Technical Note: Virtual Cell DFS protection
Description
Solution
This article has been written for a specific environment located in Monaco, it is not intended to be used in other locations. However, this script could be used internally in a lab environment.
For other sites, a fallback could be used that will allow the choice of the channel to be used when a pulse is detected.
While running in a virtual Cell environment, it is sometimes necessary to protect the DFS detection that trigger channel back off to avoid breaking the single channel infrastructure that allow seamless hand over.
The local regulation must be followed dependent upon location.
Europe: ETSI
For other sites, a fallback could be used that will allow the choice of the channel to be used when a pulse is detected.
While running in a virtual Cell environment, it is sometimes necessary to protect the DFS detection that trigger channel back off to avoid breaking the single channel infrastructure that allow seamless hand over.
The local regulation must be followed dependent upon location.
Europe: ETSI
http://www.etsi.org/deliver/etsi_en/301800_301899/301893/01.07.02_20/en_301893v010702a.pdfUS: FCC
https://apps.fcc.gov/edocs_public/attachmatch/FCC-13-22A1.pdf
Solution
To avoid such scenario, DFS protection needs to be turned on across the entire Virtual Cell radio's.
The following procedure can be used to verify DFS protection and protect the Virtual Cell environment.
Trigger a normal radar detection with fallback enable.
Config of AP 1 and 2 is shown in the following screenshots.
On AP 1 the fallback will take place on channel 44 for 30 minutes and on AP 2 the fallback will be activated for 40 minuntes on channel 40.
After 30 minutes the AP 1 is going back on channel 100.
After 40 minutes the AP 2 is going back on its original channel 100.
The VCELL area will now be protected, the idea is to load a protection script on the different radios that form the VCELL.
DFS protection implemented on the entire VCELL (AP 1 and AP 2 in the following example):
Double check the script loaded on the VCELL’s AP (The AP's need to be rebooted for the script to be loaded):
Now trigger a radar pulse and check the fallback behavior on the Controller:
It can be seen that the protection is working as expected and that the VCELL is not impacted.
The following procedure can be used to verify DFS protection and protect the Virtual Cell environment.
Trigger a normal radar detection with fallback enable.
Config of AP 1 and 2 is shown in the following screenshots.
On AP 1 the fallback will take place on channel 44 for 30 minutes and on AP 2 the fallback will be activated for 40 minuntes on channel 40.
wifilab-ctrl(15)# date
Mon Jan 9 08:55:10 UTC 2017
wifilab-ctrl(15)# show ess-ap essid wifilab
2 AP-2 2 100 40 Up 0 00:0c:e6:22:0b:57
2 AP-2 1 6 6 Up 0 00:0c:e6:22:3a:8c
1 AP-1 2 100 44 Up 0 00:0c:e6:22:70:bf
1 AP-1 1 6 6 Up 0 00:0c:e6:22:3a:8c
ESS-AP Configuration(4 entries)
After 30 minutes the AP 1 is going back on channel 100.
wifilab-ctrl(15)# show ess-ap essid wifilab
AP ID AP Name IfIndex Channel Oper Channel Admin State Max Calls BSSID
2 AP-2 2 100 40 Up 0 00:0c:e6:22:0b:57
2 AP-2 1 6 6 Up 0 00:0c:e6:22:3a:8c
1 AP-1 2 100 100 Up 0 00:0c:e6:22:95:65
1 AP-1 1 6 6 Up 0 00:0c:e6:22:3a:8c
ESS-AP Configuration(4 entries)
After 40 minutes the AP 2 is going back on its original channel 100.
wifilab-ctrl(15)# show ess-ap essid wifilab
2 AP-2 2 100 100 Up 0 00:0c:e6:22:18:dd
2 AP-2 1 6 6 Up 0 00:0c:e6:22:3a:8c
1 AP-1 2 100 100 Up 0 00:0c:e6:22:95:65
1 AP-1 1 6 6 Up 0 00:0c:e6:22:3a:8c
ESS-AP Configuration(4 entries)
The VCELL area will now be protected, the idea is to load a protection script on the different radios that form the VCELL.
“dev cmd radio1 dfs_test_mode on”.
DFS protection implemented on the entire VCELL (AP 1 and AP 2 in the following example):
Use Bulk Update to load the script on the VCELL AP's:
Double check the script loaded on the VCELL’s AP (The AP's need to be rebooted for the script to be loaded):
wifilab-ctrl(15)# show ap 1
AP Table
AP ID : 1
AP Name : AP-1
MAC Address : 00:0c:e6:1a:12:35
Uptime : 02d:19h:41m:34s
Location :
Building :
Floor :
Contact :
Operational State : Enabled
Availability Status : Online
Alarm State : No Alarm
LED Mode : Normal
AP Init Script : DFS_Protection.scr
Boot Image Version : rev-0.5 (Aug
FPGA Version :
Runtime Image Version : 8.2-3-0
Connectivity Layer : L3
Dataplane Encryption : off
Parent MAC Address : 00:00:00:00:00:00
Parent AP ID : 0
Link Probing Duration : 120
AP IP Address for L3 : 10.5.51.130
AP Model : AP832e
Hardware Revision : Rev 1
Power Supply Type : 802.3-at
AP Indoor/Outdoor type : Indoor
KeepAlive Timeout(seconds) : 60
VLAN Name :
wifilab-ctrl(15)# show ap 2
AP Table
AP ID : 2
AP Name : AP-2
MAC Address : 00:0c:e6:1b:23:c7
Uptime : 02d:19h:41m:01s
Location :
Building :
Floor :
Contact :
Operational State : Enabled
Availability Status : Online
Alarm State : No Alarm
LED Mode : Normal
AP Init Script : DFS_Protection.scr
Boot Image Version : rev-0.5 (Aug
FPGA Version :
Runtime Image Version : 8.2-3-0
Connectivity Layer : L3
Dataplane Encryption : off
Parent MAC Address : 00:00:00:00:00:00
Parent AP ID : 0
Link Probing Duration : 120
AP IP Address for L3 : 10.5.51.130
AP Model : AP832i
Hardware Revision : Rev 1
Power Supply Type : 802.3-at
AP Indoor/Outdoor type : Indoor
KeepAlive Timeout(seconds) : 60
VLAN Name :
Now trigger a radar pulse and check the fallback behavior on the Controller:
wifilab-ctrl(15)# show ess-ap essid wifilab
AP ID AP Name IfIndex Channel Oper Channel Admin State Max Calls BSSID
2 AP-2 2 100 100 Up 0 00:0c:e6:22:0b:57
2 AP-2 1 6 6 Up 0 00:0c:e6:22:3a:8c
1 AP-1 2 100 100 Up 0 00:0c:e6:22:95:65
1 AP-1 1 6 6 Up 0 00:0c:e6:22:3a:8c
ESS-AP Configuration(4 entries)
It can be seen that the protection is working as expected and that the VCELL is not impacted.