[Free] Download Latest (May 2016) Cisco 640-911 Real Exam 11-20

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QUESTION 11

In an IEEE 802.3 Ethernet frame, what is the significance of the DSAP field?

 

A.

The DSAP field specifies the TCP or UDP port that is associated with the transport protocol.

B.

The DSAP field is only used on United States Department of Defense networks to indicate the information classification level.

C.

The DSAP field is only used in Ethernet II frames.

D.

The DSAP field indicates the network layer protocol.

 

Correct Answer: D

 

 

QUESTION 12

Which field in an Ethernet II frame performs the same function as the DSAP field in an 802.3 Ethernet frame?

 

A.

Start of frame

B.

EtherType

C.

Frame check sequence

D.

Subnetwork Access Protocol

E.

Logical Link Control

 

Correct Answer: B

 

 

QUESTION 13

What are two features of a bridge? (Choose two.)

 

A.

Reliable transmission

B.

Operate at OSI Layer 2

C.

Operate at OSI Layer 3

D.

Create multiple broadcast domains

E.

Create multiple collision domains

F.

Flood input packets to all ports

G.

Drop IP packets with invalid destination ports

 

Correct Answer: BE

Explanation:

“- a bridge is a two interfaces device that creates 2 collision domains, since it forwards the traffic it receives from one interface only to the interface where the destination layer 2 device (based on his mac address) is connected to. A bridge is considered as an “intelligent hub” since it reads the destination mac address in order to forward the traffic only to the interface where it is connected”

https://learningnetwork.cisco.com/thread/1734

 

 

QUESTION 14

What are three reasons that switches supersede bridges? (Choose three.)

 

A.

Smaller frame buffers decrease latency.

B.

Forward, filter, or flood frames.

C.

Multiple simultaneous communications between ports.

D.

Larger inspection engine allows for higher throughput.

E.

Switches have many ports.

Correct Answer: BCE

Explanation:

http://docwiki.cisco.com/wiki/Bridging_and_Switching_Basics

 

 

QUESTION 15

What action does a switch take if the destination MAC address is unknown?

 

A.

Discard frame

B.

Send ICMP unreachable message to source

C.

Flood packet on all ports

D.

Compare destination IP address against an ACL to determine if it is permitted

E.

Send gratuitous ARP on all ports and wait for reply before forwarding

 

Correct Answer: C

Explanation:

“What happens though when the switch receives a frame with a destination MAC address that is not included in the table? In that case the switch will just broadcast/flood the frame with theunknown destination address to all of its ports (apart from the port where the frame came from). This process is called unknown unicast flooding. “

http://telconotes.wordpress.com/2013/03/09/how-a-switch-works/

 

 

QUESTION 16

Which statement describes the purpose of the MAC address forwarding table of a switch?

 

A.

The switch consults the forwarding table to determine the best route to a destination.

B.

The switch consults the forwarding table to determine the output port.

C.

The switch consults the forwarding table to determine if the packet is routable.

D.

The switch consults the forwarding table to determine if access control permits the packet.

 

Correct Answer: B

 

 

QUESTION 17

What are two attributes of a VLAN? (Choose two.)

 

A.

A VLAN defines a collision domain.

B.

A VLAN defines a broadcast domain.

C.

Broadcasts are flooded to all VLANs.

D.

Collisions are flooded to all VLANs.

E.

A Layer 3 device is required to route packets between VLANs.

F.

A Layer 2 device is required to route packets between VLANs.

 

Correct Answer: BE

Explanation:

“In computer networking, a single layer-2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them via one or more routers; such a domain is referred to as a virtual local area network, virtual LAN or VLAN.”

“A router (Layer 3 device) serves as the backbone for network traffic going across different VLANs.”

http://en.wikipedia.org/wiki/Virtual_LAN

 

QUESTION 18

Which four statements indicate unique properties of VLAN 1 on Cisco Nexus switches? (Choose four.)

 

A.

VLAN 1 is used to flood multicast traffic.

B.

VLAN 1 cannot be deleted.

C.

VLAN 1 is used for Cisco Discovery Protocol.

D.

VLAN 1 is used for VTP advertisements.

E.

VLAN 1 defines a collision domain.< /p>

F.

VLAN 1 defines a broadcast domain.

 

Correct Answer: BCDF

Explanation:

http://www.cisco.com/en/US/docs/switches/datacenter/sw/5_x/nx- os/layer2/configuration/guide/Cisco_Nexus_7000_Series_NX- S_Layer_2_Switching_Configuration_Guide_Release_5.x_chapter4.html

 

 

QUESTION 19

Which command displays the Trunking Native Mode VLAN on port Ethernet 1/18?

 

A.

show running-config switchport e1/18

B.

show running-config e1/18 switchport

C.

show interface e1/18

D.

show interface e1/18 switchport

E.

show interface e1/18 native

 

Correct Answer: D

Explanation:

NX# show interface e1/18 switchport

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Trunking VLANs Allowed: 1-4094

Voice VLAN: none

 

 

QUESTION 20

Which VTP mode disallows the creation of local VLANs?

 

A.

transparent

B.

tunneling

C.

server

D.

client

E.

off

F.

native

 

Correct Answer: D

Explanation:

“A VTP client behaves like a VTP server and transmits and receives VTP updates on its trunks, but you cannot create, change, or delete VLANs on a VTP client. VLANs are configured on another switch in the domain that is in server mode.”

http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_52_se/configurat
ion/guide/swvtp.html#wp1205076

 

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