How to set up LAG interface on USG FLEX H Firewall?

Zyxel_James

Question: How to set up LAG interface on USG FLEX H?

Answer:
A Link Aggregation Group (LAG) combines multiple Ethernet ports into a single logical link, LAG interface, between network devices. It helps to increase bandwidth and provide link redundancy.
The LAG interface of Zyxel USG FLEX H firewalls combines multiple Ethernet interfaces as members and supports three types of modes, Active-Backup, LACP (802.3ad), and Static.

Prerequisites of Ethernet interface member
To be a member of LAG interface, the Ethernet interface must Meet all of the following
conditions:

1. The Ethernet interface can only bind to one port. And the port cannot be used by
   other VLAN interface.
2. The Ethernet interface cannot be a member of other bridge, or LAG interface.
3. It does not have an IP address (must be set to unassigned).
4. It cannot have MAC address overwrite settings, must use default MAC address.
5. The interface must not be referenced by any other configurations except the Zone.

Create a LAG interface

1. Edit the member Ethernet interfaces and make sure the MAC address is set to use default MAC address and the Address Assignment is set to unassigned.

2. Click +Add to create an interface and select the Interface Type as LAG.

3. Select the LAG mode

LAG mode: Active-Backup

Provides automatic link failover by keeping backup ports not transmitting traffic until the primary port experiences a link-down event.

Mii Monitoring Interval: Defines how frequently the system checks if a LAG memberinterface is active or down

Primary: Allows you to specify which member interface should be preferred as the active link

LAG mode: LACP (802.3ad)

Provides automatic link failover and load sharing by allowing all ports in the LAG groupto transmit traffic. The LACP messages will be periodically sent. When in LACP mode, the connected Switch must also configure LACP mode for thephysical ports that connect to the USG FLEX H Firewall.

Transmit Hash Policy: Determine how outgoing traffic is distributed across the aggregated links. The default option is src-dst-ip-mac. Select src-dst-ip-mac to distribute traffic more efficiently by considering both source-destination IP and MAC.

LAG Mode: Static

All ports in the LAG group will be always active for link failover and load balancing. The use case is when using legacy networking equipment that doesn’t support LACP. When in LACP mode, the connected Switch must also configure LACP mode for the physical ports that connect to the USG FLEX H Firewall. When in Static mode, the connected Switch must also configure Static Trunk mode for the physical ports that connect to theUSG FLEX H Firewall.