Last year, I have written a blog post entitled "5GHz Band Channel Availability in Canada" explaining what 5GHz channels were available in Canada. This was based on a document from Industry Canada named "RSS-210 - Licence-exempt Radio Apparatus (All Frequency Bands): Category I Equipment" Annex 9 - Local Area Network Devices. If you go visit the Industry Canada's website today, you will see that this annex is no longer applicable and has been replaced in May 2015:

So, in this article, it is time for me to update the information provided in my previous blog post and keep things up to date!

The new document covers the new radio standards specifications for the Wi-Fi equipment operating in all the 5GHz frequency bands:
 - UNII1 (5150-5250MHz)
 - UNII2 (5250-5350MHz)
 - UNII2-Extended (5470-5600MHz and 5650-5725MHz)
 - UNII3 (5725-5850MHz)

Here are the updated radio standards specifications:

As you can see, nothing much changed from the last standards. Basically, the channel availability and the output powers were kept unchanged. 
So what has changed? According to me, two important regulations were added. They are detailed below.

Transmitter Power Control or TPC is a feature that enables a Wi-Fi device to dynamically switch between several transmission power levels in the transmission process. This is mainly used to reduce interference if another device is transmitting on the same frequency.
For Wi-Fi devices operating the UNII2 and UNII2-Extended, Industry Canada states that "devices with a maximum e.i.r.p. greater than 500mW shall implement TPC in order to have the capability to operate at least 6dB below the maximum permitted e.i.r.p. of 1W". This information can be important to keep in mind while designing a WLAN.

Concerning the UNII3 & ISM bands (5725-5850MHz), the conducted output power shall not exceed 1W. If directional antennas are used with a gain greater than 6dBi, the maximum conducted output power shall be reduced  by the amount in dB that the directional gain of the antenna exceeds 6dBi. So basically the maximum e.i.r.p. will never exceed 4W and if the gain of the antenna is greater than 6dBi, the output power will be adjusted accordingly.
However the standards stats that "fixed point-to-point devices operating in this band may employ transmitting antennas with directional gain greater than 6dBi without any corresponding reduction in transmitter conducted power".

Here is an example to explain this regulation:

So, on the left part of the drawing, we are using an antenna gain of 9dBi; which is 3dBi greater than 6dBi. If we were to use the maximum conducted power possible (i.e. 1W), the total e.i.r.p. would be: 30dBm (1W) + 9dBi = 39dBm (8W). 8W is over the maximum allowed (4W). So in order to stay under the regulations, we need to lower the conducted power by the number of the antenna gain dB greater than 6 (in our case 9-6 = 3dB). So the new conducted power would be: 30dBm (1W) - 3dB = 27dBm (500mW).
If we use a conducted power of 500mW we will have the following e.i.r.p.: 27dBm (500mW) + 9dBi = 36dBm (4W). This complies with the regulations!

On the right part of the drawing, we are setting up a point-to-point bridge link with an antenna gain of 13dBi; which is also greater than 6dBi. Even though the e.i.r.p. exceed 4W, we are still allowed to use a maximum conducted power of 1W.

If you are installing Wi-Fi on the 5GHz band in Canada, I would invite you to read the full official document from Industry Canada named "RSS-247 Digital Transmission Systems (DTSs), Frequency Hopping Systems (FHSs) and Licence-Exempt Local Area Network (LE-LAN) Devices". The section #6 details the regulations concerning Wi-Fi devices.

I hope this information will be useful for some of you.

Written by François Vergès

In the lab, we currently have a little Cisco WLC 2504 with 2 APs Aironet 1702 running on AireOS v8.0. We wanted to try out the new Cisco wireless mobile application released by Cisco (more details here). In order to be able to use this application, you need to be running the new version of AireOS on your controller. 
Here is the message I got when I tried to use the Android application:

The latest version of AireOS is v8.1 and, this article guide you through the process of upgrading the OS version of you Cisco WLC using the graphical user interface.

The screenshot below shows that our current version is v8.0.115.0. This is our starting point:

We now need to download the new version of the AireOS on the cisco.com website. In our case, we chose the v8.1.110.0 for the Cisco 2504 WLC.

Once your have downloaded the .aes file, you are ready to download it onto your controller. To do so, you will need a TFTP server. In our case, we are using this free TFTP server for Mac OS X.
Launch the TFTP Server and place the .aes file in your TFTP directory:

Let's now login into the controller GUI and download the file from the TFTP server. Once logged in, browse to the "Command" tab and configure the following informations:

• Choose "Code" as the type of file you want to download
• Choose "TFTP" as your transfer mode
• Set the IP address of your TFTP server (192.168.88.240 in our case)
• Set the file path (./ in our case since we placed the .aes file in the TFTP root directory)
• Set the name of the file your want to download to the controller (AIR-CT2500-K9-8-1-111-0.aes in our case)

Once everything is in place, your can click on the "Download" button. The system will ask you to confirm that you want to go ahead with the downloading process. Click "OK" to start the download.

Note: You cannot download a file onto the controller if you are connected to the WLAN. You will need to connect your TFTP server with a wire somewhere in your LAN network.

A series of messages are going to appear on the screen once the file as been downloaded to the WLC. At this point, the controller is processing the new .aes file:

At the end of the processing, the controller will ask you to reboot in order to apply the new version:

You can go ahead and click on the link. This will redirect you to this page:

The final step is to click on "Save and Reboot". At this point, the controller will reboot loading the new version of AireOS. Then, your APs will also reboot loading the new version from the controller. This process took about 5 minutes in our case.

Once everything is back up and running, go ahead and login into your controller GUI. You will notice right away that the new version has been installed since it now looks like this:

In order to double check that the new version has been installed, click on "Advanced" on the top right corner of the screen. This will redirect you to the "old" dashboard where the version number is displayed:

It's now time to go back to the Cisco Wireless Mobile Application. As shown below, the application now works and we were able to login into the controller:

Thank you for reading this post and, hopefully, it has been useful to you!

Cheers'


Written by François Vergès

Studying for the CWAP exam, I was using Wireshark and wondering how to see if the traffic (data frames) I was capturing was using HT (or 802.11n). So this article will show you how to find out!

Let's start by talking about the Wi-Fi frames:
 - PPDU (PLCP Packet Data Unit) : This is the frame at the physical layer (Layer 1 of the OSI Model).
 - MPDU (Mac Protocol Data Unit) : This is the frame at the Data-Link layer (Layer 2 of the OSI Model).

The MPDU is encapsulated into the PPDU as shown in the drawing below (taken from the CWAP study guide):

There is 3 formats of PPDU introduced with the 802.11n technology (see image below taken from the CWAP study guide):
 - non-HT Legacy: used with non 802.11n clients
 - HT Mixed: used for both 802.11n and non 802.11n clients
 - HT Greenfield: used and understood only by 802.11n clients

Looking at the name of these PPDUs, you can easily understand that if we could see them, we could determine if the frame is using 802.11n or not. However, it is not that simple. Since, these preambles are present at the Layer 1, they are trimmed by the NIC before reaching Wireshark.

However, Wireshark is still able to tell you if the frame is sent with 802.11n. Here is where to find it:
 - Filter data frames using the following filter: "wlan.fc.type==2"
 - Click on the frame you want to check
 - Open the "Radiotap Header" tab in the packet detail view

So how does Wireshark do it? It uses a combination of information available to him from the RadioTap Header. This RadioTap Header is added in from of the MPDU by the Wireless NIC when capturing frames. (For more information on the RadioTap Header, read this great article written by Nigel Bowden). Wireshark uses the following information from this RadioTap Header:

• Type of modulation (OFDM in our case)
• Frequency Band (5GHz in our case)
• Channel width (40MHz in our case)

However, some data frames, like the "Null function" frames, are not sent with 40MHz width channels even if the network is configured that way. Therefore, Wireshark does not see these frames as 802.11n frames. Instead (because of the OFDM modulation and the use of the 5GHz band), Wireshark tags these frames as being 802.11a frames:

So looking at the RadioTap Header, Wireshark can have a good idea of the Wi-Fi technology used to transmit the frame. If you want to double check what technologies are supported for a specific SSID, the best is to have a look at the beacon frame (which is a management frame). To filter beacon frames in Wireshark, use the following filter: "wlan.fc.type==0 && wlan.fc.subtype==8".

Cheers'


Written by François Vergès

Source: CWAP Study Guide by CWNP

Here is a timeline concerning important standards and protocols related to Wi-Fi security. (Click for full size image)

This following table completes the timeline with some more details:

Of course, this timeline will change with time and I will update it to keep it up to date!

As always, comments and feedbacks are welcomed! Let's make it better together :)

Written by François Vergès

As we all know, Wi-Fi is amazing. The only thing is... it’s invisible.

So let’s start by explaining what makes Wi-Fi invisible? Wi-Fi uses radio frequencies electromagnetic waves to transfer information. These waves have wavelengths that are not within the visible space.

Light is also an electromagnetic wave. However, its wavelength is within the visible spectrum (between 330 nm and 700 nm). This is what make the light visible to the human eye. In fact, any electromagntic radiation having a wavelength between 330 nm and 700 nm is called “light” or to be precise “visible light”.

This means that we can explain Wi-Fi concepts using light analogies. In this set of articles, that is what we are going to do using simple drawings.

As a Wi-Fi professional, it important to remember that as the scattering of a signal continues to occur, the signal will lose its integrity and eventually die off. Scattering could happen indoor if you have a lot of inside trees. It could also happen on outdoor Wi-Fi bridges while raining as the signal hits rain drops.


Written by François Vergès

"Episode #1 - Radio Frequency Propagation" is still available!
"Episode #2 - Radio Frequency Reflection" is still available!
"Episode #3 - Radio Frequency Refraction" is still available!
"Episode #4 - Radio Frequency Diffraction" is still available!
"Episode #6 - Radio Frequency Absorption" coming next!

As we all know, Wi-Fi is amazing. The only thing is... it’s invisible.

So let’s start by explaining what makes Wi-Fi invisible? Wi-Fi uses radio frequencies electromagnetic waves to transfer information. These waves have wavelengths that are not within the visible space.

Light is also an electromagnetic wave. However, its wavelength is within the visible spectrum (between 330 nm and 700 nm). This is what make the light visible to the human eye. In fact, any electromagntic radiation having a wavelength between 330 nm and 700 nm is called “light” or to be precise “visible light”.

This means that we can explain Wi-Fi concepts using light analogies. In this set of articles, that is what we are going to do using simple drawings.

Diffraction, in combination with reflexion, allows Wi-Fi to go around objects in a typical indoor environment avoiding it from being totally blocked. This could be very good advantage if you think about it. However, everything has a cost. A diffracted wave is indeed losing power. This is an important fact to keep in mind! Another important fact to know about diffraction: the higher the frequency, the higher the loss. In Wi-Fi deployments, diffraction will, therefore, generate more loss on 5GHz transmissions than 2.4GHz transmissions.


Written by François Vergès

"Episode #1 - Radio Frequency Propagation" is still available!
"Episode #2 - Radio Frequency Reflection" is still available!
"Episode #3 - Radio Frequency Refraction" is still available!
"Episode #5 - Radio Frequency Scattering" coming next!

As we all know, Wi-Fi is amazing. The only thing is... it’s invisible.

So let’s start by explaining what makes Wi-Fi invisible? Wi-Fi uses radio frequencies electromagnetic waves to transfer information. These waves have wavelengths that are not within the visible space.

Light is also an electromagnetic wave. However, its wavelength is within the visible spectrum (between 330 nm and 700 nm). This is what make the light visible to the human eye. In fact, any electromagntic radiation having a wavelength between 330 nm and 700 nm is called “light” or to be precise “visible light”.

This means that we can explain Wi-Fi concepts using light analogies. In this set of articles, that is what we are going to do using simple drawings.

Drywalls, wood, metal or plastic might each, in their own way, refract radio frequency since the density of the materials are different. This can have a little impact on indoor Wi-Fi deployment.

However, refraction is most likely to occur in outdoor site-to-site Wi-Fi links since refraction is usually the result of atmospheric conditions changes. Changes in temperature, existence of water vapor or air pressure can cause refraction. And since the outdoor point-to-point link has to be perfectly aligned in order to work properly, a little bit of refraction can have a bad impact on the Wi-Fi connection.

Written by François Vergès

"Episode #1 - Radio Frequency Propagation" is still available!
"Episode #2 - Radio Frequency Reflection" is still available!
"Episode #4 - Radio Frequency Diffraction" coming next!

As we all know, Wi-Fi is amazing. The only thing is... it’s invisible.

So let’s start by explaining what makes Wi-Fi invisible? Wi-Fi uses radio frequencies electromagnetic waves to transfer information. These waves have wavelengths that are not within the visible space.

Light is also an electromagnetic wave. However, its wavelength is within the visible spectrum (between 330 nm and 700 nm). This is what make the light visible to the human eye. In fact, any electromagntic radiation having a wavelength between 330 nm and 700 nm is called “light” or to be precise “visible light”.

This means that we can explain Wi-Fi concepts using light analogies. In this set of articles, that is what we are going to do using simple drawings.

Reflection and multipath can have a bad impact on a Wi-Fi network since several signals, that had taken different paths, will overlap one another and will then interfere when received by the receiver.

To overcome this issue and take advantage of multipath, multiple streams and antennas are now used by the Wi-Fi technology. This has been introduced with MIMO and IEEE 802.11n.


Written by François Vergès

"Episode #1 - Radio Frequency Propagation" is still available!
"Episode #3 - Radio Frequency Refraction" coming next!

As we all know, Wi-Fi is amazing. The only thing is... it’s invisible.

So let’s start by explaining what makes Wi-Fi invisible? Wi-Fi uses radio frequencies electromagnetic waves to transfer information. These waves have wavelengths that are not within the visible space.

Light is also an electromagnetic wave. However, its wavelength is within the visible spectrum (between 330 nm and 700 nm). This is what make the light visible to the human eye. In fact, any electromagntic radiation having a wavelength between 330 nm and 700 nm is called “light” or to be precise “visible light”.

This means that we can explain Wi-Fi concepts using light analogies. In this set of articles, that is what we are going to do using simple drawings.

If we compare this example to Wi-Fi, the bulb could be an Access Point using an omnidirectional antenna. The signal strength would be the highest near the AP and it would decrease as you go away from the AP.
Does it make more sense?

"Episode #2 - Radio Frequency Reflection" coming next!

Written by François Vergès

Talking to a lot of small and medium business owners, they often tell me that they don’t really see any need in proposing free Wi-Fi to their customers. It sounds like it will be a real struggle for them.
The new Wi-Fi technologies actually bring a lot of advantages for businesses to deploy Wi-Fi and offer free Wi-Fi to their customers.

Here are the top 5 reasons why business owners need to provide free Wi-Fi to their customers:

Providing Free Wi-Fi to your customers makes them stay longer. Therefore, you are increasing the probability that they will spend money in your business.
Secondly, they would most likely come back to your shop knowing that they will be able to connect to the internet via Wi-Fi for free. According to a study conducted by the Yankee Group, “96% of customers prefer location that offer Free Wi-Fi and would return to stores that offer it”.

Having a Free Guest Wi-Fi is a wonderful tool to promote your business through social medias.
Some tools provided by Wi-Fi vendors (Airtight) or by third party companies (Purple Wi-Fi, Cloud4Wi,...) allow the users to authenticate through their social medias account. Doing so, they use their own credentials to connect to the business Wi-Fi network. There is no need to share a password anymore! This way, it is way more secured and easier to manage.
Business owners also have the opportunity to link their Facebook Page to their Free Wi-Fi network and ask the users to “like” their page if they want to use the internet. The users will basically promote the business in exchange of using the business internet. Knowing that a Facebook like is worth 174$, setting up a Free Wi-Fi can be a very good investment!
Of course, this process also works with the other big social medias (Twitter, LinkedIn, Google+).

In exchange of connecting to your Wi-Fi for free, you can ask for your guest name and email addresses. This way, you will be able to send them coupons and vouchers to keep them engaged. Using the social medias, you will also be able to performed targeted marketing based on your guest profiles.

When I go places, I always check if Wi-Fi will be available or not. It is important for me and I am sure it is for a lot of people. So to stand out from the competition or to not be left behind, you should start offering Free Wi-Fi to your guest. It has now became a must-have and you could actually lose customers (like me) if you are not. Think about all these teenagers out there with smartphones but no data plan. All they are looking for all day long is a Wi-Fi connection!

With the power of analytics, businesses that offer Guest Wi-Fi are now able to retrieve a lot of useful information for the development and growth of their business. Here are a few examples of type of data you can get:

• Age of your guests
  
• Email addresses of your guests
  
• Gender of your guests
  
• Times spent in your store
  
• Number of people passing by your store (potential customers)
  
• Locations of your guests
  
• Number of visits (engagement)
  

So as you can see, it can be quite powerful as a business intelligence tool!

Providing free Wi-Fi to your customers can be very beneficial. I see it as a win-win solution. However, you need to make sure that the service is working as expected. Indeed, remember than poor guest Wi-Fi is worse than no guest Wi-Fi!

Do not hesitate to contact us for more information! We will be happy to help you out.

written by François Vergès