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Provider-aided Distance Information System (PaDIS)

Today, a large fraction of Internet traffic is originating from Content Delivery Networks (CDN). To cope with the increasing demand for content, CDNs deploy massively distributed server infrastructures. Thus the content hosted by CDNS is available at different locations on the Internet. To minimize their cost, CDNs perform their own traffic optimization by assigning end-users to their servers. Such an assignment made by the CDN is at large unaware of the network conditions and is based on inaccurate information about the location of the end-user. Thus, users are not always assigned to the CDN servers that lead to optimal end-user performance. In contrast, an ISP has detailed and accurate knowledge about the status of its own network. However, today ISPs are unable to utilize their knowledge as there are no mechanisms available to influence the assignment of users to CDN servers.

To improve user assignment, especially from a performance perspective, we propose and deploy a Provider-aided Distance Information System (PaDIS). PaDIS is a novel system operated by an ISP that allows ISPs to influence the assignment of users to servers by utilizing information available only to ISPs as well as by exploiting server diversity exposed by the CDN server selection process. PaDIS ranks any user and available CDN server pair based on current network conditions and accurate network locations. It then returns back the most preferable servers to the end-user regarding a performance metric chosen by the ISP. As a result, PaDIS utilizes the deployed CDN server infrastructure to improve end-user performance.

To evaluate the performance improvements we have implemented and deployed a PaDIS prototype. Our field test results show that significant improvements in download time up to a factor of four for content offered by popular content distributors can be achieved when PaDIS is used.


  • Ingmar Poese [1]
  • Benjamin Frank [2]
  • Georgios Smaragdakis [3]
  • Anja Feldmann [4]


  • Bernhard Ager [5]
  • Steve Uhlig [6]

Selected Publications

Improving Content Delivery using Provider-aided Distance Information
Zitatschlüssel PFASF-ICDUPADI-10
Autor Poese, Ingmar and Frank, Benjamin and Ager, Bernhard and Smaragdakis, Georgios and Feldmann, Anja
Buchtitel Proceedings of Internet Measurement Conference (IMC '10)
Seiten 22–34
Jahr 2010
ISBN 978-1-4503-0483-2
DOI http://dx.doi.org/10.1145/1879141.1879145
Ort Melbourne, Australia
Adresse New York, NY, USA
Monat November
Verlag ACM
Zusammenfassung Content delivery systems constitute a major portion of today's Internet traffic. While they are a good source of revenue for Internet Service Providers (ISPs), the huge volume of content delivery traffic also poses a significant burden and traffic engineering challenge for the ISP. The difficulty is due to the immense volume of transfers, while the traffic engineering challenge stems from the fact that most content delivery systems themselves utilize a distributed infrastructure. They perform their own traffic flow optimization and realize this using the DNS system. While content delivery systems may, to some extent, consider the user's performance within their optimization criteria, they currently have no incentive to consider any of the ISP's constraints. As a consequence, the ISP has ''lost control'' over a major part of its traffic. To overcome this impairment, we propose a solution where the ISP offers a Provider-aided Distance Information System (PaDIS). PaDIS uses information available only to the ISP to rank any client-host pair based on distance information, such as delay, bandwidth or number of hops. In this paper we show that the applicability of the system is significant. More than 70% of the HTTP traffic of a major European ISP can be accessed via multiple different locations. Moreover, we show that deploying PaDIS is not only beneficial to ISPs, but also to users. Experiments with different content providers show that improvements in download times of up to a factor of four are possible. Furthermore, we describe a high performance implementation of PaDIS and show how it can be deployed within an ISP.
Link zur Publikation [7] Download Bibtex Eintrag [8]
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