CFM Over Double-Tagged Layer 3 VLANs with EVC

The CFM over double-tagged Layer 3 VLANs with EVC feature explains the implementation of Connectivity Fault Management (CFM) on double-VLAN-tagged Layer 3 subinterfaces.

Restrictions for CFM Over Double-Tagged Layer 3 VLANs with EVC

  • Connectivity Fault Management (CFM) over double-tagged Layer 3 VLANs with EVC features is supported only on Cisco Integrated Services Routers (ISR) G2.

  • You cannot configure multiple CFM Maintenance Associations (MA) using different VLAN-IDs and the same Ethernet Virtual Circuit (EVC).

  • EVC names for different VLANs must be unique.

  • Multiple CFM MAs using different EVCs but the same VLAN tags are not permitted.

  • The EVC name must always be specified when configuring a CFM MA.

Down MEPs over Double-VLAN-Tagged Layer 3 Subinterfaces

In Connectivity Fault Management (CFM) configuration, to configure a down maintenance endpoint (MEP) on a single-VLAN-tagged L3 subinterfaces, first a CFM maintenance association (MA) service is associated with a VLAN. When a down MEP is configured on a trunk Ethernet interface using the maintenance association ID, the MEP is associated with the Layer 3 subinterface that has the configured VLAN ID.

To support configuration of down MEPs on double-VLAN-tagged L3 sub-interfaces, a CFM MA service is associated with an additional VLAN. The additional VLAN is configured using the inner-vlan <vlan-id> keyword-argument pair.

When the associated MA is configured with an inner VLAN-ID, then the MEP is associated with the Layer 3 subinterface that matches the outer and inner VLAN IDs.


Note
Double-VLAN-tagged L2 service-instances are already supported on provide edge devices to allow service providers to use a single VLAN to support customers who have multiple VLANs.

Configuring Down MEPs over Double-VLAN-Tagged Layer 3 Subinterfaces

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ethernet cfm domain domain-id level level

    4.    service service-name evc evc-name vlanvlan-id inner-vlaninner-vlan-id direction down{ | }

    5.    exit [

    6.    interface type/number

    7.    ethernet cfm mep domain domain-id mpid mp-id service service-name

    8.    interface type/number

    9.    encapsulation dot1q vlan-id second-dot1q inner-vlan-id


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example: 
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example: 
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 ethernet cfm domain domain-id level level


    Example: 
    Router(config)# ethernet cfm domain d level 3
     

    Configures Ethernet CFM domain.

     
    Step 4 service service-name evc evc-name vlanvlan-id inner-vlaninner-vlan-id direction down{ | }


    Example: 
    Router(config)# service service1 evc bar vlan 100 inner-vlan 200 direction down
     

    Configures an Ethernet service instance on an interface and enters Ethernet service configuration mode.

     
    Step 5 exit [


    Example: 
    Router(config-srv)# exit
     

    Exits service configuration mode and enters global configuration mode.

     
    Step 6 interface type/number


    Example: 
    Router(config-vfi-neighbor)# int Ethernet0/0
     

    Specifies an interface and enters interface configuration mode.

     
    Step 7 ethernet cfm mep domain domain-id mpid mp-id service service-name


    Example: 
    Router(config-if)# ethernet cfm mep domain domain1 mpid 1 service service1
     

    Configures Ethernet CFM domain.

     
    Step 8 interface type/number


    Example: 
    Router(config-if)# int Ethernet0/0.2
     

    Specifies a subinterface and subinterface configuration mode.

     
    Step 9 encapsulation dot1q vlan-id second-dot1q inner-vlan-id


    Example: 
    Router(config-if)# encapsulation dot1q 100 second-dot1q 200
     

    Sets the encapsulation method used by the interface.

     

    Example for Configuring Down MEPs over Double-VLAN-Tagged Layer 3 Subinterfaces

    ethernet cfm domain d level 3
  service foo evc bar vlan 100 inner-vlan 200 direction down

int Ethernet0/0
  ethernet cfm mep domain d mpid 1 service foo
  int Ethernet0/0.2
    encap dot1q 100 second-dot1q 200

    Example for Double-VLAN-tagged L2 service-instances

    ethernet cfm domain d level 3
  service foo evc bar vlan 2 direction down

int Ethernet0/0
    service instance 1 ethernet bar
       bridge-domain 2
       encap dot1q 100 second-dot1q 200
       cfm mep domain d mpid 1

    Additional References for CFM over double-tagged Layer 3 VLANs with EVC

    Related Documents

    Related Topic

    Document Title

    Carrier Ethernet Command Reference

    Cisco IOS Carrier Ethernet Command Reference

    Cisco IOS Master Command List

    Cisco IOS Master Command List, All Releases

    Configuring Ethernet connectivity fault management in a service provider network (Cisco pre-Standard CFM Draft 1)

    “Configuring Ethernet Connectivity Fault Management in a Service Provider Network” module in the Cisco IOS Carrier Ethernet Configuration Guide

    IP SLAs for Metro Ethernet

    “IP SLAs for Metro Ethernet”

    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

    MIBs

    MIB

    MIBs Link

    CISCO-ETHER-CFM-MIB

    To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

    http:/​/​www.cisco.com/​go/​mibs

    RFCs

    RFC

    Title

    No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified.

    --

    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 CFM over double-tagged Layer 3 VLANs with EVC

    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 . An account on Cisco.com is not required.
    Table 1 Feature Information for CFM over double-tagged Layer 3 VLANs with EVC

    Feature Name

    Releases

    Feature Information

    CFM over double-tagged Layer 3 VLANs with EVC

    15.5(2)T

    The CFM over double-tagged Layer 3 VLANs with EVC feature explains the implementation of Connectivity Fault Management (CFM) on double-VLAN-tagged Layer 3 subinterfaces.

    In Cisco IOS Release 15.5(2)T, this feature was introduced on Integrated Services Routers Generation 2 (ISR G2).

    No commands was introduced or modified.