Re: [WIRELESS-LAN] Running APs at full power: client transmit power levels low?

[Tristan Gulyas]

Hi all,

Some great feedback here.  This has been a traditional method of doing site 
surveys but for some reason it’s only becoming a big issue for us for this 
year.  Naturally, there’s been a historical view to reduce the amount of APs we 
deploy in these areas for financial reasons and to avoid more than three APs in 
a single corridor to reduce 2.4GHz co-channel interference.

5GHz runs at full power in these areas; traditionally 5GHz runs a lot hotter 
than 2.4GHz even with the same RRM settings.  Now here’s something super 
interesting we discovered.

Ever since moving to 7.6.130.21 WLC code, we’ve noticed more of these issues 
come in.  We’ve moved a few APs back to 7.6.100.16 and found the problems went 
away.  When looking at the client connection history graphs, we find more 5GHz 
connections on the older code.  I’m tipping there’s something weird with 
802.11h, introduced with this code release, that’s causing the clients to drop 
their power level.  Same channels in either case, so we’re not hitting a 
transmit power restriction.

We have two cases we are currently investigating that look similar - three APs 
in corridor (Cisco 3602I), wireless dropouts seen on Apple OSX devices (MacBook 
Pro Retina), three brick walls between client and AP and in both cases, we’re 
told that an iPhone 5 was used to test the signal and was working in both 
cases. 

Our APs are running at 20dBm transmit power at 2.4GHz; 17dBm at 5GHz when at 
full power, especially in these cases I have verified.  I’m aware that a “power 
level 1” can mean different things depending on channel (especially in 5GHz) 
but these coverage issues have come to us from corridor deployments where 
2.4GHz is the only reliable way to connect.

I’ll consider capping our Tx power to 17dBm for future deployments and surveys.

Tristan



> On 8 May 2015, at 10:58 pm, Rogers, Michael J.  wrote:
> 
> Out of curiosity what power level do you run your 5ghz band?
>  
> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
> [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 
> <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>] On Behalf Of Hinson, Matthew P
> Sent: Monday, May 4, 2015 8:02 AM
> To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 
> <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>
> Subject: Re: [WIRELESS-LAN] Running APs at full power: client transmit power 
> levels low?
>  
> Hi Tristan,
>  
> You definitely want to match the Tx power between clients and APs as close as 
> you can. Obviously, being education, we have little to no control over the 
> hardware brought into our environment, so always knowing every device’s Tx 
> power can be hard.
>  
> Wi-Fi is a two way street. If at all possible, a client and an access point’s 
> power settings should match. Almost every frame sent to a client must be 
> acknowledged very soon after, and if the client can’t reliably talk back to 
> the AP, you’re going to have an unstable or unreliable connection.
>  
> We run our APs around 15-17dBm in the 2.4GHz band depending on the area but 
> never higher. With the proliferation of mobile devices, that’s about all you 
> can get away with without causing a mismatch.
>  
> Aerohive had a blog post a while back about the iPhone 5 and its 16dBm output 
> power in the 2.4GHz band.
> http://blogs.aerohive.com/blog/the-network-revolution/apple-iphone-5-wi-fi-specs
>  
> <http://blogs.aerohive.com/blog/the-network-revolution/apple-iphone-5-wi-fi-specs>
>  
>  
> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
> [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 
> <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>] On Behalf Of Tristan Gulyas
> Sent: Monday, May 4, 2015 3:55 AM
> To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 
> <mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>
> Subject: [WIRELESS-LAN] Running APs at full power: client transmit power 
> levels low?
>  
> Hi all,
>  
> We’ve run into an issue in some of our sparsely covered areas (2.4GHz 
> coverage optimised, not density optimised) where we have APs in a corridor 
> style deployment.  This is typically found in older buildings which means 
> we’re dealing with solid brick interior walls. 
>  
> These APs are typically running at maximum power levels (typically 3600/3700 
> series Cisco radios). 
>  
> In one case, we measured the client end (MacBook Pro) as -71dBm with an SNR 
> of 22; the AP end saw the client with an SNR of 14 and a signal of -81dBm and 
> connectivity was unreliable.  I have seen similar results elsewhere with a 
> similar deployment model.
>  
> Has anyone else experienced similar issues with corridor style deployments at 
> full power?
>  
> Cheers,
> Tristan
>  
>  
> Tristan Gulyas
> Senior Network Engineer
> Network Operations
> eSolutions | Monash

Re: [WIRELESS-LAN] Running APs at full power: client transmit power levels low?

[Harry Rauch]

We run Ruckus with a default setting of full power; the APs will adjust 
power as needed to individual devices. So the AP will focus with it's 
beamforming abilities and adjust power as needed on the fly when it 
senses a device. Using a simple Speedtest run will show the power level 
adjusting to the enduser for max output.


Saves a major amount of headaches especially with BYODs that come on campus.

Harry Rauch Sr. Network Analyst Eckerd College 4200 - 54th Ave S St. 
Petersburg, FL 33711

On 5/8/15 8:58 AM, Rogers, Michael J. wrote:


Out of curiosity what power level do you run your 5ghz band?

*From:*The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] *On Behalf Of *Hinson, 
Matthew P

*Sent:* Monday, May 4, 2015 8:02 AM
*To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
*Subject:* Re: [WIRELESS-LAN] Running APs at full power: client 
transmit power levels low?


Hi Tristan,

You definitely want to match the Tx power between clients and APs as 
close as you can. Obviously, being education, we have little to no 
control over the hardware brought into our environment, so always 
knowing every device’s Tx power can be hard.


Wi-Fi is a two way street. If at all possible, a client and an access 
point’s power settings should match. Almost every frame sent to a 
client must be acknowledged very soon after, and if the client can’t 
reliably talk back to the AP, you’re going to have an unstable or 
unreliable connection.


We run our APs around 15-17dBm in the 2.4GHz band depending on the 
area but never higher. With the proliferation of mobile devices, 
that’s about all you can get away with without causing a mismatch.


Aerohive had a blog post a while back about the iPhone 5 and its 16dBm 
output power in the 2.4GHz band.


http://blogs.aerohive.com/blog/the-network-revolution/apple-iphone-5-wi-fi-specs

*From:*The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] *On Behalf Of *Tristan Gulyas

*Sent:* Monday, May 4, 2015 3:55 AM
*To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 
<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>
*Subject:* [WIRELESS-LAN] Running APs at full power: client transmit 
power levels low?


Hi all,

We’ve run into an issue in some of our sparsely covered areas (2.4GHz 
coverage optimised, not density optimised) where we have APs in a 
corridor style deployment.  This is typically found in older buildings 
which means we’re dealing with solid brick interior walls.


These APs are typically running at maximum power levels (typically 
3600/3700 series Cisco radios).


In one case, we measured the client end (MacBook Pro) as -71dBm with 
an SNR of 22; the AP end saw the client with an SNR of 14 and a signal 
of -81dBm and connectivity was unreliable.  I have seen similar 
results elsewhere with a similar deployment model.


Has anyone else experienced similar issues with corridor style 
deployments at full power?


Cheers,

Tristan

**

*Tristan Gulyas*

Senior Network Engineer
Network Operations

eSolutions | Monash University

738 Blackburn Road Clayton 3800

www.monash.edu <http://www.monash.edu/> | tristan.gul...@monash.edu 
<mailto:tristan.gul...@monash.edu>


** Participation and subscription information for this 
EDUCAUSE Constituent Group discussion list can be found at 
http://www.educause.edu/groups/.





**
Participation and subscription information for this EDUCAUSE Constituent Group 
discussion list can be found at http://www.educause.edu/groups/.

RE: [WIRELESS-LAN] Running APs at full power: client transmit power levels low?

[Rogers, Michael J.]

Out of curiosity what power level do you run your 5ghz band?

From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Hinson, Matthew P
Sent: Monday, May 4, 2015 8:02 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Running APs at full power: client transmit power 
levels low?

Hi Tristan,

You definitely want to match the Tx power between clients and APs as close as 
you can. Obviously, being education, we have little to no control over the 
hardware brought into our environment, so always knowing every device’s Tx 
power can be hard.

Wi-Fi is a two way street. If at all possible, a client and an access point’s 
power settings should match. Almost every frame sent to a client must be 
acknowledged very soon after, and if the client can’t reliably talk back to the 
AP, you’re going to have an unstable or unreliable connection.

We run our APs around 15-17dBm in the 2.4GHz band depending on the area but 
never higher. With the proliferation of mobile devices, that’s about all you 
can get away with without causing a mismatch.

Aerohive had a blog post a while back about the iPhone 5 and its 16dBm output 
power in the 2.4GHz band.
http://blogs.aerohive.com/blog/the-network-revolution/apple-iphone-5-wi-fi-specs


From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Tristan Gulyas
Sent: Monday, May 4, 2015 3:55 AM
To: 
WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>
Subject: [WIRELESS-LAN] Running APs at full power: client transmit power levels 
low?

Hi all,

We’ve run into an issue in some of our sparsely covered areas (2.4GHz coverage 
optimised, not density optimised) where we have APs in a corridor style 
deployment.  This is typically found in older buildings which means we’re 
dealing with solid brick interior walls.

These APs are typically running at maximum power levels (typically 3600/3700 
series Cisco radios).

In one case, we measured the client end (MacBook Pro) as -71dBm with an SNR of 
22; the AP end saw the client with an SNR of 14 and a signal of -81dBm and 
connectivity was unreliable.  I have seen similar results elsewhere with a 
similar deployment model.

Has anyone else experienced similar issues with corridor style deployments at 
full power?

Cheers,
Tristan


Tristan Gulyas
Senior Network Engineer
Network Operations
eSolutions | Monash University
738 Blackburn Road Clayton 3800
www.monash.edu<http://www.monash.edu/> | 
tristan.gul...@monash.edu<mailto:tristan.gul...@monash.edu>





** Participation and subscription information for this EDUCAUSE 
Constituent Group discussion list can be found at 
http://www.educause.edu/groups/.

RE: [WIRELESS-LAN] Running APs at full power: client transmit power levels low?

[Hinson, Matthew P]

Hi Tristan,



You definitely want to match the Tx power between clients and APs as close as 
you can. Obviously, being education, we have little to no control over the 
hardware brought into our environment, so always knowing every device’s Tx 
power can be hard.



Wi-Fi is a two way street. If at all possible, a client and an access point’s 
power settings should match. Almost every frame sent to a client must be 
acknowledged very soon after, and if the client can’t reliably talk back to the 
AP, you’re going to have an unstable or unreliable connection.



We run our APs around 15-17dBm in the 2.4GHz band depending on the area but 
never higher. With the proliferation of mobile devices, that’s about all you 
can get away with without causing a mismatch.



Aerohive had a blog post a while back about the iPhone 5 and its 16dBm output 
power in the 2.4GHz band.

http://blogs.aerohive.com/blog/the-network-revolution/apple-iphone-5-wi-fi-specs





From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Tristan Gulyas
Sent: Monday, May 4, 2015 3:55 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: [WIRELESS-LAN] Running APs at full power: client transmit power levels 
low?



Hi all,



We’ve run into an issue in some of our sparsely covered areas (2.4GHz coverage 
optimised, not density optimised) where we have APs in a corridor style 
deployment.  This is typically found in older buildings which means we’re 
dealing with solid brick interior walls.



These APs are typically running at maximum power levels (typically 3600/3700 
series Cisco radios).



In one case, we measured the client end (MacBook Pro) as -71dBm with an SNR of 
22; the AP end saw the client with an SNR of 14 and a signal of -81dBm and 
connectivity was unreliable.  I have seen similar results elsewhere with a 
similar deployment model.



Has anyone else experienced similar issues with corridor style deployments at 
full power?



Cheers,

Tristan





Tristan Gulyas

Senior Network Engineer
Network Operations

eSolutions | Monash University

738 Blackburn Road Clayton 3800

www.monash.edu<http://www.monash.edu/> | 
tristan.gul...@monash.edu<mailto:tristan.gul...@monash.edu>









** Participation and subscription information for this EDUCAUSE 
Constituent Group discussion list can be found at 
http://www.educause.edu/groups/.

Running APs at full power: client transmit power levels low?

[Tristan Gulyas]

Hi all,

We’ve run into an issue in some of our sparsely covered areas (2.4GHz coverage 
optimised, not density optimised) where we have APs in a corridor style 
deployment.  This is typically found in older buildings which means we’re 
dealing with solid brick interior walls. 

These APs are typically running at maximum power levels (typically 3600/3700 
series Cisco radios). 

In one case, we measured the client end (MacBook Pro) as -71dBm with an SNR of 
22; the AP end saw the client with an SNR of 14 and a signal of -81dBm and 
connectivity was unreliable.  I have seen similar results elsewhere with a 
similar deployment model.

Has anyone else experienced similar issues with corridor style deployments at 
full power?

Cheers,
Tristan
 
 
Tristan Gulyas
Senior Network Engineer
Network Operations
eSolutions | Monash University
738 Blackburn Road Clayton 3800
www.monash.edu  | tristan.gul...@monash.edu 

 




**
Participation and subscription information for this EDUCAUSE Constituent Group 
discussion list can be found at http://www.educause.edu/groups/.