Hi,
You may have covered this before, but I probably missed it in your
original post. What equipment are you running for each of the different
frequencies (2.4ghz, 900mhz, 5.8ghz, etc.).
Is it possible the 2.4ghz AP's are just not able to handle the high
packet loads (broadcast storms, viruses, whatever) that the others are?
Also, I have never seen high noise on a band actually cause high
latency... usually it causes packet loss. My guess is you have an
"internal" problem, not external.
Travis
Microserv
David E. Smith wrote:
Mac Dearman wrote:
I tend to believe you will find your answer on your network -vs- "big
bad
leak" somewhere and the only real suggestion I can offer you would be
to do
what we do here when we start having weird issues
[ snip: Mac's good advice on how to track down broadcast storms and
other network-related problems ]
If it were a backhaul problem, though, wouldn't I see high latency on
my backhaul links? I haven't, to date.
Here's one of the (many) experiments I've done in the past (this one
was yesterday, actually): I logged into an affected AP, while the
problem was happening, and firewalled off THE WHOLE INTERNET except
for one IP address, that being the PC in my office I was using to log
into that AP. Then, from that AP, I pinged a CPE associated with it.
The problem persisted, high packet loss and 5000-10000 millisecond
latency.
I quickly undid my changes on that AP, then did exactly the same thing
on another AP, about twenty miles away, with a different radio card,
on a different channel, connected to me through a different backhaul
link, and saw exactly the same performance (high packet loss, obscene
latency, et cetera).
Meanwhile, pings to and through our backhaul links, to the APs
themselves, various managed switches at tower locations, and so on,
never skipped a beat. (Heck, most of 'em improved a bit, since there
wasn't as much pesky customer traffic going through them. :)
For that matter, why do I have three towers with a mixture of 2.4GHz
and "other" APs (two with a 900MHz AP, one with a 5.3GHz AP and a
5.8GHz AP) and the non-2.4 customers aren't affected? Keep in mind
that, for annoying historical reasons, much of our network is still
"flat," bridged addresses flying willy-nilly across four counties. If
it were a network storm, I'd expect it to hit all our towers, on all
channels, and not conveniently skip over the most geographically
remote ones.
There's also all the nasty logistical problems of my company not
having twenty extra hands that we can just have sitting at all our
towers for days, or weeks, at a time, waiting for a problem that shows
up completely randomly, hoping I can call everyone to start unplugging
stuff before the problem magically goes away, but that's another issue
altogether ;)
Last, remember this really is amazingly random, and usually only shows
up for a minute or two at a time, brief enough that I only see it in
our logs well after the fact. (Yesterday it visited us for a good
twenty minutes, long enough for customers to really notice, and for me
to have time to dig into it again.)
I certainly don't mean to sound dismissive of any suggestions, it's
just that I've tried most of the "obvious" ones before.
David Smith
MVN.net
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