Cross-Layer Architectures

Abstract

This chapter presents proposed cross-layer architectures for ad hoc and sensor networks. Cross-layer architectures provide a holistic view of the cross-layer model, focusing on how to interface or integrate layers from across the communication stack. Recent cross-layer architectures have promoted information sharing across existing protocol layers while maintaining the separation of functionality between layers. The domination of information sharing over design coupling in cross-layer architectures is not a coincidence. By definition, an architecture creates clearly defines entities and outlines the interactions between these entities. Because design coupling combines the functionalities of different layers, it essentially creates new superlayer entities. The superlayer entities are treated as layers that must interact with the remaining entities, leading back to the architectural issues. Information sharing, on the other hand, fits well within a well-defined architecture, since it only requires the specification of new interfaces or the expansion of existing interfaces.