LAG Virtual Interface
The LAG virtual interface is a logical interface that represents a bundle of physical interfaces that form a LAG. The primary port that anchored the LAG no longer exists beginning with FastIron release 08.0.61. Instead, all features running over a LAG are anchored on the LAG virtual interface. All member ports of the LAG are treated as secondary ports and therefore, any physical port can be added or removed from the LAG without tearing down the LAG. The LAG virtual interface is created when a LAG is configured.
The LAG can be added, modified, or deleted using the respective commands in the LAG virtual interface mode. The LAG virtual interface and the properties it supports are similar to an Ethernet interface. The configuration of the LAGs using the LAG virtual interface is described in Creating a Link Aggregation Group (LAG). Like Ethernet interfaces, the LAG virtual interface also supports multi-interface mode.
Any new configuration or changes made to the LAG virtual interface are propagated to all ports in the LAG, ensuring a consistent configuration of the member ports. Interface-level configurations can be applied only on the LAG virtual interface and not on any member ports.
LAG virtual interface is included among the list
of interfaces displayed for various show commands.
To view the LAG virtual interface details, refer to Displaying LAG information.
LAG MAC Address
The Layer 2 protocols (xSTP and MRP) running over
the LAG use the LAG MAC address as the source MAC address. The first physical
port
that is being added to the LAG becomes the MAC provider for the LAG virtual
interface. When the first physical port (MAC provider) becomes unavailable, the
next
port is chosen as the MAC provider. However, a static MAC address can be assigned
to
the LAG virtual interface using the lag-mac command.