Link Aggregation – Part 3 (LACP Configuration on Juniper Devices) :

LACP Configuration on Juniper Devices

We have talked about LACP in the previous articles on Cisco Routers. Here we will focus on how to do this configuration on Juniper devices on ethernet links. As you know the protocol is the same, but there are some configuration differencies between different vendor’s devices.

By the way, we do not need to use LACP for ethernet bundlings, this is only a way with LACP protocol.

By default, there can be also maximum 8 ports in a bundle on Juniper devices. This can be changed by commands.

The typical usage of the LAG is to aggregate trunk links, between the access switch and the distribution switch.

Link Aggregation Example Topology on Juniper, JUNOS

Link Aggregation on Juniper Devices

In Juniper swithes, for aggregated links, firstly we need to configure, aggregated Etnernet interfaces.

[edit chassis]
gk@switch# set aggregated-devices interfaces device-count 1

After creating aggregated Ethernet interfaces, it is time to define minimum link count while the bundle is up. To do this use the below command:

[edit interfaces]
gk@switch#  set  interface-name  aggregated-ether-options  minimum-links  3

Lastly you can specify the link speed.

[edit interfaces]
gk@switch#  set  interface-name  aggregated-ether-options  link-speed  10g

It is time to specify the members that will be in the bundle.

[edit interfaces]
user@switch# set  ge-0/0/1 ether-options  802.3ad  aex
[edit interfaces]
user@switch# set  ge-0/0/2 ether-options  802.3ad  aex

You can also configura the vlan.

[edit vlans]
user@switch# set  gklan  vlan-id  20

After configuration of the aggregated ethernet interface, let’s configure the lacp protocol.

[edit interfaces]
gk@switch#  set  aex  aggregated-ether-options  lacp  active

If you woldu like to check your configuration, use the below show commands under the related hierarchy:

[edit chassis] 
user@switch# show 
aggregated-devices { 
    ethernet {
        device-count 1; 

[edit interfaces ae0] 
aggregated-ether-options { 
    lacp { 

[edit interfaces] 
user@switch# show 
    ether-options { 
        802.3ad ae0 
    ether-options { 
        802.3ad ae0 

And you can also check the bundle link status with the port status by the following command.

user@switch> show interfaces terse | match ae0 
ge-0/0/1.0 up up aenet -->ae0.0 
ge-0/0/2.0 up up aenet -->ae0.0 
ae0 up up 
ae0.0 up up eth-switch

I hope this link aggregation article will be helpful for you. To learn about Alcatel-Lucent Service Router’s link aggregation, go to the next part of this article series ;)

Link Aggregation – Part 1 (Link Aggregation Control Protocol, LACP)
Link Aggregation – Part 2 (LACP Configuration on Cisco Devices)
Link Aggregation – Part 3 (LACP Configuration on Juniper Devices)
Link Aggregation – Part 4 (LAG Configuration on Alcatel-Lucent Devices)

About the Author
Gokhan Kosem is a telecommunation and network engineer. His ambition to IP networks and end-to-end system installation made him to prepare this web-site. By sharing his experiences about various networking protocols beside different system installation experiences and Cisco, Juniper, Alcatel-Lucent devices configurations, he is aimed to be helpful for his collegues in all over the world. He is currently lives in Istanbul, Turkey.

2 comments for “Link Aggregation – Part 3 (LACP Configuration on Juniper Devices)”


Hi, Gokhan

This article is absolutely a good piece to get the general meaning of this concept.

I want to know why the speed was set to 10g as we have only 2 ge port validated in the AE port. This may waste your time to answer.


February 13th, 2014 at 06:02

should I give IP Address to port LAG?

August 25th, 2014 at 11:21

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