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Create LAG Interface

You can connect an SRX Series Customer Premise Equipment (CPE) to an EX series switch or an access point (AP) through a trunk port. However, you can use two or more trunk ports to connect the CPE and the switch, and combine them to form a Link Aggregation Group (LAG) for higher throughput and redundancy. If you want to use a LAG interface to manage the connectivity between the CPE and the switch, create a LAG interface (aggregated Ethernet or ae interface) on the CPE.

To create a LAG interface:

  1. Click Resources > Devices.

    The Devices page is displayed.

  2. Select a CPE device from the list of devices displayed and click More > Manage Switch Connectivity.

    The Manage Switch Connectivity page is displayed. To access this page, the Management Status of the device selected should be Provisioned.

    Alternatively, click device-name from the Device Name column to open the Device Details page and then click CONFIGURATION (tab) > Interfaces (tab).

    You can also access the Device Details page from the Site Management page (Resources > Site Management site-name > DEVICES (tab) >device-name).

  3. Click Add LAG Interface.

    The Create LAG Interface page is displayed.

  4. Complete the configuration settings according to the guidelines provided in Table 1.
  5. Click OK.

    The LAG interface is listed in the interfaces section on the Manage Switch Connectivity page.

Table 1: Fields on the Add LAG Interface Page



LAG Interface

Select a LAG interface. This must be an Aggregated Ethernet (ae) interface.

CPE Port(s)

Select the physical interfaces (of the CPE) to be included as the member links in the LAG. These interfaces are used for data or management traffic between the EX Series switch and the CPE. Select at least two ports for redundancy.


Applicable only to SRX Series Firewalls.

Specify the maximum transmission unit (MTU) size for the media or protocol. The supported MTU range varies depending on the device.


Ensure that the MTU size configured on the SRX Series Firewall is within the MTU range supported by the switch or router connected to the SRX device.


Enable Link Aggregation Control Protocol (LACP), a monitoring protocol that detects link-layer failure within a network, if you want to monitor the local and remote ends of member links in a LAG.


Not applicable for vSRX Virtual Firewall devices.


If you have enabled LACP on the interface, select the LACP mode.

  • Active—To initiate transmission of LACP packets and response to LACP packets, you must configure LACP in active mode. If either the actor (transmitting link) or partner (receiving link) is active, they exchange LACP packets.

  • Passive—There is no exchange of LACP packets. This is the default transmission mode.


If you have enabled LACP on the interface, select an interval for periodic transmission of LACP packets:

  • fast—Transmits packets every second.

  • slow—Transmits packets every 30 seconds.

Force up

If you have enabled LACP on the interface, click the toggle button if you want to enable the Force Up state on the interface. Enabling this feature sets the state of the interface as UP even when the peer has limited LACP capability.


Use the toggle button to enable Link Layer Discovery Protocol (LLDP) on the interface. LLDP allows networked devices to advertise capabilities, identity, and other information onto a LAN. LLDP-capable devices transmit information in type, length, and value (TLV) messages to neighbor devices.


Not applicable for vSRX Virtual Firewall devices.