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ihernandez
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DFS Mode

Tue May 13, 2008 12:58 am

Hello, I have a question about what exactly is DFS mode and how do I implement it. I have not found Info about this on the forums. Apparently everyone has it on dfs mode=none
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Ignacio
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jwcn
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Re: DFS Mode

Tue May 13, 2008 1:10 am

DFS is dynamic frequency selection. In theory, in a perfect world, it picks the best frequency automatically and uses it.
 
ihernandez
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Re: DFS Mode

Tue May 13, 2008 3:32 am

Thank you for your reply, how would I set it up and what tests do I have to do to ensure its working
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Ignacio
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raftak
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Re: DFS Mode

Wed May 14, 2008 9:19 am

Hi, MT has two modes of operation "not detect radar" and "radar detect," you'll find that it is working on a view that if the "status" of the interface (wlanx) you will see a channel other than possibly have selected in "Frequency" in that wlan!

regards,


(hola, MT tiene dos modos de funcionamiento "no radar detect" y "radar detect", te darás cuenta de qe está funcionando por que si miras el "status" de la interfaz(wlanx) te va aparaecer un canal distinto del que posiblemente tengas seleccionado en "Frequency" en esa wlan!! Selecciona siempre "no radar detect")
 
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Re: DFS Mode

Thu May 15, 2008 1:39 am

DFS is dynamic frequency selection. In theory, in a perfect world, it picks the best frequency automatically and uses it.
1. How often can Mikrotik DFS change channels?
2. When there is a channel change, is it coordinated with station units, or do they disassociate and scan?
3. If coordinated, how long is the outage in ms?
 
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Re: DFS Mode

Tue May 20, 2008 10:41 pm

Mikrotik please respond!
1. How often can Mikrotik DFS change channels?
2. When there is a channel change, is it coordinated with station units, or do they disassociate and scan?
3. If coordinated, how long is the outage in ms?
 
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normis
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Re: DFS Mode

Wed May 21, 2008 8:59 am

DFS without radar detect will select and choose a frequency only once.

DFS with radar detect will change the frequency only when it identify a military radar in it's frequency
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scintilla
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Re: DFS Mode

Wed May 21, 2008 12:53 pm

We implemented a private civic hiperlan network in venice ancient water city.

Initially we set DFS to radar detect (to be compliant with italian regulations).

In this environment, probably with a lot of boats radar we found poor performances caused by strange DFS activity.
We found each RB using 5180 frequency.

To get best troughput we setted manually each RB to a free channel and DFS to none.

ROS was 2.9, several versione because RB buying was in different times.
 
cmit
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Re: DFS Mode

Wed May 28, 2008 11:27 am

DFS with radar detect will change the frequency only when it identify a military radar in it's frequency
Which is not really OK in ETSI countries. There are more things you have to do (re-scan every 24 hours etc.)...
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Christian Meis
 
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jorj
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Re: DFS Mode

Thu May 29, 2008 5:14 pm

DFS without radar detect will select and choose a frequency only once.

DFS with radar detect will change the frequency only when it identify a military radar in it's frequency
What exactly is classified as a "military radar" ? How is this decision made ?

I found in legislation only DFS requirements, not military radar or else.
From the manual, it seems that radar detect seeks another radar detect, presumably from another DFS enabled device, MT or else.

Can you please explain a little more ?
 
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meconet
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Re: DFS Mode

Fri May 30, 2008 1:18 am

You will find a lot of information above DFS, and what must be implemented in ETSI regulated countries in the EN 30189 (5Ghz outdoorband), actuall version is 1.4.1 and EN 302502 (5GHz BFWA band), actuall version is 1.1.1

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el berto
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Re: DFS Mode

Mon Jun 30, 2008 4:38 pm

We implemented a private civic hiperlan network in venice ancient water city.
Initially we set DFS to radar detect (to be compliant with italian regulations).
In this environment, probably with a lot of boats radar we found poor performances caused by strange DFS activity.
We found each RB using 5180 frequency.
To get best troughput we setted manually each RB to a free channel and DFS to none.
ROS was 2.9, several versione because RB buying was in different times.
Ciao, che configurazioni usi per le radio, Access Point o bridge?
Io ho una RB112 e una RB411; se imposto dfs-mode=radar-detect su entrambe, allora perdo il collegamento. Tu come le hai configurate?
Grazie!

I have an RB112 and RB411; if I set dfs-mode=radar-detect on both radios I loose connection (I'm working in bridge mode).
 
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meconet
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Re: DFS Mode

Mon Jun 30, 2008 4:41 pm

Maybe setting the right scan-list value should help you.


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Lutz
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el berto
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Re: DFS Mode

Tue Jul 01, 2008 4:17 pm

Ok, but dfs works on AP; in bridge mode both work as AP, if I'm not wrong.
My couple of RB works only if only one has got the DFS enable, is correct this?
The correct scan-list (let's imaging I'm working at 5GHz-5MHz band, at 5535 MHz) is 5535-5540-5545 or 5540-5545?
Thanks.
 
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meconet
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Re: DFS Mode

Tue Jul 01, 2008 4:39 pm

Hello,

all we know, is that DFS should work in RouterOS, but MT wrote here in this thread, that they didn't scan each 24 hour for a radar signal, but this is a must in ETSI regulation. No word to DFS2 (scan for 6 radar pattern instead of only 3 radar pattern in DFS).

Your scan-list must be like 5470-5720 (for Germany). If you reduce your scan-list to only a few MHz wide channel and the system see a radar, to which frequency it should move? Also the System must be able to scan all allowed channels for a radar signal.

From the RouterOS 3.0 manual:
dfs-mode (none | radar-detect | no-radar-detect; default: none) - used for APs to dynamically
select frequency at which this AP will operate
• none - do not use DFS
• no-radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is
with the lowest amount of other networks detected
• radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is with
the lowest amount of other networks detected, if no radar is detected in this channel for 60
seconds, the AP starts to operate at this channel, if radar is detected, the AP continues searching
for the next available channel which is with the lowest amount of other networks detected
No word that it also work on a Client, only on a AP. But ETSI regulation say: If the Client don't support DFS/DFS2, your max. TX-Power is 200mWatt EIRP..

We always see, that the AP take the lowest allowed frequency. So in Germany he will always choose 5.500 MHz, this make no sence if you have 3 5GHz sectors at one point running DFS!


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Lutz
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el berto
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Re: DFS Mode

Wed Jul 02, 2008 6:18 pm

It's said Bridge mode (only two radios) is like AP mode, but I can use only one radio, so I suppose dfs-mode is suitable also for bridge mode, not only for AP mode.
Then, if it wouldn't be available on bridge mode, it means I can't use bridge mode on 5GHz band due the presence of radars, doesn't it?
So, how can I make a radio link of about xy Km if it's said for longer distances to use bridge mode?
About dfs, if I'm working with 5MHz band, I think it only should detect the radar, not regarding the band: If I have a radar at 5000 MHz (using 20MHz band), it means I detect the radar on frequencies 5000,5005,5010,5020, so 5025 frequency is free.


By the way, I'll try to use "standard" bands:

# scan-list (multiple choice: integer | default-ism; default: default-ism) - the list of channels to scan
# default-ism - for 2.4GHz modes: 2412, 2417, 2422, 2427, 2432, 2437, 2442, 2447, 2452, 2457, 2462, 2467, 2472; for 5GHz mode: 5180, 5200, 5220, 5240, 5260, 5280, 5300, 5320, 5745, 5765, 5785, 5805; for 5GHz-turbo: 5210, 5250, 5290, 5760, 5800

if I'm working at 5GHz (scan-list 5180, 5200, ....), so I set dfs-mode on BOTH radios or not?
I haven't still understood this.
Thanks.
 
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meconet
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Re: DFS Mode

Wed Jul 02, 2008 6:40 pm

Hello,

1. Bridge-Mode = AP, but restricted to 1 Client only. It's only a licence feature, nothing more.
2. Where in Europe are you allowed to use the lower bands outside?
3. For a PtP-Link you never configure both sides in Bridge-Mode. You need one AP (or Bridge if you have L3 licence only) and a Client-Interface (Station in RouterOS).

And at last: Only Mikrotik can explain how to fullfill all the EN directives for europeen countries. Here is missing a lot.


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Lutz
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Re: DFS Mode

Thu Jul 23, 2009 6:11 pm

I am running RouterOS Version 3.10 and I am trying to get DFS to work with a simple point to point link made up of two wireless bridges running in WDS mode. One of the two units is configured as AP-Bridge and the other is configured as Station WDS.

I start both units at 5180MHz and then set DFS to "radar detect". As soon as I enable DFS, the AP goes into "detecting radar" for 60 seconds and then to "running AP". As long as there is no radar interferer the link stays up. Once we add the radar signal interference, the AP appears to stop transmitting because we loose the link and the station starts "searching for network". The AP never appears to change the channel. I am looking at the Frequency field on the Status tab of the Interface <wlan1> dialog box to determine if the Frequency of the AP changes when the interference is present.

I also tried adding a list of channels in the "Scan List" field on the Wireless Tab of the Interface <wlan1> dialog box to see if this would cause the AP to go to one of the other channels.

For reference, the testing is being done in a "closed-loop" environment (RF Cables, attenuators, directional couplers, etc.) so we know that we are not getting interference from unknown sources.

Any help that can be provided would be greatly appreciated.
 
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normis
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Re: DFS Mode

Fri Jul 24, 2009 8:32 am

AFAIK this happens only once - when you enable the card:
dfs-mode (none | radar-detect | no-radar-detect; default: none) - used for APs to dynamically select frequency at which this AP will operate
none - do not use DFS
no-radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is with the lowest amount of other networks detected
radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is with the lowest amount of other networks detected, if no radar is detected in this channel for 60 seconds, the AP starts to operate at this channel, if radar is detected, the AP continues searching for the next available channel which is with the lowest amount of other networks detected


if you add some radar later, nothing will happen
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readycool
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Re: DFS Mode

Thu Apr 28, 2011 2:14 pm

I found this topic closest to my issue..

I was wondering, I have p2p links (only, where one side is bridge and remote is WDS slave).

What I need to set exactly so my devices don't use one static frequency?
dfs-mode (none | radar-detect | no-radar-detect; default: none) - used for APs to dynamically select frequency at which this AP will operate
none - do not use DFS
no-radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is with the lowest amount of other networks detected
radar-detect - AP scans channel list from "scan-list" and chooses the frequency which is with the lowest amount of other networks detected, if no radar is detected in this channel for 60 seconds, the AP starts to operate at this channel, if radar is detected, the AP continues searching for the next available channel which is with the lowest amount of other networks detected

if you add some radar later, nothing will happen
Now is set as none.

For no-radar-detect it say: In 'wds-slave' mode this setting has no effect.

So, is radar-detect correct answer for both sides?

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