Wednesday, June 4, 2008

CISCO SEMESTER 3: MODULE 4

1

Which attribute is used by a bridge to make forwarding decisions?

source IP address

source MAC address

destination IP address

destination MAC address

Layer 4-7 protocol address



2

What is the effect of adding additional hosts to a half-duplex Ethernet network? (Choose three.)

collisions increase

collisions decrease

jam signals increase

jam signals decrease

throughput decreases

throughput increases



3

How does an Ethernet bridge handle an incoming frame? (Choose three.)

The source MAC address and input interface pair are added to the bridging table.

The destination MAC address and input interface pair are added to the bridging table.

If no match to the destination MAC address is found in the bridging table, the frame is discarded.

If no match to the destination MAC address is found in the bridging table, the frame is flooded out all other interfaces.

If a match to the destination MAC address is found in the bridging table, the frame is forwarded out the associated interface.

If a match to the source MAC address is found in the bridging table, the frame is forwarded to all ports.



4

Which of the following is used to build a switching table?

source IP addresses

destination IP addresses

destination MAC addresses

source MAC addresses



5

After a collision occurs on a half-duplex Ethernet network, how does a transmitting host proceed? (Choose two.)

It does not stop transmitting.

It listens to determine if the network is in use before attempting to retransmit.

It resumes transmitting while the jam signal clears the wire.

It resumes transmitting based on the NIC back-off algorithm.

It will take priority and be the first host to transmit after the collision.



6

Which statements describe asymmetric switching? (Choose three.)

It uses data compression algorithms to manage higher bandwidth interfaces.

It is often used to provide high bandwidth uplinks for a number of lower bandwidth client interfaces.

It provides connections between network segments that operate at different bandwidths.

It uses cut-through forwarding when going from a lower bandwidth to a higher bandwidth interface.

It is used to provide more bandwidth to network clients than to backbone or server links.

It may require buffering frames before forwarding to the destination interface.



7

Which statements are true concerning the shared memory buffering used by an Ethernet switch? (Choose two.)

Frames are processed through a single queue.

All frames are placed in a common memory buffer.

Frames are placed in a queue for the destination port.

A port with a full memory buffer can cause frames for available ports to be delayed.

Each switch port is statically assigned a buffer of equal size.



8

Which statements are true regarding hubs? (Choose three.)

Hubs operate at Layer 1 of the OSI model.

They create separate collision domains.

Signals are distributed through all ports.

Layer 2 addresses are used to make decisions.

They calculate the CRC for each frame received prior to forwarding.

Bandwidth is shared among all connected users.



9

What are the functions of routers? (Choose three.)

improving network performance by increasing latency by twenty to thirty percent

segmenting broadcast domains

forwarding packets based on destination network layer addresses

segmenting collision domains

forwarding packets as soon as the destination MAC address is read

developing routing table entries based on source IP addresses



10

Which of the following devices use physical addresses to make forwarding decisions? (Choose two.)

hub

bridge

router

switch

concentrator

multi-port repeater



11

Which form of buffering is used by bridges?

cut-through

fragment-free

fast-forward

store-and-forward



12

Switching may be implemented to improve the performance of which of the following networking technologies? (Choose three.)

Ethernet 10BASE-T

Ethernet 10BASE2

FDDI

Token Ring

EIA-232



13

Hubs are concerned with which PDU?

bits

frames

packets

datagrams



14

What does switch latency describe?

forwarding method used by a switch

time it takes for a frame to be received by a switch

improvement in network performance from using a switch

time delay between when a frame enters and exits a switch

increase in the size of a collision domain from using a switch



15

Where are switching tables stored in a Cisco LAN switch?

ROM

CAM

Flash

SIMM

NRAM



16

Which switching mode changes to store-and-forward mode after it detects a given number of errors?

cut-through

adaptive fast-forward

fragment-free

adaptive cut-through





17

Which of the following is a Layer 2 broadcast address?

0.0.0.0

255.255.255.255

11:11:11:11

FF:FF:FF:FF

FF:FF:FF:FF:FF:FF





18



Refer to the graphic. Which point in the frame must be reached before it is forwarded by a switch that is using fast-forward mode?

A

B

C

D

E

F





19

Why does a switch have higher throughput compared to a bridge?

Switching occurs in software.

Switching occurs in hardware.

Switches create virtual circuits.

Switches segment LANs.





20

What is the potential throughput of a 10 Mbps Ethernet connection operating in full-duplex mode? (Choose two.)

10 Mbps total

20 Mbps total

5 Mbps TX and 5 Mbps RX

10 Mbps TX and 10 Mbps RX

40 to 60 percent on TX and RX





21



An Ethernet switch has developed the MAC address table shown at the top of the graphic. What action will the switch take when it receives the frame shown at the bottom of the graphic?

forward the frame out all interfaces

forward the frame out all interfaces except Interface3

discard the frame

forward the frame out Interface1

forward the frame out Interface2

forward the frame out Interface3





22

Which of the following are true regarding the addition of switches to a network? (Choose two.)

They increase the number of collision domains.

They decrease the number of collision domains.

They increase the number of broadcast domains.

They decrease the number of broadcast domains.

They increase the amount of bandwidth available to users.

They decrease the amount of bandwidth available to users.





23

What is designed to prevent multiple devices on an Ethernet network from transmitting at the same time?

synchronization clock

CSMA/CD access method

token access method

shared medium





24



Refer to the graphic. Which point must be reached before a frame is forwarded when the switch is using store-and-forward mode?

A

B

C

D

E

F





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