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?