Presentation by Mr. Vibin Chander, CEO, Shabari Software Solutions, CBE during the Faculty development Programm on NS2 organized by Department of Computer Science, Rathinam College of Arts and Computer Science (Autonomous), Eachanari, Coimbatore - 641021.
3. Overview
What is NS2?
- Event driven network simulator
- Developed at UC Berkely
- Implements network protocols
1) TCP, UDP
2) Traffic source mechanism: FTP, TELNET, Web, CBR and VBR
3) Router Queue management mechanism: Drop Tail, RED, CBQ
4) Routing Algorithm: Dijkstra, and etc…
5) Multicasting, Mac layer protocols for LAN
4. Overview
Background on the ns Simulator
- based on two languages( an object-oriented
simulator (C++), and OTcl (object-oriented Tcl)
interpreter.
- has rich library of network and protocol object
- Compiled C++ hierarchy gives efficiency in
simulation and faster execution times.
- With OTcl script provided by user, a network
topology is simulated.
5. Overview
Ns2 is event simulator where the advance of
time depends on the timing of events which are
maintained by a scheduler.
Event – an object in C++ hierarchy.
unique ID, Scheduled time,
pointer to an object
Scheduler – maintains ordered data structure
with the events to be executed and fires them
one by one, invoking the handler of the event.
6. How to Install
-Window XP-
Go to Website:
http://nsnam.isi.edu/nsnam/index.php/Running_Ns_and_Nam_Under_Windows_9x/2000/XP_Using_Cygwin
Read “Requirements and Installation Tips”
Carefully.
Download cygwin.exe from http://www.cygwin.com/
Click the “cygwin.exe”
9. How to Install
Select browse for “cygwin” file( I selected as “default”)
10. How to Install
Local package directory (I recommend c:cygwin).
11. How to Install
Select to Install all ( I recommend it)
You can select “install”, “default”, “uninstall”, “install”, and “reinstall” behind the first
line “all”. If you select “install”, then all sub items will be automatically selected.
Otherwise you may lose some items.
15. How to Install
NS2 Installation
Download ns-allinone-2.29.2.tar.gz from
Website and Save it to the c:/cygwin
/usr/local
Unpack it: tar xvfz ns-allinone-
2.29.2.tar.gz
Click on desktop icon “cygwin”
29. How to Install
Add the following path separated with “;”
make sure to not change the existing path.
/usr/local/ns-allinone-2.29.2/bin
/usr/local/ns-allinone-2.29.2/tcl8.4.11/unix
/usr/local/ns-allinone-2.29.2/tk8.4.11/unix
30. How to Install
Go to cygwin and type the following
content
Export LD_LIBRARY_PATH=/usr/local/ns-
allinone-2.29/otcl-1.11
Export LD_LIBRARY_PATH=/usr/local/ns-
allinone-2.29/lib
Export TCL_LIBRARY_PATH=/usr/local/ns-
allinone-2.29/tcl8.4.11/library
32. OTcl – The User Language
NS2 is basically an OTcl interpreter with network
simulation object libraries
Very simple syntax and easy integration with
other languages.
Characteristics:
- fast development
- provide graphic interface
- compatible with many platforms
- flexible for integration
- easy to use
- free
34. OTcl – The User Language
Proc: define a procedure, followed by an
procedure name and arguments
Set: assign a value to a variable
[expr …]: to make the interpreter calculate
the value of expression within the bracket
To assign to variable x the value that
variable a has, then write “set x $a”.
Put: prints out
36. Event Scheduler
Main users of an event scheduler are network components that
simulate packet-handling delay or that need time
37. Event Scheduler
Two different types of event schedulers
- real time: for emulation which allow the
simulator to interact with a real network
- non-real time: three implementations are
available (Heap, List, Calendar). The
default is set as Calendar
39. Packet
NS2 packet is composed of a stack of
headers and optional dataspace.
Packet format is initialized when a
Simulator object is created. So, a network
object can access any header in the stack
of a packet it processes using
corresponding offset value.
43. Simple Simulation Implement
Click on desktop icon “cygwin”
Make sure to put the exe files under
C:cygwinusrlocal
Do the following steps to execute
example.
45. Simple Simulation Implement
However you will fail to run the “ns-simple.tcl” with the displayed
notice. This is because you did not open “XWin” yet
46. Simple Simulation Implement
Open “Xwin” from “C:cygwinusrX11R6bin”. If everything is fine,
you will then get the following figures.
48. Simple Simulation Implement
That means some components missed. You can then copy these
files from “C:cygwinbin” to “C:cygwinusrX11R6bin”
After you open X11, you may still can not run “ns-simple.tcl”