Antenna Disconnection Detection

Feature History for Antenna Disconnection Detection

This table provides release and related information for the features explained in this module.

These features are available in all releases subsequent to the one they were introduced in, unless noted otherwise.

Release

Feature

Feature Information

Cisco IOS XE Bengaluru 17.4.1

Antenna Disconnection Detection

This feature detects the signal strength delta across the antennas on the receiver. If the delta is more than the defined limit for a specific duration, the corresponding antenna is considered to have issues.

Information About Antenna Disconnection Detection

Having multiple antennas on the transmitter and receiver of an access point (AP) results in better performance and reliability. Multiple antennas improve reception through the selection of the stronger signal or a combination of individual signals at the receiver. Therefore, detection of an impaired antenna or physical breakage of an antenna is critical to the reliability of APs.

The Antenna Disconnection Detection feature is based on the signal strength delta across the antennas on the receiver. If the delta is more than the defined limit for a specific duration, the antenna is considered to have issues.

For every detection time period that you configure, the AP sends an Inter-Access Point Protocol (IAPP) message that carries the antenna condition. This message is sent only once when the issue is detected and is displayed in the controller trap messages, SNMP traps, and controller debug logs.

Configuration Workflow

  1. Configure APs.

  2. Configure an AP profile.

  3. Enable the feature in AP profile.

  4. Configure feature parameters.

  5. Verify the configuration.

Recommendations and Limitations

  • The feature is supported only on the following APs:

    • Cisco Catalyst 9120AX Series Access Points

    • Cisco Catalyst 9130AX Series Access Points

    • Cisco Aironet 2800e Access Points

    • Cisco Aironet 3800e Access Points

  • The SNMP trap is not supported on the Cisco Embedded Wireless Controller.

  • The IAPP message is sent only when there is a change in the error condition.

Configuring Antenna Disconnection Detection (CLI)

Antenna disconnection detection works by comparing the received signal strength intensity (RSSI) of each antenna with the antenna receiving the higher RSSI. If the delta is higher than the RSSI failure threshold, the corresponding antenna is declared as broken.

The weak-rssi is an absolute RSSI threshold value, expressed in dBm. If the antennas detect a lower RSSI value than the one configured in weak-rssi, all the antennas are reported as malfunctioning. The RSSI failure threshold is evaluated only if an antenna detects a signal over the weak-rssi value.

Follow the procedure given below to configure antenna disconnection detection:

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

ap profile ap-profile

Example:

Device(config)# ap profile xyz-ap-profile

Configures an AP profile and enters AP profile configuration mode.

Step 3

antenna monitoring

Example:

Device(config-ap-profile)# antenna monitoring

Enables antenna disconnection detection.

To disable antenna disconnection detection, use the no antenna monitoring command.

Step 4

antenna monitoring rssi-failure-threshold threshold-value

Example:

Device(config-ap-profile)# antenna monitoring rssi-failure-threshold 20

Configures RSSI failure threshold value, in dB. Valid values range from 10 to 90, with a default of 40.

Step 5

antenna monitoring weak-rssi weak-rssi-value

Example:

Device(config-ap-profile)# antenna monitoring weak-rssi -90

Configures weak RSSI value, in dBm. Valid values range from -90 to -10, with a default of 60.

Step 6

antenna monitoring detection-time detect-time-in-mins

Example:

Device(config-ap-profile)# antenna monitoring detection-time 20

Configures the antenna disconnection detection time, in minutes. Valid values range from 9 to 180, with a default of 120.

Step 7

end

Example:

Device(config-ap-profile)# end

Saves the configuration and returns to privileged EXEC mode.

Configuring Antenna Disconnection Detection (GUI)

Procedure

Step 1

Choose Configuration > Tags & Profiles > AP Join.

Step 2

In the AP Join Profile window, click the General tab.

Step 3

In the Antenna Monitoring check box to enable antenna monitoring.

Step 4

In the RSSI Fail Threshold(dB) field, enter a value, in dB. Valid values range from 10 to 90, with a default of 40.

Step 5

In the Weak RSSI(dBm) field, enter a value, in dBm. Valid values range from -90 to -10, with a default of 60.

Step 6

In the Detection Time(min) field, enter the antenna disconnection detection time, in minutes. Valid values range from 9 to 180, with a default of 120.

Step 7

Click Update & Apply to Device.

Detecting Broken Antenna Using SNMP Trap (CLI)

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

snmp-server enable traps

Example:

Device(config)# snmp-server enable traps

Enables all the SNMP notification types that are available on the system.

Step 3

trapflags ap broken-antenna

Example:

Device(config)# trapflags ap broken-antenna

Enables an SNMP trap, which will be sent when an antenna fails in any Cisco AP.

Step 4

end

Example:

Device(config)# end

Returns to privileged EXEC mode.

Detecting Broken Antenna Using SNMP Trap (GUI)

Procedure

Step 1

Choose Administration > Management > SNMP.

Step 2

Click the Wireless Traps tab.

Step 3

Set the Access Point status as Enabled, if not done already.

Step 4

Check the Broken Antenna check box to enable the trap.

Step 5

Click Apply.

Verifying Antenna Disconnection Detection

To verify the Antenna Disconnection Detection feature configuration on an AP, use the following command:

Device# show ap name 3800-AP config general 
 
Cisco AP Name: 3800-AP
=================================================
 
Cisco AP Identifier                             : f4db.e632.df40
Country Code                                    : Multiple Countries : US,IN,CN,CU
Regulatory Domain Allowed by Country            : 802.11bg:-ACE   802.11a:-ABCDHN
AP Country Code                                 : CN  - China
AP Regulatory Domain
  Slot 0                                        : -E
  Slot 1                                        : -C
MAC Address                                     : f4db.e62f.165a
IP Address Configuration                        : DHCP
IP Address                                      : 9.9.33.3
IP Netmask                                      : 255.255.255.0
Gateway IP Address                              : 9.9.33.1
Fallback IP Address Being Used                  : 
Domain                                          : 
Name Server                                     : 
CAPWAP Path MTU                                 : 1485
Capwap Active Window Size                       : 1
 
.
.
.
 
AP broken antenna detection                             : Enabled
RSSI threshold                                          : 40
Weak RSSI                                               : -80
Detection Time                                          : 120

.
.
.

To verify the Antenna Disconnection Detection feature configuration on an AP profile, use the following command:

Device# show ap profile name rf-profile-24g detailed 

AP Profile Name: rf-profile-24g
.
.
.
AP broken antenna detection:
  Status                                                 : ENABLED
  RSSI threshold                                         : 40
  Weak RSSI                                              : -80
  Detection Time                                         : 120

Verifying Antenna Disconnection Detection (GUI)

Procedure

Step 1

Choose Monitoring > Wireless > AP Statistics.

Step 2

Click an AP name or anywhere on the row corresponding to an AP in order to activate General window.

Step 3

Click the 360 View tab.

The 360 View tab is the default selection. The Antenna Monitoring field indicates whether the AP supports monitoring or not.