CCNA Practice Exam Test Sample – Question 64

Which two of these are characteristics of the 802.1Q protocol? (Choose two.)

A. It is used exclusively for tagging VLAN frames and does not address network reconvergence following switched network topology changes.
B. It modifies the 802.3 frame header, and thus requires that the FCS be recomputed.
C. It is a Layer 2 messaging protocol which maintains VLAN configurations across networks.
D. It includes an 8-bit field which specifies the priority of a frame.
E. It is a trunking protocol capable of carrying untagged frames.

Correct Answers: B,E
Section: LAN Switching Technologies

Explanation:
802.1Q protocol, or Virtual Bridged Local Area Networks protocol, mainly stipulates the realization of the VLAN. 802.1Q is a standardized relay method that inserts 4 bytes field into the original Ethernet frame and re-calculate the FCS. 802.1Q frame relay supports two types of frame: marked and non-marked. Non-marked frame carries no VLAN identification information.