Configuring PPPoE over ATM

This section provides an example of a common PPPoE over ATM configuration. See Figure 7-2. Additional information is provided in the following chapters:

• Chapter 1, Configuring ATM - Provides detailed information about ATM technology and line interface module capabilities.
• Chapter 9, Configuring Bridged Ethernet - Provides configuration information about Bridged Ethernet, which allows multiple upper-layer interface types (IP, PPPoE, and CBF) to be simultaneously multiplexed over the same interface.
• Chapter 13, Configuring Dynamic Interfaces - Provides detailed information about configuring ATM to support dynamic interfaces.

To configure PPPoE over ATM:

1. Configure a physical interface.

host1(config)#interface atm 0/1 

2. Configure the ATM 1483 subinterface.

host1(config-if)#interface atm 0/1.20

3. Configure a PVC by specifying the vcd (virtual circuit descriptor), the vci (virtual channel identifier), the vpi (virtual path identifier), and the encapsulation type.

host1(config-if)#atm pvc 10 22 100 aal5snap

4. Select PPPoE as the encapsulation method.

host1(config-subif)#encapsulation pppoe

5. Configure a maximum number of PPPoE sessions on the interface.

host1(config-if)#pppoe sessions 128

6. Create a PPPoE subinterface.

host1(config-subif)#interface atm 0/1.20.1

7. Select PPP as the encapsulation method.

host1(config-subif)#encapsulation ppp 

8. (Optional) Configure an access concentrator (AC) name on the PPPoE interface.

host1(config-subif)#pppoe acname CYM9876

9. (Optional) Set up the system to prevent a client from establishing more than one session using the same MAC address

host1(config-subif)#pppoe duplicate-protection

10. Assign an IP address and subnet mask to the PVC.

host1(config-subif)#ip address 192.32.10.20 255.255.255.

11. (Optional) Configure additional PPPoE subinterfaces by completing steps 6 through 8 using unique numbering.

host1(config-subif)#interface atm 0/1.20.2

Figure 7-2 Example of PPPoE over ATM stacking configuration steps

    atm pvc

• Use to configure a PVC on an ATM interface.
• The following parameters are mandatory:

• vcd - virtual circuit descriptor, which identifies a virtual circuit in the range 1-2147483647. The vcd is a unique number that you assign, which identifies a virtual circuit. The vcd value has no relationship to the vpi and vci values and has meaning only to the ERX-700 series or ERX-1400 series edge router.
• vpi - virtual path identifier of the PVC. The VPI is an 8-bit field in the ATM cell header. The VPI value is unique on a single link, not throughout the ATM network, because it has meaning only to the ERX-700 series or ERX-1400 series edge router. The VPI value must match the value on the switch. The parameters vpi and vci cannot be both set to 0; if one is 0, the other cannot be 0.
• vci - virtual channel identifier. The VCI is a 16-bit field in the ATM cell header. The VCI value is unique on a single link, not throughout the ATM network, because it has meaning only to the ERX-700 series or ERX-1400 series edge router. The parameters vpi and vci cannot be both set to 0; if one is 0, the other cannot be 0.
• encapsulation type:

• aal5snap - specifies a logical link control (LLC) encapsulated circuit. An LLC/Subnetwork Access Protocol (LLC/SNAP) precedes the protocol datagram.
• aal5mux ip - specifies a multiplexed circuit used for IP only
• aal5autoconfig - enables the autodetection of a 1483 encapsulation (LLC/SNAP or VC multiplexed)

• Example

host1(config-if)#atm pvc 10 100 22 aal5autoconfig

• Use the no version to remove the specified PVC.

    encapsulation ppp

• Use to specify PPP as the encapsulation method for the interface.
• Example

host1(config-subif)#encapsulation ppp

• Use the no version to disable PPP on an interface.

    encapsulation pppoe

• Use to specify PPPoE as the encapsulation method for the interface.
• Example

host1(config-subif)#encapsulation pppoe

• Use the no version to disable PPPoE on an interface.

    interface atm

• Use to configure an ATM interface in slot/port.subinterface format:

• A slot refers to a system chassis slot.
• A port refers to a T3 module port.
• A subinterface is a mechanism that allows a single physical interface to support multiple logical interfaces or networks. Several logical interfaces or networks can be associated with a single hardware interface. Protocols, such as ATM, require that you create one or more virtual circuits over which your data traffic is transmitted to higher layers in the protocol stack. A subinterface is identified by a user-defined number from 1 to 4294967293.

• Example

host1(config)#interface atm 0/1.19 

• Use the no version to remove the interface or subinterface.

    ip address

• Use to assign an IP address and subnet mask to a subinterface.
• Example

host1(config-if)#ip address 192.1.1.1 255.255.255.0

• Use the no version to remove an IP address or disable IP processing.

    pppoe acName

• Use to configure an access concentrator (AC) name on the PPPoE interface. When the AC (the server) receives a PPPoE Active Discovery Initiation (PADI) packet that it can serve, it replies by sending a PPPoE Active Discovery Offer (PADO) packet. The PADO packet will contain the AC name as configured.
• If the AC name is not configured, the system name is used.
• The AC name can be a maximum of 64 characters.
• Example

host1(config-subif)#pppoe acname CYM9876

• Use the no version to remove the AC name.

    pppoe duplicate-protection

• Use to prevent a client from establishing more than one session using the same MAC address.
• This feature is disabled by default
• Example

host1(config-subif)#pppoe duplicate-protection 

• Use the no version to disable duplicate protection.

    pppoe sessions

• Use to specify the maximum number of PPPoE subinterfaces permitted on an interface in the range 1-4094. The default value is 4094.
• The pppoe sessions command affects only subinterfaces that are created after the command is entered. Previously created interfaces remain, even if their number exceeds the new value of the sessions parameter.
• Example

host1(config-if)#pppoe sessions 128

• Use the no version to restore the default value.