Overlay transport virtualization (OTV) is a Cisco proprietary protocol for relaying layer 2 communications between layer 3 computer networks.
See also Distributed Overlay Virtual Ethernet (DOVE) Generic Routing Encapsulation (GRE) IEEE 802.1ad, an Ethernet networking standard, also known as provider bridging, Stacked VLANs, or simply QinQ. NVGRE, a similar competing specification Virtual Extensible LAN (VXLAN) Virtual LAN (VLAN)
External links Cisco Overlay Transport Virtualization overview