IPv6 Addressing

I reviewed some concepts on IPv6 Addressing so that I can make changes to Mirai-SF network simulator MNDL simulation script. I refer to Computer Networking (A Top Down Approach Featuring the Itnernet) by Keith W Ross & James F Kurose (Author) and the TCP/IP Guide website on IPv6 addressing topic. MIRAI-SF network simulator MNDL script uses real IPv6 addressing and subnetting to create topology of network.

Screenshot of an Animator

A screenshot of a default simulation MNDL script for FMIPv6 using MIRAI-SF network simulator version 3.1. This is similar to NAM for NS which animates the trace file of a simulation. The wired links have higher bandwidth than wireless link. As a reuslt, the mobile device received less packets than being sent by the correspondent node.

Duration of the Traffic Source

I made some changes to the MNDL simulation script. The duration of the traffic source has been increased since I noticed earlier that the receiving node did not receive any packets during the simulation run. In addition, I added a method to drop packet whenever the buffer is full.

MIRAI-SF4.2 is available now

I just visited the MIRAI-SF website and found out that there is a new release of MIRAI-SF4.2 network simulator. You need to register your particulara and it can be downloaded at here.

Configuring Simulation

Yesterday, I spent the whole day configuring the simulation script. In MIRAI=SF network simulator it is called a MNDL script. In every network simulation, it has a topology of network node. Each node consists of communication stack which is similar to OSI layers. ns network simulator uses TCL script to configure the simulation scenario.

Today,I just found out there is a problem with packet classification. I already make some changes and added few conditions that I did not covered last time.

Basic concept

I just found out that my text book for computer networking contains all the basic concept for packet scheduling and all the different type of delay definition. I wish I had refer to this book earlier. Arghhh!

Redo and make changes

The packet scheduler that coded by me is wrong. I have wrong idea of how the packet scheduler works. What I need to now is to refer to some reference to polish my understanding of a packet scheduler and basic network.

update on 08/12/2006:

I only have to change the a scheduler process code which only activate for a duration of time.The scheduler have an array list of which queue need to be serve. Every loop the scheduler will remove packet from a different packet. In short, it term of packet scheduler code not many changes I have to make. My code is not yet complicated. There is still room for improvement. However I still need worry about:-

1) The code for traffic generator that simulates background traffic.
2) I have not start on working congestion control.
3) I need to add some behaviour like dropping packet for the packet scheduler.

Scheduler is like a traffic light on the intersection and array list is a procedural list for the traffic light to signal a green light for each of the intersection in clockwise rotation.

How to monitor each other progress?

Last night, Kimin and I had a mutual agreement to monitor each other progress in our final project. Since the year 2007 is around the corner, we agreed to use the blog as a medium to monitor our project's progress. We hope through this method it will boost our motivation to finish off the project as soon as possible. Let see how the pact (i.e a new word that I learned to today from Kimin) will turn out. Click here to check out Kimin's UHF RFID Tag Antenna Design Blog.

Malam kelmarin, saya dan Kimin telah berjanji untuk memantau kemajuan projek masing-masing agar kami dapat menyelesaikan projek kami hi hujung tahnun ini. Kami telah berpakat untuk mencatat segala kemajuan di dalam blog untuk setiap minggu. Kami berharap dengan adanya pendekatan sebegini dapat memberi sedikit motivasi kepada diri masing-masing.

Rate Queuing

I already coded a simple packet scheduler with rate based queuing. However, there is still room for improvement due to some flaws in the code that I did not notice. In the RFC 4594 gave a analogy of rate based queuing.

a rate-based queuing system is a combination of a set ofqueues and a scheduler that empties each at a specified rate. An example of a rate-based queuing system is a road intersection with a stoplight. The stoplight acts as a scheduler, giving each lane a certain opportunity to pass traffic through the intersection.

Saya telah menprogramkan 'packet scheduler' yang mempunyai 'rate-based queuing'. Walau bagaimanapun program tersebut boleh diperbaiki kerana masih terdapat kesalahan yang belum dikenal pasti. Di dalam dokumen standard RFC 4594, memberi satu contoh tentang 'rate-based queuing' seperti tercatat di atas. 'Scheduer' digambarkan sebagai sebuah lampu isyarat yang memberi isyarat kepada setiap persimpangan jalan.

Top Ten Errors in Java

I found an article on Top Ten Errors Java Programmers Make in www.javacoffeebreak.com. The author lists the top ten the Java programmers make during coding.The number one mistake is Null pointers.I agreed with the author because I always get the NullPointerException during source code compilation.

Seperti tercatit di atas, saya juga sering mengalami kesilapan NullPointerException. Menurut penulis aritkel itu, adalah satu tanggungjawab 'programmer' untuk memastikan aturcara program bebas dari kesilapan Null Pointer ini.

How to Schedule a Process?

I would like to code so that a packet scheduler can dequeue between two queues. The scheduler must dequeue packet from first at constant interval time. In between those interval, I would like the scheduler to dequeue from the second queue.

I know that most network simulator such as NS-2 and other kind of simulators implement the scheduling method. So I going to implement one in MIRAI-SF network simulator. I did manage to implement where there is one queue. Right now, I'm scratching my head to implement the scheduler with two queues.. Blur

'Packet Scheduler' boleh ibaratkan sebagai seorang polis trafik di jalan yang mempunyai tiga laluan kemudian menjadi satu laluan. Setiap laluan mempunyai tahap kepentingan masing-masing. Sebagai contoh, laluan pertama ada khas untuk kenderaan yg bergerak laju yang biasa digunakan oleh Orang Kaya dan ambulan. Laluan kedua pula biasa digunakan kenderaan yg bergerak pada kelajuan biasa. Laluan ketiga pula digunakan oleh kenderaan yang dipandu oleh orang tua. Tugas 'polis trafik' ini memberi keutamaaan laluan pertama agar kenderaan itu sampai pada destinasi tepat pada waktunya. Jika tidak, kesesakan lalu lintas akan berlaku di laluan pertama dan menyebabkan kenderaan seperti ambulan lambat sampai ke hospital. Sebenarnya, packet itu adalah kenderaan dan scheduler tu adalah polis.

Post Processing of Trace File using grep and Excel

I always use grep command to filter out the required information from the MIRAI-SF network simulator . User of ns-2 network simulator also able to use grep command to filter their trace file. For example, the syntax command is:

grep ["keyword to filter"] [source file] > [destination file]
e.g. grep "UDP" source.out >> destination.tr

After that, launch your Microsoft Excel and open the destination file that your previously have run with grep command. Usually the information in column for ns-2 network simulator trace file is separated by space. MIRAI-SF network simulator log file is separated by comma. Text Import Wizard in Microsoft Excel will be launch automatically. In step 1 of 3 window, tab limited radio button is chosen by default and click the Next button to proceed. Now you can use the delimiters option depends on how your information is separated. For example, MIRAI-SF user will choose space option . Then click Finish button.

Now, you able to plot a graph using Microsoft Excel. Alternatively, you can use gnuplot or xgraph which requires some knowledge in their syntax command. ns-2 user can opt to use NANS to view their simulation quickly.

Traffic Class field IPv6 packet

According RFC 2460, the 8-bit Traffic Class field in the IPv6 header can be for identifying different classes or priorites of IPv6 packets. This is similat to Type of Service (TOS) in IPv4 packet.

Mirai-SF network simulator has all the source code which defined the IPv6 packet, routing of IPv6 in router and IPv6 layer which can handles protocol messages from above and below layers.

I have some trouble in extracting the traffic class information from the IPv6 packets. May be, I just dont know how to use to method to extract the information that I want.

private byte packet[];

packet = new byte[40];

The initial values are:
packet[0]=0;
packet[1]=0;

Is this true?

10:30 pm. Still no luck. I have browsed through source code which does the similar thing to extract the IPPacket from the Frame packet.

14:40 pm. Here is an update on Friday afternoon. I just received an email from the MIRAI-SF developer regarding the traffic field of the IPv6 packet. There is a bug in the source code which caused the value for traffic class does not remain when reached the destination node.

Evening of 18th Nov 2006, I found the tunnelling method which did not pass the Traffic Class information in the IPv6 packets. I will double check if this is correct.

MIRAI-SF UDP Trace does not include bit length information

Calculating throughput using the byte information in the MAC Layer 2 only produce the aggregated throughput of data packets and protocol message. The throughput Perl Script use to trace ns-2 network simulator trace file is modified so that it can process MIRAI-SF network simulator log file.

A reminder to myself,I have to modify the traceUDP method in MIRAI-SF TraceLog class so it can include byte information. I was wandering why the developer left this out. The developer did made the TCP trace to include the bit length information. NS-2 trace also include the bit length of data payload which is called packet length. Perhaps, I can calculate the end-to-end to delay using the modified AWK script.

note: It is ok to measure in frame because it reflects the utilization of the bandwidth.

How to Model a 3G Bandwidth

Oh Man, I'm so desperate! How to implement Bandwidth on Demand for 3G in this network simulator? Somebody out there? Any hints...

I have some rough idea how to code it. I have to create a simple admission control, congestion control, variables queues and a process method to simulate the packet scheduler on the downlink

Throughput Algorithm not from Trace File

I found a thread from Velocity Reviews, the author was trying to implement a method in JAVA programming language to calculate the UDP throughput while the simulation is running. The throughput is calculated when the simulation ends. This is not the same as calculating the throughput from ns-2 discrete event network simulator trace file. Click here to view the thread.

Right Shift Operator >>

In the last post, I mentioned about the left shift operator in Java. The right shift operator is to shift the binary to the right. A right shift for non-negative integer is similar to :

value >> 3 is equivalent to value / 2^3

For more information.Click here [source]

Left Shift Operator <<

Silly me, I did not realized that the code:-

size << 3 is actually similar to size*2^3 or size * 8

The size in bytes are converted to the number of bits. I solved the flaw when the VBR generic traffic source transmit higher than the defined maxrate parameter.

Next plan to code call admission into MIRAI-SF3.1 network simulator. So far I have not seen any free source code on the Internet. For the time being, I have to reviewed some literature on call admission to get the basic idea.

Perl Throughput Script

Throughput perl script can be use to calculate the througpuht from the ns-2 trace file.This perl script is available from NS Simulator Course for Beginners page. Click here.

ALternatively, ns-2 user has another option to analyze their ns-2 trace file quickly. Ankur Jain has written a Java program called Network Analyzer for Network Simulator ns-2 (NANS) to quickly analyze and view results in graph. Clik here to find out more.

AvgStats, Instant Jitter and Instant Throughput Awk Script

In the previous post, I mentioned I use instant Troughput awk script from Marco Fiore Website. The downloadable tar file includes avgStats.awk, instantThroughput.awk and instantJitter.awk to analyze your ns-2 trace file.

Click here to get your awk scripts.

Awk script to compute the average and standard deviation from NS Simulator Course for Beginners website. Click here.

Lloyd Wood made a simple awk script to calculate end-to-end delay.Click here.

User of discrete event network simulator ns-2 has another option to analyze their ns-2 trace file quickly. Ankur Jain has written a Java program called Network Analyzer for Network Simulator ns-2 (NANS) to quickly analyze and view results in graph. Clik here to find out more.

Mersenne Twister

MIRAI-SF3.1 network simulator does not include random generator class. The purpose of random generator because I need to find use the uniform distribution. I was translating the source code of Håkan Byström's VBR traffic model which is C++ to JAVA. A little adjustment have to be made so it can be integrate inside MIRAI-SF3.1 network simulator. Then, I found out that I need a code to generate the uniform distribution.

After some googling on the web, I found a website which offers a Free Java & JavaScript Source code. A random number generator which is I think based on Merseene Twister developed by by Makoto Matsumoto and Takuji Nishimura (alphabetical order) in 1996/1997.

Mersenne Twister(MT) is a pseudorandom number generating algorithm developped by Makoto Matsumoto and Takuji Nishimura (alphabetical order) in 1996/1997. An improvement on initialization was given on 2002 Jan.[source]

The random number generateor code is succefully integrated in to MIRAI-SF network simulator.

Instant Throughput Dilemma

After numerous compiling the code and observing the output, I think have achieve in calculating the instant throughput and hope it will be accurate enough. Instant throughput is the total number of bits divided the total time. The total time is the difference between the current packet time and the previous time. So why is throughput is important?

It is a good measure of the channel capacity of a communications link, and connections to the internet are usually rated in terms of their bitrate, how many bits they transmit per second (bit/s).[Wikipedia]

The idea of calculating the instant looks simple but I was having a hard time coding the method lol.I added two methods in MIRAI-SF3.1 network simulator's 3g base station subclass.

Instant Throughput method is based on an awk script that can be found at Marco Fiore website.

Here my Pseudocode:

instantThroughput method {

Calibrate tk if the currentpackettime > tk when the method is called for the first time.
Sum the total bytes of data being transmitted.
Sum the total by add the time different between the currentpackettime and previous packet time.
Check if the currentpackettime is larger or equal to time interval, if true then calculate the instant throughput, set the totalBytes and totalTime to zero.
Increase tk by adding interval constant value.
Set the currentpackettime to previouspackettime.

}

calibratetk method{
//check if the method is running for the first time, if true then set the first
//boolean flag to true and add the current tk to the current packet time and return //the tk value.

}

Sometimes, I noticed the currentpackettime is greater than tk when the method is called. The logical reason behind is that the base station does not transmit any packet all time. Instant throughput is calculated every
time the method is called until the tk becomes larger than then
currentpackettime(i.e. Every time instant throughput is calculated, tk is
increased, tk+=interval). To make sure that the current packet time is smaller than tk when the first transmission of packet. Thanks to Kentaro a MIRAI-SF developer from NICT for replying my email.

Now, how do i code a variable bit rate (VBR) application? Scratching my head again.

How to fold a shirt in Japan

Shirt folding is all the rave in japan

By the way, I'm lazy at folding my T-shirt but like to hang them straight away.

Riding the Superconducting Maglev Train - Linear Motor Car

Riding Japan's Superconducting Maglev "Linear Motor Car" Train at 502 kilometers/hour on a beautiful day at JR Railway Technical Research Institute's Yamanashi Maglev Test Line. This was shot with a JVC Everio GZ-MC500 3CCD hard disk drive camcorder. The length is 6 minutes and 11 seconds. Courtesy of Harvard Club of Japan and Central Japan Railway Company

Obfuscate

I came acrosss a new word Obsfuscate while reading Kathy Sierra's Book. Haha there is a note from the author asking the reader to look up the word and email back the author. It is on the page 296. I googled with the keyword "define obfuscate". One of the definition which definitely that I am looking is:

Obfuscated code is source code that is (perhaps intentionally) very hard to read and understand. Some languages are more prone to obfuscation than others. C, C++ and Perl are most often cited as easily obfuscatable languages. Macro preprocessors are often used to create hard to read code by masking the standard language syntax and grammar from the main body of code. The term shrouded code has also been used.

[Source]

Olympus

Olympus Mons or Nix Olympica is the tallest mountain in our solar system located at Planet Mars. Click to Google Mars Map

Olympus Mons (Latin, "Mount Olympus") is the tallest known mountain in our solar system, located on the planet Mars at approximately 18° N 133° W. Before space probes revealed its identity as a mountain, Olympus Mons was known to astronomers as the albedo feature, Nix Olympica ("Snows of Olympus").

It is about three times the height of Mount Everest from sea level and 2.6 times higher than Maune Kea which a dormant volcano locate the Hawaiian Island measured from the base. [Source]

Talking about Olympus, I saw advertisement on two latest Digital Camera from Olympus in theStar newspaper. FE-190 and FE-180 both priced at RM 899 and RM 599. I would love to have FE-190 because it has a sleek and slim metal constructed body measured at 0.7 inches. This six megapixels digital camera features Digital Image Stablization, 2.5 inches LCD screen, built-in help guide and comes with Li-Ion Rechargeable Battery.

Hahahaha, I still have problem in implementing the instant Throughput. Ok, instant throughput is total bits divided by interval time. This methods that I did was based on the instantThroughput.awk script obtained from the Internet. I ran the network simulation with one mobile node moving around but the throughput is constantly at 30 kbps. The funny thing is still at 30 kbps when there are many mobile node during the simulation. I think the reason why this is happening because of the constant packet size, data rate is constant due to the application is pumping a constant bit rate and no variable delay. The simpler reasons are bugs in the code or the person who wrote the code. That's me. haha

MIRAI-SF3.1 does not have any application that uses a bit rate parameter for its interval calculation but MIRAI-SF4.1 does have constant bit rate application. I just need to make a little adjustment to the source code and then integrate into MIRAI-SF3.1. In additon, I need create some applications that generate variable data rate using exponential and pareto distribution. I just need to take a look at NS-2 source code and enhanced the source code in MIRAI-SF3.1.

KingMax USB FLash

Have you ever experienced when your favourite USB thumb drive or flash drive failed? I have two thumb drives which are 64MB and 128MB. The 64MB carries an APACER brand which cost about RM 120 in 2003. Today, the prices for USB flash drive are getting cheaper. I apparently ‘stole’ the 128MB from my dad’s collection of USB drives.

Unfortunately, two days ago my dad’s KINGMAX USB drive just failed. The light indicator stops blinking and no matter how much I banged it against the surface of my desk and threw against the wall. The blue and black USB flash drive just stops working. All the important data are lost. I remembered when my room mate accidentally had his USB thumb drive wash in a washing machine. Luckily, the APACER USB flash drive stills work after he dismantled and dried.

So far I have some experience in using OMNET++, NS-2 and MIRAI-SF which is based on SSFnet network simulator. You can find more information on the simulators by using the google search. I just found out there is a commercial of OMNET++ called OMNEST.

Canon DigiCam

A digital cameral is another cool gadget on my wish list. I'm looking for a camera that is under RM 1000. Steves Digicams website reviewed Canon PowerShot A540 features six megapixels resolution and 4x optical zoom. CNET rated as 7.6 out of 10. There is a CNET Video review which you can watch and gauge how big the camera is. Canon Powershot A540 has optional accessories such as Underwater casing that you can purchased. It is priced at RM 888.


In the previous post, I did mentioned that I implementing a method to measure the throughput on certain interval of time. Well, I'm still doing it and I'm stuck. I can not seem to get the method working to my preference. Ideas please come to me. MIRAI-SF network simulator has some codes which has similar concept but it is calculater based on how many packets are passed through a node on certain interval.

Free Laptop

Anyone of you want to give their for free? I received forwarded email saying that there is a marketing company in Canada would give an Acer notebook for free. I think have received similar email not so long time ago. All you have to do is register with their web. It's a hoax. Who would want to give a mobile pc for free. Click here!
I bet that website would just want to collect emails so they can spam peoples' inbox with stupid advertisements.

Anyway, my dad is thinking of buying an entry level Acer notebook. I checked the price list at lowyat.net which is quoted at RM 2199 with a Linux OS.

I used to play around with Knoppix which is an OS runs from your CD-ROM drive. You would need at least 256Mbytes of random access memory. Once the OS is loaded, you could access all the partition of Windows's Hard Drive.In addition, you could even connect to the Internet or join the local area network. Cool eh. Go and download the *.iso disk image and burn it onto a cd.

'akashah on the world map

Haha gotcha, I'm still in Malaysia lah!. I was surprised that when I googled and found that `Akashah is located in Northern Sudan, Afrika. Click `Akashah google map. :P

An update of my work. I'm still in the progress implementing a method to measure the throughput of the packets when the 3g base station is transmitting the packets to mobile node. The packets is actually had been traced in the log file. The problem is that I have still have to do some simple script to calculate the throughtput. It would save some time and memory space if I implements directly into the code.

I have some problem with queue. I still thinking how I'm going to integrate the simulator. Right now, I have no idea. I stumbled upon which explained the modelling of queue. I have got time to read it yet.

Broadband BandWagon

Currently, I'm on 512kbps TMnet Streamyx which I pay for RM 66 per month which is quite reasonable compared to the TMnet 1515 dial-up service which can cost a bomb when you go online for 24 hours a day. Not to mention the 56kbps which is extremely slow.

TheStar online reported that Maxis which going to roll out High Speed Broadband for home over its 3G network. TMnet only offers maximun 1Mbps for Home user. I hope Maxis would offer a greater bandwidth than the current TMnet 1 Mbps at a reasoble price. I would be the one to be sign up. Hahaha maybe.

Maxis mentioned the Broadband service will be using HSDPA (High Speed Data Packet Access) technology. Hey, I used to research this topic before I move to Fast Handover for Mobile IP. HSDPA simulation could be simulated using ns-2 extension called EURANE. Back to the topic, So I bet we have to use a wireless Modem not like our TMnet Streamyx modem which connected to normal copper phone line. Cool!

More? Click here

drop tail

It seems I dont really have to implement OVSF tree. I just to need concentrate on queue and simple bandwidth allocation.MIRAI-SF3.1 does not implement any queue in routers, switches and accesspoints. So I think my job would be implementing a drop tail queue that can be integrate in network components.I started off by making a simple queue in two nodes and using the MIRAI-SF3.1 simulator core libraries.Messages are transmiited between the two nodes.

OVSF

I just found out that when the mobile node is trying to connect to the base station. The basestation will allocate a code. This code is allocated from a binary tree called Orthogonal variable spreading factor (OVSF). It is a unique code that allows to differentiate each user on the same resource. It is like two persons talking to each other in a noisy and crowded area. Only the two persons can understand and hear each other because of them has the unique code that have been allocated. The people around of them only hear background noise.

Changes...

I got a new task for my final project. I got to make some change in the current 3G base station and 3G device implementation.

The changes are :-
1) bandwidth for the link between the bs and mobile node
2) the incoming connection from a mobile node will be defer and packet loss or drop will occur.
3) each mobile node is allocated some of the total bandwidth
3) the bandwidth is return when mobile node disconnects from the bs.

How? where? what?

Handover latency

Mana aku nak cari nilai handover latency ni. Aku baru halfway cari kat ts 25 series kat 3gpp.org. aku ada gak cari kat journal dr ieee. so far tak jumpe lagi. argh geram aku..namun usaha harus teruskan.

aku nak jerit kuat2.....arghhhhhhhhhhhhhhhhhhhh gerammnya aku.........

Codes...

I have not write something in this blog for a while. So what I did for my project in the last seven days? I have to understand the source code in the simulator in order to make some changes which I dont know where I must changes. As recommended by the developer, I study the SoftRadio class which is responsible in deciding whether it must connect to the WLAN access points or the 3G base station. It is assummed in the simulator the 3G radio will have more coverage than the WLAN. However, WLAN has much bigger bandwidth than the 3G radio. WLAN connection are usually deploy inside a buidling. Both WLAN and 3G are modeled in Java programming language on certain important parameters and less important attributes are omitted out.

I'm currently trying simulate Fast Handover for Mobile IPv6 which can do a vertical handover between WLAN ap and 3G base station using MIRAI-SF simulator. The current version has problem in connecting with the WLAN ap. The developer has decided not to maintain the SoftRadio class but concentrate on developing Media Independant Handover (MIH) for next release of the simulator. The next thing that I have to do is to implement some methods so that bitrate for the 3G link can be set.

So I have managed to identified part of the problem, there are methods inside the WLANRadioDevice class return only null value. The methods does contain any implementation to evaluate a certain scenario. For example, the findAccessPoint method immediately return a null value which cause the SoftRadio class to select the 3G interface most of time. I reckon my next step, is to find out how i can make the SoftRadio class to initiate a WLAN connection using the available package. I thinking using the wlan package which is only availabe in MIRAI-SF. With this package, I can take the advantage of using the IEEE802.11 standard implementation.

Mirai

Yesterday, 13th April I had a meeting with my supervisor. I showed what I had done for the last 1 month. We disscused some problem regarding the simulation using the HS-DSCH transport channel.

So at the end of the meeting, he introduced me a new discrete network simulator called mirai developed by Wireless Applications Group on the Next Generation Mobile Network Project, National Institute of Information and Communications Technology (NICT).

So my simulation DiffServ in EURANE core network using HS-DSCH is still pending until I find a solution.

Do you have Path Problems when running Java J2SE 5.0 on PCs. Well click here!

NS-2 Link

Click Here
Click here too

what to do...

Things that I have achieved so far:-
-----------------------------------
1. A simple simulation on DCH channel with DiffServ in the core network. Two UDP sources with constant bit rate traffic are to simulate the VoIP data packets. Throughput at the ssgn which is configure as an edge router are measured in term of Mbps.

Things that I did:-
-------------------
1. Read the Seacorn deliverable D3.2v2.
2. Read thesis on QoS provisioning.
3. Read TS 23.207


Things to do:-
--------------
1.Read 3gpp technical document on End-to-end QoS and HS-DSCH.
2.Find out why simulation on HS-DSCH channel with DiffServ in the core network stop abruptly. It should not have any problem because Diffserv is working on the network layer. Mac-Hs is the important mechanism for HS-DSCH which is on the data link layer.
3. Find some script to analyse the trace file for end-to-end delay and jitter.

Things to do as on 20th March
-----------------------------
1.Read and understand
2.Build some simple simulation scenarios.
Check with 3gpp standard for QoS

Max HSDPA Throughput in EURANE = 1.3Mbps

I think have similar observation of the throughput



Greetings,

I have simulated an HSDPA cell with two UEs but only one active CBR source sending at 4Mbps. The input trace file is the same as the idealtrace but I changed all CQI values to 29 in order to achieve maximum throughput. However, the throughput was saturating at only 1.3Mbps !!
Can someone clarify why? There might be a configuration parameter limiting the number of codes or coding rate??


regards.

AMM

source

TCP Window

The variable "window_" in ns2 corresponds to "awnd" in the literature.
Using this variable you can set an upper bound for the TCP window at the
source. So, if you wish to "set the TCP maximum windows size to 50",
just
set window_ to 50 in your tcl script.
Note that "window_" is binded as "wnd_" in the c++ code
(tcp/tcp.{h,cc}).


source

Had some problem in calculating the throughput from the trace file. Still searching the method to implement flowmon.

I came across posting where it explain that TCP adjust its sending rate when there is a congestion in the link.


TCP adjusts its sending rate using a congestion control algorithm

Take a look at the following paper, it could help you

Van Jacobson, “Congestion Avoidance and Control,” in Proceedings of ACM
Sigcomm’88, Stanford CA, August 1988, 314-329.

Best Regards

Alfredo

---------------------------------------------
Luigi Alfredo Grieco, Ph. D
Assistant Professor
DEE Politecnico di Bari,
Via Orabona 4 - 70125 Bari, Italy
Ph. +39-080-5963301
Fax +39-080-5963410
http://www-ictserv.poliba.it/grieco


-----Messaggio originale-----
Da: ns-users-bounces at ISI.EDU [mailto:ns-users-bounces at ISI.EDU] Per conto
di mehri rajayi
Inviato: martedì 12 aprile 2005 11.11
A: ns ns
Oggetto: [ns] how create tcp connection with spesific rate?



i want to create a tcp connection with ftp traafic sourse, with this
parameter (rate:128Kbps pktsize:1000byte ) but tcp hasn't rate
parameter. I set packetSize_ to 1000 but in trace file PKTsize is equal
40. can you help me.


-source-

Link

Met with the supervisor on 16th March. Wrote a progress report to submit to the supervisor. The report mentioned some literature reviews and preliminary simulation works. Supervisor kind of agreed with the idea and ask to come out with some simulations for the next meeting.

Things to do:
Read and understand.
Build some simple simulation scenarios.
Check with 3gpp standard for QoS


Link

RED again..

I think I solved the problem. Actually it is not a problem.

I think in ns2.28 the paramater "Queue/RED set queue-in-bytes_ true" is set to true by default. In ns2.27, the parameter is set to false by default.

I want the queue size in term of packets. To over ride this just add the following parameter in red.tcl script when using ns228.

"Queue/RED set queue-in-bytes_ false"

I think this is also apply for ns229.

Any reason why we want to monitor the queue in bytes rather than in packest?

Windows reads linux partition...

Click here for the website

Why use simulator ?

Simulation is often based on random events.

Therefore, if you want a real time implementation, then if 2 events are
seperated by minutes, then you would just have to wait. Ns-2 is
event-oriented, and therefore if there is nothing to do between 2
events, then the clock is incremented, and you do not have to wait.

In the other hand, suppose you have a large simulation with a lot of
users. In case a complex treatment has to be done at each user's
equipment, then the computer would have to do it all, with NO real-time
guarantee !

Thirdly, ns-2 is a supported by a whole community, and freely available;
if you can find a real-time simulator please let me know, but I do not
see any.

-source-

VoIP...

Since many VoIP codecs send data at the constant rate, you can use normal UDP/CBR application to simulate VoIP. You have to set appropriate parameters so that the rate and the packet size correspond to the codec you use.

mount hard disk

Click here

RED queue

I have some problem while simulating a simple scenario using 3 TCP sources with RED queue at the bottleneck lick. The tcl script was obtainde for this website. The result that I got is totally different from this document. The queue just grew beyond the limit of 100. The same thing is happening when I rerun the simulation script using UDP protocols under Constant bit rate traffic.

Steps to find the root the problem
1. Recompile ns-2.28 and run the simulation again
2. Run the simulation under ns-2.27
3. Or if this does not work run under ns-2.29
4. Try running the simulation on Fedora

link

link

Finish...

I have completed my exam and waiting for my result to be out. The result will be out in two weeks from now. I hope my cpga will fulfill my graduation requirement. I'm not keen to repeat any paper just to improve my grades.

'akashah on the world map

Haha gotcha, I'm still in Malaysia lah!. I was surprised that when I googled and found that `Akashah is located in Northern Sudan, Afrika. Click `Akashah google map. :P

An update of my work. I'm still in the progress implementing a method to measure the throughput of the packets when the 3g base station is transmitting the packets to mobile node. The packets is actually had been traced in the log file. The problem is that I have still have to do some simple script to calculate the throughtput. It would save some time and memory space if I implements directly into the code.

I have some problem with queue. I still thinking how I'm going to integrate the simulator. Right now, I have no idea. I stumbled upon which explained the modelling of queue. I have got time to read it yet.