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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 switch varies according to the switch model and the version of Juniper Networks Junos operating system (Junos OS) that is running on that switch. Be aware of the maximum number of interfaces per LAG and the maximum number of LAGs that are supported on your switches 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 switch 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 switch is selected in the View Pane.

Note:

MC-LAG, or Multi-Chassis Link Aggregation Group, is a type of LAG with constituent ports that terminate on separate chassis, thereby providing node-level redundancy. Unlike link aggregation in general, MC-LAG is not covered under IEEE 802.1AX-2008. Its implementation varies by vendor. For directions to create an MC-LAG, see Creating and Managing Multichassis Link Aggregation Groups (MC-LAGs).

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.

  • Manage ICCP settings for the selected device by clicking Manage ICCP Settings. See Managing ICCP Settings for more information.

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 in Network Director. The number of interfaces that can be grouped into a LAG and the total number of LAGs supported on a switch varies according to switch model.

Tip:

You can also create one or more MC-LAGs for Virtual Chassis—see Creating and Managing Multichassis Link Aggregation Groups (MC-LAGs).

To create a link aggregation group:

  1. In the View pane, select a switch for link aggregation.
    Note:

    The Manage LAG task is only available when a qualified switch is selected in the View pane.

  2. Click in the Network Director banner.
  3. Select Wired > Manage LAG in the Tasks pane.

    The Manage LAG page opens.

  4. Click Create.

    The Create Link Aggregation window opens.

  5. 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.
  6. 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.

  7. Enter a description for the link aggregation.
  8. 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.

  9. If the device is capable of using MC-LAGs, an MC-LAGs section also appears in the Create Link Aggregation window. .
  10. 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.

  11. Click OK to close the information message.

    The LAG appears in the Manage LAG list.

Managing ICCP Settings

When a QFX Series device is the selected scope, you can use the ICCP LAG Settings window to manage ICCP on the selected device. Table 2 describes the fields in this window.

Table 2: ICCP Settings

Field

Description

Disable (Delete) ICCP Settings

Disable ICCP on the device.

AE Name

Select the aggregated Ethernet interface to use for the ICCP connection.

Local IP

Configure the local IP address to be used by all switches hosting the MC-LAG.

Peer IP

Configure the IP address of the ICCP peer.

VLAN

Enter the name of the VLAN to use for the ICCP connection.

VLAN ID

Enter the ID of the VLAN to use for the ICCP connection.

Liveness detection min receive interval

Configure the minimum interval at which the switch must receive a reply from the other switch with which it has established a Bidirectional Forwarding Detection (BFD) session.

Liveness detection min transmit interval

Configure the minimum transmit interval during which a switch must receive a reply from a switch with which it has established a BFD session.

Liveness detection backup peer IP

Configure the IP address of the liveness detection backup.

Session establish hold time

Configure the time during which an ICCP connection must succeed between the switches hosting the MC-LAG. Configured session establishment hold time results in faster ICCP connection establishment. The recommended value is 50 seconds.

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 switches in Deploy mode. For details, see Deploying Configuration to Devices.

Tip:

Even though link aggregation configuration is not contained within a profile, you can view the link aggregation groups assigned to a switch by using the View Assigned Profiles task in Build mode.

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