Overlay Networks: An Akamai Perspective

A novel idea to bridge the gap is overlay networks, or just overlays for short. Overlays use the functional primitives that the underlay has to offer. In turn, the overlay provides richer functionality to services that are built on top of it. The different types of overlays include: the caching overlay, routing overlay, and the security overlay. The security overlays are at the core of some of the most sought after Akamai services. This chapter discusses the architecture and techniques of each type of overlay. It provides background information on the Internet (the underlay) and what it can or cannot provide an overlay designer. Next, the chapter traces the evolution of overlays from both an industry and academic research perspective. Finally, it describes the high level architecture of the overlays.