# Configuring 802.3ad Link Aggregation

To configure link aggregation on Ethernet interfaces, you must configure the Ethernet interface, create the LAG bundle, and add the Ethernet interface as a member link in the LAG bundle. Optionally, you can then configure IP, a VLAN subinterface, a PPPoE subinterface, or MPLS for the LAG bundle.

For more information about specifying LAG interfaces and subinterfaces on E Series routers, see Interface Types and Specifiers in JunosE Command Reference Guide.

Tasks to configure 802.3ad link aggregation interfaces are:

- Configuring an Ethernet Physical Interface
- Configuring a LAG Bundle
- Configuring IP for a LAG Bundle
- Configuring a VLAN Subinterface for a LAG Bundle
- Configuring a PPPoE Subinterface for a LAG Bundle
- Configuring MPLS for a LAG Bundle

## Configuring an Ethernet Physical Interface

To configure a member link, perform the following steps:

1. Specify a Fast Ethernet or Gigabit Ethernet interface for which you want to create a member link.
   host1(config)#interface gigabitEthernet 2/0
2. Configure LACP in passive or active mode.
   host1(config-if)#lacp active
3. Specify the speed and the duplex mode for the Ethernet interface.
   host1(config-if)#speed 100 host1(config-if)#duplex full
4. Specify the MTU.
   host1(config-if)#mtu 9000
5. To configure additional member links, repeat steps 1 through 4.

   | Note: All of the member links that you configure must be on the same line module and have the same physical layer characteristics, such as speed, duplex mode, and MTU.

## Configuring a LAG Bundle

To configure a LAG bundle and add member links, perform the following steps:

1. Create the LAG bundle.
   host1(config)#interface lag bundleBoston
2. Add a member link to the LAG bundle.
   host1(config-if)#member–interface gigabitEthernet 2/0
3. (Optional) Configure the minimum number of member links required in the LAG bundle for the LAG interface to be considered up.
   host1(config-if)#minimum-links 2

## Configuring IP for a LAG Bundle

To configure IP for a LAG bundle, perform the following steps:

1. Specify the LAG bundle.
   host1(config)#interface lag bundleBoston
2. Assign an IP address and mask.
   host1(config-if)#ip address 192.5.127.8 255.255.255.0

## Configuring a VLAN Subinterface for a LAG Bundle

To configure a VLAN subinterface for the LAG bundle, perform the following steps:

1. Specify VLAN as the encapsulation method.
   host1(config-if)#encapsulation vlan
2. Specify the VLAN subinterface for the LAG bundle by adding a unique subinterface number to the LAG interface identification command.
   host1(config)#interface lag bundleBoston.1
3. Assign a VLAN ID for the subinterface.
   host1(config-if)#vlan id 203
4. Assign an IP address and mask.
   host1(config-if)#ip address 192.168.1.1 255.255.0.0

## Configuring a PPPoE Subinterface for a LAG Bundle

To configure a PPPoE subinterface for the LAG bundle, perform the following steps:

1. Specify PPPoE as the encapsulation method.
   host1(config-if)#encapsulation pppoe
2. Specify the PPPoE subinterface for the LAG bundle in either of the following ways:
   - Use the interface lag command to add a unique subinterface number to the LAG bundle name.
     host1(config)#interface lag bundleBoston.2
   - Use the pppoe subinterface lag command to add a unique subinterface number to the LAG bundle name.
     host1(config)#pppoe subinterface lag bundleBoston.2
3. Specify PPP as the encapsulation method on the PPPoE subinterface.
   host1(config-if)#encapsulation ppp
4. Assign an IP address and mask.
   host1(config-if)#ip address 192.168.1.2 255.255.0.0

You can also configure a PPPoE subinterface over a VLAN subinterface over a LAG bundle. For an example of this configuration, see Example: Configuring a PPPoE Subinterface over a VLAN for a LAG Bundle.

## Configuring MPLS for a LAG Bundle

To configure MPLS for a LAG bundle, perform the following steps:

1. Specify the LAG bundle.
   host1(config)#interface lag bundleBoston
2. Create an MPLS interface.
   host1(config-if)#mpls

interface lag

- Use to create an IEEE 802.3ad LAG interface, also known as a LAG bundle, or a subinterface for the LAG bundle.
- Examples
  host1(config)#interface lag boston host1(config)#interface lag boston.2 host1(config)#interface lag boston.2.1
- Use the no version to delete the LAG bundle.
- See interface lag.

lacp

- Use to configure whether an Ethernet link in a LAG bundle participates actively or passively in the LACP.
- Use the active keyword to indicate that the Ethernet link participates in the protocol regardless of whether its Partner member link is set to active or passive LACP PDU participation.
- Use the passive keyword to indicate that the Ethernet link to transmit LACP PDUs only when it receives LACP PDUs from its Partner member link.
- By default, Ethernet links in a LAG bundle do not send LACP PDUs.
- Example
  host1(config-if)#lacp active
- Use the no version to restore the default behavior.
- See lacp.

lacp port-priority

- Use to set the priority for an Ethernet link in a LAG bundle.
- The member with the lowest value has the highest priority, and is selected to join the LAG bundle first.
- Valid values are in the range 0–65535.
- Example
  host1(config-if)#lacp port-priority 100
- Use the no version to restore the default value of 32768.
- See lacp port-priority.

member-interface

- Use to add a Fast Ethernet interface or Gigabit Ethernet interface, also known as a bundle member, to a LAG bundle.
- Example
  host1(config-if)#member-interface fastEthernet 4/0
- Use the no version to remove the specified Ethernet link from the bundle.
- See member-interface.

minimum-links

- Use to configure the minimum number of member links in the link aggregation group (LAG) bundle for the LAG interface to be considered up. The minimum number of member links that you can configure, depends on the IOA. For example, for ES2–S1 GE-4 IOA, the number of minimum links is in the range 0–4. For ES2–S1 GE-8 IOA, the number of minimum links is in the range 0–8 and for ES2–S3 GE-20 IOA, the number of minimum links is in the range 0–8.
- Example
  host1(config-if)#minimum—links 2
- Use the no version to reset the minimum number of member links to the default value, 1.
- See minimum-links

mpls

- Use to enable, disable, or delete MPLS on an interface. MPLS is disabled by default.
- Example
  host1(config)#mpls
- Use the no version to halt MPLS on the interface and delete the MPLS interface configuration.
- See mpls.

mtu

- Use to specify the MTU for a LAG bundle.
- Specify a value in the range 64–9188 bytes. The range for FE-8 I/O modules is 64–9042 bytes.
- This command does not work for the Fast Ethernet port on the SRP module.
- Example
  host1(config-if)#mtu 9000
- Use the no version to specify the default, 1518.
- See mtu.

pppoe subinterface lag

- Use to create a PPPoE subinterface on a LAG bundle.
- Example
  host1(config-if)#pppoe subinterface lag boston.1
- Use the no version to remove the PPPoE subinterface from the LAG bundle.
- See pppoe subinterface.

virtual-router

- From Global Configuration mode, use this command to create a virtual router or access the context of a previously created virtual router or a VRF.
- Example
  host1(config)#virtual-router boston
- Use the no version of the command only to delete the VR and return the router to the default VR.
- See virtual-router.