Wireless Access

Hello Aruba Team!

We have 15 access points (315s) in our fabrication plant. We use zebra (ZT 230) units to print labels and ras pi units to RDP. These APs are all connected to 1gig ports via Aruba (2930Fs or HP zl switching, using POE)

We can physically see the zebra printers move access points. (even though they are stationary)

In this example we are showing zebra printer 5, its literally 10 feet away from the AP. In this example there are 3 APs within 150 feet. 2 on the other side of steel walls, one in the open air (within the 10 feet)
Zebra 5 connected to a 4th AP more than 300 feet away, in this picture you can see the ping drops. Clearly....makes no sense.

We have dropped the power from 28/MAX to 12/21 so that its not so strong and the devices dont get confused as easily? (this is an assumption)

All Arubas are on 8.6.0.2

We pushed the controller to a syslog to gather more information

I am at a loss as to why these printers would jump.

My only thought is to try and force them to 5g, sometimes they are on 2.4.....

We have tried to remove select APs, and it just leaves a dead zone.

We are not wireless experts by any means, and are still actively

reading and troubleshooting this issue.

AP3 as shown has noise issues, as do a few others. We don't know what that means or how to fix it. The zebra in question, happens to connect to one of these with noise issues.

Any help would be appreciated.

Regards,
Wally

To see what's happening I would take a wireless packet capture....

But maybe you can check if the clients has the correct channel in their scan lists? 

So you have 802.11 k, v, r enabled? 

Here is the scan list, we assumed its ok, I think its default.

as for So you have 802.11 k, v, r enabled? 

I am not sure. How do I check?

Are those printers 5ghz capable?  If yes, you would need to turn off 80mhz channels, turn off Wide channels (40mhz) and limit the regulatory domain to the channels to the Zebra printers support, otherwise you would be creating coverage holes.

How high up are the access points mounted?

Yes printers are 5g capable. Currently the pull down on allowed bands says all.
We can specifically set this to 2.4g or 5g We were going to test.

APs vary in height depending on forklift clearance. In this case its about 12 feet up, and this zebra is almost directly under it. Now there is also a transformer closer to this hop. We could in theory move this AP, however I dont think that will make much difference. There are other access points for it to choose from, and it still goes to one very very far away......

We can also force the zebra to use specific channels by removing or adding.

Some chanels we noticed have a E or a + like 149E or 36+ We dont know what the E or + means, but noticed that the zebra does not have E or + in any lists, yet still will show 149 as an option.

E means 80mhz channels.  Which means fewer channels.  According to the specifications here:  https://www.zebra.com/content/dam/zebra_new_ia/en-us/manuals/printers/industrial/zt200/zt200-ug-en.pdf the maximum transmit power is 18.62 dbm, so you can try capping your maximum transmit power to 18 maximum to avoid constant roaming.

The access points you have are downtilt omnidirectional antennas, so the best coverage is not right under it, but on average 45 degrees away from center.  There should be overlapping coverage.  I would use the Aruba Utilities app in the Android store to get a sense of the coverage in the area of the printer(s).

These are just guesses so use things like the ping utility to see how things are going and the GUI to determine if the device continues to roam.

Your accesspoints still send 21dBm what is 125mW of tx-power thats quite high.

Three thing to try:

1. Lower you tx-power more to max. 15dBm what is 32 mW.
2. Disable the lower basic and transmit rates (all below 12mbit to start with).
3. Dont use 80Mhz channels, go to 40Mhz.

Lower the power give you less co-channel interference. Disable the lower rates force a device to roam more early to a nearby AP. Change from 80 to 40Mhz channels give your more channels available to avoid channel re-use and also co-channel interference.

Marcel,

Here is a picture of the AP radio settings before we changed them yesterday. I can reduce the power a bit more thats easy.

I dont know how to do the other things.

Interesting on the direction.

The closest AP is pointing UP to the ceiling, the next closest is in between two steel beams, also pointing up.

AP 14 is mounted properly on a steel beam (these beams hold up our building hehe)

Do you have any pictures?  All access points, (unless they have external antennas) should be pointing down...

I could go and take some, but they are for sure 100% not facing down, they are facing up.

What are they mounted to, if they are facing up?  Just one picture might answer that question...

Very few of them in the plant space are mounted. Most of them are basically sitting INSIDE the rack. The rack is strapped to a steel wall with a custom mount.

If they are not sitting INSIDE the rack, they are sitting on top of the rack. I could have them mounted with the standard HP mounts that come with them.

The transmit rates can set in the WLAN settings, you have to click "advanced settings". Put both radio to min.12 - max.54

Never place AP inside a rack, thats known as #badfi.

As Collin mentioned to, always place AP with internal antenna's facing down to get the right polarization of the antenna's. Placing AP in the right way is extremely important for every Wi-Fi design to avoid issues.

In the image you send you will see 80Mhz support is enabled, turn it off.

Is there a reason why you disabled clientmatch, recommended to leave it on.

Ok, we can make a few changes. I don't want to make too many at once.

The person that set this up said that the Client Match was disabled by default.

Let me make some changes and see what happens.

Marcel,

Here is a picture of the settings for that network.

The image you sent is slightly different but I think that the basics still apply.

We would like to help you but you really need to place your AP in the right way with the right mountkits.

Do not place access points like a clock but use hook mounts to face them down. Also don’t place them inside a rack or inside a steel collum. That is a bad idea.

Best you would consult a certified wlan engineer to do proper design your WiFi. Also a validation wifi survey is more a must then recommended.

see example of good placement below

How high up can I have these mounted?

Our truss height in the warehouse is sometimes 32 feet. Its a perfect spot to mount them, and way out of forklift smashing range.

If way up high is not an option, could I do say 2 Arubas on a steel beam using the mount you have shown here, and cover almost a full 360 around the beam?

Our warehouse is 640,000 square feet, with moving steel in it. We are working on basic coverage in 2-3 key areas only at this time.

32 feet would be fine with current downtilt omnidirectional antennas.  You would want to plan for some overlap, however so you should do a survey after you mount a few APs at that height to understand the coverage.

The content in this document, even though 10 years old, is still valid:  https://community.arubanetworks.com/t5/Community-Tribal-Knowledge-Base/Wireless-Design-for-Stores-Warehouses-amp-Manufacturing/ta-p/21618

To be clear, deploying wifi in a warehouse is probably one of the most difficult challenges, so if you can obtain professional advice to do it, that would be key.

In general, at 32 feet, you could deploy APS every 150 feet with some overlapping coverage to account for the null that is created right under some access points.  You would still have to make decisions based on whether or not the product directly under the access point will change or not.  The document listed in my previous posts details some of those challenges and ideas of how to mitigate.

Thanks guys, I will start making changes and do more testing.

Is there a tool for us to do our own survey? One of the issues is that steel moves around, we have baskets of parts that are literally 24++ feet high that get moved daily by forklift as customers order products.

Our current wireless stations are fixed, HOWEVER, they are on rolling carts and could in theory move later.

So we have all kinds of fluke network testing stuff for deployments just nothing to test wireless anything. Any recommendations?

Oh one more idea, we dont have a heat map. What software do I use to build one? Visio?

Again, deploying a warehouse is not easy and you would typically engage a professional who has deployed a challenging deployment like a warehouse before.  You would typically deploy access points in Aisles where it would not be disrupted by stacks of product.

Professionals typically use Ekahau Survey Pro to do an actual site survey.  I am sure there are lower cost options, but nothing that I would recommend.

Forklifts are always a issue to keep APs safe in warehouses. 

The IAP-315 has integrated antenna's with some downtill. I see other deployments at max. 10 meter without any issues but this is the ultimate maximum. 

Most warehouses use AP with external downtill antennes for optimal performance and avoid channel interference. In open space keep your tx-power low as possible for the -60dBm/-65dBm signal strength on the clients.

Mounting on a steel beam have a negative impact by the nature of steel surfaces but when place it 5cm away from it will be fine. Off course the steel beam works as a shield in that direction, so don't suspect 360 degrees coverage on a steel beam.

Warehousing in a "steel factory" is always a challenge but take into account the filling of the storage racks that can be variable and that your devices maintain a visual connection to your access point (not blocked by some filled storage racks from client device perspective).

See this video from wlan proffesional with usefull information about wlan design in warehouse. But as Collin said to, it isn't an easy task without the right knownledge and tools.

https://www.youtube.com/watch?v=GHLNVywpARE

Note. WLAN Proffesionals have a lot of good documents and video's.

If you want more about WLAN design i recommend to books, but you will need a lot of time to read it

• https://www.amazon.com/Certified-Wireless-Network-Administrator-Study/dp/1119425786
• https://hpepress.hpe.com/product/Aruba+Certified+Design+Professional+Official+Certification+Study+Guide++HPE6-A47-eBook-18743

For WLAN surveys i use Ekahau Site Survey Pro with a Ekahau Sidekick Spectrum Analyzer. But you need a building map on scale to create an good heatmap. Maybe an emergency map can help you.

This is great thank you. In the covid era I have nothing but time to read and study.

We also have engineers on staff in various functions so I'm sure we have an autocad to scale of our building somewhere. They did provide me with a map this week that I have been drawing on it to figure out where all the access points are. I inherited this project so just getting up to speed, and trying to troubleshoot some issues.

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@wlacroix wrote:

Very few of them in the plant space are mounted. Most of them are basically sitting INSIDE the rack. The rack is strapped to a steel wall with a custom mount.

If they are not sitting INSIDE the rack, they are sitting on top of the rack. I could have them mounted with the standard HP mounts that come with them.

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If they are in a rack/cable tray, they should be pointed down, so that you can see the lights from the ground.... 

Here are pictures of the Arubas, only one is mounted nicely

Aruba 14 was easy because the beam is right there.
Aruba 3 is inside the cabinet, Aruba 11 is literally inside the steel beam because that is a firewall.

Yes that is also a transformer beside Aruba 3 cabinet. The zebra printer is below and to the left. We had it 25 feet

Sorry for the bad iphone pictures.