Part 1 – The Assessment
Before any wireless project, I recommend an assessment. If there are reoccurring issues with a current wireless deployment, I recommend an assessment. If a site wants to expand their wireless into new areas with new applications, I recommend an assess…. well, you get the idea.
I also prefer the term “Wireless Assessment” over a “Site Survey”. Sure, my assessments include passive surveys (and on occasion active ones), but there is so much more to it than that. There are interviews with key personnel and users, there are end devices to evaluate and software requirements to understand. Let’s not forget my favorite part, spectrum analysis! So, a “Site Survey” just doesn’t cut it.
All of that being said, let’s jump right into what I do for a wireless assessment in an industrial/manufacturing environment.
Info Gathering & Recon!
The first, and arguably the most important question I ask is WHY? I need to know why I am doing this assessment.
Is it a “greenfield” location that doesn’t have any wireless connectivity? Are they wanting to expand a current deployment? Is their current wireless infrastructure plagued with device drops and disconnects? Is the wireless painfully slow? Is it indoors, outdoors or some combination of both? Is this assessment even for a standard data access deployment or is it for wireless IIoT sensors and devices?
The next thing I push for is information on the wireless devices they are either using currently or want to deploy on the factory floor. I ask for specifics like device type (handheld scanners, tablets, smartphones, etc.), device manufacturer and model numbers. Why is this important? Because I need to know what the capabilities of those devices are. For example: What are their max TX values? How many spatial streams do they support? What types of wireless security are they capable of? Do they support 802.11k, v and r for fast roaming?
Then, before going on site, I am after the client to get me any/all site plans they have for the areas that are in scope of the project. These drawings are obviously important for active/passive surveys, but also for predictive planning.
Now, does this mean you will always get them? That would be a big NO! I have been to sites that the only drawings they had were the mandatory fire escape plans that showed available exits and were nowhere near to any sort of scale. Some sites didn’t even have those. I have actually had two different customers hand me over weird drawings done in Microsoft Excel. One plant in particular had just lost all of their CAD drawings due to ransomware that hit their business side servers. I ended up digging through their archive of old physical drawings (which were from the 1950’s and 60’s) to find material to use for the assessment.
At some point during the Recon phase, I’ll punch up the site address on Google Earth Pro (which is free) to get a feel for the physical space the plant takes up and what the environment looks like around the facility. Is it in the middle of town? On the coast or other body of water? Is it out in the middle of nowhere? All of these factors are important and can influence the sites wireless in one fashion or another. I will grab some preliminary measurements of buildings that are part of the assessment. These measurements have saved me several times when all I got from the customer were drawings with no measurable scale.
Talking and Walk-about
Most often, the first day that I am on location I don’t even break out my wireless gear. I like to use this time to finish up any info gathering that could not be completed beforehand, and for talking.
Lots of talking.
I like to talk to my main site contacts to gain further understanding of the project and its scope. I can usually get a really good idea of any additional problems there may be that didn’t get passed through in the main request for assistance.
I also try to understand any wireless policies they may or may not have in place. The assessment will reveal quite a bit of information about their environment, and I need to know what to focus on. More often than not, many wireless networks are discovered that the client was not aware of and can lead to more serious policy discussions.
I like to get out and talk to the users on the factory floor. What are their experiences like? Are there specific areas where they have drops or slowdowns? Are there places where everything works great? Do some of their devices work better than others? Does the wireless seem to work better or worse at certain times of the day? Sometimes I get some the best information from these conversations.
After talking until I am blue in the face, its time to go walk-about. This is where I have my site contact walk me through the entire area of the assessment. As I walk, I am paying attention to building materials looking to identify things like reinforced concrete, steel framework for ceiling grids and walls. I look for specific items like Variable Frequency Drives (VFDs) and their associated motors which if not shielded properly can create non-WiFi based interference. I ask questions about the various types of machinery used throughout the facility. I look for tangles of piping and conduit and other things that cause large amounts of RF reflection. I try to identify primary pathing for industrial trucks and automated vehicles.
While on walk-about I am also looking at physical environment. Is everything indoors or outdoors? Is it a mix of both? Is the space covered with a roof and walls but still exposed to the elements? (Which is actually very common by the way) Also, what are the temperatures and humidity levels like? What about dust?
Finally, I play Eye Spy and try to find as many of their currently deployed access points as possible. What kind of antennas are being used? How and where are the antennas mounted? What about the AP’s, how are they mounted? If exposed to the elements, are they properly weatherized? Are they industrial grade or standard indoor office models? I take a lot of pictures while doing so to look back at later.
Now that I have gathered a mountain of information, attained, and calibrated some kind of site drawing/plans, and gone walk-about to familiarize myself with the site, it’s time to break out the toys!
For active/passive surveys and predictive planning I use AirMagnet by NetAlly. The nice thing is that now that I have my AirCheck G2, I can use that for spot checks and troubleshooting as well as portions of my surveys too! Such a useful tool. After my first run through with either my AirCheck or on my Surface Pro, I take a quick look at the preliminary results to see if I missed anywhere important. If so, I make another pass through those areas. Once I have verified that I have surveyed everywhere I needed to, I put away AirMagnet and break out my box of MetaGeek adapters!
For standard WiFi scanning, wireless PCAPs and spectrum analysis, I use the MetaGeek suite of wireless tools. I have been a fan of Chanalyzer for a long time and have the adapters to capture 2.4GHz, 5GHz and 900MHz. (As soon as they have one for 6GHz, I’ll pick that up too!) Then I head back out and hunt down the locations that I took notes on earlier during my walk-about and start getting spectrum recordings. I sample with everything thing I have and note my recording locations. As the old saying goes, I would rather have and not need than need and not have!
After all of this complete and I am armed with a boat load of information about the client’s airspace, it’s time to pack it up and head home to begin the analysis and reporting process.
But I’ll talk about all of that in Part II. See y’all next time!
If you have enjoyed what you have read, follow this blog as I share my experiences, blunders, how-to’s, tips and opinions in all things OT Wireless from the wonderful world of industrial WiFi!