SOURCEFORGE » RALF » 2015 Improving TCP over satellite QoE

h3. 2. Simulation program

h4. 2.1. Simulation

Insertion des lignes de commandes SANS MODEM sur PEP right:

#!/bin/bash

~~~{.bash}

 Remote Terminal: ssh connexion

ssh labo@192.168.0.200

 Super User Connexion 

sudo su

~~~

# Definition of p5p1 IP adress

ifconfig p5p1 192.168.2.2

# Definition of p6p1 IP adress

ifconfig p5p1 192.168.3.1

# Add space delay to user interface

tc qdisc add dev p5p1 root netem delay 600ms

# Test connection and delay

# from 192.168.2.1 to 192.168.3.1

ping 192.168.3.1 -I 192.168.2.1

# Re-routing rule to in order to use PEPSal

iptables -t mangle -A PREROUTING -s 192.168.2.1 --proto tcp --tcp-flags ALL SYN -j QUEUE

iptables -t nat -A PREROUTING -s 192.168.2.1 --proto tcp -j REDIRECT --to-port 5000

iptables -t mangle -A PREROUTING -d 192.168.3.1 --proto tcp --tcp-flags ALL SYN -j QUEUE

iptables -t nat -A PREROUTING -d 192.168.3.1 --proto tcp -j REDIRECT --to-port 5000

# Display all rules

iptables -t mangle -t nat -L

# Proxy PEPSal

# pepsal -a 192.168.2.1

Then a TCP flow is simulated thanks to the iperf command.

h4. 2.2. Post processing

In order to get information on TCP packets, the tcpdump commmand is executed. The save option is run and data are collected in a file.pcap.

Command is:

tcpdump tcp -w fileName.pcap

# Files transfert from PC engine right to local computer

scp labo@192.168.0.201:Proj3/*. 

The file generated by tcpdump command is compatibile with wireshark. Wireshark is a free network protocol analyzer. It lets you see what's happening on your network at a microscopic level. Thanks to this tool, we could compare with and without PEPSal:

* throughput,

* sequence number packets,

* windows size evolution.

Tests in terms of quality of usage, such as download a web browser, were planed. However due to difficulties in network configuration, those tests will not be run.