In network lots of open source network simulators are available from that ns-3 is one of the efficient and moderate open source network simulator.
In ns3 waf play vital role.
- Waf is a general purpose build system in ns-3.
- This is used for configure, compile and install purposes.
- It’s based upon the python languages.
- Instead of using ./configure; make type ./waf in ns3.
- waf not only builds ns–3 , it can be used to run example programs.
Uses of helpers in Ns3:
- it’s used to allows for quick scenario/topology construction.
- entities are not directly manipulated by the user one by one.
- overlay API which allows manipulating these in groups.
Functionalities of Tracing in ns3:
- lowest level functionalities are:
- a queue drops a packet.
- NetDevice receives a frame.
- TCP congestion window changes.
- Random sending application sends a packet etc.
- This allows simulation writers access to exactly the interesting simulation info.
- Use primary methods of data collection for analysis.
- Use “hook” to generate PCAP output, collect statistics and results etc.
- Uses a namespace resembling operating system paths to connect a callback to an event