Pushing CDN-ISP collaboration to the limit

Benjamin Frank, Ingmar Poese, Yin Lin, Georgios Smaragdakis, Anja Feldmann, Bruce Maggs, Jannis Rake, Steve Uhlig, Rick Weber
Appears in: 
CCR July 2013

Today a spectrum of solutions are available for istributing content over the Internet, ranging from commercial CDNs to ISP-operated CDNs to content-provider-operated CDNs to peer-to-peer CDNs. Some deploy servers in just a few large data centers while others deploy in thousands of locations or even on millions of desktops. Recently, major CDNs have formed strategic alliances with large ISPs to provide content delivery network solutions. Such alliances show the natural evolution of content delivery today driven by the need to address scalability issues and to take advantage of new technology and business opportunities. In this paper we revisit the design and operating space of CDN-ISP collaboration in light of recent ISP and CDN alliances. We identify two key enablers for supporting collaboration and improving content delivery performance: informed end-user to server assignment and in-network server allocation. We report on the design and evaluation of a prototype system, NetPaaS, that materializes them. Relying on traces from the largest commercial CDN and a large tier-1 ISP, we show that NetPaaS is able to increase CDN capacity on-demand, enable coordination, reduce download time, and achieve multiple traffic engineering goals leading to a win-win situation for both ISP and CDN.

Public Review By: 
Fabián E. Bustamante

Content delivery has become the Internet's primary purpose and its main source of traffic. Current statistics are staggering, with Netflix alone being responsible for 30% of the peak traffic in North America. Not surprisingly, the variety of architectural models for distributing this content is rapidly expanding with approaches that involve, to different degrees, all parties in the content delivery ecosystem - CDNs, content providers, ISPs and end users. This paper presents the design and evaluation of a system – NetPaaS – to enable the collaboration of two key stakeholders – ISPs and CDNs. NetPaaS builds on the authors' previous work on CaTE*, expanding the forms of collaboration to the placement of content servers in a network. Reviewers have a number of comments on the paper’s early draft, including the apparent simplicity of the system, the potential for information leakage (from CDN to ISP and vice-versa) and a lack of novelty when compared with the authors’ own and other's related efforts. In the final version, the authors addressed most of the comments – pointing out, for instance, to the challenge of incorporating in a scalable manner all network updates and clarifying that NetPaaS assumes that the information exchange is between trusted parties that have already formed strategic alliances. Reviewers uniformly agreed that even if the ideas put forward are not particularly new, the impressive empirical evaluation of the proposed ideas, leveraging traces from the largest commercial CDN and a large tier1 ISP, is a unique and interesting contribution in itself.