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Access Link Capacity Monitoring with TFRC Probe


Accurate estimation of network characteristics based on end to end measurements is an important and challenging problem. With the increasing variety and sophistication of Internet access methods, the mobility of the users and the need for seamless handoff across them, monitoring access link capacity becomes critical for efficient 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 passive, 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 flexible tool that can accurately track frequent changes in access capacity.

Paper: PDF file of paper

Information & Date

The 2nd Workshop on End-to-End Monitoring Techniques and Services (E2EMON), , January. 2004


Ling-Jyh Chen
Tony Sun
Dan Xu
M. Y. Sanadidi
Mario Gerla