Managing and Creating a Link Aggregation Group

IEEE 802.3ad link aggregation enables you to group Ethernet interfaces to form a single link layer interface, also known as a link aggregation group (LAG) or bundle.

Aggregating multiple links between physical interfaces creates a single logical point-to-point trunk link or a LAG. Link Aggregation Control Protocol (LACP), a component of IEEE 802.3ad, provides additional functionality for LAGs.

LACP ensures that both ends of the Ethernet link are functional and are members of the aggregation group before the link is added to the LAG. If you use LACP, make sure that LACP is enabled at both the local and remote ends of the link. When LACP is configured, it detects misconfigurations on the local end or the remote end of the link. Thus, LACP can help to prevent communication failure. When LACP is not enabled, a local LAG might attempt to transmit packets to a remote single interface, which causes the communication to fail. However, when LACP is enabled, a local LAG cannot transmit packets unless a LAG with LACP is also configured on the remote end of the link.

The maximum number of interfaces that can be grouped into a LAG and the maximum number of LAGs supported on a router varies according to the router model and the version of Juniper Networks Junos operating system (Junos OS) that is running on that router. Be aware of the maximum number of interfaces per LAG and the maximum number of LAGs that are supported on your routers by referring to your device specific documentation before implementing LAG in your network.

Note:

You only see the Manage Lag option under Device Management when a qualified router is selected in the View Pane.

When creating LAGs, follow these guidelines:

You must configure the LAG on both sides of the link.
You must set the interfaces on either side of the link to the same speed.
You can configure and apply firewall filters on a LAG.

Note:

You only see the Manage Lag option under Device Management when a qualified router is selected in the View Pane.

This topic includes:

Link Aggregation Group Options

From the Manage LAG page, you can:

Create a new Link Aggregation by clicking Create. The Create Link Aggregation window opens—for directions, see Creating a Link Aggregation Group.
Modify an existing Link Aggregation by selecting it and clicking Edit. The Modify Link Aggregation window opens. You can modify all the fields in the Modify Link Aggregation window, except the Interface Name field.
Delete a Link Aggregation Group by selecting it and clicking Delete.

Table 1 describes the information provided about the link aggregation configurations on the LACP (Link Aggregation Control Protocol) Configuration page. This page lists all link aggregation groups defined on the selected device.

Table 1: LACP (Link Aggregation Control Protocol) Configuration Fields
Field	Description
Logical Interface Name	Name given to the aggregated interface when the LAG was created.
Member Interfaces	Names of individual member interfaces.
LACP Mode	Mode in which LACP packets are exchanged between the interfaces. The possible modes are: Active—Indicates that the interface initiates transmission of LACP packets Passive—Indicates that the interface responds only to LACP packets.
Description	The description for the LAG. Tip: If you cannot view the entire description, you can resize the Description column by clicking the column border in the heading and dragging it.
Deployment State	The deployment state of the link aggregation. Deployment state can be: Pending Deployment—Indicates that the LAG is not yet deployed on the device. Deployed—Indicates that the LAG is deployed on the device. Pending Removal—Indicates that the LAG is deleted.
Creation Time	Date and time when this profile was created.
Update Time	Date and time when this profile was last modified.
User Name	The username of the user who created or modified the profile.

Tip:

All columns might not be displayed. To show or hide fields in the LACP (Link Aggregation Control Protocol) Configuration table, click the DOWN arrow on the field header, select Columns, and select or clear the check box adjacent to the field that you want to show or hide.

Creating a Link Aggregation Group

You can create one or more LAGs for your device in Device view. The number of interfaces that can be grouped into a LAG and the total number of LAGs supported on a router varies according to router model.

To create a link aggregation group:

In the View pane, select a router for link aggregation.
Note:
The Manage LAG task is only available when a qualified router is selected in the View pane.
Click the Build icon in the Connectivity Services Director banner.
Select Wired > Manage LAG in the Tasks pane.
The Manage LAG page opens.
Click Create.
The Create Link Aggregation window opens.
Use the up and down arrows to select an AE Name for the aggregation interface. The interface name begins with ae followed by an interface number.
Select the mode in which LACP packets are to be exchanged between interfaces, either Active or Passive.
- Active—Indicates that the interface initiates transmission of LACP packets
- Passive—Indicates that the interface responds only to LACP packets.
Enter a description for the link aggregation.
Configure up to eight available interfaces on the LAG. Select one or more interfaces from the Available list and then click the RIGHT arrow to move them to the Selected list.
Note:
The Available interfaces list displays only those interfaces that are not part of any link aggregation.
If the device is capable of using MC-LAGs, an MC-LAGs section also appears in the Create Link Aggregation window. .
Click OK to save the link aggregation configuration.
A message confirms that the link aggregation is created successfully and ready to be deployed to a device. If the configuration contains an error, the message instead indicates the error.
Click OK to close the information message.
The LAG appears in the Manage LAG list.

What To Do Next

The configuration changes that you make in the Build mode are not deployed to devices automatically. After you create a link aggregation group, you must manually deploy the changes to the routerss in Deploy mode. .