Exam Prep Questions

Question 1

What is maintained in a switch's forwarding table?

  • A. A device's IP address and the IP network on which the device resides

  • B. A device's MAC address and the physical segment on which that device resides

  • C. The MAC addresses and the best interfaces to use to forward a frame to a destination MAC address

  • D. The IP network and MAC address of devices

A1:

The correct answer is C. Forwarding tables maintain MAC addresses. In addition, forwarding tables maintain the best interfaces to use to forward a frame to a destination MAC address. Answer A is incorrect because a bridge does not maintain IP addresses in its forwarding table. IP is a Layer 3 protocol and is used by routers, not bridges. Answer B is a trick answer because it is partially correct. However, bridges do not maintain the physical segment on which a device resides. Bridges only maintain the next physical segment to forward a frame en route to the device's physical segment. In some cases, the device will exist on this physical segment, but not in all cases. Answer D is incorrect because bridges do not maintain IP network information.

Question 2

What is the name of the protocol used to eliminate loops ?

  • A. Switching

  • B. ISL

  • C. Frame tagging

  • D. Spanning Tree Protocol

A2:

The correct answer is D. The Spanning Tree Protocol is used to remove circular routes in bridged and switched networks. Answer A is incorrect because switching is a Layer 2 technology, not a protocol. Answer B is incorrect because interswitch link (ISL) is used to allow VLANs to span multiple physical switches. Answer C is incorrect because frame tagging is a process used to identify the VLAN of a frame between switches.

Question 3

Which of the following switching methods provides the greatest frame throughput?

  • A. Store-and-forward switching

  • B. Frame-tag switching

  • C. Cut-through switching

  • D. ISL switching

A3:

The correct answer is C. Cut-through switching provides high-throughput frame switching because it reads only a portion of the frame before making the forwarding decision. Cut-through switching does not provide error checking. Answer A is incorrect because store-and-forward switching has slower frame throughput rates than cut-through switching because of its error-checking capabilities and because it reads the entire frame before making a forwarding decision. Answer B is incorrect because frame-tag switching does not exist; frame tagging is a process used to identify a frame's VLAN between switches. Answer D is incorrect because it is used to allow VLANs to span multiple switches as well.

Question 4

Which of the following are advantages of VLANs? (Choose the two best answers.)

  • A. They reduce switching overhead.

  • B. They increase switching throughput.

  • C. They simplify the adding, moving, and changing of users.

  • D. They allow users to be grouped by functional area, not physical location.

A4:

The correct answers are C and D. VLANs increase the flexibility of assigning users to LANs. This increased simplicity allows users to be grouped by functional area rather than physical location, because VLANs can span multiple switches. Answer A is incorrect because VLANs do not reduce the amount of overhead required to switch a frame. Answer B is incorrect because VLANs do not provide any increased switching throughput.

Question 5

What must you do to allow a VLAN to span two or more switches?

  • A. Set up a VTP domain.

  • B. Set up a trunk connection.

  • C. Configure the duplex setting on the ports.

  • D. Configure port security on the switch.

A5:

The correct answer is B. A trunk connection must be established in order for a VLAN to span multiple switches. Trunk ports recognize frame tags and are therefore able to carry information on multiple VLANs. Answer A is incorrect because a VTP domain is not necessary for switches to share VLAN information. Answer C is incorrect because the duplex setting does not have to be configured manually to connect two switches. Answer D is incorrect because port security is not necessary for a VLAN to span switches.

Question 6

Which of the following are advantages of using VTP in a switching environment? (Choose the two best answers.)

  • A. It enables VLANs to span multiple switches.

  • B. It simplifies the management of VLANs.

  • C. It simplifies the scalability of the switched network.

  • D. It allows switches to read frame tags.

A6:

The correct answers are B and C. VTP simplifies the management of VLANs because configuration information is propagated automatically throughout the switching fabric when changes are made. Without VTP, each switch would have to be configured manually; therefore, VTP makes it easier to scale to a larger switched environment. Answer A is incorrect because VTP is not necessary for VLANs to span multiple switches. Answer D is incorrect because VTP does not allow the switch to read frame tags.

Question 7

What is ISL used for?

  • A. To allow an Ethernet interface to understand frame tags

  • B. To make two Ethernet interfaces appear as one

  • C. To connect an Ethernet switch with a high-speed core switch such as ATM

  • D. To allow simultaneous routing and switching

A7:

The correct answer is A. ISL allows an Ethernet interface to understand frame tags, which identify the VLAN to which a packet belongs. For this reason, an ISL interface can participate in multiple VLANs, which is necessary for a trunk connection. Answer B is incorrect because ISL can actually have the opposite effect of this ”a single Ethernet interface may appear to be several by having multiple Layer 3 addresses. Answers C and D are incorrect because these are not functions of ISL.

Question 8

What is the purpose of VTP pruning?

  • A. To detect loops in the switching fabric

  • B. To disable a trunk connection that creates a bridging loop

  • C. To simplify the management of VLANs

  • D. To prevent flooding unnecessary traffic across trunk connections

A8:

The correct answer is D. VTP pruning is used to prevent flooding of unnecessary traffic across trunk connections. Answer A is incorrect because this is a function of the Spanning Tree Protocol. Answer B is incorrect because this is not the purpose of VTP pruning. Answer C is incorrect because this is the purpose of the VTP, not VTP pruning.

Question 9

When a network has multiple bridges and is using Spanning Tree Protocol, how is the root bridge determined?

  • A. The first bridge to initiate service becomes the root bridge.

  • B. The bridge with the lowest ID number assumes the root bridge role.

  • C. The bridge with the lowest MAC address is always the root bridge.

  • D. The bridge with the highest serial number is the root bridge.

A9:

The correct answer is B. The bridge's ID number is a combination of its MAC address and its assigned priority number. The bridges broadcast their ID numbers and the one with the lowest ID becomes the root. If two bridges have the same priority number then the one with the lower MAC address becomes the root. Answer A is not correct because the first bridge to enter service may or may not be an appropriate root bridge. C is incorrect because the root bridge is determined ID number, which is a combination of the MAC address and priority number. Answer D is incorrect for the same reason.

Question 10

A network administrator wants to pass traffic between two VLANs on the same switch. What will he need to accomplish this?

  • A. Nothing. If VLANs are on the same switch, the administrator can simply turn on cross filtering by MAC address.

  • B. A bridge running Spanning Tree Protocol.

  • C. A router.

  • D. A second switch connecting the two VLANs.

A10:

Answer C is correct. A router is required for two VLANs to pass traffic, even if they are on the same switch. Answer A is incorrect because there is no cross filtering option on a Layer 2 switch. Answer B is incorrect because a single bridge in this configuration would pass all traffic between the two VLANs, negating the entire purpose of the VLANs. The spanning tree protocol would make no difference where only one bridge is employed. Answer D is incorrect for the same reason answer B is incorrect.




CCNA Exam Cram[tm] 2 (Exams 640-821, 640-811, 640-801)
CCNA Exam Cram[tm] 2 (Exams 640-821, 640-811, 640-801)
ISBN: 789730197
EAN: N/A
Year: 2005
Pages: 155

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