Slide 1

Performance Evaluation on Buddy-TCP By Felix

Slide 2

Simulation Setup S C1C1 CNCN T_Sink1 T_SinkN T1T1 TNTN U U_Sink 4N Mbps 50 ms L Types of traffic: S -> C i {1..N} : Joint-TCP flows T i {1..N} ->T_Sink i {1..N} : Ordinary TCP Reno flows U -> U_Sink : Background Poison UDP traffic at the rate of 40x2xN kbps Others: TCP MSS: 1460bytes TCP advertised window: 64Kbytes UDP Pkt Size: 500 bytes Queuing Decipline: DropTail N : # of Joint-TCP flows Links: All links except link L have bandwidth of 100Mbps and propagation delay of 10ms 0.98) regardless of the number of Joint-TCP streams and the allocation ratio The performance difference when RED is adopted is negligible.">

Allocation Accuracy (Cont) Summary: The allocation accuracy of MulTCP (with or without SACK) degrades when the allocation ratio increases (e.g. from 1:2:3 to 1:4:8). Buddy-TCP maintains high allocation accuracy (>0.98) regardless of the number of Joint-TCP streams and the allocation ratio The performance difference when RED is adopted is negligible.

Slide 8

Impact Ratio Impact Ratio for Droptail

Slide 9

Impact Ratio (Cont) Impact Ratio for RED

Slide 10

Impact Ratio (Cont) Summary: MulTCP (with and without SACK) causes an decrease in the average throughput of the competing ordinary TCP traffic. The decrease can be upto 70% when SACK is used. Buddy-TCP causes an increase (10 20%) in the average throughput of the competing ordinary TCP traffic. RED has negligible effect on the Impact Ratio

Slide 11

Effect of Random Packet Loss S C1C1 CNCN T_Sink1 T_SinkN T1T1 TNTN U U_Sink 4N Mbps 50 ms L -Random packet loss is introduced in the bottleneck link L -N = 3

Slide 12

Effect of Random Packet Loss (Cont) Allocation Accuracy for the allocation ratio (1:2:3)

Slide 13

Effect of Random Packet Loss (Cont) Allocation Accuracy for the allocation ratio (1:4:8)

Slide 14

Effect of Random Packet Loss (Cont) Impact Ratio for different loss probability

Slide 15

Effect of Random Packet Loss (Cont) Summary When random packet loss probability is increased at the bottleneck link, the allocation accuracy will be increased, and the impact ratio will approach to 1. The effect is more apparent for MulTCP (with and without SACK) Reason: When random packet loss probability increase to certain level, the total throughput is NOT limited by the bottleneck bandwidth anymore. Probability of TCP Timeout due to burst of packet losses at the bottleneck node is reduced.

Slide 16

Whats Next? Convergence of bandwidth allocation Vs RTT Application on adaptive video streaming (some preliminary results)