Critical Voice VLAN Support

Critical Voice VLAN Support puts phone traffic into the configured voice VLAN of a port if the authentication server becomes unreachable.

With normal network connectivity, when an IP phone successfully authenticates on a port, the authentication server puts the phone into the voice domain. If the authentication server becomes unreachable, IP phones cannot authenticate. In multidomain authentication (MDA) mode or multiauthentication mode, you can configure the Critical Voice VLAN support feature to put phone traffic into the configured voice VLAN of the port.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for Critical Voice VLAN Support

  • Use different VLANs for voice and data.

  • The voice VLAN must be configured on the switch.

  • ACLs are not supported on fixed Cisco Integrated Services Routers (ISRs).

  • This feature does not support standard ACLs on the switch port.

Information About Critical Voice VLAN Support

Critical Voice VLAN Support in Multidomain Authentication Mode

If a critical voice VLAN is deployed using an interface in multidomain authentication (MDA) mode, the host mode is changed to multihost and the first phone device is installed as a static forwarding entries. Any additional phone devices are installed as dynamic forwarding entry in the Host Access Table (HAT).

For further information about host modes, see the 802.1X Authentication Services Configuration Guide.

Note

If a critical port is already authorized and reauthentication occurs, the switch puts the port in the critical-authentication state in the current VLAN, which might be the one previously assigned by the RADIUS server.


Note

Inaccessible authentication bypass is compatible with guest VLAN. When a guest VLAN is enabled on a 802.1X port, the features interact as follows: if all RADIUS servers are not available and if a client is connected to a critical port and was previously assigned to a guest VLAN, the switch keeps the port in the guest VLAN.

Critical Voice VLAN Support in Multiauthentication Mode

If the critical authentication feature is deployed in multiauthentication mode, only one phone device will be allowed and a second phone trying to authorize will trigger a violation.

The show authentication sessions command displays the critical voice client data. A critically authorized voice client in multiauthentication host mode will be in the “authz success” and “authz fail” state.


Note

If critical voice is required, then critical data should be configured too. Otherwise, the critical voice client will be displayed in the “authz fail” state while the voice VLAN will be open.

How to Configure Critical Voice VLAN Support

Configuring Critical Voice VLAN Support in Multidomain Authentication Mode

Perform this task on a port to configure critical voice VLAN support in multidomain authentication (MDA) mode.

Note

To configure MDA mode, see the “Configuring the Host Mode” section of the “Configuring IEEE 802.1X Port-Based Authentication” chapter.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    interface type slot/port

    4.    authentication event server dead action authorize vlan vlan-id

    5.    authentication event server dead action authorize voice


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Switch> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Switch# configure terminal
     

    Enters global configuration mode.

     
    Step 3interface type slot/port


    Example:
    Switch(config)# interface gigabitethernet 0/1
     

    Specifies the port to be configured and enters interface configuration mode.

     
    Step 4authentication event server dead action authorize vlan vlan-id


    Example:
    Switch(config-if)# authentication event server dead action authorize vlan 40
     
    Configures a critical data VLAN.
    Note   

    This step is only required if the authentication event server dead action authorize vlan vlan-id command is not configured on the port.

     
    Step 5authentication event server dead action authorize voice


    Example:
    Switch(config-if)# authentication event server dead action authorize voice
     

    Enables the Critical Voice VLAN feature, which puts phone traffic into the configured voice VLAN of a port if the authentication server becomes unreachable.

     

    Configuring Critical Voice VLAN Support in Multiauthentication Mode

    Perform this task to configure critical voice VLAN support in multiauthentication mode.

    Note

    To configure multiauthentication mode, see the “Configuring the Host Mode” section of the “Configuring IEEE 802.1X Port-Based Authentication” chapter.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type slot/port

      4.    authentication event server dead action reinitialize vlan vlan-id

      5.    authentication event server dead action authorize voice


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Switch> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 configure terminal


      Example:
      Switch# configure terminal
       

      Enters global configuration mode.

       
      Step 3interface type slot/port


      Example:
      Switch(config)# interface gigabitethernet 0/1
       

      Specifies the port to be configured and enters interface configuration mode.

       
      Step 4authentication event server dead action reinitialize vlan vlan-id


      Example:
      Switch(config-if)# authentication event server dead action reinitialize vlan 40
       
      Configures a critical data VLAN.
      Note   

      This step is only required if the authentication event server dead action authorize vlan critical-data-vlan-id command is not configured on the port.

       
      Step 5authentication event server dead action authorize voice


      Example:
      Switch(config-if)# authentication event server dead action authorize voice
       

      Enables the Critical Voice VLAN support feature, which puts phone traffic into the configured voice VLAN of a port if the authentication server becomes unreachable.

       

      Configuration Examples for Critical Voice VLAN Support

      Example: Critical Voice VLAN Support in Multidomain Authentication Mode

      The following example shows how to enable the Critical Voice VLAN feature in MDA host-mode: 

      Switch(config) interface GigabitEthernet 0/0/0
Switch(config-if)# switchport access vlan 110
Switch(config-if)# switchport voice vlan 110
Switch(config-if)# no ip address
Switch(config-if)# authentication event server dead action authorize vlan 12
Switch(config-if)# authentication event server dead action authorize voice
Switch(config-if)# authentication host-mode multi-domain
Switch(config-if)# authentication port-control auto
Switch(config-if)# mab
Switch(config-if)# dot1x pae authenticator
Switch(config-if)# end

      Example: Critical Voice VLAN Support in Multiauthentication Mode

      The following example shows how to enable the Critical Voice VLAN support feature in multiauthentication mode: 

      Switch(config) interface GigabitEthernet 0/0/0
Switch(config-if)# switchport access vlan 110
Switch(config-if)# switchport voice vlan 110
Switch(config-if)# no ip address
Switch(config-if)# authentication event server dead action reinitialize vlan 12
Switch(config-if)# authentication event server dead action authorize voice
Switch(config-if)# authentication host-mode multi-auth
Switch(config-if)# authentication port-control auto
Switch(config-if)# mab
Switch(config-if)# dot1x pae authenticator
Switch(config-if)# end

      Additional References

      Related Documents

      Related Topic

      Document Title

      Cisco IOS commands

      Cisco IOS Master Commands List, All Releases

      IEEE 802.1X commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

      • Catalyst 4500 Series Switch Cisco IOS Command Reference, Release 12.2(25)SGA

      • Catalyst 3750 Switch Command Reference, Cisco IOS Release 12.2(25)SEE

      Standards and RFCs

      Standard/RFC

      Title

      IEEE 802.1X

      Port Based Network Access Control

      Technical Assistance

      Description

      Link

      The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

      Feature Information for Critical Voice VLAN Support

      The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

      Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.
      Table 1 Feature Information for Critical Voice VLAN Support

      Feature Name

      Releases

      Feature Information

      Critical Voice VLAN Support

      Cisco IOS 15.2(2)T

      This feature enables critical voice VLAN support, which puts phone traffic into the configured voice VLAN of a port if the authentication server becomes unreachable.

      Critical VLAN with Multi-auth

      Cisco IOS 15.2(2)T

      This feature adds support for the Critical Voice VLAN feature in multiauthentication mode.