Overlay networks and the future of the internet

Abstract

Abstract: In recent years, we have seen the emergence of numerous types of so-called "overlay " networks in the internet. There are many diverse examples of such overlay networks including the content-delivery-caching networks, implemented by companies like Akamai, the peer-to-peer file sharing networks associated with applications such as BitTorrent, the voice-over-IP services offered via Skype, and various testbed networks such as PlanetLab. Such overlays have important technological and policy implications for the evolution of next generation internet architecture. This paper provides a first attempt to understand the implications of such overlays for internet architecture, industry structure, and policy. We introduce a taxonomy for thinking about these overlays with some examples of their scale and growing importance in the internet, and suggest some preliminary thoughts on the implications of these overlays for industry structure and policy. Key words: internet architecture, overlay networks, ISPs, internet policy. T he internet started out as a government-funded research network running on top of the Public Switched Telecommunications Network (PSTN). The internet was a data application, mostly unregulated, that was supported on top of the public-utility regulated telephone networks. The internet was an "overlay " that complemented the underlying basic infrastructure of the PSTN by adding new functionality (packet-switched data network) to support the special needs of the research community (peer-topeer computer communications). Most of the incremental investment in routers, servers, and access devices (PCs) was undertaken by new types of providers (Internet Service Providers or ISPs) and by end-users (Customer Premise Equipment or CPE) to complement the PSTN basic infrastructure already in place. With the commercialization of the internet in the 1980s and its emergence as a mass market platform for broadband communications in the 1990s, the internet has evolved into the principal platform for our global public communications infrastructure. Increasingly, IP packet transport is