Application-compliant networking on embedded systems

Network protocol stacks are traditionally encapsulated within system software, forcing the application programmer to use general-purpose communication end-point abstractions. The application programmer is denied the flexibility of implementing application-specific performance improvements. Application-level networking provides the application programmer with the ability to tailor the protocol stack to the needs of the application. This is particularly useful in special-purpose systems, such as embedded networked appliances. We describe the design of an application-compliant TCP/IP implementation for the Arena runtime library operating system, which aims at separating mechanism from policy. The role of policy and mechanism in network protocols and their effects on networked embedded systems is investigated. The resulting system is optimised for embedded systems based on a multithreaded single-application model. Experiments were carried out on an embedded system test platform and performance results are given.