End-to-End Available Bandwidth: Measurement Methodology, Dynamics, and Relation With TCP ThroughputPurposeSlide 3Definition End-to-end Avail-bwMethodology Self-Loading Periodic Streams (SLoPS)Implementation PathloadVerification (NS Simulation)Verification (Experimental)Dynamics: Variability and Load ConditionsDynamics Variability and Statistical MultiplexingDynamics: Effect of the Stream LengthDynamics Effect of the Fleet LengthTCP and Avail-BWIntrusiveness PathloadConclusionReferencesByManish Jain and Constantinos Dovrolis2003Presented by Caroline Williams End-to-End Available Bandwidth 1Rosa WilliamsPurposeThe authors are not satisfied with the current definition of available bandwidth nor the tools to measure available bandwidth.The authors propose:A concise available bandwidth definitionA methodology to measure available bandwidthA tool that implements the methodologyEnd-to-End Available Bandwidth 2Rosa WilliamsMotivationAvailable bandwidth is an important metric for:–Congestion control–Streaming applications–Quality-of-service verification–Server selection–Overlay networksAs such, the definition should be agreed upon, the measurements accurate and nonintrusive.End-to-End Available Bandwidth 3Rosa WilliamsDefinitionEnd-to-end Avail-bwEnd-to-End Available Bandwidth 4Rosa WilliamsMethodologySelf-Loading Periodic Streams (SLoPS)A stream consists of K packets of size L, sent at constant rate ROne-way delays (OWD) of successive packets at RCV show an increasing trend when R > AA is converged upon through an iterative algorithm at RCV. RCV notifies SND of new R. The “algorithm will converge to a range [Rmin, Rmax] that includes A.”End-to-End Available Bandwidth 5Rosa WilliamsImplementationPathloadProcess SND generates fleets of timestamped packet streams for RProcess RCV determines the OWD trend for the fleet. Then, adjusts Rmin or Rmax according to the SLoPS algorithm. A new R (halfway between Rmin and Rmax) is fed back to SND.Continue the above two steps until Rmax – Rmin a user defined resolution[Rmin, Rmax] can be calculated in less than 15 seconds using default parameters End-to-End Available Bandwidth 6Rosa WilliamsVerification (NS Simulation)End-to-End Available Bandwidth 7Rosa WilliamsVerification (Experimental)End-to-End Available Bandwidth 8Rosa WilliamsDynamics: Variability and Load ConditionsEnd-to-End Available Bandwidth 9Rosa WilliamsDynamicsVariability and Statistical MultiplexingEnd-to-End Available Bandwidth 10Rosa WilliamsDynamics: Effect of the Stream LengthEnd-to-End Available Bandwidth 11Rosa WilliamsDynamicsEffect of the Fleet LengthEnd-to-End Available Bandwidth 12Rosa WilliamsTCP and Avail-BWEnd-to-End Available Bandwidth 13Rosa WilliamsIntrusivenessPathloadEnd-to-End Available Bandwidth 14Rosa WilliamsConclusionAvailable bandwidth is elusiveJain and Dovrolis have provided a methodology that reports a range of rates that includes avail-bw Their tool is nonintrusive and reliable in a “wide range of load conditions and path configurations”.End-to-End Available Bandwidth 15Rosa WilliamsReferencesInformation Sciences Institute. ns-2. http://nsnam.isi.edu/nsnam/index.php/Main_Page. October 21, 2007.M. Jain, C. Dovrolis. End-to-end available bandwidth: measurement methodology, dynamics, and relation with TCP throughput. IEEE/ACM Trans. Netw. 11(4): 537-549 (2003) T. Oetiker. MRTG - The Multi Router Traffic Grapher. http://oss.oetiker.ch/mrtg/. October 21, 2007.End-to-End Available Bandwidth 16Rosa
View Full Document