Wireless Access

Reply
Highlighted
Contributor I

Random wireless drop outs

Hi, 

I have a customer (school setup) on AP 515 on instant mode running firmware version 8.5.0.5 (go to version). They have been experiencing random wireless disconnects. This happens to users who are static in their locations or to users who move to another area, open their laptop and failed to connect to the wireless. Usually, a manual off/on wireless resolves the problem or disconnect and reconnect the SSID. 2 behaviors were seen:

(A) A few users in the same room could be affected at the same time. A globe with no entry icon instead of wireless icon is seen at the bottom right on the toolbar. Failed to ping to default gateway. 

(B) Only random users are affected

 

They had 80MHz enabled previously and had about 5 SSIDs enabled. I have disabled 80MHz and support only 40MHz on 5GHz radio and consolidated the SSIDs to 2. Tx power settings were configured as follows: 2.4GHz min 6 max 9. 5GHz min 15 max 18

 

The school had upgraded from previous IAP225 on ver 6.x last Dec. According to them, they did not experience similar issues before the AP switch.

 

I had previously seen this behavior before at another school with same AP model but it was on firmware version 8.6.0.0. We downgraded it to 8.5.0.5 and the problem was resolved since. However, success is not seen for this school. 

 

Appreciate your advice. Thanks.

Highlighted
Guru Elite

Re: Random wireless drop outs

Do you have encryption enabled on this SSID?

 


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
ArubaOS 8.5 User Guide
InstantOS 8.5 User Guide
Airheads Knowledgebase
Airheads Video Knowledge Base
Remote Access Point Solution Guide
ArubaOS Consolidated Release Notes
ArubaOS 8 ViA VPN Solution Guide
Highlighted
Contributor I

Re: Random wireless drop outs

Hi, yes. wpa2-aes. Authentication to CPPM. Sorry, should have included some config. 

I have attached extracts of the configuration. 

 

 

Highlighted
Guru Elite

Re: Random wireless drop outs

Thank you.

 

What is the density of those access points?  What are the walls made of,?  How many a cess points can you see in a room?  Is broadcast filtering be enabled on All SSIDs?


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
ArubaOS 8.5 User Guide
InstantOS 8.5 User Guide
Airheads Knowledgebase
Airheads Video Knowledge Base
Remote Access Point Solution Guide
ArubaOS Consolidated Release Notes
ArubaOS 8 ViA VPN Solution Guide
Highlighted
Contributor I

Re: Random wireless drop outs

Hi,

In general, it would be safe to say 1 AP per classroom. Unfortunately this was the case when we went in. 

Regarding the IT room where the client was, it is standalone on the ground floor. There are classrooms in the levels above. I have attached spectrum analysis done in one of the staff area in L1 and L2 of new building and IT room. There is also a cross-section diagram of the building where IT room locates. 

In the new building, the classrooms are separated by glass wall. The older buildings would be separated by dry wall.

There's only 2 SSIDs broadcasting. This and guest (via guest captive portal). Config for the guest SSID as follows:

wlan ssid-profile vilxx_guest
enable
index 2
type guest
essid vilxx_guest
opmode opensystem
max-authentication-failures 0
vlan 128
auth-server clearpass
set-role-pre-auth guest_logon
rf-band all
captive-portal external profile V-Guest
dtim-period 1
broadcast-filter arp
radius-reauth-interval 240
radius-accounting
radius-interim-accounting-interval 10
g-min-tx-rate 6
a-min-tx-rate 18
multicast-rate-optimization
dmo-channel-utilization-threshold 90
local-probe-req-thresh 0
max-clients-threshold 64

I know there's co-channel interference in new building. In IT room, it looks clean.

Highlighted
Guru Elite

Re: Random wireless drop outs

It should be noted what band/channel the client is on when there are drop outs:

"netsh wlan show interface" on the Windows Commandline

 

Questions:

 

wlan ssid-profile Vilxxx
 enable
 index 7
 type employee
 essid Vilxxx
 opmode wpa2-aes
 max-authentication-failures 0
 auth-server clearpass
 auth-survivability  <----Any idea why this is there?
 rf-band all  <-----If all enterprise clients support 5ghz, consider making this 5ghz only
 broadcast-filter arp
 radius-reauth-interval 600  <---Do you want your enterprise clients forcing reauthentication every 600 seconds?  That could put additional strain on the ClearPass server.

wlan ssid-profile vilxx_guest
enable
index 2
type guest
essid vilxx_guest
opmode opensystem
max-authentication-failures 0
vlan 128
auth-server clearpass
set-role-pre-auth guest_logon
rf-band all
captive-portal external profile V-Guest
dtim-period 1
a-min-tx-rate 18  <---That would be a little high unless you want clients to roam more frequently.  Was this intentional?


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
ArubaOS 8.5 User Guide
InstantOS 8.5 User Guide
Airheads Knowledgebase
Airheads Video Knowledge Base
Remote Access Point Solution Guide
ArubaOS Consolidated Release Notes
ArubaOS 8 ViA VPN Solution Guide
Highlighted
Guru Elite

Re: Random wireless drop outs


@simon168 wrote:

Hi,

In general, it would be safe to say 1 AP per classroom.


To be clear, there is nothing wrong with 1 AP per classroom unless there are maybe 35 students  or more in there.

 

Do you ever get to look at what the RF utilization is for access points on the front page?  That would indicate if things are truly congested in realtime.

 

I cannot interpret that spectrum graph, because I cannot tell which APS are from the business and which are foreign...


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
ArubaOS 8.5 User Guide
InstantOS 8.5 User Guide
Airheads Knowledgebase
Airheads Video Knowledge Base
Remote Access Point Solution Guide
ArubaOS Consolidated Release Notes
ArubaOS 8 ViA VPN Solution Guide
Highlighted
Contributor I

Re: Random wireless drop outs

Hi, 

Auth-survivability: They want authenticated users to remain authenticated though (next point: re-auth interval) it may be unnecessary given the long re-authentication interval

Re-authentication interval: 600 min

simon168_0-1596155427887.png

Rf-band all: The students are allowed to bring their own laptops so there is no telling if all the laptops are 5GHz or not.

 

Sorry, guest configuration was dated. Below is fresh from the oven.

wlan ssid-profile vilxx_guest
enable
index 3
type guest
essid vilxx_guest
opmode opensystem
max-authentication-failures 0
vlan 128
auth-server clearpass
set-role-pre-auth guest_logon
rf-band all
captive-portal external profile V-Guest
dtim-period 1
broadcast-filter arp
dmo-channel-utilization-threshold 90
local-probe-req-thresh 0
max-clients-threshold 64

Highlighted
Contributor I

Re: Random wireless drop outs

Hi

Yes, I have looked at the utilization of the AP under Dashboard. I was focusing on the ITroom AP since I know there are reports of wireless drop out there. There are typically about 19 connected clients. Noise level for 5GHz would sometimes increase to about -83 to -87. Utilization was less than 10%.

Regarding the spectrum, the APs starting with D0.15 are the school's AP. I have indicated other SSID where possible especially if it is interfering. This SSID is advertised by external AP.

Search Airheads
cancel
Showing results for 
Search instead for 
Did you mean: