topic Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ? in Aerohive Migrated Content

We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

ken_vanden_bran — Thu, 27 Dec 2018 20:27:39 GMT

My guess would be there's other devices interfering. Is this the best to measure these?

show interface wifi1 _counter

--------------------------------------------------------------------------------

215 recv eol interrupts

1397703 rx frames

15868 rx data frames

14596 rx unicast data frames

855 rx multicast data frames

417 rx broadcast data frames

1381003 rx management frames

832 rx control frames

1181 rx unknown frames

111 rx BAR (Block Ack Request) frames

1398884 11n rx frames

703 rx chip antenna errors

962 rx Retries

6% rx retry rate

685040 rx CRC errors

684600 rx CRC errors with no physical error

32% rx CRC rate

54040 tx data frames

9544 tx unicast data frames

32683 tx multicast data frames

11813 tx broadcast data frames

--------------------------------

52669 tx WMM best effort data frames

60 tx WMM background data frames

616 tx WMM video data frames

695 tx WMM voice data frames

1504421 tx management frames other than beacon

1462603 tx beacon frames

1 tx global timeout interrupts

1 tx carrier sense timeout interrupts

140 tx BAR (Block Ack Request) frames

742 tx aggregated completions

5936 tx retries

2444 tx RTS failures

3492 tx retries

2893 unicast data tx retries

2444 unicast data tx RTS failures

449 unicast tx retries

23% unicast data tx retry rate

1390 tx retries of sub frames

44513 tx frames with no ack marked

4556 tx frames with short preamble

781 tx frames with an alternate rate

304 tx frame errors

304 too many hw retries

511 tx available buffers

512 rx PHY error summary count

61905 tx frames succeed

rx phy err:

1 transmit override receive

511 OFDM restart

-128(invalid) tx rssi of last ack

13 rx rssi from histogram

21730 periodic calibrations

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

samantha_lynn — Thu, 27 Dec 2018 21:41:29 GMT

Yes, that's exactly what you want to be looking at for RF interference. CRC errors are usually related to environmental interference factors. These factors include mainly metal, glass, water, or large amounts of people. All of these factors tend to reflect, refract, or generally damage your signal, leading to more retries, which leads to slower WiFi speeds. So for your output, we can see that 32% of your packets are failing at least once. Anything below 10% is negligible, but 32% is certainly a problem.

You've also got some unicast data TX retries as well (23%). I'd be interested to see what the results of "show acsp neighbor" are. With that output we want to look at the RSSI column. These values depict how loud the neighboring APs are, or in other words how much air space they are taking up. For these values we want to see -75 or lower. The closer to 0 this value is, the louder that AP is, and the more interference you will be experiencing.

Some other things we could do to help with interference would be to disable lower data rates to only allow clients to connect to APs they have a strong connection to, disable short guard interval if it is in use, and make sure we are using 20MHz or 40MHz channel widths instead of 80MHz. If you can let me know which HiveManager platform you are using, I can give you more specific instructions on how to do this things within the GUI; HiveManager Classic (myhive.aerohive.com) or HiveManager (formerly NG, cloud.aerohive.com)?

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

ken_vanden_bran — Thu, 27 Dec 2018 22:00:29 GMT

Hi Sam,

Quick response. Loving it  cheers for the information.

I got this data through the "tech data" dump. We're still on the hivemanager classic.

Here are the neighbors in this case (see attachment). Mind you the 32% crc rate is both on the 2.4 and the 5 ghz bands.

And that's just this AP. I'm encountering AP's on different other floors with as much as 80%. Pretty sure i'm gonna learn a lot handling this 🙂

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

ken_vanden_bran — Thu, 27 Dec 2018 22:04:48 GMT

I believe the quite decent neighbor values mean that we have other factors contributing to our situation. We have a lot of other wireless equipment though.

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

samantha_lynn — Thu, 27 Dec 2018 22:13:45 GMT

Thanks for the neighbor output, I'm seeing three neighbors in the -50's, which is too loud so that would be causing some overlap and interference. Fortunately they are Aerohive devices, so we should be able to adjust their power down to fix this.

To do this we want to go to the Monitor Tab> Select the check box next to the AP> Modify> and lower the power on the drop down menu. If you have Maps uploaded to your HiveManager with the APs placed in their respective locations, and if you can provide your VHM ID, I can take a look and give you specific power recommendations. In general, I recommend lowering by 2dBm from wherever you are now per test, so as to avoid dramatic shifts of coverage. If you lower by 2dBm, then let the APs run for at least an hour (so we can be sure to get at least one background scan in) and then look at the neighbors list again to see if we still have any -50 values, that would be the best way to dial in on the correct power level.

Additionally, if you could disable the lower data rates on your SSIDs, this will require a stronger connection between the AP and the client device. This will mean that the client device needs to be closer to the AP before connecting. Not only will this reduce the chances of unintentional roaming, but it will also reduce the distance the packets need to travel, which will also reduce collision and interference on your network. To disable the lower data rates we need to go to Configuration> Open the Network Policy> Open the SSID> Expand radio and rates> In the 2.4 GHz 11/bg Rate Setting box, we want to turn 1Mbps-9Mbps to N/A. In the 5.0 GHz 11a Rate Setting box we want to turn 6Mbps and 9 Mbps to N/A.

Finally, we want to check the Radio Profile. The first thing we want to check is your Channel Width, which you can see by expanding Channel and Power. We want to see this at less than 80MHz channel width. This is because the large the channel width, the more overlap we have between channels, and if there is a problem on one channel (RF Interference for instance) it is now shared with all of the channels we are combining.

The second thing we want to check is that we have Short Guard Interval disabled, which we can see by expanding Radio Settings. This setting is designed to shorten the time we have to wait between when we send one packet and when we can send the next one. The problem with this is, if we have an environment with interference, we would just be sending more packets in to a crowded environment faster, increasing the damage we are causing. If this is enabled, please disable it.

I usually also recommend band steering on the 2.4GHz profile as 5GHz typically has less interference than 2.4GHz, but I can't say that for sure in this case and you've stated you see the CRC failures on both, so I think we should hold on on this change for now.

Once you are able, please push these changes out to your APs. A delta configuration push should be enough so we won't have to interrupt client traffic. To push a delta configuration out to your APs you will want to go to Monitor> Select the check box next to the AP> Update> Advanced> Upload and Activate Configuration> Make sure it says Delta at the top (if it doesn't, click on "Settings" in the right hand corner, select one of the options for Delta and click on the floppy disk icon in the top right to save these settings)> Upload.

After we've let these new settings run for about an hour, we will want to pull tech data. if you can send that tech data to me either on this post or directly at communityhelp@aerohive.com, I can take a look and let you know how the interference levels are doing.

Sorry for the wall of text, please let me know if I can clarify anything.

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

ken_vanden_bran — Thu, 27 Dec 2018 22:36:35 GMT

Hi Sam, Great help. I appreciate it. I'll be mailing that VHM ID soon.

I just want to clarify: this specific access point is operating at channel 13 at this point. So is the -55 dBm still an issue as it happens on channel 1? I thought that was the point of auto adjusting channels?

Or am I misunderstanding this and mixing things up ?

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

samantha_lynn — Thu, 27 Dec 2018 22:39:55 GMT

It will be an issue for neighboring devices regardless of channel because you still have to share the same air space. The auto channel settings will allow the APs to choose different channels based on channel cost, which takes interference in to account as well. So it's likely that neighboring APs did move to different channels to help with the issue, but it will still cause some problems for you.

Re: We have some wifi issues in the performance and associating category. I checked the neighbors and RSSI is wel below 60. Though is a 33% CRC Rate normal (see copy paste below) ?

ken_vanden_bran — Tue, 08 Jan 2019 21:17:50 GMT

Hi Sam,

I checked the radio profiles first (it seemed the more safe approach in production).

In the 2.4Ghz everything from 1 to 11 Mbps was already put on N/A and in the 5ghz area everything from 6 to 9 Mbps.

I'll start playing around by lowering the power of the neighbours.