Hi James,
We've been slowly marching down this path for about a year and a half. We have
a branded WPA2-Enterprise SSID, eduroam, and an i-PSK SSID. After applying a
new 5GHz-Only design we communicate the benefits to building occupants and
migrate our branded SSID (which 90% of users already connect to) in that
building to 5GHz-Only. Then eduroam and our i-PSK SSID remain dual-band.
We are 50+ buildings into the process out of 250-ish. In our first 40
buildings (IT bldg, student housing, union, library) I think we got one ticket
for an Android phone, and pointed the user to eduroam. In our last 10
buildings (primarily hospitals) I think we got 2 tickets - one for a small
batch of laptops, and one for an ultrasound machine. We pointed the Client
Manager to Amazon/Campus store for a 5GHz Wi-Fi dongle and put the ultrasound
device on our i-PSK SSID ...and on we go to the next set of buildings.
User experience was night/day for us in our new IT building - much, much
better. Stats indicate much lower channel utilization and many fewer
interference sources. My only recommendation would be to have proof that the
RF design supports the change (for even the least-capable 5GHz device) before
you do it, and to have several rock-solid fallback plans for the 2.4 only
devices/use cases. The gotchas are the time and cost to get the AP density
up-to-snuff organization-wide. Honestly, I'm not sure if the entire campus
will ever reach the goal at the rate we're going - but it sure has been nice to
eliminate many of the most common problems from some of our most
mission-critical buildings.
Thanks,
--
Curtis K. Larsen
Network Engineer III
Infrastructure Ops
CWNA, CWDP, CWSP, CWAP
The University of Utah
________________________________________
From: The EDUCAUSE Wireless Issues Community Group Listserv
<WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> on behalf of Jake Snyder
<jsnyde...@gmail.com>
Sent: Friday, January 31, 2020 4:38 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] New and separate SSID for 2.4Ghz?
A fun story that happened to me at a university:
They did as you propose. 2.4GHz only and 5GHz only separate SSIDs. first week
of school they had ~80% of clients on 5GHz.
About three weeks before the end of the semester, Wi-Fi complaints have gone
up, and the percentage of clients on 2.4GHz had grown to 50%. This is when i
got a call to come look at it.
Over the course of the semester, a DHCP outage and internet circuit outage led
folks to try “to see if the other network was working.” But, when students
arrived on campus every morning, they picked up the 2.4GHz only network first.
Then they spend all day, because client won’t leave the 2.4GHz SSID while it’s
present.
I asked for a 2 minute outage for the 2.4GHz network. I disabled it for 2
minute and then re-enabled. 10 minutes later it was back to 80% 5GHz and 20%
2.4GHz.
The moral of the story: you can’t out engineer people’s behavior. When things
break, when they experience issues, they will try to work around it. As much
as some folks might imagine their networks are perfect, I’ve yet to find one
that is.
The best way to overcome this, have a 5GHz only SSID and a Dual Band SSID.
That way if students do choose to connect to the other SSID, they have a way
for their device to make a better choice most of the time. This also ensures
that you can do the Apple Watch with a 2.4GHz radio without dramatically
hurting their iPhone’s connectivity.
In summary:
Use dual band instead of a 2.4 GHz only network
Make sure 5GHz is 6db greater than 2.4GHz in transmit power.
I would also add, make sure you don’t use band steering on either network.
Jake Snyder
Sent from my iPad
On Jan 31, 2020, at 4:13 PM, Seddon, James
<00000159faeb9fd9-dmarc-requ...@listserv.educause.edu> wrote:
Happy Friday, everyone!
In high density areas of our campus (library, center of campus
food courts, large lecture halls, etc), we often turn off some 2.4Ghz radios to
help avoid co-channel interference issues.
We think we’re seeing behavior where client devices in motion attach to an AP
in 2.4, then stubbornly hang on to that frequency (and sometimes AP), even if
they end up in a location with a much stronger 5 Ghz signal from a closer AP.
And of course, with the messy nature of the 2.4 band, they’re even more
susceptible to interference using a weak signal from a distant AP.
We do have Cisco’s band steering already in play, but we think it might be of
limited benefit in situations like this. Our general advice is for clients to
prefer 5.0GHz when they can. But we think most users are just letting their
devices do what they want, and we really have no control over that.
We’re considering converting our main SSIDs to offer 5 GHz only. And then
creating a new SSID that offers 2.4 service (MainSSID2-4, or Legacy2-4, or
something).
Because we believe we have good 5.0GHz coverage, we think this change would be
invisible to most users who have 5 GHz capable devices. Their devices are
already configured to connect to our main SSID, and they would just do so in
5Ghz from then on. They’d see the 2.4 SSID offered if they looked, of course.
Clients that are 2.4 only would see our SSID disappear, and need
reconfiguration/reattachment, accept the cert…all the usual onboarding stuff.
Because of this, we’d only make this change after an extensive communication
period to include our support teams, campus partners, and customers.
Most of our campuses IOT-kinda-stuff (which tend both to be 2.4 and need more
attention/configuration) are already on a separate SSID that we wouldn’t be
touching. So nothing would change for them.
Questions:
1. Have other large campuses done this? We have ~400 buildings and
~7,300 access points. We have upwards of 60,000 peak concurrent WiFi
connections, with maybe 14,000 of those in 2.4. We don’t know how to tell how
many of those can ONLY do 2.4, and how many are 5Ghz capable, but just aren’t
for some reason.
2. How did it work?
3. What were the lessons learned/gotchas, either from a technical or
non-technical/communication perspective?
Other advice?
Best Regards,
James Seddon
Enterprise Network Operations - Voice and Data
Information Technology Services (ITS)
UC San Diego
858-822-4040
jsed...@ucsd.edu<mailto:jsed...@ucsd.edu>
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