Saturday, December 31, 2016

Using Sensors for Client-side Wi-Fi Troubleshooting


Building wireless networks is something that, with the right amount of engineering and experience, can be simple to do for the right people. Choosing equipment, locations to mount that equipment, and choosing how that equipment operates are essential elements to wireless network design. They are also things that we can control. But what we can't control are our end users. We cannot control what type of device they use, when they use it, what they use it for, or how often they use it. 

When troubleshooting wireless networks there are essentially two sides to the process: one side is from the network equipment and the other side is from the client. 


While there are thousands of tools available to assist in monitoring, managing, and manipulating the way the wireless networks work from behind the access point there are very few good tools that are built for collecting data, analyzing data, and automating the troubleshooting process from in front of, or on the client side of, wireless networks. This is one of them.


Enter a New Breed of Tools: Wi-Fi Client Devices as Monitors

A few years ago a new set of equipment and tools started to make its way into the market that would help give a better holistic view of a wireless network to administrators and support staff monitoring in maintaining wireless networks. As sensors for all types of devices have become more common, they stand to change the way we interact with almost every aspect of our jobs. Now, wireless network engineering is no different. While some of the tools that tried to take this on have fizzled out, a few have made their way to the top of that marketplace.

One of the early groups with a viable product for the market, NetBeez, a graduate of Y Combinator, continues to provide a fantastic product that can operate on standard equipment, something as simple as a Raspberry Pi. It's dashboard is simple and straight forward and gives you great information about the networks the NetBeez sensors are connected to. You load the software on to the Pi or buy one of the devices pre-loaded, and fire it up. It connects back to the cloud data collection service, and you are set!


A benefit to the NetBeez product is that the Wi-Fi adapters are external to the Pi hardware which allows you to change out the adapters to work with new technology (assuming the drivers support it!) 

As a presenting product at Mobility Field Day 1, we got to learn all about what their product does, how it works, and why they built it. Watch more below:




As NetBeez continues to innovate their software, another entrant into this segment appeared, manufacturing it's own hardware and including a slew of new features as a result of self-manufacturing. 


One of the early innovators in that segment was a company called Asimmetric. Asimmetric gave you the ability to set up a client on an existing wireless network and that client would report back a number of different measurements and metrics to let you know how the wireless network was behaving from the client-side perspective. Founded by a group from Cape Town South Africa and funded by some North American VCs (including Bolt who seed funded one of my favorite products for non-profits - DipJar and Highway 1 who backed this year's must have Christmas gift - Loop) this product has now been re-branded Cape Networks. In late 2015, the first commercial production run of their sensors were sent out to a few very lucky people in the industry. I just happened to be one of 'em :-)

About the Cape Networks Client-side Wi-Fi Sensor 



At 6" x 6" and about 2 inches tall, the Cape Networks sensor looks like a small form factor access point. It is very low profile, statically pleasing, and ships with a number of different mounting types to allow for a simple installation. It supports up to 802.11a/b/n and both 2.4 & 5GHz frequencies. 

Installation and configuration 

There is not a lot to the installation of this product, you can either supply power over Ethernet, or a combination of power and Ethernet, or simply plug the device into a power source for it to get online. Wait, power only? Yup.



One of the key differentiators of this product is that it has a built-in chip set to support T-Mobile so that it does not need a network connection in order to transmit it's data back to the Cape networks cloud service for you to review. To me that's pretty awesome and also takes a very commonsense approach to a sensor like this: how is it supposed to monitor the network and report that the networks down if the network is down?


Once able to communicate with cape's cloud services, it uses its unique identifier that is assigned to your account to pull its configuration from the cloud and associate to the wireless network it's supposed to be looking for. It immediately starts monitoring and reporting that data in real-time back to the cloud dashboard.

What the Cape Networks Sensor Monitors & Measures


Simple measurements such as RSSI level, SNR, which frequency and channel the client is on, as well as which access point The client is associated with are obtained, stored, and graphed. Values like jitter are calculated while latency, round-trip time, and throughput to public sites like Google, YouTube, Facebook, and Dropbox are measured from the client side.


All of this is reported back in a very easy to understand webpage complete with graphs, spark lines, and measurements that are synchronized as you move your mouse across the timeline of events. An event log on the left-hand side shows you what events are taking place and as your mouse over them it shows you where on the timeline that event took place, which usually coincides with the network event such as a channel change, frequency change, or an access point change. All in all, it makes seeing what's happening on your network very easy to see and understand as each event and it's related effect are captured and correlated in real-time. 

How Cape Networks Sensors Monitor Client Wi-Fi 

One of the things that I like the most about the platform is it's interface. I have been hoping for years that someone would come up with a wi-fi experience index; a way to have a number from 1-10 that would be an all-encompassing statistics letting you know what the client experience is like. This is almost like that, except it uses the traffic signal system: red for bad, yellow for functional but issues, green for good.


With a quick glance you can see how your clients are viewing your network. 
What happens behind the scenes is the magic component that makes this solution some thing awesome. By combining the massive amounts of real-time data and crunching it together a score or indicator value is produced. I'm not sure what the exact formula is, but something like slow DHCP address assignment can make a user unhappy, therefore give you a yellow face. When combined with poor signal or low SNR, that's definitely a "red face" situation. 


So what happens when the power goes out? This is pretty cool: they call it last gasp power. 4 built-in supercapacitors maintain power to the device for about 40 seconds so it can figure out if power is down on the Cape monitor, the AP, or both to let you know why it lost a connection. Pretty smart.

What are the Benefits of client-side Wi-Fi Monitoring?

There are a few. From a VAR / Integrator / Managed Service Provider perspective it is blatantly apparent: you get to see the network you're monitoring from the end-user's perspective.
When a customer tells you "the Wi-Fi sucks", now you can quickly and easily understand why they say that. Even if it's not the Wi-Fi.
This helps you know where problems are by giving you a complete 360 degree view of your customer's deployment.  When there are issues that arise, even though everything looks good from the top down, this is a fantastic tool to give you the visibility you've been missing from the bottom up.



From the customer's perspective it helps you hold your MSP to the flame while giving you statistics about how your network is functioning in addition to validating all your crazy claims of "the Wi-Fi isn't working".  A tool like this can be an asset to an enterprise environment looking to streamline troubleshooting while being proactive about network issues. It's robust enough for the I.T. team and simple enough for management to see what's working and what isn't.

Final Thoughts


So, all in all I love where this space is headed. These devices are providing vital visibility into wireless networks that can impact the way networks are built, maintained and administrated.
The Cape Networks sensor is sleek, simple to use, and does exactly what it's supposed to do. It has saved me money, made me money, and made me look great all at the same time.

No matter which side of the fold you're on, customer or integrator, it can be a view into your network that you would be foolish not to take advantage of. 

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