LAG Interface Now Supported in uOS 1.32

Zyxel_Claudia

Zyxel’s uOS 1.32 introduces Link Aggregation Group (LAG) interface support for H Series firewalls, enabling administrators to combine multiple physical interfaces into a single logical link. This provides improved bandwidth, redundancy, and failover capability—ideal for demanding network environments.

What is a LAG Interface?

A Link Aggregation Group (LAG) interface bundles two or more physical Ethernet interfaces into a single logical interface. The benefits include:

• Higher bandwidth by combining interface speeds (e.g., 2x 10Gbps = 20Gbps)
• Redundancy/failover in case one link goes down
• Traffic load sharing (depending on LAG mode)

Key Configuration Parameters

LAG Members:

• Minimum: 1 port
• Maximum: 4 ports
• A physical port can only belong to one interface at a time.
• IP address of Interfaces must be unassigned.
• MAC address must use default MAC.
• Cannot be part of VLAN interfaces or used by other configurations, except the zone.

Zone Application Logic

For security policy application, the zone setting on the LAG interface itself takes precedence—not the zone of the individual member interfaces. This differs from bridge interfaces, where member zone may apply.

Supported Models

All USG FLEX H Series models support LAG. USG FLEX 50H supports a maximum of 2 LAG interfaces, and other models support up to 4.

LAG Modes Supported

Active/Backup: One link is active, another serves as backup. Simple redundancy without load balancing.

LACP (802.3ad): Industry-standard dynamic link aggregation using protocol-based negotiation.

Static: Manually defines member ports, load-sharing without LACP messages.

Additional Options:

• Preferred primary link (Active/Backup mode): Configure Preferred Active Link in Active/Backup mode to specify the primary link.
• Monitoring interval: default 100ms. Defines how frequently the system checks if a LAG member interface is active or down.
• Hash policy (LACP/Static): Source and Destination IP-MAC based load distribution

CLI & Monitoring

Use the CLI command to check interface status:

show state interface <interface-name>

Examples:

usgflex200h> show state vrf main interface lag LAG0

• LAG1 Active/Backup: shows active link up, backup standby
• LAG2 in LACP: all members show as active and up