Question 9

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

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

Answer: D E

Explanation

IEEE 802.1Q is the networking standard that supports Virtual LANs (VLANs) on an Ethernet network. It is a protocol that allows VLANs to communicate with one another using a router. 802.1Q trunks support tagged and untagged frames.

If a switch receives untagged frames on a trunk port, it believes that frame is a part of the native VLAN. Also, frames from a native VLAN are not tagged when exiting the switch via a trunk port.

The 802.1q frame format is same as 802.3. The only change is the addition of 4 bytes fields. That additional header includes a field with which to identify the VLAN number. Because inserting this header changes the frame, 802.1Q encapsulation forces a recalculation of the original FCS field in the Ethernet trailer.

Note: Frame Check Sequence (FCS) is a four-octet field used to verify that the frame was received without loss or error. FCS is based on the contents of the entire frame.

Question 10

What are the possible trunking modes for a switch port? (Choose three)

A. transparent
B. auto
C. on
D. desirable
E. client
F. forwarding

Answer: B C D

CCNA Trunking Questions 2

Question 1

What is the function of the command switchport trunk native vlan 999 on a trunk port?

A. It designates VLAN 999 for untagged traffic.
B. It blocks VLAN 999 traffic from passing on the trunk.
C. It creates a VLAN 999 interface.
D. It designates VLAN 999 as the default for all unknown tagged traffic.

Answer: A

Question 2

Which three elements must be used when you configure a router interface for vlan trunking? (Choose three)

A. one IP network or subnetwork for each subinterface
B. subinterface numbering that matches vlan tages
C. subinterface encapsulation identifiers that match vlan tags
D. a management domain for each subinterface G E. one physical interface for each subinterface
F. one subinterface per vlan

Answer: A C F

Question 3

Which two link protocols are used to carry multiple VLANs over a single link? (Choose two)

A. VTP
B. 802.1q
C. IGP
D. ISL
E. 802.3u

Answer: B D

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