Data Packets could not received due to low RSSI on 9130AXE and 9130AXI

[brian zhang1]

WLC 3504:8.10.151.0

AP C9130AXE-H, External antenna for AXE(enable port A+B): AIR-CAB002-D8-R=  + 2*AIR-ANT2524DW-R 

And AP C9130AXI-H(Enable All ports)

From the client side, RSSI is very strong(-20dBm), but the data packets send from Cisco AP is very low：

AXI：data packet -48dBm, Beacon -19dBm

AXE:data packet -63dBm,Beacon -25dBm

The result is, from the client, RSSI is very strong, but when moving client away from AP, even RSSI is still very strong from the display, because the TX power of data packets is so poor, client is not able to receive data packets. this can be easily obervered as well in air sniffer. and client roaming is not able to trigger due to RSSI is still strong(from Beacon)

The measurement was done by close the client with antenna and air sniffer.

How can we increase the TX power for data packets?(disable 11ax to use 11a see same issue)

This is a serious issue to deploy this serial APs to warehouse etc.

[Rich R]

Thanks Brian - can you share the bug id for reference?

[patoberli]

Might be CSCvx37875, which is fixed in beta 8.10.158.60, but I hope Brian can confirm this.

[brian zhang1]

Looks like the scenario is match, but TAC told me not this one, will provide once get confirmed

[saravlak]

are the issue seen on both 2.4 and 5g bands.

if 5G, are all bands or specific band/channels impacted -like what's the impacted condition

let know if you've that detail. thanks.

[brian zhang1]

All channels on 5G only as I recall, thanks.

[brian zhang1]

yes, confirmed , bug id CSCvx37875,

[JEFFREY SESSLER]

I just upgrade from 17.3.5b to 17.9.3, for support of 9136APs, and my 9130's are showing a significant performance problem and I'm wondering what the typical symptom was for this bug. 

In my case, the download speed to the client will be terrible, but upload speeds seem more consistent.  If the client connects to the flexible radio, which is typically running at 7/8 power, it can be near impossible to associate and pass traffic. 

[WiFi_Guy93]

@JEFFREY SESSLERDid you ever resolve that problem with poor download speed? I'm seeing the same issue with 9130s on an 8540 running 8.10.183.

[JEFFREY SESSLER]

I've not seen the problem since moving to 17.9.4, and I implemented the mDNS gateway to limit the amount of mDNS traffic that was passing to/from my APs. What does the channel and TX utilization look like when a client is connected to the FRA radio?  Do you have the mDNS gateway setup/configured on your 8540? 

[WiFi_Guy93]

Channel and Tx utilization are both low. We don't have mDNS configured.

[Rich R]

Upgrade to 8.10.190.0 because there have been a number of fixes since 8.10.183.0.
EG: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwe19858 fixed in 8.10.185.0
If it's still not fixed in 8.10.190.0 then you can open a TAC case but unless they already have a bug open for it then it's unlikely you will get a fix for it because 8.10.190.0 is intended be the last maintenance release of AireOS.  If there's already a bug for it you might be able to get a special escalation image with the fix.

[Rich R]

CSCvx37875 : Bug Search Tool (cisco.com) should be fixed in 17.9.3.

If you're sure it's a Tx power issue then open a TAC case.