Network Emulator

Network Emulator emulates tracking of packets over TCP/IP stack. The emulator emulates network conditions using NetFilter, a packet filtering framework.

As following the main features :

• The emulator application runs on a dedicated machine, which is connected to the network.

• Capturing the IP traffic using IPTables, and enforce the rules as defined by destinied XML file.

• Supporting on following conditions (the policy) :

  Parameter	Description	Valid range/type	Default Value
  Packet Loss	The amount of packets discarded	Rational Num (%)	0
  Packet ordering	How are the packet released out ?A proportion of the packets which change their place on the queue	Rational Num (%)	0
  Delay on Queue	The time the packet wait on the Queue before it’s released	Rational Num	0
  Throughput	The data that pass per second	Num (Bits/sec)	Infinite

Configuration File

The file defines the Link Properties (5-tuple) and its Metrics for each rule.

The emulator supports only XML file as following :

• First line defines XML Specifications.

• Each file defines single policy, which is unique by numeric Identifier (ID attribute).

• Policy configuration may includes several rules. Means, Policy element may includes several Rule elements.

• LinkProperties and Metrics elements validates as follows :

  • Order doesn’t matter attributes and subelements inside
  • Flow attribute is unique by numeric Identifier.
  • Port attribute is assigned by integer number.
  • Metrics attributes is assigned by numeric values.
  • IPAdress is combined by 4 Integer numbers separated by dot.
  • Chain attribute is assigned either INPUT, OUTPUT or FORWARD.

<?xml version="1.0" encoding="UTF-8"?>
<Policy ID=”1”>
    <Rule>
        <LinkProperties Protocol="tcp" Chain="INPUT" Flow="2">
            <Source Port="" IPAddress=""/>
            <Destination Port="8999" IPAddress="127.0.0.1"/>
        </LinkProperties>
            <Metrics Delay="34.5" Reordering="25"
	            PacketLoss="50" Throughput="1.5"/>
    </Rule>
</Policy>

Installation

Although NetFilter is embedded inside the linux kernel, development versions of packages IPTable and libnetfilter_queue are necessary. Therefore, ensure their installation.

• sudo apt-get install iptables-dev
• sudo apt-get install libnetfilter-queue-dev

These libraries handle the incoming packets.

Additional necessary library is Poco, which builds the lifecycle of Emulator.

Visit in the website to download and install of Poco.

Running

The emulator runs under root privileges (sudo su)

Firstly, inform the dynamic link loader on Poco library. Use one of these options of LD_LIBRARY_PATH :

• sudo export LD_LIBRARY_PATH=":$LD_LIBRARY_PATH"
• sudo env LD_LIBRARY_PATH=":$LD_LIBRARY_PATH"

Finally, run the provided executable file (under bin directory) with a full path of configuration file. The enclosed file described the hendeled rules and is formatted by XML.

make POCO_LIBRARY=<full path of POCO library>
LD_LIBRARY_PATH=/usr/local/lib:<full path of POCO library>/lib/Linux/x86_64
export LD_LIBRARY_PATH
./bin/sim <full path of configuration file>