Understanding Cisco Prime Wireless map

[erga]

I need some some help understanding the Cisco Prime map. The AP on the right I think it shows the right colors, the dbm value. Why doesn't the AP on the left have the same strength. Is it something I need to look into AP settings.

[Diego Luiz de Souza]

Hi,

Make sure you are looking the correct heatmap (2.4GHz/5GHz). Maybe some of the APs have lower power level or their radios are shut down.

[erga]

I'm looking at both 2.4 and 5GHz.

On 5GHz the tx level is set manually at 2 and I still don't see the strong rssi signal.

On 2.4GHz the tx levels are set as automatic and the automatic values are 7 and 8, meanwhile there are no coverage areas. All APs are in the same group, if I manipulate the tx values manually I get a wider coverage area in blue, but why don't I get the strong signal area surrounding the AP.

I'm not very versed in wireless and I'm trying to figure out why we're having some issues, and this is what I noticed in the maps that doesn't really make sense to me.



Erga

[Diego Luiz de Souza]

Ok, I can see the radio color of the icon on the left access point is blue. It means the AP is not associated as you can see here:

https://www.cisco.com/c/en/us/td/docs/net_mgmt/prime/infrastructure/3-2/user/guide/bk_CiscoPrimeInfrastructure_3_2_0_UserGuide/bk_CiscoPrimeInfrastructure_3_2_0_UserGuide_chapter_0111.html#concept_C7D91E4091814A719BF9420DCBDA9F62

So that's probably the reason you are getting poor signal at this place.

[erga]

I attached the wrong picture. The AP on the left there is off The AP on the left and on the right are on two different sides of the area. I am looking for -65dbm coverage and lower and I have huge areas not covered. That picture is 2.4GHz where I have left the power set to automatic. If I set it manually to 2 the area will be eventually covered but I don't get the strong dbm areas as I do on the right.

The radios are up, I'm scratching my head as to what is different and its all configured identical. As a matter of fact the power for the AP on the right is automatically set at 4, so its even lower than the AP on the left. 

[Scott Fella]

One thing you have to understand is that the Prime map is predictive and doesn’t mean that is your actual coverage. Site survey is the only way to validate your true covert at that given time. I do not show the heat map at all, usually on client count or just ap name.

[erga]

I understand its all predictive, my concern is that Prime is thinking that this AP is not offering strong signal strength. In theory my office is pretty straightforward, open space with cubicles, so if I see the right signal strength I won't have many problems on site (I do realize a site survey is a sure way to know what coverage I'm having). If Prime thinks this AP only offers this signal strength maybe something is not configured right in the AP itself and that's why Prime is reading it this way. 

Cisco TAC thinks my environment is overcrowded and APs are adjusting their power level to really low, and this is causing issues with phones bouncing from AP to AP when they use the 5HGz band.

[Diego Luiz de Souza]

I'm not sure that your Cisco Prime is able to read information from your WLC, because in the screenshot you shared there are no clients connected.
I suggest you to validate the signal in place and then validate your APs and Prime configs.

Also, what TAC said doesn't really make sense, because Auto-RF adjusts power level based on the power level of the neighbor APs (your APs within the same AP Group). If they can listen to a very strong signal from one of your APs, they will reduce their power level until it's balanced. When there are too many people/devices on the floor, there's no change on the power level.

You can also try static power levels and see if the results are good (that should be disruptive for the clients).

[erga]

Because there are no users on 2.4GHz. Here is the 5GHz map, there are users connected.

I have had good results by manipulating the power level manually, I am trying to find a good combination of AP number and distribution that offers a good coverage, and configuring the power levels as automatic. That is the reason I'm using the Cisco Prime maps, but why are some APs generating normal signal strength and some are not, or why does Prime think that. Anything I should look at in the configs that could cause this map view.

[Scott Fella]

Well you have to look at what the txpower shows and compare that with other AP’s in your environment. Few things also is that you should scale your floor, Mark the areas where you want coverage and the areas that are not covered. Also look at the adjacent neighbor rssi from the ap, if you see few AP’s or adjacent neighbors with not very strong signal, that can also be why.

Again, I see that also and I don’t worry about that. I do know that I have more than enough coverage also.

[erga]

The tx powers are all the same or similar. After modifying them manually for 2.4GHz, now the map looks right, not the same thing is happening for 5GHz (which is where I'm having problems)

I don't understand how Cisco can have a tool that works so bad, and can't even show me what the map would look like in "ideal" conditions. Now I don't know if I actually have those empty spots, I certainly know I don't need more APs. 

[patoberli]

I suggest you don't trust the maps at all. It's also well possible that you are hitting a bug, there were plenty in the past.

[Scott Fella]

Don’t expect PI to tell you what coverage you have. This is what survey tools are used for. Predictive is predictive, so its 50/50 how I see it.