Thanks John this is good info.
I did find that my speedtest killed my network right away. I could only
get 10 clients on with that going. We switched to just running YouTube
videos. I know there is a lot of buffering there but really the only
thing our 90 users need to do is web browsing. It is for a residency
where they have the new distance learning students come in for a weekend
intensive during which they have them log into their account on the LMS
and setup their profile etc. Nothing fancy. I would think if I can get
30 clients on a single AP streaming Youtube then I would be fine with 30
folks clicking through web pages on an LMS.
I found performance to be acceptable on my clients with the test agent
installed while I had 30 clients connected to just the 2.4 Ghtz band.
My agent running g was getting 3 Mbs TCP download and my agent running n
got about 19Mbs. Then, when I enabled 5.0 my g client got 18Mbs and my
n client got 90 Mbs while running 26 youtube streams (some had fallen off).
I was pretty happy with that. I still do not know my upper limit but it
looks like a single AP could handle 30 clients on 2.4 only. So, even if
I only had 2.4 and 3 APs in that room I'd be ok. Now if I turn up an
additional 6 radios on 5.0 I should really be fine.
I did enabled band steering and found that every client that was able
moved to 5.0. It looks like that feature really works. I can also put
a cap on the number of clients that can connect to each radio. So I
plan to do something like 20 for each radio. That way I could run 60
2.4 clients and 120 5.0 clients. That should do it.
John
On 4/21/2011 7:53 PM, Jonn Martell wrote:
Hi John,
I knew I should have broken the rules and taken a few pictures! ;-)
If I remember right, they stayed with 1,6,11 (!). Although there was a
time where the 4 channels worked (for 802.11b only). They just had
huge overlapping cells. It's important to note that during many of
the meetings, the huge ballrooms are closed off with large partitions
so the actual working groups end up sharing smaller RF space. So it's
not always that crazy and each one of these partitions add a 3dB loss
but during the opening/closing, there is work being done and the
partitions are all open. Worth the price of the admission if there
is an IEEE meeting in your area (although I don't think the meetings
are as well attended because there's nothing really pressing to fix
these days but I could be wrong ;-)
With 6 APs to service 90 people - you should be ok but it all depends
on the applications.I should add that the bulk of the work being done
was email, VPN, and file sharing to a server. Nothing fancy like time
sensitive VOIP apps or video conference. That's when you would see
possibly break down in that environment. I still remember some
vendors recommending a max of 7 VOIP client per AP (!). Anything that
doesn't tolerate retries would have a hard time in such a congested
environment but for most apps, it just works (just more slowly but not
an issue for most users).
PS: As a rule of thumb, I'm a big fan of not playing around too much
with AP power unless you can do the same on the client-side... Why let
your client scream louder than your infrastructure?
... Jonn Martell
On Thu, Apr 21, 2011 at 4:29 PM, John Kaftan<[email protected]> wrote:
That is a crazy story. How did they do it, just with managing cell size and
channels? I mean back in those days they only had 2.4 Ghtz. I have heard
of folks cranking down the power in tight big rooms and going with a 4
channel plan. We have an event next weekend where we are going to have 90
people in a 50' x 50' room and I am freaking out about that. Maybe I
shouldn't be.
I was planning on putting in 6 APs and having only 3 radios going on 2.4 to
avoid co-channel interference.
John
On 4/21/2011 5:34 PM, Jonn Martell wrote:
Absolutely possible to have a huge number of active clients in a single
room.
When I attended the IEEE plenary and interim meetings between 2001 and
2004, there were 500-800+ engineering types *all* with active laptops
all downloading the latest versions of working group drafts. Back
then, we started on 802.11b (DSSS) without the benefit of OFDM and
some of the newer technology in 802.11n (that's the technology there
were crafting up! :) ....
It all worked even if the people installing the APs were an outside
firm that did the site surveys when the rooms were empty! ;-) I was
shocked to be at IEEE 802.11 engineering meetings and seeing APs on
the floor. :) They fixed that in subsequent meetings but even with
the APs on the floor and a room full of humans, the stuff still
worked!
Now, when everyone downloaded these huge documents simultaneously "the
latest draft of TGi is up on the server..." when announced, the speed
would drop but still downloaded fairly fast considering the number of
people and temporary deployment of these meetings.
No special sauce needed, these were autonomous Cisco APs with standard
omni-directional antennas. There's a lot more you can do these days
to optimize your setup.
I wish we were allowed to take pictures! 700+ laptops all lined up
and active on a ballroom floor is quite the scene! All I could do was
stand at the back with a big smile on my face: "This stuff is
amazing"!
... Jonn Martell
On Thu, Apr 21, 2011 at 8:11 AM, Palmer J.D.F.
<[email protected]> wrote:
Hello,
I've been posed a tricky question by someone on a planning committee for
a new campus building.
"...is it actually feasible for 500 simultaneous WiFi connections in a
lecture room?"
I was hoping that there would be someone that might have experience of
answering (or providing a solution to) such a question who could offer
some input as to whether this is possible, or how close to the figure of
500 could we realistically achieve with the technology currently
available?
We are Cisco a site so ideally any solution would need to be one Cisco
is capable of delivering, but if there are other vendors that are proven
to be able to provide this kind of coverage to good effect, then I'd be
glad to hear of your experiences.
All the best,
Jezz Palmer.
-------------------------------------
Jezz Palmer
Library& Information Services
Swansea University
Singleton Park
Swansea
SA2 8PP
-------------------------------------
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