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From: pfisterfarm on 26 Mar 2010 11:08
I've got a remote site that has a total of 25 1131 access points under
the control of a 4402 WLC. A few locations in the building (mostly
where the heaviest use is), are reporting connection drops and
slowness (connection speed changes several times).

I've been looking at the channel assignments. In one particular wing,
for example, the two downstairs APs, which are at opposite ends of the
hall, are channels 1 and 6. The floor above is has one access point,
in the middle, which is also on channel 6. It's been a while since
I've checked, but I think I can get at least some sort of signal
upstairs in that area from the APs on the lower floor.

Shouldn't the WLC have assigned channel 11 to one of those? What are
the best options here? Should I force one to channel 11?

There's another wing in this same building that's like that, and I'm
thinking it might not be as easy to fix. There's 4 APs in a relatively
close area. Two are on channel 1, one on 6, and one on 11.
From: Aaron Leonard on 26 Mar 2010 15:42
~ I've got a remote site that has a total of 25 1131 access points under
~ the control of a 4402 WLC. A few locations in the building (mostly
~ where the heaviest use is), are reporting connection drops and
~ slowness (connection speed changes several times).
~
~ I've been looking at the channel assignments. In one particular wing,
~ for example, the two downstairs APs, which are at opposite ends of the
~ hall, are channels 1 and 6. The floor above is has one access point,
~ in the middle, which is also on channel 6. It's been a while since
~ I've checked, but I think I can get at least some sort of signal
~ upstairs in that area from the APs on the lower floor.
~
~ Shouldn't the WLC have assigned channel 11 to one of those? What are
~ the best options here? Should I force one to channel 11?
~
~ There's another wing in this same building that's like that, and I'm
~ thinking it might not be as easy to fix. There's 4 APs in a relatively
~ close area. Two are on channel 1, one on 6, and one on 11.

I don't think I'd worry too much about a channel assignment here or
there. Below is my general approach for a situation like this.

First, make sure that there's appropriate coverage throughout
the coverage area (with a site survey tool) - for data, make sure
that there is at least one AP at -72 dBm (or whatever your standard
is), but not too much co-channel interference.

In addition to the site survey (by this I really just mean walking
around and seeing what APs you see), I also like to take the
"show run-config" output from the WLCs and load it into the WLC
Config Analyzer (https://supportforums.cisco.com/docs/DOC-1373).
Then look at co-channel interference, noise, etc. Make sure that
things look pretty solid.

Now get a known good client device (like a laptop) and have it run
a continuous ping and verify that it can move around everywhere
and have good connectivity. (If not, figure out why not.)

Once this is done ... focus on specific clients or specific locations
that have more or less replicable problems, and fix them up.

Btw, the Wireless area in Supportforums is quite a good place
to ask questions: https://supportforums.cisco.com/community/netpro/wireless-mobility

Cheers,

Aaron
From: bod43 on 27 Mar 2010 06:20
On 26 Mar, 19:42, Aaron Leonard <Aa...(a)Cisco.COM> wrote:
> ~ I've got a remote site that has a total of 25 1131 access points

> Now get a known good client device (like a laptop) and have it run
> a continuous ping and verify that it can move around everywhere
> and have good connectivity.  (If not, figure out why not.)

Maybe it's worth mentioning that the Windows ping utility
can not do a suitable ping. Well, not unless you have a
lot of time to wait for a diagnosotic number of packets
to be sent:), say an hour or two per sample point.

I use fping.exe from
http://www.kwakkelflap.com/downloads.html
(it's in the drop down list box)
which can do a "cisco style" continuous ping.
If you get 100's of packets per second then
the the network is working very nicely indeed
and you don't have to delay further:) I forget
typical values since it's been a while.

I think that the current linux ping does support
a "flood" ping but I don't have one handy to check.

I also like to use decent sized packets for wireless
surveys, 1400 bytes or so since this stresses the
network further.

From: alexd on 27 Mar 2010 11:41
On 27/03/10 10:20, bod43 wrote:

> I think that the current linux ping does support
> a "flood" ping but I don't have one handy to check.

ping -f [flood ping, root only.]
ping -A ['Cisco style', send next ping as soon as response is received.]

Minimum interval in all cases is 200ms for non-root users.

--
<http://ale.cx/> (AIM:troffasky) (UnSoEsNpEaTm(a)ale.cx)
15:34:23 up 51 days, 18:54, 3 users, load average: 0.03, 0.29, 0.48
It is better to have been wasted and then sober
than to never have been wasted at all
From: pfisterfarm on 29 Mar 2010 09:47
On Mar 26, 3:42 pm, Aaron Leonard <Aa...(a)Cisco.COM> wrote:
> Then look at co-channel interference, noise, etc.  Make sure that
> things look pretty solid.

Thanks everyone for the information and links... I have one more
question: How do I look at the co-channel interference and noise? Do I
need a spectrum analyzer?
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