Broadband Access Aggregation and DSL Configuration Guide, Cisco IOS XE Release 3S
PPPoE on Ethernet
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PPPoE on Ethernet

PPPoE on Ethernet

The PPPoE on Ethernet feature adds support to Point-to-Point Protocol over Ethernet (PPPoE) by adding direct connection to actual Ethernet interfaces. PPPoE provides service-provider digital subscriber line (DSL) support. This Ethernet specification can be used by multiple hosts on a shared Ethernet interface to open PPP sessions to multiple destination with one or more bridging modems.

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 at the end of this module.

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.

Prerequisites for PPPoE on Ethernet

Before you can configure the PPPoE on Ethernet feature, you need to configure a virtual private dialup network (VPDN) group using the accept dialin command, enable PPPoE, and specify a virtual template for PPPoE sessions.

Restrictions for PPPoE on Ethernet

  • PPPoE is not supported on Frame Relay.

  • PPPoE is not supported on any other LAN interfaces such as FDDI and Token Ring.

  • Fast switching is supported. PPP over Ethernet over RFC 1483 fibswitching is supported for IP. All other protocols are switched over process switching.

Information About PPPoE on Ethernet

Benefits of Using PPPoE on Ethernet

Broadband Remote Access

For a bridged-Ethernet topology, the PPPoE on Ethernet feature allows access providers to maintain session abstraction associated with PPP networks.

PPPoE

PPPoE provides the ability to connect a network of hosts over a simple bridging access device to a remote access concentrator where each host utilizes its own PPP stack. It also gives users a familiar interface.

PPPoE provides service-provider DSL support. In service-provider DSL deployments, PPPoE leverages Ethernet scale curves and it uses an embedded base.

How to Enable and Configure PPPoE on Ethernet

Enabling PPPoE on Ethernet in a VPDN Group

To configure the physical interface that will carry the PPPoE session and link it to the appropriate virtual template interface, you need to complete the following steps.

SUMMARY STEPS

    1.    Router(config)# vpdn enable

    2.    Router(config-if)# vpdn group name

    3.    Router(config-if)# accept dialin

    4.    Router(config-if)# protocol pppoe

    5.    Router(config-if)# virtual-template template-number


DETAILED STEPS
     Command or ActionPurpose
    Step 1 Router(config)# vpdn enable 

    Enables virtual private dial-up networking.

     
    Step 2 Router(config-if)# vpdn group name 

    Associates a VPDN group to a customer or VPDN profile.

     
    Step 3 Router(config-if)# accept dialin 

    Creates an accept dial-in VPDN group.

     
    Step 4 Router(config-if)# protocol pppoe 

    Specifies the VPDN group to be used to establish PPPoE sessions.

     
    Step 5 Router(config-if)# virtual-template template-number 

    Specifies which virtual template will be used to clone virtual access interfaces.

     

    Limiting PPPoE Sessions from a MAC Address

    To set the limit of sessions to be sourced from a MAC address, use the following command in VPDN configuration mode:

    Command

    Purpose

    Router(config-if)# pppoe session-limit per-mac
     
    number
    

    Sets the limit of sessions to be sourced from a MAC address.

    Creating and Configuring a Virtual Template

    Other optional configuration commands can be added to the virtual template configuration. For example, you can enable the PPP authentication on the virtual template using the ppp authentication chap command. See the " Virtual Interface Template Service " chapter in the Cisco IOS Dial S>olutions Configuration Guide for more information about configuring the virtual template.

    Although Cisco Express Forwarding switching is supported, flow, and optimum switching are not; these configurations are ignored on the PPPoE virtual access interface. Cisco Express Forwarding is enabled by default for IP. All other protocol traffic will be processed switched.


    Note


    The PPP reliable link that uses Link Access Procedure, Balanced (LAPB) is not supported.


    To create and configure a virtual template, use the following commands beginning in global configuration mode:

    SUMMARY STEPS

      1.    Router(config)# interface virtual-template number

      2.    Router(config-if)# ip unnumbered ethernet number

      3.    Router(config-if)# mtu bytes


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 Router(config)# interface virtual-template number  

      Creates a virtual template, and enters interface configuration mode.

       
      Step 2 Router(config-if)# ip unnumbered ethernet number  

      Enables IP without assigning a specific IP address on the LAN.

       
      Step 3 Router(config-if)# mtu bytes  

      Sets the maximum transmission unit (MTU) size for the interface.

       

      Specifying an Ethernet Interface

      After you create a virtual template for PPPoE on Ethernet, specify a multipoint or point-to-point interface. To specify an Ethernet multipoint interface, use the following commands in global configuration mode:

      Command

      Purpose

      Router# interface ethernet
       
      interface-number
      

      Specifies the Ethernet interface using the appropriate format of the interface ethernet command.

      Enabling PPPoE on an Ethernet Interface

      To enable PPPoE on Ethernet interfaces, use the following command in global configuration mode:

      Command

      Purpose

      Router# pppoe enable
      

      Specifies the VPDN group to be used for establishing PPPoE sessions.

      Monitoring and Maintaining VPDN Groups

      To monitor and maintain VPDN groups, use the following commands in EXEC mode:

      Command

      Purpose

      Router# show vpdn

      Displays information about active Level 2 Forwarding (L2F) Protocol tunnel and message identifiers in a VPDN.

      Router# show vpdn session packet

      Displays PPPoE session statistics.

      Router# show vpdn session all

      Displays PPPoE session information for each session ID.

      Router# show vpdn tunnel

      Displays PPPoE session count for the tunnel.

      Configuration Examples for PPPoE on Ethernet

      PPPoE on Ethernet Example

      The following are examples of the vpdn enable and interface virtual-template commands:

      vpdn enable
       
       vpdn-group 1
       accept dialin
       protocol pppoe
       virtual template 1
       pppoe limit per-mac <number>
       
       interface virtual-template 1
       ip address 10.100.100.100 255.255.255.0
       mtu 1492
      

      For PPPoE virtual template interfaces, the mtu command must be configured because Ethernet has a maximum payload size of 1500 bytes, the PPPoE header is 6 bytes, and PPP Protocol ID is 2 bytes.


      Note


      Dial-out mode will not be supported.


      Enabling PPPoE on an Ethernet Interface Example

      The following example enables PPPoE on an Ethernet interface:

      interface ethernet1/0 
       pppoe enable

      Additional References

      The following sections provide references related to the PPPoE on Ethernet feature.

      Related Documents

      Related Topic

      Document Title

      Configuring PPPoE on ATM

      PPPoE over ATM

      Configuring PPPoE on cable interfaces

      Configuring PPPoE on IEEE 802.1Q encapsulation

      PPPoE Over IEEE 802.1Q VLANs

      Standards

      Standard

      Title

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

      --

      MIBs

      MIB

      MIBs Link

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

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

      http:/​/​www.cisco.com/​go/​mibs

      RFCs

      RFC

      Title

      RFC 2516

      A Method for Transmitting PPPoE

      RFC 4813

      Multiprotocol Encapsulation over ATM Adaptation Layer 5

      Technical Assistance

      Description

      Link

      The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

      To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

      Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

      http:/​/​www.cisco.com/​techsupport

      Feature Information for PPPoE on Ethernet

      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 PPPoE on Ethernet

      Feature Name

      Releases

      Feature Information

      PPPoE on Ethernet

      Cisco IOS XE Release 2.5

      This feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers.

      The PPPoE on Ethernet feature adds support to Point-to-Point Protocol over Ethernet (PPPoE) by adding direct connection to actual Ethernet interfaces. PPPoE provides service-provider digital subscriber line (DSL) support. This Ethernet specification can be used by multiple hosts on a shared Ethernet interface to open PPP sessions to multiple destination with one or more bridging modems.