Definition: am·bush noun a surprise attack by people lying in wait in a concealed position.
Life as an Aerohive SE is never boring. I go from meetings where I get to introduce Aerohive to a prospect, to a configuration best practices session with veteran customers, and often follow that up with dinner with a partner.
Although, I always have to be on my toes, as sometimes a seemingly innocuous meeting has a hidden agenda. This is a story about how Aerohive’s HiveManager saved me in just such an ambush; when I thought I was showing up to build my relationship with a new customer and instead walked into a heated war room with a giant target on my chest.
Early on in my days with Aerohive I had a couple of established accounts turned over to me, sometimes to those customers’ chagrin. From their perspective my predecessor was moving on to bigger and better things (Florida and Georgia to be specific!) and they were getting stuck with “the B-team” engineer.
It was my job to prove them wrong and I diligently went about that job. One of those transferred accounts had only recently made a highly political decision to completely replace their existing and well-known brand Wi-Fi with our lesser-known Aerohive brand. This decision was obviously being scrutinized in the early days after the decision, and any hiccup or problem was instantly magnified into an all out emergency almost immediately.
The customer engineer who was given lead on this wireless transition project was a veteran switch engineer, but was still fairly new to wireless. He’s a pro now but when this story happened he was still wet behind the ears on Wi-Fi and this showed in his confidence about what he deployed and how.
So I show up on a Friday morning expecting an easy meeting and a good lunch with someone I was trying to befriend before I travel home. Before we could barely say hello he grabs me and immediately walks me to a strange floor and opens a locked door next to the data center. Inside is nothing less than the entire networking team and THE network architect for this entire company network with thousands of locations and tens of thousands of end users.
I barely get inside the room before the questions begin on how our access points (APs) process authentication requests. I am subjected to a good bit of grilling with frequent interjections stating that this is “your fault” and “something is wrong in your configuration". I barely had time to breathe! I actually had to ask to go to the bathroom simply to prevent myself from blowing up on the network architect who was hammering me so hard.
When I got back from my cooling off session, I started asking questions about the problem and symptoms. The problem was described to me in the following manner: On the executive floor of the main building, users were unable to consistently authenticate to the Wi-Fi that was recently deployed there. We were unable to go on-site to this floor due to certain highly sensitive meetings happening at that time (which also exacerbated the issue since those same meetings wanted Wi-Fi connectivity.)
I was repeatedly assured that the two APs that were deployed were sufficient to cover the floor based upon the statement that “two APs were all we needed with the old (wireless) system". I asked to see maps with coverage heat maps on them within HiveManager and none existed.
Our sole troubleshooting method was to review the configuration and to talk, on the phone, to the one secretary who was allowed to roam the halls on this floor with her iPad.
Since I was not allowed onsite to see myself, I insisted on floor plans and used HiveManager’s Maps tool, much to the chagrin of the Network Architect who kept repeating that Aerohive’s authentication was “all wrong". Once floor plans arrived I immediately added them into HiveManager and started building out the walls. One little detail became immediately obvious to me, there was a bank of elevators in the middle of this floor and both APs were on the same side of this elevator bank.
(WARNING: SCIENTIFIC CONTENT FOLLOWS) It seems appropriate to interject a quick discussion about why this bank of elevators and other wall contents on the floor were so important. RF signal will dissipate over time and distance naturally due to a phenomenon called Free Space Path Loss (FSPL). This degradation of signal is a known and fixed rate that is in direct correlation to the frequency that the signal is transmitted. Physical obstructions will cause additional impedance to the signal resulting in further degradation. The rate of this degradation is dependent upon numerous factors such as thickness, material composition, material density and water content, among others. A thin single-pane glass window will cause very little signal loss whereas a plate glass window with wire hatching and a tinting film will cause significant loss. An elevator shaft, due to the cement walls, imbedded steel structures, and pure thickness is another obstruction that will cause significant loss of signal.
After I finished modeling the walls and elevator banks I asked to get the secretary back on the phone. Using the map I was able to pinpoint her location and accurately predict that she would not have coverage at her desk. I was then able to direct her to the closest coverage area (at an angle away from the elevators) and she was able to connect. I then directed her into the coverage area of the other AP on the floor and she connected again.
Through this process and the visuals provided on the map, I was able to convince the entire team, including the skeptical network architect, that the problem was a matter of coverage and not configuration. This quickly turned into a discussion on where to place additional APs so I quickly went in 
to teaching mode and discussed optimal AP locations based upon the data provided to provide coverage to key locations. Hopefully an SE is always looking for a chance to educate and in this one I had an interested audience for sure.
We were not able to “save” the day that day but they were able to get additional APs deployed at their next scheduled outage window and that proved out, in actual test, what I had shown them in the site survey tool.
This story highlights the importance of good maps and knowing what you are deploying and where. It also highlights how knowing your gear and what it can do can really help save the day when you too walk into your next ambush.