90 likes | 165 Views
DiffQ: Practical Differential Backlog Congestion Control for Wireless Networks. Ajit Warrier, S. Janakiraman, Injong Rhee, NCSU Paper Seminar Presenter Jaeyong Yoo. Congestion Control. Simplified form of definition of congestion:
E N D
DiffQ: Practical Differential Backlog Congestion Control for Wireless Networks Ajit Warrier, S. Janakiraman, Injong Rhee, NCSU Paper Seminar Presenter Jaeyong Yoo
Congestion Control • Simplified form of definition of congestion: • From the perspective of a user if the service quality decreases as the load of network increases • Congestion Collapse [Nagle 1984] ISP 2 ISP 1 100kbps => 1Mbps N3 100kbps N1 300kbps R1 R2 100kbps N2 1Mbps N4 From “Network Congestion Control: managing internet traffic” Michael Welzl
Example of Problem definitions • Example 1. (approach of centralized end-to-end) • Informally: In the given network condition, how can we set the sender traffic rateto provide maximum overall throughput? Problem definition Nice function Input variables Best results
Example of Problem definitions • Example 2. (approach of distributed end-to-end such as TCP) • Informally: In the given flow condition of mine, how can we set my sender traffic rate to provide maximum my maximum throughput? • Example 3. (approach of centralized hop-by-hop) : scheduling category • Informally: In the given network condition, which link should be activated to provide best absolute fairness? • Example 4. (Bandwidth Monitoring case) • Informally: In the given monitorable parameters, how can we approximate the bandwidth as best fit to real bandwidth?
R6 Problem definition R4 R1 Which Link should be activated first? Topology, Source/Dest pair Queue Length Best absolute fairness R5 R3 R2 R7 DiffQ • Original Problem Definition
DiffQ • Original Solution (Back-pressure) R6 R4 R1 R5 R3 R2 R7
DiffQ • DiffQ: Approximated Version • In reality, we can not do centralized control, so, use IEEE 802.11e differentiated service • Differentiated CWmin, AFIS • Provide 8 quantized priority • Mapping function from (Monitored Backpressure quantized priority)
Results/Discussion • Contribution? • Actual implementation • Comparison with other many Transport protocols (TCP-SACK, TCP-FeW, TFRC-ECN, ATP, WCP) • Verbal Comparison to Horizon (2008 Mobicom)