While I don’t have a video for you to watch the entire presentation, I do have some pictures, and I’ll post the paper and slides I presented in case any one is interested. If you have any questions feel free to post on here or email me directly and I’ll be happy to answer any of them.

J.B. Ernst and M.K. Denko, “Cross-Layer Mixed Bias Scheduling for Wireless Mesh Networks,” in Proc. IEEE International Conference on Communications (ICC), Cape Town, South Africa, 2010.

Abstract—In this paper we propose a mixed bias approach which makes use of cross layer optimization. The cross-layer parameters are based on conditions in the network from multiple layers and are used to determine resource and time allocation for nodes in the network. Unlike existing proposals, we propose to bias against several parameters such as link quality and queue size in addition to node distance. We also propose a combined mixed bias approach which takes into account multiple parameters together. The scheme is evaluated using simulation experiments. The performance results are reported in this paper.

Download the paper (pdf)
Download the presentation slides (pdf)

Next is the price for these things. While they seem to be too expensive (monthly) to me, I am willing to pay it since I understand the costs of setting up a network in a country as spread as Canada. However if I try to tether a Blackberry or iPhone to my computer, all of the major carriers in Canada seem to add on extra costs which make it impractical. The other reason why I do like some of the blackberry models is for international use. For instance when I was in UK this past month, I couldn’t use my LG8100 phone at all. Some of the newer Blackberries supported by Rogers and Telus that I have looked at support many technologies and seem like they make work.

Anyways, this post has mostly been a rant, so feel free to leave your experiences or some suggestions on what I might do to try to get some solution to my needs. I have tried asking the sales staff at some of the places to help me out and they have been useless so far. But thats another story.

Update: I have decided on a Blackberry Storm 9530 since it supports international roaming and has many of the features I would like in a phone. It looks like I will just settle on buying a separate mobile stick for use with my laptop. I don’t want to have to worry about all of the hassle of getting the extra software & the questionable legality that is involved with trying to get data through my phone. So far I am quite happy with the phone, it is quite a step from my LG8100.

There were people from 40 different countries there and I feel like I met someone from almost every one of them at some point. There were over 300 people at AINA this year, which apparently is down from the last couple of years (where they had 4-500) but it was still a great conference for me. I will post my slides from my presentation in this post in case anyone is interested, along with a link to the paper once it is available. I submitted another paper last night for a conference in Toronto and am working on two more papers, so hopefully I’ll be travelling soon. I am trying to aim for ICC in South Africa next year.

Here are a few pictures from the conference.

Abstract:
This paper addresses the problem of scheduling in Wireless Mesh Networks (WMNs). The paper first discusses existing scheduling algorithms and classifies them based on the technique they use and their implementation frameworks.Then detailed discussions of the proposed scheduling method are presented. Simulation experiments are conducted to compare the performance of fair scheduling with the method that does not use fair scheduling. The simulation results confirm that the proposed scheduling method has better performance with respect to the metrics used for performance evaluation.

J.B. Ernst, M.K. Denko, “Fair Scheduling with Multiple Gateways in Wireless Mesh Networks”, in Proc. of the 22nd IEEE Int. Conf. on Advanced Information Networking and Applications (AINA 2009), Bradford UK, 2009.

The paper itself is available through IEEE Xplore

As soon as I get the thesis completed though I hope to post alot more new content on the blog (as well as a potential redesign since this one seems a little cluttered and busy to me). Check back soon for alot more in-depth info on using ns3 since that is what I have been using for my thesis experiments lately. Update: I am set to defend on May 18th at Guelph. Let me know if you are interested in attending, I will provide more details via email.

In other news, the University of Guelph has officially accepted me to their Ph.D program to start in the Fall of this year (still under Dr. Denko) so I am pretty excited about having the opportunity to continue my research in Wireless Networks. I am still waiting on responses from a couple of other schools (Waterloo & Calgary) so if I end up getting accepted to either of those I will have quite a decision to make. Update: I have accepted a position at the University of Guelph and will be starting there in the fall of 2009.

Update Ubuntu:

Download the NS-2.33 and HWMP All-in-One Package here:

Updated with new link: *

Untar the file:

Configure and Install NS2

All ready to go. Enjoy.

This is second Guest Article featured on the blog. The article is a brief look at why WPA encryption in wi-fi networks is not secure any longer. Our guest blogger this week is Maya Richard. She describes how brute force attacks can be used against captured packets which have been encrypted with WPA encryption. These attacks have become increasingly practical through the use of graphics hardware which is well-suited to brute force cracking.

Why WPA is no longer secure

Created by the Wi-Fi industry Alliance to help secure wireless networks, WPA (Wifi Protected Access) is now vulnerable to a recently discovered flaw. In particular, the packets distributed over the
network are now vulnerable to injection and spoofing, making the protocol no longer secure for sensitive use.

The vulnerability came to light when software consultants utilized advanced hardware to decrypt the protocol using brute force password guessing attempts. While experts have known about these potential vulnerabilities, many believed that the theoretical weakness could not be reasonably exploited with standard computing power. However, the firm that decrypted the packets relied upon commercially available Nvidia acceleration chips, which further calls into question the long-term security of the protocol as we transition into next generation technologies such as WiMax.

Example of current generation nVidia graphics cards

As a result of the breach, a number of companies are rushing to implement a further layer of VPN encryption. Security researchers were able to duplicate the method used in the initial breach, which has heretofore solely been considered a theoretical threat. The researchers, at Darmstadt University, were able to utilize brute force to crack a secure WiFi network within minutes. This sheds light on the
methods criminals have been used to steal credit card data distributed over wireless networks.

While security experts believed that the protocol would be a replacement for the less secure Wired Equivalent Privacy Protocol (WEP), experts point out that WPA merely adapted encryption techniques from the previous technology due to hardware limitations. Since 2006, most wireless devices are built on the WPA2 standard, which experts believe has a much more stable foundation.

This article was written by Maya Richard. She is currently writing about Comcast deals and can be reached at mayarichard@gmail.com

So back to the point of this article, a guide on how to install ns-3.2 on Ubuntu 8.04 Hardy Heron. Ns-3 installation is quite simple since an automatic build tool named waf is used to build the project. Enter the following in the terminal to download, untar and build ns-3.2.

wget http://www.nsnam.org/releases/ns-3.2.tar.bz2
tar -xvf ns-3.2.tar.bz2
./waf -d debug configure


How to start working with NS-3

So from here on out, all you have to do is use the waf tool for compiling and running your ns3 simulations. There are many example scenarios located in the /examples folder. You can run a simulation with any of the scenarios using the waf command. For example if you wanted to run a scenario file named first.cc you would enter the following command:

./waf --run=first

Notice that you do not need to include the .cc on the filename. If you do happen to misspell the file, ns3 will provide you with a list of all of the scenarios you are able to run. One other important note is that the /scratch folder automatically includes the .cc files as scenarios which you can run. This is likely where you will want to place your new scenarios when working on them. (If you try to put them in the examples folder you will need to edit the wscript file (see NS3 tutorial on how to do this). On other important thing to note is that ns3 supports improved logging / output compared with ns2 using the pcap file format which can be read using tcpdump or wireshark. These types of files were originally used for packet capturing in real working networks so it makes alot of sense to include this ability in simulation as well.

How to display exactly what is going on to the screen (Logging)

Sometimes when making changes and implementing something new, it is helpful to show everything that is happening on the screen. You can achieve this by entering the following at the linux command line:

export 'NS_LOG=*=level_all|prefix_func|prefix_time'

If you want to restrict the information to only certain parts of the simulation, for example the MAC layer of a wifi AP you could do something like this:

export 'NS_LOG=NqapWifiMac=level_all|prefix_func|prefix_time'

For more information on how to configure the logging to do exactly what you want, see the NS3 Tutorial section on logging.

If you have turned on logging, you have likely noticed that ns3 generates so much information that it scrolls by way to fast to be of any use. So you will probably want to output the results to a file. For example if you were running the first.cc file again and you have turned on logging you could do this:

./waf --run=first >& first.txt

which would send the logging output to the file first.txt where you could easily read it.

Useful Functions

So far I have found these functions make debugging scenarios easier:

static Vector
GetPosition (Ptr node)
{
Ptr mobility = node->GetObject ();
return mobility->GetPosition ();
}


static Ipv4Address
GetAddress (Ptr node, uint32_t interface)
{
Ptr ipv4 = node->GetObject ();
return ipv4->GetAddress(interface);
}


Tips

The following are a few important things I’ve discovered that may save you time when trying to work with ns3 on certain tasks:

• When simulating an ad-hoc or wireless mesh network using OLSR, make sure you set your mobility model before you install the OLSR routing on the nodes. If you do not do this, OLSR may generate link pairs for links which are actually too far away to communicate because before the mobility model is installed on the nodes they are all close enough to communicate.
  
• Also with OLSR, make sure you give OLSR enough time to determine the network topology before you allow the applications to start running on the network. I have read that about 100s of waiting time before starting is enough, however I imagine as the network size grows this may also grow (I have tested with a size of 4×4 and this is enough time – I will adjust this as I play with the numbers as well)

Useful Links

• NS3 Doxygen Documentation
• NS3 Tutorial
• NS3 Manual
• NS3 Wiki

Today I completed the listing page for all of the presentations our research group PerWin at the University of Guelph has made in the last year or so. PerWin stands for Pervasive Computing and Wireless Networking Research. The group is directed by my advisor, Dr. Mieso Denko and has several graduate students who are active research members in the group. We have given presentations on topics ranging from Wireless Mesh Networks protocols, Autonomous networks, Fair Scheduling, Load Balancing, RFID, Wireless Security and much more. We have also had special invited talks by several faculty members from various Universities around Ontario (Ryerson, UOIT).

Reynolds Building @ University of Guelph where PerWin meets regularly

Check out the schedule page here for the list of presentations, presenters and topics. There are also listings of many of the websites for the presenters which may be a good resource for people interested in our work. If you are a faculty member interested in giving a talk contact Dr. Mieso Denko at the University of Guelph.

If you are interested in any of the talks I have given, all of the powerpoint presentations are available at my Academic Website at the University of Guelph.

I recently received a request for a guest contribution to the blog from Kelly Kilpatrick so I thought it would be a nice change to have some content from someone other than me. The article is a compilation of some good sites for the latest on wireless technology and news.

5 Blogs and Sites for All Things Wireless

Guest Contribution by Kelly Kilpatrick, October 14th, 2008

As wireless technology continues to advance, it is good to stay informed on the latest technologies, advances, and setbacks related to this convenient technology. However intricate or superficial, these blogs are out there to keep you informed (to one degree or another) regarding the latest and greatest developments in the world of wireless technology.

Engadget: For the latest news and analysis on a wide variety of wireless products and new innovations, engadget has you covered. Read about new hardware and WiMax-compatible products, as well as other developments that are in the works when you visit engadget.

Network World: The contributors at Network World are fully dedicated to finding out everything they can when it comes to the world of wireless. Read comparison reviews, find out the latest news in wireless technology, and learn more about what companies are doing to meet the ever-growing demand for better, faster wireless technologies.

Wireless Week: Wireless Week has several contributors dedicated to keeping the blog up-to-date and fresh. Browse through their substantial archives or look at their latest news and commentary regarding wireless technology. Keeping track of what’s going on in this constantly-evolving segment of computing technology just became a little bit easier with Wireless Week.

WiMax News: To stay current with the latest in this rapidly-growing wireless technology sector, visit WiMax news regularly. Troubleshooting, news, reviews, potential security threats, and much more can be found with a quick search. To stay ahead of the curve, take a look at WiMax News.

MuniWireless: A visit to this particular site will give you a wealth of knowledge related to wireless technology advances and setbacks around the world. Delivering information and articles prolifically, the folks at MuniWireless are certainly in touch with the latest happenings when it comes to wireless technology.

By-line:
This post was contributed by Kelly Kilpatrick, who writes on the subject of dial up internet. She invites your feedback at kellykilpatrick24 at gmail dot com