Chapter 6. Building Ethernet LAN's with switches

Question 1

Which of the following statements describes part of the process of how a switch decides to forward a frame destined for a known unicast MAC address

a. It compares the unicast destination address to the bridging, or MAC address table.
b. It compares the unicast source address to the bridging, or MAC address table.
c. It forwards the frame out all interfaces in the same Vlan except for the incoming interface
d. It compares the destination IP address to the destination MAC address
e. It compares the frames incoming interface to the source MAC entry

Answer 1

a.It compares the unicast destination address to the bridging, or MAC address table.

Question 2

Which of the following statements describes part of the process of how a LAN switch decides to forward a frame destined for a broadcast MAC address
a. It compares the unicast destination address to the bridging, or MAC address, table.

b. It compares the unicast source address to the bridging, or MAC address, table
c. It forwards the frame out all interfaces in the same vlan except for the incoming interface
d. It compares the the destination IP address to the destination MAC address.
e. It compares the frames incoming interface to the source MAC entry in the MAC address table.

Answer 2

c.It forwards the frame out all interfaces in the same vlan except for the incoming interface

Question 3

Which of the following statements best describes what a switch does with a frame destined for a unknown unicast address?

a. It forwards out all interfaces in the same VLAN except for the incoming interface.
b. It forwards the frame out the one interface identified by the matching entry in the
MAC address table.
c. It compares the destination IP address to the destination MAC address.
d. It compares the frame’s incoming interface to the source MAC entry in the MAC address table.

Answer 3

.a. It forwards out all interfaces in the same VLAN except for the incoming interface.

Question 4

Which of the following comparisons does a switch make when deciding whether a new MAC address should be added to its MAC address table?

a. It compares the unicast destination address to the bridging, or MAC address, table.
b. It compares the unicast source address to the bridging, or MAC address, table.
c. It compares the VLAN ID to the bridging, or MAC address, table.
d. It compares the destination IP address’s ARP cache entry to the bridging, or MAC address, table.

Answer 4

b. It compares the unicast source address to the bridging, or MAC address, table.

Question 5

5. PC1, with MAC address 1111.1111.1111, is connected to Switch SW1’s Fa0/1 interface. PC2, with MAC address 2222.2222.2222, is connected to SW1’s Fa0/2 interface. PC3, with MAC address 3333.3333.3333, connects to SW1’s Fa0/3 interface. The switch begins with no dynamically learned MAC addresses, followed by PC1 sending a frame with a destination address of 2222.2222.2222. If the next frame to reach the switch is a frame sent by PC3, destined for PC2’s MAC address of 2222.2222.2222, which of the following are true? (Choose two answers.)
   a. The switch forwards the frame out interface Fa0/1.
   b. The switch forwards the frame out interface Fa0/2.
   c. The switch forwards the frame out interface Fa0/3.
   d. The switch discards (filters) the frame.

Answer 5

a. The switch forwards the frame out interface Fa0/1.

b. The switch forwards the frame out interface Fa0/2.

Question 6

6. Which of the following devices would be in the same collision domain as PC1?
   a. PC2, which is separated from PC1 by an Ethernet hub
   b. PC3, which is separated from PC1 by a transparent bridge
   c. PC4, which is separated from PC1 by an Ethernet switch
   d. PC5, which is separated from PC1 by a router

Answer 6

a. PC2, which is separated from PC1 by an Ethernet hub

Question 7

7. Which of the following devices would be in the same broadcast domain as PC1? (Choose three answers.)
   a. PC2, which is separated from PC1 by an Ethernet hub
   b. PC3, which is separated from PC1 by a transparent bridge
   c. PC4, which is separated from PC1 by an Ethernet switch
   d. PC5, which is separated from PC1 by a router

Answer 7

a. PC2, which is separated from PC1 by an Ethernet hub
b. PC3, which is separated from PC1 by a transparent bridge
c. PC4, which is separated from PC1 by an Ethernet switch

Question 8

8. Which of the following Ethernet standards support a maximum cable length of longer than 100 meters? (Choose two answers.)
   a. 100BASE-T
   b. 1000BASE-LX
   c. 1000BASE-T
   d. 100BASE-FX

Answer 8

b. 1000BASE-LX

d. 100BASE-FX

Question 9

9. A Cisco LAN switch connects to three PCs (PC1, PC2, and PC3), each directly using a cable that supports Ethernet UTP speeds up through 1000 Mbps (1 Gbps). PC1 uses a NIC that supports only 10BASE-T, while PC2 has a 10/100 NIC, and PC3 has a 10/100/1000 NIC. Assuming that the PCs and switch use IEEE autonegotiation, which PCs will use half-duplex?
   a. PC1
   b. PC2
   c. PC3
   d. None of the PCs will use half-duplex.

Answer 9

d. None of the PCs will use half-duplex.

Question 10

LAN switches receive Ethernet frames and then make a switching decision: either forward
the frame out some other port(s) or ignore the frame. To accomplish this primary mission,
switches perform three actions:

Answer 10

1. Deciding when to forward a frame or when to filter (not forward) a frame, based on
   the destination MAC address.
2. Learning MAC addresses by examining the source MAC address of each frame
   received by the switch.
3. Creating a (Layer 2) loop-free environment with other switches by using Spanning
   Tree Protocol (STP).