Cisco N1KV, when enabled for VN-Link, operates on the basis of Virtual Ethernet (vEth) interfaces. Once enabled for VN-Link, it maintains network configuration attributes, such as security and statistics for a given virtual interface across mobility events. vEth interfaces are comparable to physical network access ports. A mapping gets created between each vEth interface and the corresponding vNICs on the VM. You may ask me why you would need vEth interfaces. The main advantage of using these is that they can follow vNICs when VMs move to other ESXi hosts. Once you set up a VN-Link on N1KV switches, it enables transparent mobility of VMs across different ESXi hosts and physical access-layer switches, and it does so by virtualizing the network access port with vEth interfaces.