Drafting behind Akamai (travelocity-based detouring)

Abstract

To enhance web browsing experiences, content distribution networks (CDNs) move web content "closer" to clients by caching copies of web objects on thousands of servers worldwide. Additionally, to minimize client download times, such systems perform extensive network and server measurements, and use them to redirect clients to different servers over short time scales. In this paper, we explore techniques for inferring and exploiting network measurements performed by the largest CDN, Akamai; our objective is to locate and utilize quality Internet paths without performing extensive path probing or monitoring.Our contributions are threefold. First, we conduct a broad measurement study of Akamai's CDN. We probe Akamai's network from 140 PlanetLab vantage points for two months. We find that Akamai redirection times, while slightly higher than advertised, are sufficiently low to be useful for network control. Second, we empirically show that Akamai redirections overwhelmingly correlate with network latencies on the paths between clients and the Akamai servers. Finally, we illustrate how large-scale overlay networks can exploit Akamai redirections to identify the best detouring nodes for one-hop source routing. Our research shows that in more than 50% of investigated scenarios, it is better to route through the nodes "recommended" by Akamai, than to use the direct paths. Because this is not the case for the rest of the scenarios, we develop lowoverhead pruning algorithms that avoid Akamai-driven paths when they are not beneficial. * Drafting is a technique commonly used by bikers and longdistance runners to reduce wind resistance by moving into the air pocket created behind the leader.

Relative Network Positioning via CDN Redirections

“…To drive CRP, we employ the Akamai CDN [1] and gather CDN redirections using Yahoo 1 and Fox News 2 . As reported in [42], lookups to these names result in redirections that reflect dynamic network conditions. During each evaluation period, we determine CDN-based relative positions by issuing recursive DNS queries to reveal the mapping of hosts to replica servers.…”

“…Based on a study of CDN redirection from two different CDN providers, Johnson et al [16] argue that these CDNs commonly avoid bad recommendations rather than select optimal servers. More recently, through a detailed measurement of the Akamai CDN, we show that CDN redirections are primarily driven by network conditions, specifically network latencies on the paths between clients and the Akamai servers, and are updated frequently enough as to be useful for control [42]. Our early study illustrated the potential benefits of employing CDN redirections for identifying good detouring paths and demonstrated that in approximately 50% of scenarios, the best measured one-hop path through an Akamai server outperforms the direct path in term of latency.…”

“…In [42], we demonstrated that such redirections are primarily driven by network conditions and updated frequently enough as to be useful for control. CRP is based on the hypothesis that if two hosts see the same (or similar) set of nearby replica servers over time, they are likely to be relatively close to each other.…”

QuLa: Service Selection and Forwarding Table Population in Service-Centric Networking Using Real-Life Topologies

“…Research shows that the use of an additional selection component such as an Akamai-server is more bene¿cial than IP routing in more than 50% of the scenarios [22]. Therefore, our work uses a similar forwarding scheme to the ICN framework Content Centric Network / Named Data Networking (CCN/NDN) [4]; each router forwards a request to the next router based on the requested service name.…”

Drafting Behind Akamai: Inferring Network Conditions Based on CDN Redirections

“…Fig. 1 provides a detailed example of an Akamai DNS translation, which is explained in depth in [1]. In summary, the Akamai infrastructure returns the IP addresses of two Akamai edge servers that it expects to offer high performance to the Web client.…”