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Message from mark.duling@biola.edu

A long time ago I increased the interval for this up to a pretty high setting from the default (I think it was 10 min) at the suggestion of TAC engineer to stop them from changing channels so frequently. 802.11x > RRM > Dynamic Channel Assignment (DCA) I have no evidence that there is any issue with it, but a lot has changed since then. What intervals do others use for DCA? ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

Comments

I use 24 hours. It was originally at 5 minutes and I found clients dropping and reconnecting regularly when the channels changed. Nathan Hay Network Engineer | NOC WinWholesale Inc. 888-225-5947 From: Mark Duling To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU, Date: 10/03/2013 01:59 PM Subject: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv A long time ago I increased the interval for this up to a pretty high setting from the default (I think it was 10 min) at the suggestion of TAC engineer to stop them from changing channels so frequently. 802.11x > RRM > Dynamic Channel Assignment (DCA) I have no evidence that there is any issue with it, but a lot has changed since then. What intervals do others use for DCA? ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********************************************************************************************* This email message and any attachments is for use only by the named addressee(s) and may contain confidential, privileged and/or proprietary information. If you have received this message in error, please immediately notify the sender and delete and destroy the message and all copies. All unauthorized direct or indirect use or disclosure of this message is strictly prohibited. No right to confidentiality or privilege is waived or lost by any error in transmission. ********************************************************************************************* ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Message from ceyre@mtroyal.ca

I sent ours to change once every 24 hours but made sure I set it at 5am. This way the channels will change at 5am when there is less likelihood of affecting anyone. Depending on your channel sensitivity you could see alot of ap's flipping channels throughout the day if its set for 10 minutes but I could be mistaken.  I understand there will be alot less "random" access points at 5am as well but I'm more concerned about the rogues/surrounding area permanent ones.


Craig Eyre          
Network Analyst
IT Services Department
Mount Royal University
4825 Mount Royal Gate SW
Calgary AB T2P 3T5

P. 403.440.5199
E. ceyre@mtroyal.ca

"The difference between a successful person and others is not a lack of strength, not a lack of knowledge, but rather in a lack of will."  Vincent T. Lombardi


Mark Duling ---10/03/2013 11:59:57 AM---A long time ago I increased the interval for this up to a pretty high setting from the default (I th

From: Mark Duling <mark.duling@BIOLA.EDU>
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU,
Date: 10/03/2013 11:59 AM
Subject: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval
Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>



A long time ago I increased the interval for this up to a pretty high
setting from the default (I think it was 10 min) at the suggestion of
TAC engineer to stop them from changing channels so frequently.

802.11x > RRM > Dynamic Channel Assignment (DCA)

I have no evidence that there is any issue with it, but a lot has
changed since then.  What intervals do others use for DCA?

**********
Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

The original DCA algorithm prior to 6.0 code was problematic if you had a lots of APs. A change to a single AP could result in a cascade change to the rest of the radios in the same RF neighborhood. This could happen within a building, or if AP's in adjacent building could see each other, even campus wide.   
A lot of changes were made in 6.0 and beyond to minimize the problems. There is a hop limit on adjacent APs that will change, and changes are no longer based on the single worst radio. In theory, the defaults as they are today in 7.x code should work pretty well now.
 
Jeff

>>> On Thursday, October 03, 2013 at 11:06 AM, in message <OF9304AC17.74C680D4-ON87257BF9.0063110D-87257BF9.00637E7B@mtroyal.ca>, Craig Eyre <ceyre@MTROYAL.CA> wrote:

I sent ours to change once every 24 hours but made sure I set it at 5am. This way the channels will change at 5am when there is less likelihood of affecting anyone. Depending on your channel sensitivity you could see alot of ap's flipping channels throughout the day if its set for 10 minutes but I could be mistaken.  I understand there will be alot less "random" access points at 5am as well but I'm more concerned about the rogues/surrounding area permanent ones.


Craig Eyre          
Network Analyst
IT Services Department
Mount Royal University
4825 Mount Royal Gate SW
Calgary AB T2P 3T5

P. 403.440.5199
E. ceyre@mtroyal.ca

"The difference between a successful person and others is not a lack of strength, not a lack of knowledge, but rather in a lack of will."  Vincent T. Lombardi


Mark Duling ---10/03/2013 11:59:57 AM---A long time ago I increased the interval for this up to a pretty high setting from the default (I th

From: Mark Duling <mark.duling@BIOLA.EDU>
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU,
Date: 10/03/2013 11:59 AM
Subject: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval
Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>



A long time ago I increased the interval for this up to a pretty high
setting from the default (I think it was 10 min) at the suggestion of
TAC engineer to stop them from changing channels so frequently.

802.11x > RRM > Dynamic Channel Assignment (DCA)

I have no evidence that there is any issue with it, but a lot has
changed since then.  What intervals do others use for DCA?

**********
Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

We set this to be 1 hour. --- Dennis Xu Analyst 3, Network Infrastructure Computing and Communications Services(CCS) University of Guelph 519-824-4120 Ext 56217 dxu@uoguelph.ca www.uoguelph.ca/ccs
Can I ask what led to making this change? I am struggling trying to understand moving from a default of 10 minutes to 24 hours and the impact. I have been reading the documentation and reference for this setting in trying to determine if this is something I should implement but there is very little detail concerning the timer/interval. Based on the replies, 24 hours seems to be the choice and yet I cannot find through a google search why this is better. Appreciate any feedback given. Thanks, Don Sullivan Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu
There was a post on Cisco support forum about DCA interval and some senior contributors (not Cisco guys though) suggested to set it to 24 hours. I tried to search for it now but could not find it. We did have the AP channel change issues which affected about 50 APs at once. We thought the default 10 minutes interval is too aggressive and 24 hours is too long. We started with 1 hour to see how it went and we haven't had any issues. --- Dennis Xu Analyst 3, Network Infrastructure Computing and Communications Services(CCS) University of Guelph 519-824-4120 Ext 56217 dxu@uoguelph.ca www.uoguelph.ca/ccs
In response to my question yesterday, a Cisco engineer who is heavily involved in RRM sent me information in response to my question which has been very helpful to me in understanding what is occurring and whether I should be making any changes based on what I am observing. If you would like for me to forward this information to you please let me know and I will be happy to. I will tell you that he confirmed what one person had stated in one of the earlier emails that at code above release 6 there is no good reason to change the default interval. Don Sullivan Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu
Message from kacummings@eiu.edu

Don, Please forward me this information. Thanks, Kent Kent Cummings Network Engineer IV ITS Core Network, SSB - 3015 Eastern Illinois University (217)-581-8332
Can you forward me the info as well.

Thanks.


------------------------
Walter Reynolds
Principal Systems Security Development Engineer
Information and Technology Services
University of Michigan
(734) 615-9438


Message from dannyeaton@rice.edu

Me three.  

Connected by Motorola


Walter Reynolds <waltr@UMICH.EDU> wrote:

Can you forward me the info as well.

Thanks.


------------------------
Walter Reynolds
Principal Systems Security Development Engineer
Information and Technology Services
University of Michigan
(734) 615-9438


Hello,

please send a copy for me too.

Thanks !

--
Luis Fernando Valverde /
Director de Tecnología
Dirección de Tecnología de Información y Comunicaciones / INCAE Business School
Tel +506 2437 23 38 / www.incae.edu

INCAE Business School. La mejor escuela de negocios de América Latina. 
N°1 en América Latina. América Economía 2013.
Top 10 en el Mundo en: Estrategia Corporativa, Clientes Internacionales, y Participantes Internacionales. Financial Times 2013.
Top 50 en el Mundo en Executive Education. Financial Times 2013.

Síguenos en: Facebook / LinkedIn / Twitter / YouTube / Google+


glomming on- hit me, brother.

Lee H. Badman
Network Architect/Wireless TME
ITS, Syracuse University
315.443.3003
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando Valverde [fernando.valverde@INCAE.EDU]
Sent: Tuesday, October 08, 2013 10:08 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Hello,

please send a copy for me too.

Thanks !

--
Luis Fernando Valverde /
Director de Tecnología
Dirección de Tecnología de Información y Comunicaciones / INCAE Business School
Tel +506 2437 23 38 / www.incae.edu

INCAE Business School. La mejor escuela de negocios de América Latina. 
N°1 en América Latina. América Economía 2013.
Top 10 en el Mundo en: Estrategia Corporativa, Clientes Internacionales, y Participantes Internacionales. Financial Times 2013.
Top 50 en el Mundo en Executive Education. Financial Times 2013.

Síguenos en: Facebook / LinkedIn / Twitter / YouTube / Google+


Me too please Don.

 

john

 

From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Lee H Badman
Sent: Tuesday, October 08, 2013 9:25 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

 

glomming on- hit me, brother.

 

Lee H. Badman
Network Architect/Wireless TME
ITS, Syracuse University
315.443.3003

From: The EDUCAUSE Wireless Issues Constituent Group Listserv [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando Valverde [fernando.valverde@INCAE.EDU]
Sent: Tuesday, October 08, 2013 10:08 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Hello,

please send a copy for me too.

Thanks !


--
Luis Fernando Valverde /
Director de Tecnología

Dirección de Tecnología de Información y Comunicaciones / INCAE Business School

Tel +506 2437 23 38 / www.incae.edu

INCAE Business School. La mejor escuela de negocios de América Latina. 

N°1 en América Latina. América Economía 2013.

Top 10 en el Mundo en: Estrategia Corporativa, Clientes Internacionales, y Participantes Internacionales. Financial Times 2013.

Top 50 en el Mundo en Executive Education. Financial Times 2013.

Síguenos en: Facebook / LinkedIn / Twitter / YouTube / Google+

 

Can you not just send this to the LISTSERV to forestall all the individual requests? I also would like to see this document.

 

Thanks.

 

 

-jcw                                                                                         

                                                                                                     

John Watters                           The University of Alabama

                                                Office of Information Technology

                                                205-348-3992

 

********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.

Message from iam@st-andrews.ac.uk

It’s turning into a mid-late 1990’s AOL fest ..

 

--

ian

 

Please, me too, if it's possible. Thanks. El 08/10/2013 16:24, Lee H Badman escribió: > glomming on- hit me, brother. > > *Lee H. Badman* > Network Architect/Wireless TME > ITS, Syracuse University > 315.443.3003 > ------------------------------------------------------------------------ > *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv > [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando Valverde > [fernando.valverde@INCAE.EDU] > *Sent:* Tuesday, October 08, 2013 10:08 AM > *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU > *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) > interval > > Hello, > > please send a copy for me too. > > Thanks ! > > *-- > Luis Fernando Valverde /* */Director de Tecnología/ > * > Dirección de Tecnología de Información y Comunicaciones / *INCAE > Business School* > Tel +506 2437 23 38 / www.incae.edu > > INCAE Business School. La mejor escuela de negocios de América Latina. > *N°1* en América Latina. América Economía 2013. > *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes > Internacionales,* y *Participantes Internacionales. Financial Times 2013. > *Top 50 en el Mundo* en Executive Education.**Financial Times 2013. > > Síguenos en: Facebook / LinkedIn > / Twitter > / YouTube > / Google+ > > > > >
Ok guys, Here you go. I didn't ask the guy's permission to put on the list but I think he will be ok with it (at least I hope so). "My life is RRM, and part of my problem is that there is a lot of legacy wisdom committed to the world. Jeff Sessler hit the nail on the head. No good reason to change the default interval. One downside of this is that DCA only run's when you tell it too - which means if you are set to 24 hours - and 5 AM as I saw one individual that replied you will only quantify your channel's at a low load period - once daily. 1 major thing manages DCA's responsiveness - that is the DCA threshold. The threshold is set to medium by default which imposes a 10 dB hysteresis on a potential channel change. Meaning that a channel needs to be 10 dB better than the current channel in order for a change to be processed. You can increase the sensitivity to 5 db or decrease it to 20 db accordingly. Other things that will modify DCA behavior are Avoid Foreign AP Interference - this has to do with rogues and how we treat them. Checked it applies a higher Bias for rogue AP's and will work around the foreign AP to coordinate a channel plan. Un checked it gives less weight and will yield less to the rogues. The default is for this to be enabled - since it's a good idea. However there are use cases where this can drive a lot of channel changes - our wireless labs building is a good example as AP's come and go all day long there - channel changes are frequent if enabled. The other gotcha is load - this is disabled by default and should remain that way if channel changes are not desired. It will react quickly and the channel plan will change as loads come and go. Lastly - if you have not rebooted your RF group leader in some time (there are generally two - one for each band for each RF group) and your DCA is set to medium - it is possible that you have AP's on the edge of that 10 dB hysteresis that would be better served by a channel change. This is also true if you have added AP's over time. DCA has a startup mode where it is very aggressive with no rules applied - simply finding the best channel plan given the RF. If the number of AP's has changed over time this gets stale and re-running this is a very good idea. You can restart DCA best by using the command line argument in 7.3 and later code >config 802.11a/b channel global restart This must be run on the RF group leader (you can see which controller is in charge for the band on the DCA page). If your code is older than 7.3 - you will have to reboot the group leader to kick it in. I hope this helps shed some light. I am presently writing a guide which encompasses best practices and the long list of changes including 802.11AC and how DCA handles that (currently out for a patent by the way). The change velocity of the RRM feature set has been pretty fast - wireless as a whole is changing pretty fast - and this is likely to continue for a while." Don Sullivan Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of "Francisco J. Medina Jiménez" Sent: Tuesday, October 08, 2013 11:30 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval Please, me too, if it's possible. Thanks. El 08/10/2013 16:24, Lee H Badman escribió: > glomming on- hit me, brother. > > *Lee H. Badman* > Network Architect/Wireless TME > ITS, Syracuse University > 315.443.3003 > ---------------------------------------------------------------------- > -- > *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv > [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando > Valverde [fernando.valverde@INCAE.EDU] > *Sent:* Tuesday, October 08, 2013 10:08 AM > *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU > *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment > (DCA) interval > > Hello, > > please send a copy for me too. > > Thanks ! > > *-- > Luis Fernando Valverde /* */Director de Tecnología/ > * > Dirección de Tecnología de Información y Comunicaciones / *INCAE > Business School* Tel +506 2437 23 38 / www.incae.edu > > > INCAE Business School. La mejor escuela de negocios de América Latina. > *N°1* en América Latina. América Economía 2013. > *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes > Internacionales,* y *Participantes Internacionales. Financial Times 2013. > *Top 50 en el Mundo* en Executive Education.**Financial Times 2013. > > Síguenos en: Facebook / LinkedIn > / Twitter > / YouTube > / Google+ > > > > >
Thanks for sharing, Don. Great use of the list, as a lot of people can't seem to crack these eggs for whatever reason. -Lee -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Sullivan, Don Sent: Tuesday, October 08, 2013 3:15 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval Ok guys, Here you go. I didn't ask the guy's permission to put on the list but I think he will be ok with it (at least I hope so). "My life is RRM, and part of my problem is that there is a lot of legacy wisdom committed to the world. Jeff Sessler hit the nail on the head. No good reason to change the default interval. One downside of this is that DCA only run's when you tell it too - which means if you are set to 24 hours - and 5 AM as I saw one individual that replied you will only quantify your channel's at a low load period - once daily. 1 major thing manages DCA's responsiveness - that is the DCA threshold. The threshold is set to medium by default which imposes a 10 dB hysteresis on a potential channel change. Meaning that a channel needs to be 10 dB better than the current channel in order for a change to be processed. You can increase the sensitivity to 5 db or decrease it to 20 db accordingly. Other things that will modify DCA behavior are Avoid Foreign AP Interference - this has to do with rogues and how we treat them. Checked it applies a higher Bias for rogue AP's and will work around the foreign AP to coordinate a channel plan. Un checked it gives less weight and will yield less to the rogues. The default is for this to be enabled - since it's a good idea. However there are use cases where this can drive a lot of channel changes - our wireless labs building is a good example as AP's come and go all day long there - channel changes are frequent if enabled. The other gotcha is load - this is disabled by default and should remain that way if channel changes are not desired. It will react quickly and the channel plan will change as loads come and go. Lastly - if you have not rebooted your RF group leader in some time (there are generally two - one for each band for each RF group) and your DCA is set to medium - it is possible that you have AP's on the edge of that 10 dB hysteresis that would be better served by a channel change. This is also true if you have added AP's over time. DCA has a startup mode where it is very aggressive with no rules applied - simply finding the best channel plan given the RF. If the number of AP's has changed over time this gets stale and re-running this is a very good idea. You can restart DCA best by using the command line argument in 7.3 and later code >config 802.11a/b channel global restart This must be run on the RF group leader (you can see which controller is in charge for the band on the DCA page). If your code is older than 7.3 - you will have to reboot the group leader to kick it in. I hope this helps shed some light. I am presently writing a guide which encompasses best practices and the long list of changes including 802.11AC and how DCA handles that (currently out for a patent by the way). The change velocity of the RRM feature set has been pretty fast - wireless as a whole is changing pretty fast - and this is likely to continue for a while." Don Sullivan Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of "Francisco J. Medina Jiménez" Sent: Tuesday, October 08, 2013 11:30 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval Please, me too, if it's possible. Thanks. El 08/10/2013 16:24, Lee H Badman escribió: > glomming on- hit me, brother. > > *Lee H. Badman* > Network Architect/Wireless TME > ITS, Syracuse University > 315.443.3003 > ---------------------------------------------------------------------- > -- > *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv > [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando > Valverde [fernando.valverde@INCAE.EDU] > *Sent:* Tuesday, October 08, 2013 10:08 AM > *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU > *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment > (DCA) interval > > Hello, > > please send a copy for me too. > > Thanks ! > > *-- > Luis Fernando Valverde /* */Director de Tecnología/ > * > Dirección de Tecnología de Información y Comunicaciones / *INCAE > Business School* Tel +506 2437 23 38 / www.incae.edu > > > INCAE Business School. La mejor escuela de negocios de América Latina. > *N°1* en América Latina. América Economía 2013. > *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes > Internacionales,* y *Participantes Internacionales. Financial Times 2013. > *Top 50 en el Mundo* en Executive Education.**Financial Times 2013. > > Síguenos en: Facebook / LinkedIn > / Twitter > / YouTube > / Google+ > > > > >
Here is a good reference to the changes made in 6.0 - the whole guide is a good read if you've not looked at it since the 5.x days, and the "RF Group Leader" section has information on the changes I mentioned in my previous email.
 
Jeff

>>> On Tuesday, October 08, 2013 at 12:32 PM, in message <943DA0E70434CA499AD0088FB90EAADEFD5BFF@SUEX10-mbx-05.ad.syr.edu>, Lee H Badman <lhbadman@SYR.EDU> wrote:
Thanks for sharing, Don.  Great use of the list, as a lot of people can't seem to crack these eggs for whatever reason.

-Lee

-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Sullivan, Don
Sent: Tuesday, October 08, 2013 3:15 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Ok guys, Here you go. I didn't ask the guy's permission to put on the list but I think he will be ok with it (at least I hope so).


"My life is RRM, and part of my problem is that there is a lot of legacy wisdom committed to the world.  Jeff Sessler hit the nail on the head.  No good reason to change the default interval.  One downside of this is that DCA only run's when you tell it too - which means if you are set to 24 hours - and 5 AM as I saw one individual that replied you will only quantify your channel's at a low load period - once daily.

1 major thing manages DCA's responsiveness - that is the DCA threshold.  The threshold is set to medium by default which imposes a 10 dB hysteresis on a potential channel change.  Meaning that a channel needs to be 10 dB better than the current channel in order for a change to be processed.  You can increase the sensitivity to 5 db or decrease it to 20 db accordingly.

Other things that will modify DCA behavior are Avoid Foreign AP Interference - this has to do with rogues and how we treat them.  Checked it applies a higher Bias for rogue AP's and will work around the foreign AP to coordinate a channel plan.  Un checked  it gives less weight and will yield less to the rogues.  The default is for this to be enabled - since it's a good idea.  However there are use cases where this can drive a lot of channel changes - our wireless labs building is a good example as AP's come and go all day long there - channel changes are frequent if enabled.

The other gotcha is load - this is disabled by default and should remain that way if channel changes are not desired.  It will react quickly and the channel plan will change as loads come and go.

Lastly - if you have not rebooted your RF group leader in some time (there are generally two - one for each band for each RF group) and your DCA is set to medium - it is possible that you have AP's on the edge of that 10 dB hysteresis that would be better served by a channel change.  This is also true if you have added AP's over time.  DCA has a startup mode where it is very aggressive with no rules applied - simply finding the best channel plan given the RF.  If the number of AP's has changed over time this gets stale and re-running this is a very good idea.

You can restart DCA best by using the command line argument in 7.3 and later code   >config 802.11a/b channel global restart  This must be run on the RF group leader (you can see which controller is in charge for the band on the DCA page).  If your code is older than 7.3  - you will have to reboot the group leader to kick it in.

I hope this helps shed some light.

I am presently writing a guide which encompasses best practices and the long list of changes including 802.11AC and how DCA handles that (currently out for a patent by the way).

The change velocity of the RRM feature set has been pretty fast - wireless as a whole is changing pretty fast - and this is likely to continue for a while."


Don Sullivan
Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu





-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of "Francisco J. Medina Jiménez"
Sent: Tuesday, October 08, 2013 11:30 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Please, me too, if it's possible.
Thanks.

El 08/10/2013 16:24, Lee H Badman escribió:
> glomming on- hit me, brother.
>
> *Lee H. Badman*
> Network Architect/Wireless TME
> ITS, Syracuse University
> 315.443.3003
> ----------------------------------------------------------------------
> --
> *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
> [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando
> Valverde [fernando.valverde@INCAE.EDU]
> *Sent:* Tuesday, October 08, 2013 10:08 AM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
> *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment
> (DCA) interval
>
> Hello,
>
> please send a copy for me too.
>
> Thanks !
>
> *--
> Luis Fernando Valverde /* */Director de Tecnología/
> *
> Dirección de Tecnología de Información y Comunicaciones / *INCAE
> Business School* Tel +506 2437 23 38 / www.incae.edu
> <http://www.incae.edu/>
>
> INCAE Business School. La mejor escuela de negocios de América Latina.
> *N°1* en América Latina. América Economía 2013.
> *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes
> Internacionales,* y *Participantes Internacionales. Financial Times 2013.
> *Top 50 en el Mundo* en Executive Education.**Financial Times 2013.
>
> Síguenos en: Facebook <http://www.facebook.com/INCAE> / LinkedIn
> <http://www.linkedin.com/groups?gid=3048169> / Twitter
> <http://www.twitter.com/incae> / YouTube
> <http://www.youtube.com/incaemba> / Google+
> <https://plus.google.com/113399553262888830636/posts>
> <https://plus.google.com/113399553262888830636/posts>
>
>
>
Guess I should have included the link!
 
Jeff

>>> On Tuesday, October 08, 2013 at 2:52 PM, in message <52541C3A020000C000125BF6@SCRNCS1.scrippscollege.edu>, Jeffrey Sessler <Jeff@SCRIPPSCOLLEGE.EDU> wrote:
Here is a good reference to the changes made in 6.0 - the whole guide is a good read if you've not looked at it since the 5.x days, and the "RF Group Leader" section has information on the changes I mentioned in my previous email.
 
Jeff

>>> On Tuesday, October 08, 2013 at 12:32 PM, in message <943DA0E70434CA499AD0088FB90EAADEFD5BFF@SUEX10-mbx-05.ad.syr.edu>, Lee H Badman <lhbadman@SYR.EDU> wrote:
Thanks for sharing, Don.  Great use of the list, as a lot of people can't seem to crack these eggs for whatever reason.

-Lee

-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Sullivan, Don
Sent: Tuesday, October 08, 2013 3:15 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Ok guys, Here you go. I didn't ask the guy's permission to put on the list but I think he will be ok with it (at least I hope so).


"My life is RRM, and part of my problem is that there is a lot of legacy wisdom committed to the world.  Jeff Sessler hit the nail on the head.  No good reason to change the default interval.  One downside of this is that DCA only run's when you tell it too - which means if you are set to 24 hours - and 5 AM as I saw one individual that replied you will only quantify your channel's at a low load period - once daily.

1 major thing manages DCA's responsiveness - that is the DCA threshold.  The threshold is set to medium by default which imposes a 10 dB hysteresis on a potential channel change.  Meaning that a channel needs to be 10 dB better than the current channel in order for a change to be processed.  You can increase the sensitivity to 5 db or decrease it to 20 db accordingly.

Other things that will modify DCA behavior are Avoid Foreign AP Interference - this has to do with rogues and how we treat them.  Checked it applies a higher Bias for rogue AP's and will work around the foreign AP to coordinate a channel plan.  Un checked  it gives less weight and will yield less to the rogues.  The default is for this to be enabled - since it's a good idea.  However there are use cases where this can drive a lot of channel changes - our wireless labs building is a good example as AP's come and go all day long there - channel changes are frequent if enabled.

The other gotcha is load - this is disabled by default and should remain that way if channel changes are not desired.  It will react quickly and the channel plan will change as loads come and go.

Lastly - if you have not rebooted your RF group leader in some time (there are generally two - one for each band for each RF group) and your DCA is set to medium - it is possible that you have AP's on the edge of that 10 dB hysteresis that would be better served by a channel change.  This is also true if you have added AP's over time.  DCA has a startup mode where it is very aggressive with no rules applied - simply finding the best channel plan given the RF.  If the number of AP's has changed over time this gets stale and re-running this is a very good idea.

You can restart DCA best by using the command line argument in 7.3 and later code   >config 802.11a/b channel global restart  This must be run on the RF group leader (you can see which controller is in charge for the band on the DCA page).  If your code is older than 7.3  - you will have to reboot the group leader to kick it in.

I hope this helps shed some light.

I am presently writing a guide which encompasses best practices and the long list of changes including 802.11AC and how DCA handles that (currently out for a patent by the way).

The change velocity of the RRM feature set has been pretty fast - wireless as a whole is changing pretty fast - and this is likely to continue for a while."


Don Sullivan
Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu





-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of "Francisco J. Medina Jiménez"
Sent: Tuesday, October 08, 2013 11:30 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Please, me too, if it's possible.
Thanks.

El 08/10/2013 16:24, Lee H Badman escribió:
> glomming on- hit me, brother.
>
> *Lee H. Badman*
> Network Architect/Wireless TME
> ITS, Syracuse University
> 315.443.3003
> ----------------------------------------------------------------------
> --
> *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
> [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando
> Valverde [fernando.valverde@INCAE.EDU]
> *Sent:* Tuesday, October 08, 2013 10:08 AM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
> *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment
> (DCA) interval
>
> Hello,
>
> please send a copy for me too.
>
> Thanks !
>
> *--
> Luis Fernando Valverde /* */Director de Tecnología/
> *
> Dirección de Tecnología de Información y Comunicaciones / *INCAE
> Business School* Tel +506 2437 23 38 / www.incae.edu
> <http://www.incae.edu/>
>
> INCAE Business School. La mejor escuela de negocios de América Latina.
> *N°1* en América Latina. América Economía 2013.
> *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes
> Internacionales,* y *Participantes Internacionales. Financial Times 2013.
> *Top 50 en el Mundo* en Executive Education.**Financial Times 2013.
>
> Síguenos en: Facebook <http://www.facebook.com/INCAE> / LinkedIn
> <http://www.linkedin.com/groups?gid=3048169> / Twitter
> <http://www.twitter.com/incae> / YouTube
> <http://www.youtube.com/incaemba> / Google+
> <https://plus.google.com/113399553262888830636/posts>
> <https://plus.google.com/113399553262888830636/posts>
>
>
>

Our is still with the default 10 minutes, though we did recently see and consider the 24 hour config from the Cisco forums. We had a couple of locations where there were reports of dropouts, and all users in the area having issues at the same time. The event log for the AP in Prime showed the a lot of AP radio reset logs (sorry I don’t have a copy of the exact logs we were seeing). Most of it was due to Rogue AP’s. In investigating we also found a few forum comments on disabling Rogue AP detection on the AP individually, certainly for the reporting sites the users have been happier and those resets have disappeared. This was only recent so haven’t considered any further action yet. It’s probably more of a workaround than a solution as it typically occurs in buildings that we don’t own like hospitals but have users and network gear, recently the hospitals have started installing their own wireless so a resolution will be interesting.

We have also found that that in Prime under “Monitor-Radio Resource Management” there is some useful information, at times we have noticed AP’s with 60+ channel changes in 24 hours. Investigating the individual reasons and resolving them has worked well. I’m not really sure what acceptable numbers should be but the current list shows 2 radios at 11&14, 6 radios at 3 to 6, 8 at 2 and 30 at 1 though we are in a semester break.

--

Jason Cook

Technology Services

The University of Adelaide, AUSTRALIA 5005

Ph    : +61 8 8313 4800

 

From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jeffrey Sessler
Sent: Wednesday, 9 October 2013 8:44 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

 

Guess I should have included the link!

 

Jeff

>>> On Tuesday, October 08, 2013 at 2:52 PM, in message <52541C3A020000C000125BF6@SCRNCS1.scrippscollege.edu>, Jeffrey Sessler <Jeff@SCRIPPSCOLLEGE.EDU> wrote:

Here is a good reference to the changes made in 6.0 - the whole guide is a good read if you've not looked at it since the 5.x days, and the "RF Group Leader" section has information on the changes I mentioned in my previous email.

 

Jeff

>>> On Tuesday, October 08, 2013 at 12:32 PM, in message <943DA0E70434CA499AD0088FB90EAADEFD5BFF@SUEX10-mbx-05.ad.syr.edu>, Lee H Badman <lhbadman@SYR.EDU> wrote:

Thanks for sharing, Don.  Great use of the list, as a lot of people can't seem to crack these eggs for whatever reason.

-Lee

-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Sullivan, Don
Sent: Tuesday, October 08, 2013 3:15 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Ok guys, Here you go. I didn't ask the guy's permission to put on the list but I think he will be ok with it (at least I hope so).


"My life is RRM, and part of my problem is that there is a lot of legacy wisdom committed to the world.  Jeff Sessler hit the nail on the head.  No good reason to change the default interval.  One downside of this is that DCA only run's when you tell it too - which means if you are set to 24 hours - and 5 AM as I saw one individual that replied you will only quantify your channel's at a low load period - once daily.

1 major thing manages DCA's responsiveness - that is the DCA threshold.  The threshold is set to medium by default which imposes a 10 dB hysteresis on a potential channel change.  Meaning that a channel needs to be 10 dB better than the current channel in order for a change to be processed.  You can increase the sensitivity to 5 db or decrease it to 20 db accordingly.

Other things that will modify DCA behavior are Avoid Foreign AP Interference - this has to do with rogues and how we treat them.  Checked it applies a higher Bias for rogue AP's and will work around the foreign AP to coordinate a channel plan.  Un checked  it gives less weight and will yield less to the rogues.  The default is for this to be enabled - since it's a good idea.  However there are use cases where this can drive a lot of channel changes - our wireless labs building is a good example as AP's come and go all day long there - channel changes are frequent if enabled.

The other gotcha is load - this is disabled by default and should remain that way if channel changes are not desired.  It will react quickly and the channel plan will change as loads come and go.

Lastly - if you have not rebooted your RF group leader in some time (there are generally two - one for each band for each RF group) and your DCA is set to medium - it is possible that you have AP's on the edge of that 10 dB hysteresis that would be better served by a channel change.  This is also true if you have added AP's over time.  DCA has a startup mode where it is very aggressive with no rules applied - simply finding the best channel plan given the RF.  If the number of AP's has changed over time this gets stale and re-running this is a very good idea.

You can restart DCA best by using the command line argument in 7.3 and later code   >config 802.11a/b channel global restart  This must be run on the RF group leader (you can see which controller is in charge for the band on the DCA page).  If your code is older than 7.3  - you will have to reboot the group leader to kick it in.

I hope this helps shed some light.

I am presently writing a guide which encompasses best practices and the long list of changes including 802.11AC and how DCA handles that (currently out for a patent by the way).

The change velocity of the RRM feature set has been pretty fast - wireless as a whole is changing pretty fast - and this is likely to continue for a while."


Don Sullivan
Network Administrator | Office: 205.726.2111 | email: dsullivan@samford.edu





-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of "Francisco J. Medina Jiménez"
Sent: Tuesday, October 08, 2013 11:30 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment (DCA) interval

Please, me too, if it's possible.
Thanks.

El 08/10/2013 16:24, Lee H Badman escribió:
> glomming on- hit me, brother.
>
> *Lee H. Badman*
> Network Architect/Wireless TME
> ITS, Syracuse University
> 315.443.3003
> ----------------------------------------------------------------------
> --
> *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
> [WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] on behalf of Luis Fernando
> Valverde [fernando.valverde@INCAE.EDU]
> *Sent:* Tuesday, October 08, 2013 10:08 AM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
> *Subject:* Re: [WIRELESS-LAN] Cisco WLC dynamic channel assignment
> (DCA) interval
>
> Hello,
>
> please send a copy for me too.
>
> Thanks !
>
> *--
> Luis Fernando Valverde /* */Director de Tecnología/
> *
> Dirección de Tecnología de Información y Comunicaciones / *INCAE
> Business School* Tel +506 2437 23 38 / www.incae.edu
> <http://www.incae.edu/>
>
> INCAE Business School. La mejor escuela de negocios de América Latina.
> *N°1* en América Latina. América Economía 2013.
> *Top 10 en el Mundo* en: Estrategia Corporativa,**Clientes
> Internacionales,* y *Participantes Internacionales. Financial Times 2013.
> *Top 50 en el Mundo* en Executive Education.**Financial Times 2013.
>
> Síguenos en: Facebook <http://www.facebook.com/INCAE> / LinkedIn
> <http://www.linkedin.com/groups?gid=3048169> / Twitter
> <http://www.twitter.com/incae> / YouTube
> <http://www.youtube.com/incaemba> / Google+
> <https://plus.google.com/113399553262888830636/posts>
> <https://plus.google.com/113399553262888830636/posts>
>
>
>

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