What does enabling "Allow Ethernet Bridging" do?

What does enabling "Allow Ethernet Bridging" do?

Nodes in a Cloud Network can be allowed to perform Ethernet Bridging. Typically combined with our headless linux agent, use of this option allows Cloud Network interfaces to be "bridged" at Layer 2 with physical network interfaces on the same device. When Ethernet Bridging is enabled, additional types of traffic are permitted to pass through the Cloud Network interface.