NS 3 training huong dan su dung NS3

ns-3 Training
Computer and Communication Network Lab
Department of Electrical Engineering
National Sun Yat-Sen University

5/13/2013


Topics


Getting Started ns-3





A First ns-3 Script




What is ns-3?
Installation

Two tutorial examples

A simple example for this project


Complete the remaining parts

2


Getting Started ns-3
•

Please read the following documents
• ns-3 overview
•
•

•

ns-3 Tutorial
•

•

/> /> />
ns-3 Manual
•

/>

What is ns-3?


ns-3 is a discrete-event network simulator for
Internet systems






ns-3 allows researchers to study Internet protocols
and large-scale systems in a controlled environment
ns-3 is a new simulator (not backwards-compatible
with ns-2)

ns-3 is a free, open source software project
organized around research community
development and maintenance


the target user community is networking researchers
and educators

4


Extensible Software Core


Written in C++ with optional Python interface


extensively documented API (doxygen):



/>5


Node Basics


An ns-3 Node is a husk of a computer to which
applications, stacks, and NICs are added

6


Tracing and Statistics
Tracing is a structured form of simulation output
 Example (from ns-2):




Problem: Tracing needs vary widely



would like to change tracing output without editing the
core
would like to support multiple outputs
7


ns-3 Has A New Tracing Model



ns-3 solution: decouple trace sources from trace
sinks



Benefit: Customizable trace sinks
8


Downloading ns-3


/>

Latest release: ns-3.16 (2012/12/21)

9


Problems under Windows


Cygwin or MinGW



If you do use Cygwin or MinGW and use Logitech
products





it can cause Cygwin or MinGW DLLs to die in mysterious
way

Note that NSC is not supported on OSX or Cygwin.


Network Simulation Cradle
10


Building ns-3 (1/5)


# ./build.py

11


Building ns-3 (2/5)


# ./waf -d optimized configure


ns-3 uses the waf build system

12


Building ns-3 (3/5)


# ./waf -d debug configure

13


Building ns-3 (4/5)


# ./test.py -c core

14


Building ns-3 (5/5)

15


Running a Script


./waf --run hello-simulator

16

Building Your Script
# cp examples/tutorial/first.cc scratch/myfirst.cc
 ./waf


17


Building Your Script


# ./waf --run scratch/myfirst

18


A First ns-3 Script
•

/ns-allinone-3.10/ns-3.10/examples/tutorial
• first.cc
• third.cc


Boilerplate


The first line in the file is an emacs mode line.





The ns-3 simulator is licensed using the GNU
General Public License.


20


Module Includes


The code proper starts with a number of include
statements.




../../build/debug/ns3

21


Ns3 Namespace


The next line in the first.cc script is a namespace
declaration.





Logging


22


Main Functions


The next lines of the script you will find are,



ns3 提供的 log 訊息分成了以下幾個等級：
1.NS_LOG_ERROR — Log error messages;
2.NS_LOG_WARN — Log warning messages;
3.NS_LOG_DEBUG — Log relatively rare, ad-hoc debugging messages;
4.NS_LOG_INFO — Log informational messages about program progress;
5.NS_LOG_FUNCTION — Log a message describing each function called;
6.NS_LOG_LOGIC – Log messages describing logical flow within a function;
7.NS_LOG_ALL — Log everything.
8.NS_LOG_UNCOND – Log the associated message unconditionally.

23

Topology Helpers


Create the ns-3 Node objects that will represent
the computers in the simulation.




We are constructing a point to point link


24


Topology Helpers


We will need to have a list of all of the NetDevice
objects that are created


25