Routing - l2transport

When you configure L2 transport on a router’s interface, you enable the interface to carry Layer 2 traffic between two devices directly connected to it, similar to a switch. Essentially, the router behaves as a bridge with the specified interface.

The command can be implemented like so:

Router# configure
Router(config)# interface TenGigE 0/2/0/0
Router(config-if)# l2transport
Router(config-if-l2)#

Notice that the command line enters the l2transport configuration mode.

When applied to a sub-interface, the syntax of the command changes somewhat. You must ensure that the l2transport command is applied on the same line as the interface command for the Ethernet sub-interface.

Router# configure
Router(config)# interface TenGigE 0/1/0/3.10 l2transport
Router(config-subif)# encapsulation dot1q 10

In the above example, the encapsulation type is also configured.

The l2transport command is not always implemented alone. It is often configured with other features including MPLS, MetroEthernet and others, so you may need to configure additional encapsulation options as well, depending on the specific traffic-handling requirements in each case.

https://networklessons.com/mpls/any-transport-over-mpls-atom