Building Redundant Switched Topologies

Question 1

How does Ethernet recognize and eliminate looping of frames?

A. It does not.

B. Time to Live mechanism

C. Hop limit mechanism.

D. By using VLANs.

Answer 1

A. It does not.

Question 2

What could cause a potential problem when a redundant physical connection exists between two or more switches that share a common network segment?

A. Layer 2 loops

B. Layer 3 loops

C. Layer 3 routing

D. There is no problem.

Answer 2

A. Layer 2 loops

Question 3

How does STP prevent forwarding loops at OSI Layer 2?

A. TTL

B. MAC address forwarding

C. collision avoidance

D. port blocking

Answer 3

D. port blocking

Question 4

Where is RSTP defined?

A. IEEE 802.1w

B. IEEE 802.1s

C. IEEE 802.1d

D. IEEE 802.1p

Answer 4

A. IEEE 802.1w

Question 5

Which two characteristics does BPDU guard offer? (Choose two.)

A. If a BPDU is received, it errdisables the port.

B. It is usually used in a combination with PortFast.

C. It provides immediate transition to the forwarding state.

D. If a BPDU is sent, it shuts down the port.

E. BPDU guard is never used in a combination with PortFast.

Answer 5

A. If a BPDU is received, it errdisables the port.

B. It is usually used in a combination with PortFast.

The correct answers are: “If BPDU is received, it disables the port,” and “Usually used in a combination with PortFast.” Other answers are not correct.

Question 6

Which two RSTP port roles have not been changed compared to 802.1D? (Choose two.)

A. root

B. designated

C. alternate

D. discarding

E. learning

F. listening

G. nondesignated

Answer 6

A. root

B. designated

Question 7

In network design, can you include physical loops between switches?

A. Yes, to provide redundancy.

B. No, you should never include physical loops.

C. Yes, to provide better scalability.

D. No, you should first disable STP

Answer 7

A. Yes, to provide redundancy.

Question 8

Which BID would win election as the root, assuming that the switches with these BIDs were in the same network?

A. 32768:0200.1111.1111

B. 32768:0200.2222.2222

C. 4096:0200.1111.1111

D. 4096:0200.2222.2222

Answer 8

C. 4096:0200.1111.1111

Question 9

Which switch would win election as the root, assuming that the switches with these MAC addresses and priorities were in the same network?

A. MAC address 0200.1111.1111, priority 32768

B. MAC address 0200.2222.2222, priority 1

C. MAC address 0200.1111.1111, priority 0

D. MAC address 0200.2222.2222, priority 65535

Answer 9

C. MAC address 0200.1111.1111, priority 0

Question 10

Which risk is posed by operating a switched network with redundant paths?

A. Layer 2 loops

B. CRC errors

C. late collisions

D. interface input errors

Answer 10

A. Layer 2 loops

Question 11

Which of these is an STP port state but not an RSTP port state?

A. forwarding

B. learning

C. listening

D. discarding

Answer 11

C. listening

Question 12

Which option identifies the STP bridge priority range?

A. 0 to 65535

B. 0 to 32768

C. 1 to 65535

D. 1 to 32768

Answer 12

A. 0 to 65535

Question 13

What are two PortFast characteristics? (Choose two.)

A. configured on access ports connected to user device

B. configured on trunk ports connected to another switch

C. immediate transition to forwarding state

D. if BPDU is received, it disables the port

E. never used in a combination with BPDU guard

Answer 13

A. configured on access ports connected to user device

C. immediate transition to forwarding state

Question 14

Which feature of PVST+ is not available in RSTP?

A. fast convergence on topology changes

B. per-port STP

C. per-VLAN STP instance

D. edge ports

Answer 14

C. per-VLAN STP instance