Single SSID – anything else just adds confusion for the end-user. Then again, I 
was recently visited a spot where they had a different SSID for every building. 
:)

Thinking more about this…

If residence halls (academic buildings too) are well designed around 5 GHz and 
use in-room AP placement, the issues with 2.4 tend to melt away (or you can 
ignore them), with clients only falling back to 2.4 when they transition 
outside of a building.

If you’re a Cisco shop (I assume Aruba has something similar), their automatic 
RRM (radio resource management) and TPC (Transmit Power Control) tend to result 
in very tiny cells where there is a lot of 2.4 radios talking (which is a good 
thing - tiny cells).  Of course, this can be really problematic if the AP 
layout design is not-optimal such as in a typically budget-driven “down the 
center of the hallway” methods of deployment where adjacent AP’s tend to have 
clear line-of-sight of each other. In cases such as these, the reduction in 
radio output to reduce AP channel overlap can result in client connection 
troubles i.e. The clients are probably behind fire–proof metal clad doors, 
brick walls, etc. Coupled with coverage hole detection (where AP power is 
increased for client connectivity), you now have an environment that’s in 
constant chaos, where someone has to do a lot of manual adjusting of AP radios 
or disable the auto-adjusting.

On the other hand, if AP layout is optimal where you’re deploying AP’s in-room, 
lower on the wall, avoiding line-of-sight, etc. then you get the benefit of the 
room’s construction (doors, floors, walls, what inside the walls, bed, desks, 
etc.). All of which help promote small cell isolation and reduce the number of 
adjacent neighbor AP’s you’ll see, resulting in less 2.4 GHz channel overlap.

Now then, the same issues can crop up in 5 GHz, but it doesn’t propagate as 
far, so if you're using the in-room deployment method, it’s likely not as big 
of an issue even in dense deployments. That said, if you do have dense 5 GHz 
deployments, Cisco’s 8.1 code introduces 5 GHz dynamic channel-width 
allocation, somewhat eliminating the issue by dynamically moving between 20, 
40, and 80 MHz channels.

In my opinion, 2.4 GHz is slowly marching to its demise, and I’m focusing all 
of my attention on 5 GHz. We have the luxury of of a robust Mac population 
(~80% of the students), and Apple laptops and desktops have long since had 
access to 5GHz, so I’m not sure how much effort should be put into maintaining 
2.4 if it’s ultimately only being used by old phones, devices that move little 
data, or have alternative data paths such as cellular, why expend a lot of 
effort on it?

Jeff



From: 
"wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>" 
on behalf of Stephen Oglesby
Reply-To: 
"wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>"
Date: Wednesday, August 12, 2015 at 9:41 AM
To: 
"wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>"
Subject: Re: [WIRELESS-LAN] Exclusive 2.4 Ghz and 5 Ghz SSIDs

Paul,

We're an Aruba shop and, as Bruce of Liberty mentioned, for dense deployments 
we turn 2.4 ghz radios off on every other AP (typically edge of building APs). 
Our main performance issues were due to interference and channel utilization on 
the 2.4 ghz spectrum. We attempted reducing 2.4 ghz (20 mhz channel)  transmit 
power but still had issues.

I also agree with keeping to the simplicity of a single SSID if at all 
possible.  I can't imagine the number of issues that would be reported to me 
simply because the user exited the ideal range for 5ghz spectrum. Our student 
and staff networks support a wide range of client wireless cards, antenna 
configurations, and spectrum compatibility (many are including 2.4ghz only). 
Having users manually switch networks as needed may cause HelpDesk to become 
very popular.

Good Luck,

Stephen Oglesby
Network and Telecommunications Architect
Aims Community College
5401 W. 20th Street
Greeley, CO 80634
970.339.6350 (Office)
stephen.ogle...@aims.edu<mailto:stephen.ogle...@aims.edu>


IT staff will never ask you for your username and password.
Always decline to provide the information and report such
attempts to the help desk (x6380).

On Wed, Aug 12, 2015 at 8:24 AM, Philippe Hanset 
<phan...@anyroam.net<mailto:phan...@anyroam.net>> wrote:
Paul,

Dorm design is an animal of itself and each school has its own set of 
challenges based on
locations and policies. As much as I agree that 2.4 GHz and 5 GHz shouldn’t be 
on separate SSIDs for main campus,
I have really changed my mind for dormitories. Those buildings are really micro 
houses stacked on top of each other
with people bringing anything and everything they want which is quite different 
than academic buildings. We all spend our summers designing
the best coverage that we can for those residential areas, and as soon as 
students move in, the interference in 2.4 GHz makes our entire effort look
pointless in the eyes of the complaining student who is actually partly 
responsible for the problem.
So, in dormitories only, I would have the regular set of SSIDs that the campus 
provides plus and extra 5 GHz only called something like 
"residential-preferred".
But I wouldn’t use “fast” or “5GHz” in the SSID name.

Best,

Philippe


Philippe Hanset
www.eduroam.us<http://www.eduroam.us>



On Aug 11, 2015, at 4:22 PM, Paul Sedy 
<rps...@masters.edu<mailto:rps...@masters.edu>> wrote:

Hello everyone,

We are a Cisco shop and have, up until now, employed a single SSID for 
students, supporting both 2.4 Ghz and 5Ghz connections.  During this summer, we 
have been working to develop sufficient AP density to ensure good 5Ghz cells 
throughout our dorms.  In the past, we have seen numerous instances of poorer 
performance on the 2.4 Ghz spectrum, but up to this point, have relied on the 
client to make the decision between these two options.

We are thinking of deploying two separate SSIDs, a 5Ghz network and a 2.4 Ghz 
network, that are exclusive in order to promote a better experience for the 
students with devices capable of 5Ghz connectivity.  We would probably use the 
original SSID name with an appended (5 Ghz) or (2.4 Ghz).

Are any of you currently employing this type of configuration and how well has 
it worked for you?

We would appreciate any insights that anyone might have.

Paul Sedy
The Master’s College
Director of IT Operations
21726 Placerita Canyon Rd, Santa Clarita, CA 91321
661.362.2340<tel:661.362.2340> | rps...@masters.edu<mailto:rps...@masters.edu>
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