Virtual links can originate from converged network adapters that typically host a
dual 10 Gigabit Ethernet NIC and a dual HBA from either Emulex or Q-Logic, along
with circuitry to multiplex the four streams of traffic onto two 10-Gbps unified fabric
links. Cisco innovations first brought this concept to market, with the first generation
of converged network adapters (CNAs) supported by Cisco silicon that multiplexed
multiple traffic flows onto the unified fabric.

With servers connected to Cisco UCS through CNAs, the traffic from each of the
interface’s four devices is passed over four virtual links that terminate at virtual ports
within the fabric interconnects.