# Configuring Bridged Ethernet

This section shows how to configure IP with PPPoE terminated at the E Series router. With each step, an illustration shows how the router is building the interface columns.

## Configuring IP with PPPoE Terminated at the Router

This section shows how to create IP with PPPoE interfaces that terminate the connection and route the data received on the PVC, as shown in the example in Figure 43. To create a terminated PVC:

1. Create an ATM 1483 subinterface and associated PVC.
   host1(config)#interface atm 9/1.1 point-to-point host1(config-subif)#atm pvc 1 0 32 aal5snap 0 0 0
2. Encapsulate the ATM 1483 subinterface with bridged Ethernet. The use of the encapsulation keyword implies that the bridged Ethernet interface is the only interface stacked directly above the ATM 1483 subinterface. As a result, the bridged Ethernet interface cannot have a peer interface stacked above the same lower-layer interface.
   host1(config-subif)#encapsulation bridge1483
3. Create a PPPoE major interface over the bridged Ethernet interface. This command does not use the encapsulation keyword.
   host1(config-subif)#pppoe
4. Create an IP interface over the bridged Ethernet interface as a peer to the PPPoE interface.
   host1(config-subif)#ip address 160.1.0.1 255.255.255.0
5. (Optional) Set up the router to validate MAC addresses on the IP interface.
   host1(config-subif)#ip mac-validate strict
6. Exit the subinterface context.
   host1(config-subif)#exit
7. Create a PPPoE subinterface over the major interface.
   host1(config)#pppoe subinterface atm 9/1.1.1
8. Configure PPP encapsulation over the PPPoE subinterface, and the IP interface over the PPP interface.
   host1(config-subif)#encapsulation ppp host1(config-subif)#ip address 160.1.1.1 255.255.255.0

atm pvc

- Use to configure a PVC on an ATM interface. Specify one of the following encapsulation types:
  - aal5snap—Specifies a logical link control (LLC) encapsulated circuit; LLC/Subnetwork Access Protocol (LLC/SNAP) header precedes the protocol datagram.
  - aal5mux ip—Specifies a VC multiplexed circuit. This option is used for IP only.
- Example
  host1(config-subif)#atm pvc 1 0 32 aal5snap 0 0 0
- Use the no version to remove the specified PVC.
- See atm pvc.

encapsulation bridge1483

- Use to configure bridged Ethernet as the encapsulation method on an interface, and to optionally assign the MAC address to the interface.
- Use the mac-address keyword to configure a specific MAC address for the interface. Otherwise, the system MAC address is used. The same MAC address can be used on multiple interfaces.
- If the MAC address is configured, you must use the same MAC address whenever you reenter the encapsulation bridge1483 command for the interface.
- The MAC address can be configured only when the interface is created. To change a MAC address, you must remove the interface and create it again.
- Example
  host1(config-subif)#encapsulation bridge1483 mac-address 0090.1a01.1234
- Use the no version, without the MAC address, to remove bridged Ethernet as the encapsulation method on the interface.
- See encapsulation bridge1483.

encapsulation ppp

- Use to configure PPP as the encapsulation method for an interface.
- Example
  host1(config-subif)#encapsulation ppp
- Use the no version to remove PPP as the encapsulation method on the interface.
- See encapsulation ppp.

interface atm

- Use to configure an ATM interface or subinterface type.
- To specify an ATM interface for ERX7xx models, ERX14xx models, and ERX310 router, use the slot/port.[subinterface ] format.
  - slot—Number of the chassis slot
  - port—Port number on the I/O module
  - subinterface—Number of the subinterface in the range 1–2147483647
- To specify an ATM interface for E120 and E320 routers, use the slot/adapter/port[.subinterface ] format.
- slot—Number of the chassis slot
  - adapter—Identifier for the IOA within the E320 chassis, either 0 or 1, where:
    - 0 indicates that the IOA is installed in the right IOA bay (E120 router) or the upper IOA bay (E320 router).
    - 1 indicates that the IOA is installed in the left IOA bay (E120 router) or the lower IOA bay (E320 router).
  - port—Port number on the IOA
  - subinterface—Number of the subinterface in the range 1–2147483647
- For more information, see Creating a Basic Configuration in Configuring ATM .
- Examples
  host1(config)#interface atm 9/1.1 point-to-point host1(config)#interface atm 5/0/1.1 point-to-point
- Use the no version to remove the interface or subinterface.
- See interface atm.

ip address

- Use to set an IP address for the interface.
- Note that you cannot add more than one IP address to bridged Ethernet interfaces.
- Example
  host1(config-subif)#ip address 160.1.0.1 255.255.255.0
- Use the no version to remove the IP address.
- See ip address.

ip mac-validate

- Use to enable or disable MAC address validation on a per interface basis.
- When MAC address validation is enabled, the router checks the entry in the MAC validation table that corresponds to the IP source address of an incoming packet. The MAC source address of the packet must match the MAC source address of the table entry for the router to forward the packet.
- Use the strict keyword to prevent transmission of IP packets that do not reside in the validation table.
- Use the loose keyword to allow IP packets to pass through even though the packets do not have entries in the validation table. Only packets that have matching IP–MAC pair entries in the table are validated. This is the default setting.
- The default behavior is not to perform MAC address validation.
- Example
  host1(config-subif)#ip mac-validate strict
- Use the no version to disable the command.

  | Note: For more information, see MAC Address Validation in JunosE IP, IPv6, and IGP Configuration Guide.

- See ip mac-validate.

pppoe

- Use to create a PPPoE major interface.
- Example
  host1(config-subif)#pppoe
- Use the no version to remove the PPPoE major interface.
- See pppoe.

pppoe subinterface atm

- Use to create a PPPoE subinterface on an ATM interface.
- On ERX7xx models, ERX14xx models, and the ERX310 router, use the slot/port.atmSubinterface.pppoeSubinterface format.
- On the E120 and E320 routers, use the slot/adapter/port.atmSubinterface.pppoeSubinterface format. RLI-1050
- Examples
  host1(config)#pppoe subinterface atm 9/1.1.1 host1(config)#pppoe subinterface atm 5/0/1.1.1
- Use the no version to remove the PPPoE subinterface.
- See pppoe subinterface.

## Alternative Configuration

In previous releases, you could configure a PPPoE major interface directly over ATM 1483 only. The router still supports this stacking and configuration method for PPPoE. Although the older and newer interface stacks are different, they behave the same in terms of frame encapsulation and handling. As a result, an interface created using the older stacking will interoperate with an interface using the new stacking. Note, however, that the previous command syntax (encapsulation pppoe) cannot be used when a bridged Ethernet interface already exists, because it is intended to produce the old stacking for PPPoE over ATM 1483.

1. Create the ATM 1483 subinterface and associated PVC:
   host1(config)#interface atm 9/1.1 point-to-point host1(config-subif)#atm pvc 1 0 32 aal5snap 0 0 0
2. Create a PPPoE major interface over the ATM 1483 subinterface. Note that since this command uses the encapsulation keyword, it will fail if a bridged Ethernet interface was already created over the ATM 1483 subinterface using the new syntax.
   host1(config-subif)#encapsulation pppoe
3. Create a PPPoE subinterface over the major interface. Because PPPoE is the only top layer protocol in the stack, there is no need to use pppoe to identify the subinterface type (it is implied).
   host1(config)#interface atm 9/1.1.1
4. Configure the PPP encapsulation over the PPPoE subinterface, and the IP interface over the PPP interface.
   host1(config-subif)#encapsulation ppp host1(config-subif)#ip address 160.1.1.1 255.255.255.0