How The Army Prepared Me For A Career In Wi-Fi
WLAN professionals come from many diverse backgrounds and their careers often take different paths. The majority of people in the Wi-Fi industry started in wired networking. As 802.11 technology grew in popularity, these same wired networking professionals also acquired WLAN skillsets.
I took a different path via the military. In the pre-802.11 era, I spent a few years in the Dutch Army as a communications specialist. We used a point-to-point wireless system called Zodiac. With a little luck and the right conditions, we managed to achieve the tremendous speed of 2Mbps at distances over 40 Kilometers.
The point-to-point wireless link enabled the military to send data and make phone calls over a secured connection. Zodiac needed few components to work, but these components where so large you needed big lorries to transport and operate the entire solution. To provide power for the system, a 6 kW generator, which required a few litres of diesel every 24 hours, was embedded on the truck. The entire combination weight was around 25,000 Kilograms.
Figure 1 shows a rapid deployment mast capable of elevating the antenna up to 26 meters. In the rear of the vehicle was the communication shelter, which was equipped with two redundant radio systems and antenna steering elements. Rapid deployment masts were a luxury because 90% of the total deployment work was manual.
Once deployed, we had to run redundant cables and connect them to a central nerve system where all the other connections came together. The central box on wheels functioned as the switch of the network and provided centralized network management and security.
We would manually load crypto keys in order to secure the connection. We also had to make the necessary RF link budget calculations for the Fresnel Zone and free space path loss (FSPL). Because these were point-to-point wireless links, we always needed the same antenna polarization and crypto keys. A highly-trained group of people could get a link up and running under 10 minutes. An entire company of a signals battalion could deploy eight or nine operational point-point links within an hour. A proper deployment required cable runs, radio setup, crypto setup, as well as camouflage and physical security of the site.
Are there any similarities to the wireless of my military past to the modern-day Wi-Fi?
For an outdoor 802.11 point-to-point link, we no longer need a giant trunk with a radios, diesel generator, and a rapid deployment mast. Instead we can use a much smaller outdoor bridge such as the Aerohive AP1130 along with directional MIMO patch antenna. We still need to make sure the Fresnel zone is free as much as possible, and we have to run a cable between a switch and modern-day access points.
The basic laws of physics apply to both 802.11 WLANs as well as the RF links we deployed in the military. Instead of using crypto key for security validation, we now use certificates within an 802.1X/EAP security framework. A modern-day centralized network management system (NMS) no longer sits on a truck but instead can exist in the cloud.
Of course the WLAN solutions of today are much more affordable and they also weigh a lot less than a truck. Even today, the military uses commercial enterprise WLAN solutions for some of their wireless communication needs.
I wonder what the next twenty years will look like!