Cisco 642-812 Exam - PassITexam.com
Free 642-812 Sample Questions:
1. Which switch command enables a trunking protocol that appends a four byte CRC to the packet?
A. Switch(configif)#switchport trunk encapsulation dot1q
B. Switch(configif)#switchport trunk encapsulation itef
C. Switch(configif)#switchport trunk encapsulation fddi
D. Switch(configif)#switchport trunk encapsulation isl
2. What action should a network administrator take to enable VTP pruning on an entire management domain?
A. enable VTP pruning on any client switch in the domain
B. enable VTP pruning on every switch in the domain
C. enable VTP pruning on any switch in the management domain
D. enable VTP pruning on a VTP server in the management domain
3. Which statement describes Dynamic Trunking Protocol (DTP) mode 'desirable'?
A. The interface is put into permanent trunking mode and negotiates to convert the link into a trunk link.
B. The interface actively attempts to convert the link to a trunk link.
C. The interface is put into permanent trunking mode but prevented from generating DTP frames.
D. The interface is put into a passive mode, waiting to convert the link to a trunk link.
4. Which three statements are correct with regard to the IEEE 802.1Q standard? (Choose three.)
A. the packet is encapsulated with a 26 byte header and a 4 byte FCS
B. the IEEE 802.1Q frame format adds a 4 byte field to a Ethernet frame
C. the IEEE 802.1Q frame retains the original MAC destination address
D. the IEEE 802.1Q frame uses multicast destination of 0x01000c0000
E. protocol uses pointtopoint connectivity
F. protocol uses pointtomultipoint connectivity
Answer: B, C, E
5. In a customer's network, VLAN Trunking Protocol (VTP) is running with a domain named main1. VLANs
1,2,3,4,5,10,20 are active on the network. Suddenly the whole network goes down. No traffic is being passed on VLANs 2,3,4,5,10,20, however traffic passes on VLAN 1 and indicates all switches are operational. Right before the network problem occurred, a switch named TEST1 was added to the network. What three configuration issues on TEST1 could be causing the network outage? (Choose three.)
A. TEST1 is configured as a VTP server with a different domain name.
B. TEST1 is not configured to participate in VTP.
C. TEST1 is configured as a VTP server with the domain name main1.
D. TEST1 has a lower VTP configuration revision than the current VTP revision.
E. TEST1 has a higher VTP configuration revision than the current VTP revision.
F. TEST1 is configured with only VLAN1.
Answer: C, E, F
6. Which DTP switchport mode parameter sets the switch port to actively send and respond to DTP negotiation frames?
C. no negotiate
D. dynamic desirable
E. dynamic auto
7. Which method of Layer 3 switching uses a forwarding information base (FIB)?
A. route caching
B. flowbased switching
C. demandbased switching
D. topologybased switching
8. Which protocol specified by RFC 2281 provides network redundancy for IP networks, ensuring that user traffic immediately and transparently recovers from firsthop failures in network edge devices or access circuits?
9. In which three HSRP states do routers send hello messages? (Choose three.)
Answer: A, D, E
10. Which protocol enables a group of routers to form a single virtual router and use the real IP address of a router as the gateway address?
A. Proxy ARP
11. Which protocol inserts a four byte tag into the Ethernet frame and recalculates CRC value?
12. What is the cause of jitter?
A. variable queue delays
B. packet drops
C. transmitting too many small packets
13. The original frame is encapsulated and an additional header is added before the frame is carried over
a trunk link. At the receiving end, the header is removed and the frame is forwarded to the assigned VLAN. This describes which technology?
C. IEEE 802.1Q
14. Which statement is true regarding the configuration of ISL trunks?
A. All Catalyst switches support ISL trunking.
B. A Catalyst switch will report giants if one side is configured for ISL while the other side is not.
C. ISL trunking requires that native VLANs match.
D. A Catalyst switch cannot have ISL and IEEE 802.1q trunks enabled.
15. On a multilayer Catalyst switch, which interface command is used to convert a Layer 3 interface to a
Layer 2 interface?
B. no switchport
C. switchport mode access
D. swithport access vlan vlanid
16. Which two statements concerning STP state changes are true? (Choose two.)
A. Upon bootup, a port transitions from blocking to forwarding because it assumes itself as root.
B. Upon bootup, a port transitions from blocking to listening because it assumes itself as root.
C. Upon bootup, a port transitions from listening to forwarding because it assumes itself as root.
D. If a forwarding port receives no BPDUs by the max_age time limit, it will transition to listening.
E. If a forwarding port receives an inferior BPDU, it will transition to listening.
F. If a blocked port receives no BPDUs by the max_age time limit, it will transition to listening.
Answer: B, F
17. How does 802.1q trunking keep track of multiple VLAN's? A. modifies the port index of a data frame to indicate the VLAN B. adds a new header containing the VLAN ID to the data frame
C. encapsulates the data frame with a new header and frame check sequence D. tags the data frame with
VLAN information and recalculates the CRC value