what does the IEEE 802.1Q standard describe?

In a switched environment, what does the IEEE 802.1Q standard describe?

A.
the operation of VTP

B.
a method of VLAN trunking

C.
an approach to wireless LAN communication

D.
the process for root bridge selection

E.
VLAN pruning

Explanation:
A broadcast domain must sometimes exist on more than one switch in the network. To accomplish
this, one switch must send frames to another switch and indicate which VLAN a particular frame
belongs to. On Cisco switches, a trunk link is created to accomplish this VLAN identification. ISL
and IEEE 802.1Q are different methods of putting a VLAN identifier in a Layer 2 frame.
The IEEE 802.1Q protocol interconnects VLANs between multiple switches, routers, and servers.
With 802.1Q, a network administrator can define a VLAN topology to span multiple physical
devices.
Cisco switches support IEEE 802.1Q for FastEthernet and Gigabit Ethernet interfaces. An 802.1Q
trunk link provides VLAN identification by adding a 4-byte tag to an Ethernet Frame as it leaves a
trunk port.