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Journal Paper


Monitoring Access Link Capacity Using TFRC Probe


Accurate estimation of network characteristics based on end to end measurements is an important and chal- lenging problem. With the increasing variety and sophistication of Internet access methods, the mobility of the users and the need for seamless hando® across them, monitoring access link capacity becomes critical for e±cient multimedia delivery. In fact, this allows the multimedia server to properly adjust its sending rate to the rapidly changing access speed of the mobile client. This problem is challenging because most of the existing capacity monitoring schemes are active, like Pathrate (and therefore introduce extra overhead on the bandwidth limited access link). Moreover, the access link is often asymmetric (eg, ADSL, 1xRTT, etc) thus preventing the use of round trip monitoring schemes such as Pathchar and CapProbe. In this study, we propose and evaluate a pas- sive, one-way link capacity monitoring tool called TFRC Probe. With TFRC Probe the source can monitor the forward direction capacity of both asymmetric and symmetric access links, and can rapidly and accurately adapt its transmissions rate accordingly. We validate TFRC Probe with both simulation and testbed experiments, and show that TFRC Probe is a very °exible tool that can accurately track frequent changes in access capacity. Keywords: Passive capacity estimation; TFRC Probe; CapProbe.

Paper: PDF file of paper

Information & Date

Accepted by the Computer Communications Journal (ComCom), Special Issue on Monitoring and Measurements of IP Networks, , January. 2005


L.-J. Chen