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Packet Triplet: An Enhanced Packet Pair Probing for Path Capacity Estimation. Nanyang Technological University Zou ZiXuan. OUTLINE. The purpose of Packet Triplet Previous Packet-Pair based techniques Packet Triplet probing Detailed approach Filtering scheme Experimental Results.
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Packet Triplet: An Enhanced Packet Pair Probing for Path Capacity Estimation Nanyang Technological University Zou ZiXuan
OUTLINE • The purpose of Packet Triplet • Previous Packet-Pair based techniques • Packet Triplet probing • Detailed approach • Filtering scheme • Experimental Results
The purpose of Packet Triplet • Measuring the path capacity (bottleneck) • Packet-Pair based • Robust to cross traffic
Previous Packet-Pair based technique • Packet-Pair dispersion • Originated by Keshav for congestion control • Cross traffic effect—expression and extension • Variants of Packet-Pair to deal with the effects of cross traffic.
Previous Packet-Pair based technique • Statistical method • Sending many packet pairs, using statistical approach • Union and Intersection • Kernel density • Do not always lead to correct estimation • Not a global modal but the local modal • Observed by Paxson, investigated by Dovrolis
Previous Packet-Pair based technique • Model based detection • Based on Multimodal distribution • Packet-Train and Packet-Pair
Packet-Triplet probing • Deal with multimodal distribution • Accurately estimate path capacity in different load traffic • Different from model-based detection
Detailed approach • Three back-to-back probing packets and dispersion pair
Detailed approach • Packet Triplet probing • Idea condition • No cross traffic • The variation of Latency of probing packets • Equivalent estimates
Detailed approach • Cross traffic effect • When • When • Narrow link capacity estimates (NLE)
Cont’d • Post-narrow link estimates (PNLE) • Equivalent noise (EN) • Occur in low frequency
Filtering scheme • filter out the estimates in case of as the noises. • Of the remaining estimates, the estimate of lowest value and relatively high frequency of occurrence is selected as the set of NLE. The mean of the NLE estimates is considered as the bottleneck of measured path.
Experimental Results • Simulation setup • ns-2 • Topology • P={50,20,10,30,25,40} Mps • 1000 packet triplet experiments are done.
Cont’d • Packet-Pair vs. Packet-Triplet • L=100bytes cross traffic load=20%, 50%, 80%
Cont’d • L=700bytes CL=20%, 80%
Cont’d • L=1000 bytes CL=20%, 80%
Conclusion • The noise filtering and bottleneck detection are always efficient whenever the cross traffic is light or heavy when we choose the small probing packet size • how to set is a remaining issue for our research on this topic