience provides several lessons which they believe extend to other embedded design domains: the system architecture required to meet performance goals is often not isomorphic to the structure of the specification; system-level performance analysis is an essential part of system architecture design; architectural decisions must be made on the basis of estimates before complete implementations of the components are available; and most allocations of functions to software or custom hardware are obvious, while a few are very difficult