Experiment Comparison of PI and RED over Internet

1
Experiment Comparison of PI and RED over
Internet
A joint work with UIUC
By Honggang Zhang
2
Experiment Topology Internet

• A tunnel is setup between UMASS and UIUC
• PI AQM is implemented in Linux router at UMASS

Traffic Sender
Internet
Traffic Receiver
Router (Linux)
100Mbps NIC
10 Mbps NIC bottleneck link AQM controls this NIC
Tunnel Two-way Propagation delay is 40ms
3
Experiment Topology Local TestBed

• A Dummynet in FreeBSD is used to emulate WAN
• PI AQM is implemented in Linux router at UMASS

Traffic Sender
Traffic Receiver
Router (Linux)
100Mbps NIC
10 Mbps NIC bottleneck link AQM controls this NIC
Dummynet To emulate WAN, add in 40ms two-way
propagation delay
4
Internet Experiment Results
Note Results from experiments on local testbed
are similar, so, they are not presented here.
5
Experiment Settings and AQM Parameters

• Network Settings
• Four Load level
• 20, 40, 60, 80 flows
• Bottleneck Link BW10Mbps
• Buffer Size 50kB
• TCP packet size 536 Bytes
• Traffic generator iperf
• Each experiment consists of
• RED tested at each load level
• PI tested at each load level
• Each experiment lasts two minutes
• All flows uniformly start within the first
  minute statistics are computed for the second
  minute.
• Each experiment repeated five times
• The following plots computed from the average of
  five runs of each experiment

• RED parameters
• th_min4kB
• th_max12kB
• max_p0.02
• ECN marking

• PI parameters
• target queue length 8kB
• a0.001136
• b0.001086
• ECN marking

6
Data averaged over five experiment runs PI target
queue length 8kbytes RED min_th 4kbytes,
max_th 12kbytes
7
Data averaged over five experiment runs
8
Data averaged over five experiment runs
9
Data averaged over five experiment runs
10
Plots from a single experiment (the number of
flows is 80)
11
Comparison of Instantaneous Queue Length
Statistics is from a single experiment run where
the number of flows is 80 PI target queue length
8kbytes RED min_th 4kbytes, max_th
12kbytes Buffer size 50kbytes Data sampled
every 10ms
12
The End