Re: [WIRELESS-LAN] Plastered buildings

[David Callisch]

Ruckus wireless 

David Callisch
+1 408 504 5487


> On Aug 28, 2017, at 9:20 PM, John Rodkey  wrote:
> 
> How do you deal with buildings that have plaster and fine metal mesh 
> enclosing them?  We have placed access points on the exterior of the 
> building, but the signal isn't getting through.  The rooms all open onto an 
> outside hallway - there is no common internal hallway.
> 
> John Rodkey
> Director of Servers and Networks
> ** Participation and subscription information for this EDUCAUSE 
> Constituent Group discussion list can be found at 
> http://www.educause.edu/discuss.

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

Plastered buildings

[John Rodkey]

How do you deal with buildings that have plaster and fine metal mesh
enclosing them?  We have placed access points on the exterior of the
building, but the signal isn't getting through.  The rooms all open onto an
outside hallway - there is no common internal hallway.

John Rodkey
Director of Servers and Networks

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

RE: [WIRELESS-LAN] 5GHz Micro Adapters

[Jason Cook]

We’ve been very happy with these
http://www.edimax.com/edimax/merchandise/merchandise_detail/data/edimax/global/wireless_adapters_ac1200_dual-band/ew-7822uac/
but they are full size

http://www.edimax.com/edimax/merchandise/merchandise_list/data/edimax/global/wireless_adapters/
I’ve heard good things about the micro and nano’s (we know the full size is 
great) and have been meaning buy a couple for testing.
As understand it the smaller ones may have a weaker antenna which could lead to 
issues. But haven’t tested it myself


--
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 Norton, Thomas 
(Network Operations)
Sent: Tuesday, 29 August 2017 8:33 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] 5GHz Micro Adapters

Due to poor performance with them, we moved away from recommending micro usb 
for 2.4 only clients...  We now recommend a 802.11ac 2x2 USB adapter, typically 
the Linksys  (AC1200) WUSB6300. To provide the best user experience possible, 
we always keep a couple on hand to issue out for affected students. The big 
downfall we have found with these is the size, but for the price point you 
can't beat the performance.


T.J. Norton
Wireless Network Architect
Network Operations

(434) 592-6552

[http://www.liberty.edu/media/1616/40themail/wordmark-for-email.jpg]

Liberty University  |  Training Champions for Christ since 1971

On Aug 28, 2017, at 6:47 PM, Johnson, Christopher 
> wrote:
Good Evening,



  1.  Has anyone had any experience and would recommend a particular 5GHz Wifi 
Micro USB adapter for students that have a Windows Laptop with a 2.4GHz only 
integrated adapter?
  2.  How is the quality/performance of a 5GHz Micro USB Adapter?

 *   I can’t imagine it performing as well as a laptop with Wi-Fi antennas 
integrated throughout the monitor.
 *   Would it be better to recommended the internal Wi-Fi NIC be swapped 
out for another compatible model – although I could see this being an issue if 
the antennas weren’t dual-band capable.

Thank you and have a great night!

Christopher Johnson
Wireless Network Engineer
AT Infrastructure Operations & Networking (ION)
Illinois State University
(309) 438-8444
Stay connected with ISU IT news and tips with @ISU IT Help on 
Facebook
 and 
Twitter

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

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

Re: [WIRELESS-LAN] 5GHz Micro Adapters

[Norton, Thomas (Network Operations)]

Due to poor performance with them, we moved away from recommending micro usb 
for 2.4 only clients...  We now recommend a 802.11ac 2x2 USB adapter, typically 
the Linksys  (AC1200) WUSB6300. To provide the best user experience possible, 
we always keep a couple on hand to issue out for affected students. The big 
downfall we have found with these is the size, but for the price point you 
can't beat the performance.


T.J. Norton
Wireless Network Architect
Network Operations

(434) 592-6552

[http://www.liberty.edu/media/1616/40themail/wordmark-for-email.jpg]

Liberty University  |  Training Champions for Christ since 1971

On Aug 28, 2017, at 6:47 PM, Johnson, Christopher 
> wrote:

Good Evening,


1.   Has anyone had any experience and would recommend a particular 5GHz 
Wifi Micro USB adapter for students that have a Windows Laptop with a 2.4GHz 
only integrated adapter?

2.   How is the quality/performance of a 5GHz Micro USB Adapter?

a.   I can’t imagine it performing as well as a laptop with Wi-Fi antennas 
integrated throughout the monitor.

b.   Would it be better to recommended the internal Wi-Fi NIC be swapped 
out for another compatible model – although I could see this being an issue if 
the antennas weren’t dual-band capable.

Thank you and have a great night!

Christopher Johnson
Wireless Network Engineer
AT Infrastructure Operations & Networking (ION)
Illinois State University
(309) 438-8444
Stay connected with ISU IT news and tips with @ISU IT Help on 
Facebook
 and 
Twitter

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

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

Re: 5GHz Micro Adapters

[Curtis K. Larsen]

I carry a couple of these for those occasions when an end-user laptop radio is 
fubar and they don't believe it:

https://www.amazon.com/Linksys-Wireless-Mini-Adapter-AE6000/dp/B00BWT1IFE/ref=sr_1_1?ie=UTF8=1503960935=8-1-spons=Linksys+AE6000=1

The drivers autoinstall on Windows.

I have not measured the performance but it seems decent when I have used it.  
Few people these days I think will apply the effort to research and replace the 
internal radio.


Thanks,

--
Curtis K. Larsen
Senior Network Engineer
University of Utah IT/CIS


From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
 on behalf of Johnson, Christopher 

Sent: Monday, August 28, 2017 4:47 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: [WIRELESS-LAN] 5GHz Micro Adapters

Good Evening,


1.   Has anyone had any experience and would recommend a particular 5GHz 
Wifi Micro USB adapter for students that have a Windows Laptop with a 2.4GHz 
only integrated adapter?

2.   How is the quality/performance of a 5GHz Micro USB Adapter?

a.   I can’t imagine it performing as well as a laptop with Wi-Fi antennas 
integrated throughout the monitor.

b.   Would it be better to recommended the internal Wi-Fi NIC be swapped 
out for another compatible model – although I could see this being an issue if 
the antennas weren’t dual-band capable.

Thank you and have a great night!

Christopher Johnson
Wireless Network Engineer
AT Infrastructure Operations & Networking (ION)
Illinois State University
(309) 438-8444
Stay connected with ISU IT news and tips with @ISU IT Help on 
Facebook and 
Twitter

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

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

Re: [WIRELESS-LAN] 5GHz Micro Adapters

[Coehoorn, Joel]

I've seen some laptop vendors lock down the internal adapter in the bios to
the original approved model only, claiming recent FCC rules as the excuse.

On Aug 28, 2017 5:47 PM, "Johnson, Christopher"  wrote:

> Good Evening,
>
> 1.   Has anyone had any experience and would recommend a particular
> 5GHz Wifi Micro USB adapter for students that have a Windows Laptop with a
> 2.4GHz only integrated adapter?
>
> 2.   How is the quality/performance of a 5GHz Micro USB Adapter?
>
> a.   I can’t imagine it performing as well as a laptop with Wi-Fi
> antennas integrated throughout the monitor.
>
> b.   Would it be better to recommended the internal Wi-Fi NIC be
> swapped out for another compatible model – although I could see this being
> an issue if the antennas weren’t dual-band capable.
>
>
>
> Thank you and have a great night!
>
>
>
> *Christopher Johnson*
>
> Wireless Network Engineer
>
> AT Infrastructure Operations & Networking (ION)
>
> Illinois State University
>
> (309) 438-8444
>
> Stay connected with ISU IT news and tips with @ISU IT Help on Facebook
>  and Twitter
> 
>
>
> ** Participation and subscription information for this EDUCAUSE
> Constituent Group discussion list can be found at http://www.educause.edu/
> discuss.
>
>

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

5GHz Micro Adapters

[Johnson, Christopher]

Good Evening,


1.   Has anyone had any experience and would recommend a particular 5GHz 
Wifi Micro USB adapter for students that have a Windows Laptop with a 2.4GHz 
only integrated adapter?

2.   How is the quality/performance of a 5GHz Micro USB Adapter?

a.   I can't imagine it performing as well as a laptop with Wi-Fi antennas 
integrated throughout the monitor.

b.   Would it be better to recommended the internal Wi-Fi NIC be swapped 
out for another compatible model - although I could see this being an issue if 
the antennas weren't dual-band capable.

Thank you and have a great night!

Christopher Johnson
Wireless Network Engineer
AT Infrastructure Operations & Networking (ION)
Illinois State University
(309) 438-8444
Stay connected with ISU IT news and tips with @ISU IT Help on 
Facebook and 
Twitter


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

Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

[Jeffrey D. Sessler]

John,

The link I included has the process for requesting the build. It’s TAC 
recommended if you have x700-series.

Jeff

From: "wireless-lan@listserv.educause.edu"  
on behalf of "Watters, John" 
Reply-To: "wireless-lan@listserv.educause.edu" 

Date: Monday, August 28, 2017 at 9:39 AM
To: "wireless-lan@listserv.educause.edu" 
Subject: Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

TAC has not mentioned 8.0.141.46 (or any other 8.0 version). They would like 
for me to move to 8.2. However, school just started. This is not the time to 
make a level change. Maybe in a month or so though.

However, I would strongly consider 8.0.141.46 if I could find it (which I 
can’t; it is not listed on the Cisco software download site). Maybe my local 
Cisco tech can get it for me. I wonder why TAC didn’t even mention it.

Thanks.



John Watters
Network Engineer, Office of Information Technology
The University of Alabama
A115 Gordon Palmer Hall
Box 870346
Tuscaloosa, AL 35487
Phone 205-348-3992
john.watt...@ua.edu
[he University of Alabama]

From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jeffrey D. Sessler
Sent: Monday, August 28, 2017 10:10 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

TAC will likely suggest you install 8.0MR5 interim (8.0.141.46) given you have 
2700’s (couple of radio bugs are fixed). DFS is as much art as science and 
older code isn’t always perfect i.e. I’ve seen newer devices that much older 
code sees as radar. You can request the code here and see the fixes including a 
number of DFS-related.
https://supportforums.cisco.com/t5/wireless-mobility-blogs/8-0mr5-interim-release-availability/ba-p/3098510

Probably too late, but you may want to consider getting to newer code. If you 
have x700 series WAPs, it’s strongly recommended to be on at least 8.2.  8.2 
and beyond have additional innovation in DFS area among many other improvements.

Jeff

From: 
"wireless-lan@listserv.educause.edu" 
> 
on behalf of "Watters, John" >
Reply-To: 
"wireless-lan@listserv.educause.edu" 
>
Date: Monday, August 28, 2017 at 7:42 AM
To: 
"wireless-lan@listserv.educause.edu" 
>
Subject: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

We are a Cisco shop running 8510 HA WLCs and a variety of AP including 1142s, 
2702s, others in smaller quantities for a current total of 6600+ APs. We are 
running WLC code 8.0.140.16. This was installed on JAN 4.

A couple of months ago we started seeing a lot of DFS scans. This was several 
months after our last code upgrade. When these scans are done, the users of the 
5 GHz radio that is doing the scanning for a clear frequency are all kicked off 
of their connections. Since the scans lasts for 1 minute & 2 seconds, this is 
very disruptive to the clients. We do not understand why this behavior has 
suddenly started all over campus. We are not particularly near an airport. 
There in one on the other side of town but it does not handle commercial 
service – private planes only plus an occasional charter for a sporting event. 
And, the APs that do the most frequent DFS scans are located in interior rooms, 
often on the ground floor of a multistory building. APs located near windows 
are rarely affected. This is happening in a lot of buildings, and not just in 
buildings that may tend to have noise in the 5 GHz range (e.g., an engineering 
building).

Has anyone else seen this problem? And, have you found the cause of this 
behavior. And, more importantly, a fix for the problem.

Following is an example from one AP (BRU-202-E2) showing two DSF scans almost 
back-to-back (2 sec gap) which lasted 3+ minutes:

*Aug 28 04:15:52.930: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5540 
MHz
*Aug 28 04:15:53.708: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to 
down
*Aug 28 04:15:53.710: %LINK-5-CHANGED: Interface Dot11Radio1, changed state to 
reset
*Aug 28 04:15:54.707: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to down
*Aug 28 04:15:54.739: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to up
*Aug 28 04:15:55.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to up
*Aug 28 04:17:53.253: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5280 
MHz
*Aug 28 04:17:54.747: 

Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

[Mccormick, Kevin]

Make sure 8.2 supports all the APs you have since 8.2 does drop support for
some older AP models.

Kevin McCormick

Network Administrator
University Technology - Western Illinois University
ke-mccorm...@wiu.edu | (309) 298-1335 <3092981335> | Morgan Hall 106b
Connect with uTech: Website  | Facebook
 | Twitter



On Mon, Aug 28, 2017 at 11:39 AM, Watters, John  wrote:

> TAC has not mentioned 8.0.141.46 (or any other 8.0 version). They would
> like for me to move to 8.2. However, school just started. This is not the
> time to make a level change. Maybe in a month or so though.
>
>
>
> However, I would strongly consider 8.0.141.46 if I could find it (which I
> can’t; it is not listed on the Cisco software download site). Maybe my
> local Cisco tech can get it for me. I wonder why TAC didn’t even mention it.
>
>
>
> Thanks.
>
>
>
>
>
>
>
> *John Watters*
>
> Network Engineer, Office of Information Technology
>
> The University of Alabama 
> A115 Gordon Palmer Hall
> Box 870346
> Tuscaloosa, AL 35487
> Phone 205-348-3992
> john.watt...@ua.edu
>
> [image: The University of Alabama] 
>
>
>
> *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:
> WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] *On Behalf Of *Jeffrey D. Sessler
> *Sent:* Monday, August 28, 2017 10:10 AM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
> *Subject:* Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok
>
>
>
> TAC will likely suggest you install 8.0MR5 interim (8.0.141.46) given you
> have 2700’s (couple of radio bugs are fixed). DFS is as much art as science
> and older code isn’t always perfect i.e. I’ve seen newer devices that much
> older code sees as radar. You can request the code here and see the fixes
> including a number of DFS-related.
>
> https://supportforums.cisco.com/t5/wireless-mobility-
> blogs/8-0mr5-interim-release-availability/ba-p/3098510
>
>
>
> Probably too late, but you may want to consider getting to newer code. If
> you have x700 series WAPs, it’s strongly recommended to be on at least 8.2.
>  8.2 and beyond have additional innovation in DFS area among many other
> improvements.
>
>
>
> Jeff
>
>
>
> *From: *"wireless-lan@listserv.educause.edu"  EDUCAUSE.EDU> on behalf of "Watters, John" 
> *Reply-To: *"wireless-lan@listserv.educause.edu"  EDUCAUSE.EDU>
> *Date: *Monday, August 28, 2017 at 7:42 AM
> *To: *"wireless-lan@listserv.educause.edu"  EDUCAUSE.EDU>
> *Subject: *[WIRELESS-LAN] DFS Scans Seem to Have Run Amok
>
>
>
> We are a Cisco shop running 8510 HA WLCs and a variety of AP including
> 1142s, 2702s, others in smaller quantities for a current total of 6600+
> APs. We are running WLC code 8.0.140.16. This was installed on JAN 4.
>
>
>
> A couple of months ago we started seeing a lot of DFS scans. This was
> several months after our last code upgrade. When these scans are done, the
> users of the 5 GHz radio that is doing the scanning for a clear frequency
> are all kicked off of their connections. Since the scans lasts for 1 minute
> & 2 seconds, this is very disruptive to the clients. We do not understand
> why this behavior has suddenly started all over campus. We are not
> particularly near an airport. There in one on the other side of town but it
> does not handle commercial service – private planes only plus an occasional
> charter for a sporting event. And, the APs that do the most frequent DFS
> scans are located in interior rooms, often on the ground floor of a
> multistory building. APs located near windows are rarely affected. This is
> happening in a lot of buildings, and not just in buildings that may tend to
> have noise in the 5 GHz range (e.g., an engineering building).
>
>
>
> Has anyone else seen this problem? And, have you found the cause of this
> behavior. And, more importantly, a fix for the problem.
>
>
>
> Following is an example from one AP (BRU-202-E2) showing two DSF scans
> almost back-to-back (2 sec gap) which lasted 3+ minutes:
>
>
>
> *Aug 28 04:15:52.930: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency
> 5540 MHz
>
> *Aug 28 04:15:53.708: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state
> to down
>
> *Aug 28 04:15:53.710: %LINK-5-CHANGED: Interface Dot11Radio1, changed
> state to reset
>
> *Aug 28 04:15:54.707: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Dot11Radio1, changed state to down
>
> *Aug 28 04:15:54.739: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state
> to up
>
> *Aug 28 04:15:55.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface
> Dot11Radio1, changed state to up
>
> *Aug 28 04:17:53.253: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency
> 5280 MHz
>
> *Aug 28 04:17:54.747: %LINK-6-UPDOWN: Interface 

RE: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

[Watters, John]

TAC has not mentioned 8.0.141.46 (or any other 8.0 version). They would like 
for me to move to 8.2. However, school just started. This is not the time to 
make a level change. Maybe in a month or so though.

However, I would strongly consider 8.0.141.46 if I could find it (which I 
can’t; it is not listed on the Cisco software download site). Maybe my local 
Cisco tech can get it for me. I wonder why TAC didn’t even mention it.

Thanks.



John Watters
Network Engineer, Office of Information Technology
The University of Alabama
A115 Gordon Palmer Hall
Box 870346
Tuscaloosa, AL 35487
Phone 205-348-3992
john.watt...@ua.edu
[The University of Alabama]

From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jeffrey D. Sessler
Sent: Monday, August 28, 2017 10:10 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

TAC will likely suggest you install 8.0MR5 interim (8.0.141.46) given you have 
2700’s (couple of radio bugs are fixed). DFS is as much art as science and 
older code isn’t always perfect i.e. I’ve seen newer devices that much older 
code sees as radar. You can request the code here and see the fixes including a 
number of DFS-related.
https://supportforums.cisco.com/t5/wireless-mobility-blogs/8-0mr5-interim-release-availability/ba-p/3098510

Probably too late, but you may want to consider getting to newer code. If you 
have x700 series WAPs, it’s strongly recommended to be on at least 8.2.  8.2 
and beyond have additional innovation in DFS area among many other improvements.

Jeff

From: 
"wireless-lan@listserv.educause.edu" 
> 
on behalf of "Watters, John" >
Reply-To: 
"wireless-lan@listserv.educause.edu" 
>
Date: Monday, August 28, 2017 at 7:42 AM
To: 
"wireless-lan@listserv.educause.edu" 
>
Subject: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

We are a Cisco shop running 8510 HA WLCs and a variety of AP including 1142s, 
2702s, others in smaller quantities for a current total of 6600+ APs. We are 
running WLC code 8.0.140.16. This was installed on JAN 4.

A couple of months ago we started seeing a lot of DFS scans. This was several 
months after our last code upgrade. When these scans are done, the users of the 
5 GHz radio that is doing the scanning for a clear frequency are all kicked off 
of their connections. Since the scans lasts for 1 minute & 2 seconds, this is 
very disruptive to the clients. We do not understand why this behavior has 
suddenly started all over campus. We are not particularly near an airport. 
There in one on the other side of town but it does not handle commercial 
service – private planes only plus an occasional charter for a sporting event. 
And, the APs that do the most frequent DFS scans are located in interior rooms, 
often on the ground floor of a multistory building. APs located near windows 
are rarely affected. This is happening in a lot of buildings, and not just in 
buildings that may tend to have noise in the 5 GHz range (e.g., an engineering 
building).

Has anyone else seen this problem? And, have you found the cause of this 
behavior. And, more importantly, a fix for the problem.

Following is an example from one AP (BRU-202-E2) showing two DSF scans almost 
back-to-back (2 sec gap) which lasted 3+ minutes:

*Aug 28 04:15:52.930: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5540 
MHz
*Aug 28 04:15:53.708: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to 
down
*Aug 28 04:15:53.710: %LINK-5-CHANGED: Interface Dot11Radio1, changed state to 
reset
*Aug 28 04:15:54.707: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to down
*Aug 28 04:15:54.739: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to up
*Aug 28 04:15:55.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to up
*Aug 28 04:17:53.253: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5280 
MHz
*Aug 28 04:17:54.747: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to 
down
*Aug 28 04:17:54.750: %LINK-5-CHANGED: Interface Dot11Radio1, changed state to 
reset
*Aug 28 04:17:55.747: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to down
*Aug 28 04:17:55.773: %DOT11-6-DFS_SCAN_START: DFS: Scanning frequency 5300 MHz 
for 60 seconds.
*Aug 28 04:17:55.774: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to up
*Aug 28 04:17:56.774: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state 

Re: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

[Jeffrey D. Sessler]

TAC will likely suggest you install 8.0MR5 interim (8.0.141.46) given you have 
2700’s (couple of radio bugs are fixed). DFS is as much art as science and 
older code isn’t always perfect i.e. I’ve seen newer devices that much older 
code sees as radar. You can request the code here and see the fixes including a 
number of DFS-related.
https://supportforums.cisco.com/t5/wireless-mobility-blogs/8-0mr5-interim-release-availability/ba-p/3098510

Probably too late, but you may want to consider getting to newer code. If you 
have x700 series WAPs, it’s strongly recommended to be on at least 8.2.  8.2 
and beyond have additional innovation in DFS area among many other improvements.

Jeff

From: "wireless-lan@listserv.educause.edu"  
on behalf of "Watters, John" 
Reply-To: "wireless-lan@listserv.educause.edu" 

Date: Monday, August 28, 2017 at 7:42 AM
To: "wireless-lan@listserv.educause.edu" 
Subject: [WIRELESS-LAN] DFS Scans Seem to Have Run Amok

We are a Cisco shop running 8510 HA WLCs and a variety of AP including 1142s, 
2702s, others in smaller quantities for a current total of 6600+ APs. We are 
running WLC code 8.0.140.16. This was installed on JAN 4.

A couple of months ago we started seeing a lot of DFS scans. This was several 
months after our last code upgrade. When these scans are done, the users of the 
5 GHz radio that is doing the scanning for a clear frequency are all kicked off 
of their connections. Since the scans lasts for 1 minute & 2 seconds, this is 
very disruptive to the clients. We do not understand why this behavior has 
suddenly started all over campus. We are not particularly near an airport. 
There in one on the other side of town but it does not handle commercial 
service – private planes only plus an occasional charter for a sporting event. 
And, the APs that do the most frequent DFS scans are located in interior rooms, 
often on the ground floor of a multistory building. APs located near windows 
are rarely affected. This is happening in a lot of buildings, and not just in 
buildings that may tend to have noise in the 5 GHz range (e.g., an engineering 
building).

Has anyone else seen this problem? And, have you found the cause of this 
behavior. And, more importantly, a fix for the problem.

Following is an example from one AP (BRU-202-E2) showing two DSF scans almost 
back-to-back (2 sec gap) which lasted 3+ minutes:

*Aug 28 04:15:52.930: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5540 
MHz
*Aug 28 04:15:53.708: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to 
down
*Aug 28 04:15:53.710: %LINK-5-CHANGED: Interface Dot11Radio1, changed state to 
reset
*Aug 28 04:15:54.707: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to down
*Aug 28 04:15:54.739: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to up
*Aug 28 04:15:55.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to up
*Aug 28 04:17:53.253: %DOT11-6-DFS_TRIGGERED: DFS: triggered on frequency 5280 
MHz
*Aug 28 04:17:54.747: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to 
down
*Aug 28 04:17:54.750: %LINK-5-CHANGED: Interface Dot11Radio1, changed state to 
reset
*Aug 28 04:17:55.747: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to down
*Aug 28 04:17:55.773: %DOT11-6-DFS_SCAN_START: DFS: Scanning frequency 5300 MHz 
for 60 seconds.
*Aug 28 04:17:55.774: %LINK-6-UPDOWN: Interface Dot11Radio1, changed state to up
*Aug 28 04:17:56.774: %LINEPROTO-5-UPDOWN: Line protocol on Interface 
Dot11Radio1, changed state to up
*Aug 28 04:18:57.382: %DOT11-6-DFS_SCAN_COMPLETE: DFS scan complete on 
frequency 5300 MHz


THANKS.


John Watters
Network Engineer, Office of Information Technology
The University of Alabama
A115 Gordon Palmer Hall
Box 870346
Tuscaloosa, AL 35487
Phone 205-348-3992
john.watt...@ua.edu
[he University of Alabama]

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