Measuring User-Perceived Internet Performance in Multiple Locations

Measurement studies of Internet performance are critical forvalidating or refuting widely held beliefs about Web behavior, and forshedding light on unknown behaviors. Results from these studies canguide Internet architects in making decisions that affect InternetService Providers (ISPs), content providers and end-users. Examples ofdecisions that can benefit from measurement information includeprovisioning network capacity, placing Domain Name System (DNS) andWeb servers, and tuning parameters of transport layer protocols.Internet protocols and services may exhibit different performancecharacteristics when observed from different locations in the Internettopology; to date, however, there has been little work investigatingthe differences in these characteristics from multiple vantagepoints. Typically, performance studies present results of measurementstaken in only one or two locations. Some of the reasons for the lackof work in this area are the following. First, performancemeasurement was not a high priority of Internet design and was notbuilt into the network architecture. Second, it is difficult to obtainthe necessary level of privilege at many different locations in theInternet topology to perform measurement studies. Finally, highexpectations for real-time Internet performance is a relatively recentphenomenon.In this thesis we develop several methods for gatheringInternet performance data from multiple locations throughout theworld, and to analyze data gathered. Our focus is on the protocolsand services that support the World Wide Web.In the first method we utilize a modified Web proxy. Our proxycaptures and logs fine-grained performance information on a per-userbasis. Our second method is to create and deploy a measurement packagefor examining DNS performance. We modified the BIND DNS server andpackaged it with a script to drive the data collection. Our finalmethod is to create and distribute an application to be run at usersites worldwide. One of the primary tasks of the application is toprovide performance data from each instance of the applicationexecuting at locations throughout Internet topology. We can use theinformation provided by this application to examine user-perceivedInternet performance throughout the globe.