Rambling About Network Simulators

Good Questions about Network Simulation.. and Trace File

2011-01-23T09:01:00.000-08:00

This is a comment from my old blog, which I seldom update now.. its a good question.. I dont answer the question though... :(

1.How to find out the number of nodes in the network from the trace file? Also can u give any examples that would help please??

2.How to discover the “visible network topology” from the trace file? Give examples pleeeeeeeease.

3.Which parameters of the event descriptor in the trace file can be used for calculation of the throughput on the link? examples would really help

4. Which parameters of the event descriptor in the trace file can be used for calculation of the throughput on the end-to-end route? any examples??.

5.What typical functions are needed in order to extract useful data from trace files (think in terms of getting values from some text columns, sorting of strings, etc.)? Can u please make a pseudo-code for the postprocessing algorithm. Aslo do u know Which standard Unix utilities may help to extract necessary data from the trace files and process them? Give examples of sequences pleaseeeeeeeee (i.e. which to run first, which is next, etc.).

Good questions.. but what are the answers.....

Dual Boot Ubuntu Crash - My Experience

2011-01-08T21:03:00.000-08:00

I use Ubuntu together with windows. However last 2 weeks, I have problem where my ubuntu crash. This is the chronology of what happened to my ubuntu installation until it has been successfully reinstalled yesterday.

First of all. I am installed ubuntu using Wubi installer. The first installation is through Wubi, I'm using Windows 7 Home Premium and ASUS laptop. Everything goes very good at first, installed NS2, TCL, TK easily.

First phase of the try and error.

Updated my ubuntu, and somehow the ubuntu crash maybe power off during the update or maybe because of the compability problem with my hardware.
Tried to reinstall ubuntu via wubi. Wubi will detect whether the ubuntu already installed, and will try to remove current installation.
At first 2,3 try, wubi are able to remove ubuntu but unable to finish ubuntu installation where the installation hang at update-grub.
Frustrating with wubi, I used USB drive to reinstall ubuntu. However the process hang at early stage of installation.
Tried to reinstall ubuntu again using Wubi. However wubi unable to remove current ubuntu installation due to missing file. I suspect it is because Kaspersky antivirus deleted the file.

I was stuck at this installation. At this time, there are no choice but to format the partition. When I checked my partition in Windows Computer Manager. It seems that there are 3 unknown partition which represent ubuntu partition. The partition are messed up already, maybe due to the repeated re-installation tryout. So it left me with two options: (1) to format the partition and reinstall ubuntu at the partition. (2) start over with windows recovery followed by ubuntu installation. The second option is my choice. Why? because I feel everything is messed up = ( .

2nd Phase of Try and Error.

This is the sequence for my solution.

Backup Data
Recover window - During boot, in grub screen - choose another windows loader (Yes you have two windows loader - one for windows 7 the other one for recovery, in my case it is Windows ME (Loader) ] . Or you can use recovery CD.
Once the windows is reinstalled, I had a problem to enter windows, due to GRUB problem. Grub is the bootloader, however grub was working due to windows re-installation.
Its okay! Reinstall ubuntu using USB. It automatically reinstall GRUB. Now I have my windows and Ubuntu back.

This is my solution, with help of few friends! Thanks to them. However the solution maybe not very good for you. You can try to just format the partition for ubuntu installation, it will affect grub. Some of my friends recommends to use other bootloader to replace grub. I personally never try it out yet.

IMHO, having ubuntu in windows is not a good option. Ubuntu and windows is better to be in separate partition.

Happy New Year 2011 from RANS

2011-01-04T11:25:00.000-08:00

Its already 5 Jan 2010.

I would like to wish you a happy new year 2011. I hope its not too late. I'm too consumed with solving the Ubuntu Installation. I wish that, all your work especially the one related to network simulations will be a successful one.

BTW, this Rambling About Network Simulators Blog now have it short form (RaNS)

Happy new year and all the best!

Ubuntu Installation hang at Update-Grub

2011-01-02T18:46:00.000-08:00

This is a bad news for me. I dont actually know what happened.

My ubuntu is not functioning well after an update. What happened? I suspect because of the newest update does not support my ASUS laptop hardware.

So I reinstall my ubuntu. Unfortunately, this time the installation hang at update-grub. Still searching for the solution. I'll update here when the installation are successful.

Installing NS2 and NAM, Lyx, and other application are quite easy with ubuntu.So i guess I need to find the solution asap.

Run NS2 Example in Ubuntu 10.10 easier

2010-12-29T03:47:00.000-08:00

One of the problem in installing NS-2 in ubuntu is that it will be installed in other folder automatically.

Problem

There are two problem occured with this kind of installation.

The path are too long. In my case the path for the ns2 examples are located at : usr/share/doc/ns2/examples/. It means that we need to do more clicking to reach that folder. Or if we are going to run through console, we need to cd to longer sentence.
The simulation script cannot be executed due to read/write and access properties of the installed folder. You need to logged in in administrator mode to access the file.

Solution

Luckily the solution is quite simple. Killing two birds with one stone. What I did is really simple, I copied the examples folder and paste it at the Desktop. It solved both problem! :)

Easy NS2 Installation in Ubuntu

2010-12-28T15:01:00.000-08:00

NS2 installation is quite a troublesome process before. There are a lot of step to be done, and a few errors encountered during installation process were quite frustrating. After installation you need to edit bash profile.

Say goodbye to this hassle process. Thanks to ubuntu! :)

In the last blog post, I show how easy to install NAM in ubuntu. Eventually you can do the same to install NS2. No more needless hassle :)

You can search NS2 from ubuntu software centre. and click install!

do not forget to install the documentation and examples too.

After that please test whether the ns interpreter is working or not by running ns interpreter in the terminal.

NS2 Installing Network Animator From Ubuntu

2010-12-27T07:16:00.000-08:00

Now it is really easy to install NAM - network animator in Ubuntu.

I accidentally found the nam while installing Tcl distribution.

If you want to install nam in ubuntu.

1. Open the ubuntu software centre and search for nam.

2. Just click the install button.

3. Test whether the installation is successful or not by typing nam at the linux terminal.

Easy.Good Luck!

Installing NS2 in Ubuntu?

2010-11-23T15:38:00.000-08:00

I want to install NS2 in Ubuntu. Just Installed ubuntu in my new lappy. I use ubuntu 10.10. Telling the truth I hate installing NS2. But let see. Will be sharing any info on installing NS2 in Ubuntu.

TraceGraph Download Link - Tracegraph.com no more ?

2010-09-16T02:39:00.000-07:00

Some people emailing me about the download page of the famous TraceGraph. Telling the truth I am also dont know what is the download link for trace graph.

It used to be in tracegraph.com , however it look like the domain name tracegraph.com is not renewed. However there are one page of the similar content available but unfortunately the download link in the page is pointed to tracegraph.com. By the way this is the link:

https: / / www.iterasi. net/ public/ archive/ Vv3uXZDReUCu7dRi KilcjA

If you are looking for tracegraph download, I believe the best way is to contact the person who create the software. But I am not sure whether the information is up to date or not since it is stored in ..../archive/

Go to Mailing List if you have question..

2010-09-09T08:03:00.000-07:00

Sorry this is straight forward!

I sometimes eceived a lot of email asking how to use NS2, I believe other bloggers who have topic on ns2 in their blog experience the same.

When you have some problem with the code or anything regarding your simulation please go to respective mailing list, and read the tutorials, thats how you work with open source especially ns2.

Coming to other peoples blog, never give input or exchange information in provided comment section, but merely ask to debug your code or to solve your problem, is just rude! Plain RUDE. Some of the problem are already asked in respective mailing list.

It will be worst if the questions are regarding your assignment that your lecturer gave you!

Network SImulator with large user base

2010-09-07T13:04:00.001-07:00

For me to choose a network simulator, one of the factor is to use a network simulator that used by a lot of user. Here why :

1. More popular the network simulators. Me myself would prefer a network simulator with a lot of user using it compared to simulator with only one user using it.

2. Build confidence in the result . The more user using it, the more validation work can be done. Validation work build confidence in network simulators.

3. Easy support. By joining their mailing list we can easily get support from the user. There are a lot of people discussing about the network simulators.

User Interface in Network Simulator

2010-09-07T01:22:00.000-07:00

User interface in network simulator can be divided into two:

Graphical User Interface
Language based Interface

Example of network simulator utilising GUI are OPNET and OMNET++

Example language based interface are NS2 and NS3

Graphical user interface is easy to be used if it is well designed, however building GUI is not an easy tasks.

Language Interface is not easy for beginner, but it is very flexible.

Giving the language and user interface , which are my choice? I rather choose for both. I want to have flexibility and I want to have an easy to use simulator. But which simulator support both?

NS2 is lack of support tools

2010-09-07T01:17:00.000-07:00

NS2, is lack of support tool! This is my commnet about NS2. Yeah. It is popular, but without support tool it wont be easy for beginners to learn NS2.

To use NS2, we need to create a simulation script - which is in Tcl which is not taught in universities syllabus.

To run ns2, we need to run the ns interpreter, through console.

To analyze ns2 result, we need to create our own program or use third party tools developed by others.

NAM Graphical Editor for NS2

2009-12-15T08:52:00.000-08:00

Heard NAM? If you are familiar with ns2, you should know what is NAM. NAM stands for Network AniMator. The purpose is for animation at packet level.

But do you realize that NAM has another function which can be used to draw network topology, and create simulation script from it?

I tested it out but it seems that there are segmentation faults when dragging the components.

NS-3 Tutorial ?

2009-10-06T23:36:00.000-07:00

I have been looking for NS-3 tutorials on the net. After some searching I found out these two tutorial are quite good.

If you have any suggestion for other tutorial feel free to drop the link in comment sections.

OPNET Modeler Popular Comercial Network Simulator

2009-05-29T01:37:00.001-07:00

OPNET Modeler is one of famous simulation tools provided by OPNET Technologies.
OPNET is a commercial software unlike Network Simulator 2 (NS-2) & Network Simulator 3 (NS-3)

As far as I know, NS2 is based on descrete event-driven model , while OPNET engine is based on Finite State Machine combined with analytical model.

I have no particular experience about OPNET, but I'm searching for papers comparing NS-2 with OPNET. Sure both has their own disadvantages and advantages. And what about NS-3?

Hrm by the way, I need to find info about
1) Descrete event-driven model
2) Analytical Model
3) Finite State Machine Model

what does it really means?

Network simulation and network simulator area are very wide area. It is normal since network system (eg. Internet) is the biggest system ever created by human.

back to OPNET, , OPNET have more features than NS-2 but NS-2 is moreattractive due to its open source nature.

NSBM - Network Simulation By Mouse

2009-05-26T20:07:00.000-07:00

NSBM is another effort to ease NS2 usage.

" NSBM ("Network Simulation By Mouse") is a GUI that allows you to graphically develop simulation scenarios and then generate a tcl script. It requires java (1.4 recommended, it doesn't properly work with 1.5; here's a BETA version that should work with Java 1.5). The source code is also available - feel free to change it!"

I read the paper regarding NSBM. It is a very good effort actually to have this kind of GUI to help user develops network simulations. The GUI get good feedback from the target audience (Student). If you are new to NS2 I suggest that you use NSBM.

JNS JAVA Network SImulator

2009-05-26T05:42:00.000-07:00

NS2 is claimed to be difficult to use. So thats why JNS is developed.

What is JNS?

This is the detail given by the oficail website of JNS.

http://jns.sourceforge.net/

"The Java Network Simulator is a Java implementation of the ns-2 simulator originally from Berkeley. It is by no means as complete as ns-2, but it is a lot more accessible to programmers not familiar with Object Tcl.

JNS allows developers of networking protocols to simulate their protocols in a controlled environment. The simulator then produces a trace file (same format as NAM trace files) which can be viewed in a network animator such as Javis. Below is a screen shot of a simulation run from JNS being animated in Javis."

I personally never used JNS since I have no problem with NS2. Is it really good?
Can the JNS catch up with NS-2 development?

RFC for Perfromance Metrices

2009-05-21T21:14:00.000-07:00

Reference in networking area is Standard and RFC.

This is the RFC for some performance metrices:

RFC 2679 : One-way delay metrices

RFC 2680 : One-Way packet Loss Metrices

RFC 2678 : IPPM Metrtices for Measuring Connectivity

RFC 2330 : Framework for IPPM

RFC 2681 : Round Trip Delay Metric for IPPM

RFC 3393 : Packet Delay Variation Metric for IP Performance Metrics

Performance Parameter

2009-05-21T20:22:00.000-07:00

When we conduct a simulation study , what we really want is the network performance of certain network.

There are four main basic parameter for network analysis

1) Delay
Measurement of how long the packet will travel from source to destinations

2) Jitter
Measurement of variations of delay

3) Packet Loss
Measurement how many packet dropped

4) Throughput
How many packets successfully sent to the

The network performance parameter can be measured at:

1) from end to end
2) between two nodes

The network performance can also be differentiated between traffic type or for all traffic.

NS-3 to replace NS-2?

2009-05-19T17:05:00.000-07:00

Have you tried out NS-3?

This is what I got from http://www.nsnam.org/ official website of NS-3.

"ns-3 is intended as an eventual replacement for the popular ns-2 simulator. The project acronym “nsnam” derives historically from the concatenation of ns (network simulator) and nam (network animator). "

From user point of view, I noticed the main difference between NS-3 and NS-2 is the changes in language. Now NS-3 is using C++ and phyton, compared to NS-2 which used C and oTCL.

This means that for those who learn TCL for the sake of using NS-2 now need to learn other language for using NS-3.

Start from zero!

NAM Editor , have you ever try it out?

2009-05-18T00:04:00.000-07:00

Another tools to support NS2 is NAM EDITOR, do you NAM Editor? I have experience trying it, it is a good tool where you can draw network graphically then convert it to NS2 simulation script. However, I have prolme when dragging the network component.

It suddenly give segmentation fault error. What is the reason? I don't know but from my reading it is because something wrong with the C coding.. but the NAM Editor is based on TCL\TK. Hrm.. A question mark there!

Tracegraph

2009-05-17T22:03:00.000-07:00

Since there are no available trace analysis tool developed in NS2, people are building their own program. A good software was designed called tracegraph, although tracegraph is good for analysis purpose, the main problem with tracegraph is it is very slow to load a trace file.

The fact that it is created using MATLAB make it clear, since, MATLAB is not suitable to read a complex data although MATLAB is good for complex calculation. Why is it slow? It is because, the trace file need to be converted into Tracegraph format, the conversion part take 90% of the whole process.

For those using Tracegraph, make sure your computer is fast enough. However, the graphing part/ processing part is quite fast.

NS2 has a very large user base

2009-05-13T01:38:00.000-07:00

Although network simulator NS2 is quite hard to use, the fact that NS2 is free to use, an open source and can be extended and added with new protocol makes a lot of people using it.

Having a large supporters is considered as a big advantage. The supporters of course will create new support tool to help using NS2.

The support tool can be in form of written materials , forums, blogs, tutorials and software.

A lot researcher develop their own tools and program to help using NS2.

NS2 lacks of support tools makes it harder

2009-05-11T21:34:00.001-07:00

NS2 - Network Simulator 2 is a very popular network simulator, but the fact that it is lack of support tool make it hard to learn. However some effort has been taken by ns2 users to improve experience in using NS2. The basic usage is by typing the simulation script, running ns interpreter, get result in form of trace file and anaylse the trace file using your familiar programming language.

The effort can be divided into three categories:

1. Development of written material
The written material available are the:
a) Ns2 manual - Complete Manual but very thick and not easy, no that suitable for beginners
b) Tutorial - There are a lot of tutorial available to be downloaded from the net. The amount of the tutorial available shows that the NS2 is not that easy to use and the manual is not that helpful.
c) Blogs - there are a lot blog sharing information about ns2 installation and how to use ns2.

2. Forum - mailing list
2) Ns2 has its own forum with very large user base, if anyone have problem with NS2 please go to the mailing list and search for answer before asking people around.

3. Development of tools
A lot of tools has been developed by individuals or group.
The tool can be divided into three part:
1) To create simulation script
2) To create topology of a lot of networks
3) To show the output such as animation and result

Using the tool will help a lot to kick start with NS2.

Network Simulator in Education(2)

2009-05-09T01:29:00.000-07:00

Simulation can be used to ease learning protocol.

1) In order to ease the learning of protocols, the utilization of illustrative examples is strongly recommended.

2) As these days the access to computers is widely available, the simulators become an appropriate learning tool in this area.

3) Selection of simulation tools is essential.

Network Simulator in Education (1)

2009-05-09T01:04:00.000-07:00

Simulator is good to be used in:
a) computer–based training,
b) virtual laboratories.
c) Problem based learning

Simulators can be effectively used as teaching aids by enhancing the quality of learning by students if these simulator tools have good quality and easy to use.

Simulators plus visualization will add more impact to the learning curve.
Visualisation can be in term of:

a) process visualization
b) model animation
c) result visualization

The visualization should reflect how a certain simulated systems work.

Educational advantages are gained due to
a) experiments in virtual networking laboratory, rather than on the actual wide-area network,
b) visualization of the protocol behavior under different conditions,
c) adjusting protocol configuration (configurable options), timers, functions.

reference: Computer Modeling and Simulation in Higher Education
Alexander Yu. Glebovsky, Vladimir M. Ivanov, Yuri G. Karpov

Why Simulation Works?

2009-05-09T00:56:00.000-07:00

Simulation works because the problem solver abstract the realities into model.
Problem Solvers is a logical persons, and work based on reality not fantasies.
The modeling is based on mathematics and logic.
The model is tested and compared to reality.
The simulation results is consistent not as in reality. Consistency is important.

Me & Network Simulator : Intro

2009-05-04T13:09:00.000-07:00

Just an introduction,

My first time introduced to network simulation area is in 2003. I has been using Network simulator 2. Network simulation area really interesting. Although it is very interesting, me my self does not have a lot of time to play with network simulators.

Jump into this new area, without knowing nothing is quite challenging. I am a person who don't believe in Simulation at first, I believe more on implementation and hardware. But when I enters this area, I know, simulation is a very attractive field.

I will be writing about network simulation here.

If you are an expert in simulation, maybe this blog is not for you, but I really appreciate of you being here. I am a beginner in network simulation. Anyway. I want to know more on network simulation.

I'll write my note here.

Welcome to My Blog

2009-04-22T21:07:00.000-07:00

Welcome to this blog where I put my note about network simulator.