Lightweight Access Point Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
Configuring Backup Switches and Failover Priority for Access Points
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Configuring Backup Switches and Failover Priority for Access Points

Contents

Configuring Backup Switches and Failover Priority for Access Points

Finding Feature Information

Prerequisites for Configuring Backup Switchs and Failover Priority for Access Points

  • You can configure primary and secondary backup switchs (which are used if primary, secondary, or tertiary switchs are not specified or are not responsive) for all access points that are connected to the switch as well as various timers, including heartbeat timers and discovery request timers. To reduce the switch failure detection time, you can configure the fast heartbeat interval (between the switch and the access point) with a smaller timeout value. When the fast heartbeat timer expires (at every heartbeat interval), the access point determines if any data packets have been received from the switch within the last interval. If no packets have been received, the access point sends a fast echo request to the switch.
  • The access point maintains a list of backup switchs and periodically sends primary discovery requests to each entry on the list. When the access point receives a new discovery response from a switch, the backup switch list is updated. Any switch that fails to respond to two consecutive primary discovery requests is removed from the list. If the access point’s local switch fails, it chooses an available switch from the backup switch list in this order: primary, secondary, tertiary, primary backup, and secondary backup. The access point waits for a discovery response from the first available switch in the backup list and joins the switch if it receives a response within the time configured for the primary discovery request timer. If the time limit is reached, the access point assumes that the switch cannot be joined and waits for a discovery response from the next available switch in the list.
  • When an access point's primary switch comes back online, the access point disassociates from the backup switch and reconnects to its primary switch. The access point falls back only to its primary switch and not to any available secondary switch for which it is configured. For example, if an access point is configured with primary, secondary, and tertiary switchs, it fails over to the tertiary switch when the primary and secondary switchs become unresponsive. If the secondary switch comes back online while the primary switch is down, the access point does not fall back to the secondary switch and stays connected to the tertiary switch. The access point waits until the primary switch comes back online to fall back from the tertiary switch to the primary switch. If the tertiary switch fails and the primary switch is still down, the access point then falls back to the available secondary switch.
  • You can configure your wireless network so that the backup switch recognizes a join request from a higher-priority access point and if necessary disassociates a lower-priority access point as a means to provide an available port.
  • You must enable failover priority on your network and assign priorities to the individual access points before you can configure this feature.

Restrictions for Configuring Backup Switchs and Failover Priority for Access Points

  • You can configure the fast heartbeat timer only for access points in local mode.
  • Failover priority is not in effect during the regular operation of your wireless network. It takes effect only if there are more association requests after a switch failure than there are available backup switch ports.
  • By default, all access points are set to priority level 1, which is the lowest priority level. Therefore, you must assign a priority level only to those access points that warrant a higher priority.

Information About Configuring Backup Switchs

A single switch at a centralized location can act as a backup for access points when they lose connectivity with the primary switch in the local region. Centralized and regional switchs do not need to be in the same mobility group. You can specify a primary, secondary, and tertiary switch for specific access points in your network. Using the switch CLI, you can specify the IP addresses of the backup switchs, which allows the access points to fail over to switchs outside of the mobility group.

Configuring Failover Priority for Access Points

Each controller has a defined number of communication ports for access points. When multiple controllers with unused access point ports are deployed on the same network and one controller fails, the dropped access points automatically poll for unused controller ports and associate with them.

Optimizing RFID Tracking on Access Points

To optimize the monitoring and location calculation of RFID tags, you can enable tracking optimization on up to four channels within the 2.4-GHz band of an 802.11b/g access point radio. This feature allows you to scan only the channels on which tags are usually programmed to operate (such as channels 1, 6, and 11).

Retrieving the Unique Device Identifier on Switchs and Access Points

The Unique Device Identifier (UDI) standard uniquely identifies products across all Cisco hardware product families, enabling customers to identify and track Cisco products throughout their business and network operations and to automate their asset management systems. The standard is consistent across all electronic, physical, and standard business communications. The UDI consists of five data elements:

  • The orderable product identifier (PID)
  • The version of the product identifier (VID)
  • The serial number (SN)
  • The entity name
  • The product description

The UDI is burned into the EEPROM of controllers and lightweight access points at the factory. It can be retrieved through either the GUI or the CLI.

How to Configure Backup Switchs for Access Points

Configuring Backup Switchs for Access Points (CLI)

SUMMARY STEPS

    1.    enable

    2.    ap name Cisco_AP controller primary primary_controller_name [primary_controller_ip_address]

    3.    ap name Cisco_AP controller secondary secondary_controller_name [secondary_controller_ip_address]

    4.    ap name Cisco_AP controller tertiary tertiary_controller_name [tertiary_controller_ip_adress]

    5.    configure terminal

    6.    ap capwap backup primary primary_backup_controller_name primary_backup_controller_ip_address

    7.    ap capwap backup secondary secondary_backup_controller_name secondary_backup_controller_ip_address

    8.    ap capwap timers fast-heartbeat-timeout {local timeout_interval}

    9.    ap capwap timers heartbeat-timeout [interval].

    10.    ap capwap timers primary-discovery-timeout [interval].

    11.    ap capwap timers discovery-timeout [interval].

    12.    end

    13.    show ap name Cisco_AP config general

    14.    show wireless client timers


DETAILED STEPS
      Command or Action Purpose
    Step 1 enable


    Example:
    Switch# enable
    
     

    Enters privileged EXEC mode.

     
    Step 2 ap name Cisco_AP controller primary primary_controller_name [primary_controller_ip_address]


    Example:
    Switch# ap name AP02 controller primary 
    pricon 10.0.0.1
     

    Configures a primary switch for a specific access point.

    Note   

    The controller_ip_address argument in Step 2 and Step 4 is optional. If the backup switch is outside the mobility group to which the access point is connected (the primary switch), you must provide the IP address of the primary, secondary, or tertiary switch, respectively. In each command, the controller_name and controller_ip_address must belong to the same primary, secondary, or tertiary switch. Otherwise, the access point cannot join the backup switch.

     
    Step 3 ap name Cisco_AP controller secondary secondary_controller_name [secondary_controller_ip_address]


    Example:
    Switch# ap name AP02 controller secondary
     seccon 10.0.0.2
     

    Configures a secondary switch for a specific access point.

     
    Step 4 ap name Cisco_AP controller tertiary tertiary_controller_name [tertiary_controller_ip_adress]


    Example:
    Switch# ap name AP02 controller tertiary
     tercon 10.0.0.3
     

    Configures a tertiary switch for a specific access point.

     
    Step 5 configure terminal


    Example:
    Switch# configure terminal
     

    Enters global configuration mode.

     
    Step 6 ap capwap backup primary primary_backup_controller_name primary_backup_controller_ip_address


    Example:
    Switch(config)# ap capwap backup primary
     advbackuppricon 10.0.0.3
     

    Configures a primary backup switch for all access points.

    Note   

    To delete the primary backup switch, enter the no ap capwap backup primary primary_backup_controller_name primary_backup_controller_ip_address command.

     
    Step 7 ap capwap backup secondary secondary_backup_controller_name secondary_backup_controller_ip_address


    Example:
    Switch(config)# ap capwap backup secondary
     advbackupseccon 10.0.0.4
     

    Configures a secondary backup switch for all access points.

    Note   

    To delete a secondary backup switch, enter the no ap capwap backup secondary secondary_backup_controller_name secondary_backup_controller_ip_address command.

     
    Step 8 ap capwap timers fast-heartbeat-timeout {local timeout_interval}


    Example:
    Switch(config)# ap capwap timers
     fast-heartbeat-timeout local 5
     

    Enables the fast heartbeat timer for local access points.

    Note   

    The timeout_Interval is from 1 to 10 seconds (inclusive). Specifying a small heartbeat interval reduces the amount of time that it takes to detect a switch failure. The default value is disabled.

    Note   

    To disable the fast heartbeat timer for local access points, enter the no ap capwap timers fast-heartbeat-timeout {local timeout_interval} command.

     
    Step 9 ap capwap timers heartbeat-timeout [interval].

    Example:
    Switch(config)# ap capwap timers
     heartbeat-timeout 15
     

    Configures the access point heartbeat timer.

    Note   

    The timeout interval is from 1 to 30 seconds (inclusive). This value should be at least three times larger than the fast heartbeat timer. The default value is 30 seconds.

    Note   

    To disable the access point heartbeat timer, enter the no ap capwap timers heartbeat-timeout [interval] command.

    Caution   

    Do not enable the fast heartbeat timer with the high latency link. If you have to enable the fast heartbeat timer, the timer value must be greater than the latency.

     
    Step 10 ap capwap timers primary-discovery-timeout [interval].

    Example:
    Switch(config)# ap capwap timers
     primary-discovery-timeout 90
     

    Configures the access point primary discovery request timer.

    Note   

    The timeout interval is from 30 to 3600 seconds. The default is 120 seconds.

    Note   

    To disable the access point primary discovery request timer, enter the no ap capwap timers primary-discovery-timeout [interval] command.

     
    Step 11 ap capwap timers discovery-timeout [interval].

    Example:
    Switch(config)# ap capwap timers
     discovery-timeout 9
     

    Configures the access point discovery timer.

    Note   

    The timeout interval is from 1 to 10 seconds (inclusive). The default is 10 seconds.

    Note   

    To disable the access point discovery timer, enter the no ap capwap timers discovery-timeout [interval] command.

     
    Step 12 end


    Example:
    Switch(config)# end
     

    Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode.

     
    Step 13 show ap name Cisco_AP config general


    Example:
    Switch# show ap name AP02 config general
     

    Displays access point configuration information.

     
    Step 14 show wireless client timers


    Example:
    Switch# show wireless client timers
     

    Displays the wireless client timer information.

     

    Configuring Backup Switches for Access Points (GUI)


      Step 1   Choose Configuration > Wireless > Access Points > Global AP Configuration.

      The Global Configuration page is displayed.

      Step 2   In the High Availability area, select the Local Mode AP Fast Heartbeat Timer State check box.
      Step 3   Enter the AP Fast Heartbeat Timeout to configure the fast heartbeat timer for access points in local mode.

      Specifying a small heartbeat interval reduces the amount of time it takes to detect a switch failure.

      Step 4   In the AP Primary Discovery Timeout text box, enter a value between 30 and 3600 seconds (inclusive) to configure the access point primary discovery request timer. The default value is 120 seconds.
      Step 5   To specify a primary backup switch for all access points, enter the IP address of the primary backup switch in the Back-up Primary Controller IP Address text box, and the name of the switch in the Backup Primary Controller Name text box.
      Note   

      The default value for the IP address is 0.0.0.0, which disables the primary backup switch.

      Step 6   To specify a secondary backup switch for all access points, enter the IP address of the secondary backup switch in the Back-up Secondary Controller IP Address text box, and the name of the switch in the Backup Secondary Controller Name text box.
      Note   

      The default value for the IP address is 0.0.0.0, which disables the primary backup switch.

      Step 7   Click Apply.
      Step 8   Click Save Configuration.
      Step 9   (Optional) Configure primary, secondary, and tertiary backup controllers for a specific access point by following these steps:
      1. Choose Configuration > Wireless > Access Points > All APs.

        The All APs page is displayed.

      2. Click the name of the access point.

        The AP > Edit page is displayed.

      3. Click the High Availability tab.
      4. Enter the name and management IP address of the primary, secondary, and tertiary switch.
      5. From the AP Failover Priority drop-down list, choose the appropriate priority.
      Step 10   Click Apply.
      Step 11   Click Save Configuration.

      How to Configure Failover Priority for Access Points

      Configuring Failover Priority for Access Points (CLI)

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    ap capwap priority

        4.    end

        5.    ap name Cisco_AP {priority priority_value}


      DETAILED STEPS
          Command or Action Purpose
        Step 1 enable


        Example:
        Switch# enable
        
         

        Enters privileged EXEC mode.

         
        Step 2 configure terminal


        Example:
        Switch# configure terminal
         

        Enters global configuration mode.

         
        Step 3 ap capwap priority


        Example:
        Switch(config)# ap capwap priority
        
         

        Enables the access point failover priority.

        Note   

        To disable access point failover priority, enter the no ap capwap priority command.

         
        Step 4 end


        Example:
        Switch(config)# end
         

        Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode.

         
        Step 5 ap name Cisco_AP {priority priority_value}


        Example:
        Switch# ap name AP02 priority 140
         

        Specifies the priority of an access point.

        Note   

        You can enter a value from 1 to 4 for the priority value parameter.

         

        Retrieving Unique Device Identifier on Switches (CLI)

        SUMMARY STEPS

          1.    enable

          2.    show inventory

          3.    show inventory oid

          4.    show inventory raw


        DETAILED STEPS
            Command or Action Purpose
          Step 1 enable


          Example:
          Switch# enable
          
           

          Enters privileged EXEC mode.

           
          Step 2 show inventory
           

          Shows the Unique Device Identifier (UDI) string of the switch.

           
          Step 3 show inventory oid
           
          Shows vendor-specific hardware registration identifier.  
          Step 4 show inventory raw
           
          Shows every entity in the container hierarchy.  

          Monitoring Failover Priority Settings (CLI)


          Note


          The procedure to perform this task using the switch GUI is not currently available.


          SUMMARY STEPS

            1.    enable

            2.    show ap capwap summary


          DETAILED STEPS
              Command or Action Purpose
            Step 1 enable


            Example:
            Switch# enable
            
             

            Enters privileged EXEC mode.

             
            Step 2 show ap capwap summary


            Example:
            Switch# show ap capwap summary
             

            Displays access point capwap summary. Using this command, you can confirm whether the access point failover priority is enabled on your network.

             

            Configuration Examples for Configuring Backup Switchs and Failover Priority for Access Points

            Displaying Access Point Configuration Information: Examples

            This example shows how to display access point configuration information:

            Switch# show ap name AP01 config general
            
            Cisco AP Identifier : 0
            Cisco AP Name : AP01
            Country Code : US - United States
            Regulatory Domain Allowed by Country : 802.11bg:-A
            802.11a:-A
            AP Country Code : US - United States
            AP Regulatory Domain : Unconfigured
            Switch Port Number : Te1/0/1
            MAC Address : 0000.2000.03f0
            IP Address Configuration : Static IP assigned
            IP Address : 9.9.9.16
            ...... ........
            ...... ........
            Primary Cisco Switch Name : 1-4404
            Primary Cisco Switch IP Address : 2.2.2.2
            Secondary Cisco Switch Name : 1-4404
            Secondary Cisco Switch IP Address : 2.2.2.2
            Tertiary Cisco Switch Name : 2-4404
            Tertiary Cisco Switch IP Address : 1.1.1.4

            Displaying Wireless Client Timer Information

            This example shows how to display wireless client timer information:

            Switch# show wireless client timers
            
            Authentication Response Timeout (seconds) : 10
            Rogue Entry Timeout (seconds) : 1300
            AP Heart Beat Timeout (seconds) : 30
            AP Discovery Timeout (seconds) : 10
            AP Local mode Fast Heartbeat (seconds) : 10 (enable)
            AP flexconnect mode Fast Heartbeat (seconds) : disable
            AP Primary Discovery Timeout (seconds) : 120

            Displaying Access Point CAPWAP Summary: Example

            This example shows how to display access point CAPWAP summary. Using this command, you can confirm whether or not the access point failover priority is enabled on your network.

            Switch# show ap capwap summary
            
            AP Fallback : Enabled
            AP Join Priority : Disabled
            AP Master : Disabled
            Primary backup Controller Name :
            Primary backup Controller IP : 0.0.0.0
            Secondary backup Controller Name :
            Secondary backup Controller IP : 0.0.0.0