You can configure a 7000 or 8000 Series device in a Layer 2 deployment so that it provides packet switching between two or more networks. In a Layer 2 deployment, you can configure virtual switches to operate as standalone broadcast domains, dividing your network into logical segments. A virtual switch uses the media access control (MAC) address from a host to determine where to send packets.
When you configure a virtual switch, the switch initially broadcasts packets through every available port on the switch. Over time, the switch uses tagged return traffic to learn which hosts reside on the networks connected to each port.
A virtual switch must contain two or more switched interfaces to handle traffic. For each virtual switch, traffic becomes limited to the set of ports configured as switched interfaces. For example, if you configure a virtual switch with four switched interfaces, packets sent in through one port for broadcast can only be sent out of the remaining three ports on the switch.
When you configure a physical switched interface, you must assign it to a virtual switch. You can also define additional logical switched interfaces on a physical port as needed. You can group multiple physical interfaces into a single logical switched interface called a link aggregation group (LAG). This single aggregate logical link provides higher bandwidth, redundancy, and load-balancing between two endpoints.
If a Layer 2 deployment fails for any reason, the device no longer passes traffic.