Experiments on Nov23.

Test Script file for the test

Network infrastructure diagram, 

Packet Flow:  Madrid:eth1==>Dublin:eth2==>Dublin:eth1==>Prague:eth2

Packet dropper is running on the Static Router (Dublin).

Packet Dropper Module code    Makefile

Module to change the dropping rate and destination address via manipulating the /proc file system:  change_kernel code,   user-space code Makefile

To use module "change", use "make install" after installing "packet_dropper" module,
then use user space program "input   rate   ip_address" it will change the rate and destination address in packet_dropper module dynamically.

To check the rate and destination ip address, use "cat /proc/linTry/foo", you will get information like:

Dropping Rate shows only the first 6 digits after '.'
Dropping Rate is: 0.000499
Destination IP is: 192.168.2.2
 

 

TCP connection. Request Size is optimal size 1448Bytes.

Kernel file modified:  /usr/src/linux/net/core/dev.c        /usr/src/linux/net/netsyms.c

The packet_dropper code has been changed to drop packets randomly. The random number is selected according to the CPU clock. Some bit operations are done after selecting the CPU cycle.

NOTE:  It's almost impossible to find an algorithm that drops the packet RANDOMLY at the EXACT rate we specified. The actual rate of packets being dropped may be a little bit different from the rate we specify in the packet_dropper.

See the UDP packet loss experiments

drop0 drop0.0001 drop0.0005 drop0.001 drop0.002 drop0.004 drop0.006 drop0.008 drop0.01 drop0.02 drop0.03 drop0.04 drop0.05 drop0.06 drop0.07 drop0.08 drop0.09 drop0.1 drop0.11 drop0.12 drop0.13 drop0.14

(The above files are stored in 132.177.67.158 because I ran out disk space on pubpages.unh.edu)

 

Time Elapse( sec ) (Randomly dropping packets)
DropRate 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th AVG Var Throughput (Bytes/Sec)
0.0000 12.32 12.31 12.31 12.31 12.31 12.31 12.31 12.31 12.31 12.31 12.31 0.00 12395418.73
0.0001 12.33 12.32 12.32 12.32 12.32 12.32 12.32 12.32 12.32 12.31 12.32 0.00 12386363.64
0.0005 12.34 12.33 12.32 12.33 12.33 12.33 12.33 12.33 12.33 12.33 12.33 0.00 12376317.92
0.0010 12.36 12.35 12.35 12.35 12.34 12.35 12.35 12.34 12.35 12.34 12.35 0.00 12358276.64
0.0020 12.38 12.37 12.76 12.38 12.37 12.57 12.56 12.56 12.37 12.37 12.47 0.11 12238351.11
0.0040 13.19 12.98 12.60 12.60 12.80 12.79 12.60 13.17 13.18 12.79 12.87 0.21 11857031.86
0.0060 12.82 12.42 13.00 13.38 12.81 12.81 13.39 13.20 13.38 13.00 13.02 0.25 11719529.99
0.0080 14.21 13.22 14.18 13.03 14.29 13.22 13.60 13.41 13.79 13.42 13.64 0.38 11190144.46
0.0100 14.40 14.60 14.79 15.39 13.64 13.62 14.44 15.58 14.89 14.77 14.61 0.47 10443471.12
0.0200 23.18 23.26 20.27 21.83 18.21 19.73 22.54 18.77 19.50 18.99 20.63 1.66 7397711.85
0.0300 30.14 29.67 30.83 29.00 30.16 32.27 38.19 31.65 27.80 28.94 30.87 1.90 4944111.45
0.0400 45.17 39.52 50.48 42.35 42.62 47.54 46.42 44.65 45.90 50.44 45.51 2.65 3353182.89
0.0500 68.78 65.78 70.92 62.93 59.25 65.20 68.24 72.56 72.21 57.98 66.39 4.16 2298712.06
0.0600 81.74 96.67 107.26 83.44 95.42 92.58 93.66 95.56 96.27 88.57 93.12 5.23 1638798.50
0.0700 115.56 119.23 117.34 122.33 117.69 125.01 136.47 134.89 110.31 125.99 122.48 6.49 1245897.36
0.0800 152.77 159.41 152.10 151.19 150.76 172.83 161.07 153.58 156.04 154.08 156.38 4.83 975809.39
0.0900 189.42 213.50 191.52 211.65 178.59 192.32 182.10 183.13 213.83 183.22 193.93 11.44 786889.98
0.1000 238.04 246.07 271.07 274.35 234.52 227.36 252.14 233.99 245.32 231.08 245.39 12.41 621857.10
0.1100 285.11 299.36 344.97 274.29 292.41 295.05 308.04 306.71 288.01 303.28 299.72 12.82 509136.77
0.1200 361.30 340.43 368.80 366.94 330.97 322.50 326.55 336.29 353.63 345.89 345.33 13.98 441896.16
0.1300 417.23 437.84 369.94 417.01 371.42 395.34 409.48 420.01 384.71 386.91 400.99 19.33 380559.07
0.1400 435.03 476.66 477.05 500.55 502.79 480.83 481.06 482.92 473.48 469.59 478 11.63 319249.53

PS version  gnuplot script Data file stat23  tcp.txt

The data for the red curve is the experiment data from "regularly dropping packet", See here

The Raw experiment data for green curve are: drop0 drop0.0001 drop0.0005 drop0.001 drop0.002 drop0.004 drop0.006 drop0.008 drop0.01 drop0.02 drop0.03 drop0.04 drop0.05 drop0.06  drop0.07 drop0.08 drop0.09 drop0.1 drop0.11 drop0.12 drop0.13   drop0.14  
 

The detailed curves between 0 and 0.01 is:

PS version  gnuplot script  Data file partTcp   startPart

 

The Linux TCP specification here