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jpjust
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Why not increase DFS scan time?

Wed Mar 18, 2009 2:25 pm

Hello, folks, specially MikroTik developers.

DFS is really a cool feature, it can simplify the process of choosing a channel. As the docs say:

"AP scans channel list from "scan-list" and chooses the frequency which is with the lowest amount of other networks detected."

So, I'd like to suggest a change. I think the time ROS takes to scan for a channel is too low. If we use Freq. Usage, we can see that some channels are a little bit free and then, suddenly, gets very busy. So, why not adding a box or something so we could choose how many milliseconds ROS would keep scanning to determine the best channel?

After the choosen time, ROS could calculate an average for each channel and then, select the best. It isn't a good idea?
 
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normis
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Re: Why not increase DFS scan time?

Wed Mar 18, 2009 2:50 pm

I think the way how it works is predefined by the 802.11h:
http://en.wikipedia.org/wiki/IEEE_802.11h
 
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jpjust
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Re: Why not increase DFS scan time?

Wed Mar 18, 2009 3:07 pm

Hummm, didn't know about it.

So, I'd still suggest another feature, something like "Dynamic Channel Selection" or "Automatic Channel", which would do all those steps I've described before.
 
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normis
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Re: Why not increase DFS scan time?

Wed Mar 18, 2009 3:20 pm

How about "Snooper" :) ?
 
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jpjust
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Re: Why not increase DFS scan time?

Wed Mar 18, 2009 3:54 pm

I know Snooper already, but what I meant was something automatic.
 
RK
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Re: Why not increase DFS scan time?

Thu Mar 19, 2009 7:48 am

Hummm, didn't know about it.

So, I'd still suggest another feature, something like "Dynamic Channel Selection" or "Automatic Channel", which would do all those steps I've described before.
Remember, you can't be scanning and have clients connected a the same time. People would rather a connection that works 10% slower and stays online 100% of the time.

Besides, the channel with the least amount of other APs is not always the best channel.
 
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 11:16 am

One day when your Call centre phone is quiet and there's little going on in your office.......

- Switch on DFS on a client loaded (50+) sector - and then forget that you did that
- sit back and watch your "call advisers" and "support staff" handle the incoming!!!
- Start clearing email from customers that are threatening all sorts of horrible things.

Interesting - best you be careful when using this funtion as it can "disturb" quiet days.

And - OH!!! - switch off the DFS - it'll help calm down your day again!!

/T
Last edited by Tanker on Fri Apr 03, 2009 11:21 am, edited 1 time in total.
 
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normis
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 11:20 am

I think DFS scans and selects only ONCE (when you enable the interface) ;)

you can make use of scripting, to disable/enable interface at 3:00AM for example, to choose best frequency every night. also the DFS does something when it finds a RADAR.
 
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jpjust
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 2:23 pm

I think DFS scans and selects only ONCE (when you enable the interface) ;)

you can make use of scripting, to disable/enable interface at 3:00AM for example, to choose best frequency every night. also the DFS does something when it finds a RADAR.
It won't work nice, because at 3 AM most of every company's customers are sleeping, so, the "sky" will be quiet. I preffer choosing the best channel at night, 8 PM, so the whole city is using their antennas and we can see the worst situation possible.
 
dingsingo
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 2:58 pm

Hi,

or you need a script, that scan the Chanel every 5 min. for CCQ an signal. Is the CCQ to low, the Board rescan the Link.


dingsingo
 
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normis
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 2:59 pm

yeah, right, and disconnect all clients every 5min, good idea :)
 
dingsingo
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Re: Why not increase DFS scan time?

Fri Apr 03, 2009 3:05 pm

yeah, right, and disconnect all clients every 5min, good idea :)

sorry, i mean. That only when CCQ under ~50%, than rescan the Interface.


dingsingo