CCNA Exam Preparation & Cisco E-Book

CCNA EXAM PREPARATION (ActualTests.com)

2009-03-08T13:05:00.001-07:00

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QUESTION 121
Part of the Certkiller switched LAN is shown below:

Based on the information show above, which device will provide the spanning-tree designated port role for the Certkiller network segment that services the printers?
A. Switch Certkiller A
B. Hub Certkiller E
C. Switch Certkiller C
D. Switch Certkiller B
E. Switch Certkiller D
F. None of the switches will provide the designated port role
Answer: C
Explanation:
Designated port A designated port is one that has been determined as having the best (lowest) cost. A designated port will be marked as a forwarding port.

QUESTION 122
The Certkiller network administrator needs to a switch named CK1 to become the root bridge for a redundant path switched network. What can be done to ensure that CK1 will always assume the role as the root bridge?
A. Assign the switch a higher MAC address than the other switches in the network have
B. Establish a direct link from the switch to all other switches in the network
C. Configure the switch full-duplex operation and configure the other switches for half-duplex operation
D. Configure the switch so that it has lower priority than other switches in the network
E. None of the above
Answer: D
Explanation:
Switch having lowest bridge ID will become the root bridge. The bridge ID is how STP keeps track of all the switches in the network. It is determined by a combination of the bridge priority (32,768 by default on all Cisco switches) and the base MAC address. The bridge with the lowest bridge ID becomes the root bridge in the network. To elect the desired switch as a root bridge, set the bridge priority lowest than other switch.

QUESTION 123
Four Certkiller PCs connect to a single switch as shown below:

In the Certkiller network shown above, switch Certkiller 1 has just been restarted and has passed the POST routine. Host Certkiller A (the one on the left) sends its initial frame to Host Certkiller C. What is the first thing the switch will do as regards to populating the switching table?
A. Switch Certkiller 1 will add 192.168.23.12 to the switching table
B. Switch Certkiller 1 will add 192.168.23.4 to the switching table
C. Switch Certkiller 1 will add 000B.DB95.2EE9 to the switching table
D. Switch Certkiller 1 will add 000A.8A47.E612 to the switching table
E. None of the above
Answer: D

QUESTION 124
CK1 is a switch in the Certkiller network. Why will CK1 never learn the broadcast address?
A. Broadcast frames are never sent to switches
B. A broadcast frame is never forwarded by a switch
C. Broadcasts only use network layer addressing
D. A broadcast address will never be the source address of a frame
E. Broadcast addresses use an incorrect format for the switching table
F. None of the above
Answer: D
Explanation:
There are three different address types:
* Unicast : One source to One destination
* Broadcast: One source to multiple destination
* Multicast: One source to multiple destination joined to group On unicast or broadcast or multicast communication, the source address is always the unicast address but the destination address can be unicast, broadcast or multicast.

QUESTION 125
DRAG DROP
You work as a network technician at Certkiller .com. Your boss, Mrs. Certkiller, is interested in basic switch configurations. Match the IOS command with the appropriate purpose.

Answer:

Explanation:
enable : This command is used to enter into User Privileges Mode
configure terminal: This command is used to enter into global configuration mode
hostname : This command is used to set the hostname of switch
ip default-gateway : This command should enter should enter on global configuration mode to set default gateway of switch.
Interface vlan 1 : Enters into the vlan 1 SVI (Switched Virtual Interface) configuration mode, where you can enter vlan 1 SVI interface specific configuration
ip add x.x.x.x y.y.y.y : Use to assign the ip address on interface
no shutdown: Brings the interface on up state from administratively down state

QUESTION 126
A Certkiller LAN is displayed in the diagram below:

Host Certkiller B sends a frame to host Certkiller C. What will the switch do with the frame?
A. Drop the frame
B. Send the frame out all ports except port 0/2
C. Return the frame to host Certkiller B
D. Send an ARP request for host Certkiller C
E. Send an ICMP Host Unreachable message to Host Certkiller B
F. Record the destination MAC address in the switching table and send the frame directly to Host Certkiller C
Answer: B
Explanation:

QUESTION 127
The following was seen on a Certkiller switch.

Certkiller 1 receives the frame with the addressing shown. According to the command output shown in the exhibit, how will Certkiller 1 handle this frame?
A. It will forward the frame out port Fa0/3 only.
B. It will drop the frame.
C. It will flood the frame out all ports except Fa0/3.
D. It will flood the frame out all ports.
Answer: C
Explanation:
Switches learn the MAC addresses of PCs or workstation the are connected to their switch ports by examining the source address of frames that are received on that port. Machines may have been removed from a port ,turned off, or moved to another port on the same switch or a different switch. This could cause confusion in frame forwarding the MAC address entry is automatically discard or ages out after 300 seconds if there is not MAC address of destination host in MAC table, switch sends broadcast to all ports except the source to find out the destination host. In the output there is no MAC address of the given host so the switch will flood to all ports except the source port, which is port fa 0/3.

QUESTION 128
Refer to the topology and MAC address table shown in the exhibit:

Host Certkiller A sends a data frame to host Certkiller D. What will the Certkiller 1 switch do when it receives the frame from host A?
A. The Certkiller 1 switch will flood the frame out of all ports except for port Fa0/3.
B. The Certkiller 1 switch will discard the frame and send an error message back to host Certkiller A.
C. The Certkiller 1 switch will add the destination address of the frame to the MAC address table and forward the frame to host D.
D. The Certkiller 1 switch will add the source address and port to the MAC address table and forward the frame to host Certkiller D.
E. None of the above
Answer: D
Explanation:
When switch receives the data frame from the host not having the MAC address already in the MAC table, it will add the MAC address to the source port on the MAC address table and sends the data frame. If the switch already has the MAC address in it's table for the destination, as it is in this case, it will forward the frame directly to the destination port. If it was not already in it's MAC table, then they frame would have been flooded out all ports except for the port that it came from.

QUESTION 129
Switch Certkiller A receives the frame with the addressing shown in the exhibit.

According to the command output also shown in the exhibit, how will Switch Certkiller A handle this frame?
A. It will flood the frame out all ports except Fa0/3.
B. It will forward the frame out port Fa0/3 only.
C. It will flood the frame out all ports.
D. It will forward the frame out port Fa0/6 only.
E. It will drop the frame.
F. None of the above
Answer: D

Explanation:
When frame receives the frame, it checks the source address on MAC table if MAC address found in MAC table it tries to forward if not in MAC table adds the Address on MAC table. After checking the source address, it checks the destination address on MAC table, if MAC address found on MAC table it forwards to proper ports otherwise floods on all ports except the source port. In this case, the MAC address shown is already in the table so it will be forwarded directly.

QUESTION 130
Please study the exhibit shown below carefully.

Why does the switch have two MAC addresses assigned to the FastEthernet 0/1 port in the switch address table?
A. Either Host3 or Host4 has just had the NIC replaced.
B. Data from Host3 and Host4 has been received by switch port FastEthernet 0/1.
C. Host3 and Host4 are on two different VLANs.
D. Data from two of the devices connected to the switch has been sent to Host3.
E. None of the above
Answer: B
Explanation:
Switches learn the MAC addresses of PCs or workstations that are connected to their switch ports by examining the source address of frames that are received on that port. When more than one device is attached to a switch port, such as via the use of a hub as shown in this example, the switch will retain the MAC address of each of the known devices on that port.

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QUESTION 111

Which two statements describe the operation of the CSMA/CD access method, which is in use on the Certkiller network? (Choose two)

A. After a collision, the station that detected the collision has first priority to resend the lost data.

B. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.

C. In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.

D. The use of hubs to enlarge the size of collision domains is one way to improve the operation of the CSMA/CD access method.

E. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.

F. After a collision, all stations involved run an identical backoff algorithm and then synchronize with each other prior to transmitting data.

Answer: B, E

Explanation:

Ethernet networking uses Carrier Sense Multiple Access with Collision Detect (CSMA/CD), a protocol that helps devices share the bandwidth evenly without having two devices transmit at the same time on the network medium. CSMA/CD was created to overcome the problem of those collisions that occur when packets are transmitted simultaneously from different nodes. And trust me, good collision management is crucial, because when a node transmits in a CSMA/CD network, all the other nodes on the network receive and examine that transmission. Only bridges and routers can effectively prevent a transmission from propagating throughout the entire network! So, how does the CSMA/CD protocol work? Like this: when a host wants to transmit over the network, it first checks for the presence of a digital signal on the wire. If all is clear (no other host is transmitting), the host will then proceed with its transmission. But it doesn't stop there. The transmitting host constantly monitors the wire to make sure no other hosts begin transmitting. If the host detects another signal on the wire, it sends out an extended jam signal that causes all nodes on the segment to stop sending data (think, busy signal). The nodes respond to that jam signal by waiting a while before attempting to transmit again. Backoff algorithms determine when the colliding stations can retransmit. If collisions keep occurring after 15 tries, the nodes attempting to transmit will then time out.

QUESTION 112

Which three statements are true about the operation of a full-duplex Ethernet network, which is being used in the Certkiller LAN? (Choose three)

A. Ethernet hub ports are preconfigured for full-duplex mode.

B. The host network card and the switch port must be capable of operating in full-duplex mode.

C. There are no collisions in full-duplex mode.

D. In a full-duplex environment, the host network card must check for the availability of the network media before transmitting.

E. A dedicated switch port is required for each full-duplex node.

Answer: B, C, E

Explanation:

Half-duplex Etherne

t is defined in the original 802.3 Ethernet and Cisco says you only use one wire pair with a digital signal running in both directions on the wire. It also uses the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a collision does occur. If a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions. Half-duplex Ethernet-typically 10BaseT-is only about 30 to 40 percent efficient as Cisco sees it, because a large 10BaseT network will usually only give you 3- to 4Mbps-at most. Full-duplex Ethernet uses two pairs of wires, instead of one wire pair like half duplex. Also, full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device, which means that with full-duplex data transfer, you get a faster data transfer compared to half duplex. And because the transmitted data is sent on a different set of wires than the received data, no collisions occur. The reason you don't need to worry about collisions is because now Full-duplex Ethernet is like a freeway with multiple lanes instead of the single-lane road provided by half duplex. Full-duplex Ethernet is supposed to offer 100 percent efficiency in both directions; this means you can get 20Mbps with a 10Mbps Ethernet running full duplex, or 200Mbps for FastEthernet.

QUESTION 113

Exhibit:

You work as a network technician at Certkiller .com. Please study the exhibit carefully. Which statement describes the operational state of the Certkiller 2 FastEthernet 0/0 interface?

A. The interface is operational and currently handling traffic.

B. The interface has failed because of a media error.

C. The interface requires a no shutdown command to be issued.

D. The interface is

generating protocol errors.

E. None of the above.

Answer: A

Explanation:

The interface is up indicates whether the interface hardware is currently active and whether it has been taken down by an administrator. "Disabled" indicates that the router hasreceived more than 5,000 errors in a keepalive interval, which is 10 seconds, by default. The line protocol indicates whether the software processes that handle the line protocol believe that the interface is usable (that is, whether keepalives are successful) or if it has been taken down by an administrator. For a complete list of the field descriptions of this command as well as troubleshooting information for Ethernet interfaces refer to the reference link listed below. Reference: "Troubleshooting Ethernet"

QUESTION 114

The Certkiller network administrator wants to use a router named CK1 to segment the local network. What are some of the advantages of using CK1 to segment the network? (Choose two)

A. Routers generally cost les

s than switches

B. Filtering can occur based on Layer 3 information

C. Broadcasts are not forwarded across the router

D. Broadcasts are eliminated

E. Adding a router to the network decreases latency

F. Routers can generally support more LAN ports than switches

Answer: B, C

Explanation:

When the router's interface receives the broadcast, it discard the broadcast without forwarding it on to other networks. Even though routers are known for breaking up broadcast domains by default, it's important to remember that they break up collision domains as well. There are two advantages of using routers in your network:

* They don't forward broadcasts by default.

* They can filter the network based on layer 3 (Network layer) information (e.g., IP address) by using IOS based firewall ie.
ACL Four router functions in your network can be listed as follows:

* Packet switching

* Packet filtering

* Internetwork communication

* Path selection

QUESTION 115

Which of the following devices can the Certkiller network administrator use to segment the LAN? (Choose all that apply)

A. Hubs

B. Repeaters

C. Switches

D. Bridges

E. Routers

F. Media Converters

G. All of the above

Answer: C, D, E

Explanation:

Switches and bridges forward broadcast but routers do not forward broadcasts by default (they can via the "ip helper-address" command). Switches, bridges and routers can segment an Ethernet collision domain via the use of VLAN's

Incorrect Answers:

A. Hubs is incorrect because a hub doesn't segment a network, it only allows more hosts on one. Hubs operate at layer one, and is used primarily to physically add more stations to the LAN.

B. This also incorrect because the job of a repeater is to repeat a signal so it can exceed distance limitations. It also operates at layer one and provides no means for logical LAN segmentation.

F. This is incorrect because media converters work by converting data from a different media type to work with the media of a LAN. It also operates at layer one and provides no means for logical LAN segmentation.

QUESTION 116

Within the Certkiller office, The Sales and Production networks are separated by a router as shown in the diagram below:

Which of the following statements most accurately describes the characteristics of the above networks broadcast and collision domains? (Select the two best answer choices)

A. There are two broadcast domains in the network.

B. There are four broadcast domains in the network.

C. There are six broadcast domains in the network.

D. There are four collision domains in the network.

E. There are five collision domains in the network.

F. There are seven collision domains in the network.

Answer: A, F

Explanation:

In this network we have a hub being used in the Sales department, and a switch being used in the Production department. Based on this, we have two broadcast domains: one for each network being separated by a router. For the collision domains, we have 5 computers and one port for E1 so we have 6 collision domains total because we use a switch in the Production Department so 5 are created there, plus one collision domain for the entire Sales department because a hub is being used.

QUESTION 117

The Certkiller corporate LAN consists of one large flat network. You decide to segment this LAN into two separate networks with a router. What will be the affect of this change?

A. The number of broadcast domains will be decreased.

B. It will make the broadcasting of traffic between domains more efficient between segments.

C. It will increase the number of collisions.

D. It will prevent segment

1's broadcasts from getting to segment 2.

E. It will connect segment 1's broadcasts to segment 2.

Answer: D

Explanation

A router does not forward broadcast traffic. It therefore breaks up a broadcast domain, reducing unnecessary network traffic. Broadcasts from one segment will not be seen on the other segment.

Incorrect Answers:

A. This will actually increase the number of broadcast domains from one to two.

B. All link level traffic from segment one to segment two will now need to be routed between the two interfaces of the router. Although this will reduce the traffic on the LAN links, it does also provide a less efficient transport between the segments.

C. Since the network size is effectively cut into half, the number of collisions should decrease dramatically.

E. Broadcasts from one segment will be completely hidden from the other segment.

QUESTION 118

You want to influence the root bridge selection within the Certkiller LAN. Which two values are used by spanning tree protocol to elect a root bridge? (Choose two.)

A. Amount of RAM

B. Speed of the links

C. IOS Version

D. MAC Address

E. Bridge Priority

F. IP Address

G. Router ID

Answer: D, E

Explanation:

Switch having lowest bridge ID will become the root bridge. The bridge ID is how STP keeps track of all the switches in the network. It is determined by a combination of the bridge priority (32,768 by default on all Cisco switches) and the base MAC address. The bridge with the lowest bridge ID becomes the root bridge in the network.

QUESTION 119

A Certkiller Ethernet switch receives a unicast frame with a destination MAC that IS listed in the switch table. What will this switch do with the frame?

A. The switch will forward the frame to a specific port

B. The switch will forward the frame to all ports except the port on which it was received

C. The switch will return a copy of the frame out the source port

D. The switch will not forward unicast frames

E. The switch will remove the destination MAC from the switch table

F. None of the above.

Answer: A

Explanation:

How Does the Switch Find Host MACs? Let's use the diagram below to help us understand how address learning process takes place.

Let's assume that we have just powered on the switch. It has nothing in its MAC table. We connect the cables from the hosts on the switch interfaces as shown in the diagram. Host A initiates a connection towards Host D, and the following takes place:

1. Host A (interface fe0/0) sends a frame to Host D (MAC address:0000.43c5.334c).

2. The switch inspects the Source Address in the frame and notes in its table the MAC address of Host A along with the Interface number from which the frame originated.

3. The switch inspects the Destination Address in the frame. Since it does not have Hosts D MAC address in its table, it constructs a broadcast frame and forwards out all interfaces except the interface from where the original frame arrived.

4. Host D identifies itself as the expected recipient and responds back to Host A. The switch receives the respond frame on interface fe0/11 and places the SA in its table along with the interface number where the frame came from.

5. From now on, further communication between the two hosts will be switched to the appropriate interfaces based on the MAC tables entries. This process takes place every time a new host is attached on the switch and initiates traffic. The switch tries to keep its MAC table up-to-date, therefore if some hosts do not initiate traffic for a certain amount of time, the switch removes them from its table and reinserts them when they begin sending traffic.

QUESTION 120

In which circumstance are multiple copies of the same unicast frame likely to be transmitted in the Certkiller Switched LAN?

A. During high traffic periods

B. In an improperly implemented redundant topology

C. After broken links are re-established

D. When upper-layer protocols require high reliability

E. When a dual ring topology is in use

F. None of the above

Answer: B

Explanation:

A redundant topology eliminates single points of failure, but it also causes broadcast storms, multiple frame copies, and MAC address table instability problems. Multiple Frame Copies--when a new switch is added, the other switches may not have learned its correct MAC address. The host may send a unicast frame to the new switch. The frame is sent through several paths at the same time. The new switch will receive several copies of the frame. This causes MAC database instability. MAC database instability results when multiple copies of a frame arrive on different ports of a switch. Layer 2 has no mechanism to stop the loop. This is the main reason for the Spanning Tree Protocol(STP) IEEE 802.1d which was developed to prevent routing loops. If multiple connections between switches are created for redundancy purposes, network loops can occur in an improperly designed topology. Spanning Tree Protocol (STP) is used to stop network loops while still permitting redundancy.

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QUESTION 101

The Certkiller internetwork shown in the diagram is experiencing network delays. On the basis of the information provided in the exhibit above, what is the problem?

A. The connection between Switch1 and Switch2 should be half-duplex.

B. The cable between Router1 and Switch1 should be a crossover.

C. The cable connecting Host A to Switch2 is too long.

D. The server is on a different subnet than router interface Fa0/0.

E. The cable between Switch1 and Switch2 should be straight-through.

F. None of the above

Answer: C

Explanation:

According to IEEE specifications, the maximum segment length of an Ethernet cable should not exceed 100 meters. The total distance between an Ethernet Transmitter and Receiver at the absolute end points of the network (maximum diameter from origin to final destination, if the wires were stretched out to form a straight line) should be no more than100 Meters (328 ft., 109 yards, or about the length of a football field). This limitation results from the timing of the Ethernet signals on the cable and not necessarily the cable characteristics, and is, therefore, a "hard" number.

QUESTION 102

What is the IEEE standard associated with Gigabit Ethernet? (Select two answer choices)

A. 802.11

B. 802.5

C. 802.3ab

D. 802.3ae

E. 802.3z

F. 802.3u

Answer: C, E

Explanation:

The IEEE 802.3z standard describes 1000BASE-SX. The 1000BaseT standard was released in June 1999, defined by IEEE 802.3ab. Incorrect Answers:

A. This describes the standard used for wireless networks.

B. This is the standard for token ring networks.

D. On June 17, 2002 the IEEE 802.3ae specification for 10 Gigabit Ethernet was approved as an IEEE standard by the IEEE Standards Association (IEEE-SA) Standards Board.

F. IEEE 802.3u describes the standard for 100BASE-TX.

QUESTION 103

Which of the following can lead to the contribution of LAN traffic congestion? (Select all that apply)

A. Too many hosts in a bro

adcast domain

B. Full duplex operation

C. Broadcast storms

D. Multicasting

E. Segmentation

F. Low bandwidth

Answer: A, C, F

Explanation:

Choice A is correct because the more hosts on a broadcast domain, the more traffic that is created. Choice Ccontributes to congestion because broadcast storms can become very problematic, and lead to complete network saturation. Multicasts are similar to broadcasts in their use on a LAN. Finally, if there is not enough bandwidth, traffic sessions can time out. This leads to new transmissions and the re-sending of data, which can lead to more congestion.

Incorrect Answers:

B, E. These are incorrect because full duplex operation and segmented networks actually result in less congestion.

D. Multicasting can actually alleviate congestion issues, as single streams of information can reach multiple hosts at the same time, instead of using a series of point to point connections.

QUESTION 104

On a half-duplex Ethernet LAN, two hosts attempt to send data simultaneously, resulting in a collision. Following this collision, what will the hosts do? (Select all valid answers)

A. The destination host sends a request to the source for retransmission.

B. The jam signal indicates

that the collision has been cleared.

C. The hosts will attempt to resume transmission after a time delay has expired.

D. An electrical pulse indicates that the collision has cleared.

E. The router on the segment will signal that the collision has cleared.

F. The hosts will do nothing, as the higher layers are responsible for data error correction and re-transmission.

Answer: C

Explanation:

When a host on an Ethernet LAN has information to send, the following steps are taken:

1. A device with a frame to send listens until Ethernet is not busy.

2. When the Ethernet is not

busy, the sender begins sending the frame.

3. The sender listens to make sure that no collision occurred.

4. Once the senders hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.

5. After the jamming is complete, each sender randomizes a timer and waits that long.

6. When each timer expires, the process starts over with step 1.

QUESTION 105

Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)

A. Full-duplex Ethernet uses CSMA/CD to prevent collisions.

B. Half-duplex Ethernet uses a loopback circuit to detect collisions.

C. A full-duplex Ethernet

card allows 20Mbps for data transmission.

D. Full-duplex Ethernet makes use of two pairs of wires for data.

E. An Ethernet hub can operate both half and full duplex simultaneously.

Answer: B, D

Explanation:

Half-duplex Ethernet send and receives on the same line, so a loopback needs to be set to detect collisions. Alternatively, full-duple Ethernet doesn't have to because it uses two pairs of wire, one to send and the other to receive. Collisions are not possible on full duplex Ethernet networks.

Incorrect Answers:

A. Full duplex uses both pairs of wires, so transmissions are sent on the first pair, and data that is received come in on the other pair. This prevents collisions.

C. Full duplex allows for data to be sent and received at the same time. It will not double the amount of bandwidth at any given

time. The speed of the Ethernet link will remain at 10/100.

E. Hubs are shared devices and can only support one mode, unlike switches.

QUESTION 106

Why is full-duplex Ethernet superior to its single-duplex counterpart? (Select two answer choices.)

A. It uses inexpensive hubs

B. It operates without collisions

C. It operates on switches

D. It provides faster data transfer

E. It utilizes fewer wiring pairs

Answer: B, D

Explanation:

Full duplex Ethernet allows concurrent sending and receiving, which allows the full bandwidth to be used for both sending and receiving. The result is a collision free network with increased throughput.

Incorrect Answers:

A, C. These are incorrect because full duplex doesn't require hubs or switches. Full duplex operation can be used on switch and router ports, as well as PC hosts.

E. This is incorrect because full duplex actually uses more wiring pairs. In full duplex, both wire pairs are used. Half duplex uses only a single pair.

QUESTION 107

When you compare the differences between half-duplex and full-duplex Ethernet, which of the following characteristics are exclusi

ve to half-duplex? (Select two answer choices)

A. Half-duplex Ethernet operates in a shared collision domain.

B. Half-duplex Ethernet operates in an exclusive broadcast domain.

C. Half-duplex Ethernet has efficient throughput.

D. Half-duplex Ethernet has lower effective throughput.

E. Half-duplex Ethernet operates in an exclusive collision domain.

Answer: A, D

Explanation:

A single device could not be sending a frame and receiving a frame at the same time because it would mean that a collision was occurring. So, devices simply chose not to send a frame while receiving a frame. That logic is called half-duplex logic. Ethernet switches allow multiple frames to be sent over different ports at the same time. Additionally, if only one device is connected to a switch port, there is never a possibility that a collision could occur. So, LAN switches with only one device cabled to each port of the switch allow the use of full-duplex operation. Full duplex means that an Ethernet card can send and receive concurrently.

Incorrect Answers:

B. Full duplex effectively doubles the throughput of half-duplex operation, because data can be both sent and received at the full 10/100 speed.

C, E. In half duplex operation, the network is shared between all devices in the collision domain.

QUESTION 108

Two stations on the Certkiller LAN transmit at the same time, resulting in a collision. What happens when a collision occurs on t

he network? (Choose all that apply)

A. Each device on the Ethernet segment stops transmitting for a short time.

B. A jam signal informs all devices that a collision occurred.

C. When data transmission resumes, the devices that were involved in the collision have priority to transmit.

D. The devices that are involved in the collision stops transmitting for a short time.

E. The collision invokes a random back-off algorithm.

Answer: B, D, E

Explanation:

When a host on an Ethernet LAN has information to send, the following steps are taken:

1. A device with a frame to send listens until Ethernet is not busy.

2. When the Ethernet is not busy, the sender begins sending the frame.

3. The sender listens to make sure that no collision occurred.

4. Once the sender

s hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.

5. After the jamming is complete, each sender randomizes a timer and waits that long.

6. When each timer expires, the process starts over with step 1. Incorrect Answers:

A. Only the stations involved in the collision stop transmitting for a short time, not all stations on the LAN.

C. No priority is given to any stations once a collision has occurred.

QUESTION 109

Which of the following are true of Ethernet technology?

A. Hosts use a logical ring topology.

B. Hosts use a logica

l bus topology

C. Hosts must wait for an electronic signal to transfer data.

D. Hosts are directly connected to a wiring concentrator called a MSAU.

E. None of the above

Answer: B

Explanation:

LAN topologies define the manner in which network devices are organized. Four common LAN topologies exist: bus, ring, star, and tree. These topologies are logical architectures, but the actual devices need not be physically organized in these configurations. Logical bus and ring topologies, for example, are commonly organized physically as a star. A bus topology is a linear LAN architecture in which transmissions from network stations propagate the length of the medium and are received by all other stations. Of the three most widely used LAN implementations, Ethernet/IEEE 802.3 networks, including 100BaseT, implement a bus topology, which is illustrated in Figure 2-3.

Figure2-3: Some networks implement a local bus topology.

QUESTION 110

With regard to Ethernet media access methods, which of the following are true? (Choose all that apply.)

A. A device waits for an electronic signal before transmitting.

B. A device listens and waits until the media is not busy before transmitting.

C. All devices on an Ethernet segment see data that passes on the network medium.

D. Only the sender and the receiver devices see data that passes on the network medium.

E. Ethernet networks allow you to configured devises with higher transmission priority.

Answer: B, C

Explanation:

Ethernet uses the CSMA/CD access method. CSMA/CD logic helps prevent collisions and also defines how to act when a collision does occur. The CSMA/CD algorithm words like this:

1. A device with a frame to send listens until the Ethernet is not busy.

2. When the Ethernet is not busy, the sender begins sending the frame.

3. The sender listens to make sure that no collision occurred.

4. Once the senders hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.

5. After the jamming is complete, each sender randomizes a timer and waits that long. 6 When each timer expires, the process starts over with Step 1. So, all devices on the Ethernet need to use CSMA/CD to avoid collisions and to recover when inadvertent collisions occur.

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QUESTION 91
Part of the Certkiller network is shown below:

Based on the diagram shown above, what kind of cable should be used to make each connection that is identified by the numbers shown?
A. 1 - Ethernet crossover cable
2 - Ethernet straight-through cable
3 - fiber optic cable
4 - rollover cable
B. 1 - Ethernet rollover cable
2 - Ethernet crossover cable
3 - serial cable
4 - null modem cable
C. 1 - Ethernet straight-through cable
2 - Ethernet straight-through cable
3 - serial cable
4 - rollover cable
D. 1 - Ethernet straight-through cable
2 - Ethernet crossover cable
3 - serial cable
4 - rollover cable
E. 1 - Ethernet straight-through cable
2 - Ethernet crossover cable
3 - serial cable
4 - Ethernet straight-through cable
Answer: C
Explanation:
When connecting other devices to a switch, such as a router or workstations, a straight through cable is used. The only exception to this rule is when you are connecting another switch to a switch, in which case a cross over cable should be used. For a serial connection to another router or to a WAN, a serial cable should be used. Finally, when connecting directly to the console port of a Cisco device, a rollover cable should be used. This cable is also commonly referred to as a console cable.

QUESTION 92
What kind of cable should be used to establish a trunked line between two Catalyst switches?
A. A straight-through cable
B. An EIA/TIA-232 serial cable
C. An auxiliary cable
D. A modem cable
E. A cross-over cable
Answer: E
Explanation:
A crossover cable is used to connect two of the same device types, or devices from the same OSI layer.

QUESTION 93
The Certkiller network Topology is displayed in the exhibit below:

A switch has been configured for three different VLANs: VLAN 2, VLAN 3, and VLAN 4. For the purposes of communication between VLANs a router is to be added. Host from one VLAN should be able to reach the hosts in the other VLANs. Based on this requirement, what type of connection is acceptable between the router
and switch?
A. 10 Mbps Ethernet
B. 56 kbps serial
C. 100 Mbps Ethernet
D. 1,544 Mbps serial
E. 1000 Mbps Ethernet
Answer: C, E
Explanation:
For all hosts to be able to reach each other, inter-VLAN routing will need to be configured. In order to provide Inter-VLAN routing between the router and the switch, a trunk will need to be set up. This trunk can be either ISL or 802.1Q. On a router, the interface that is to be used as the trunk can be 100 Mbps Ethernet, Gigabit Ethernet, or 10 Gigabit Ethernet. Therefore, only choices C or E are correct.

QUESTION 94
Part of the Certkiller LAN is shown below:

Based on the diagram shown above, which set of terms correctly identifies the cable types shown in the exhibit? (Assume that none of the switches are set to
autoconfigure)
A. A: straight-through
B: straight-through
C: rollover
B. A: crossover
B: crossover
C: rollover
C. A: crossover
B: straight-through
C: straight-through
D. A: crossover
B: straight-through
C: rollover
E. A: straight-through
B: crossover
C: rollover
Answer: D
Explanation:
Crossover Cables are Used to Connect :
Host to Host (Peer to Peer) Networking
Switch to Switch
Hub to Hub
Computer to Router's Ethernet Port
Straight through Cable:
Host to Switch
Host to Hub
Switch to Router
Serial Cable:
Router's Serial Port to Serial Port
Rollover Cable :
To connect Router/Switch Console port.
Here one switch is connected with another switch using a crossover cable. The switch connected with the router uses a straight through cable and the PC Connects to the router's console port using the console rollover cable.

QUESTION 95
The Certkiller network administrator is connecting PC hosts Certkiller A and Certkiller B directly through their Ethernet interfaces as shown in the graphic. Ping attempts between the hosts are unsuccessful. What can be done to provide connectivity between the hosts? (Choose two.)

A. The subnet masks should be set to 255.255.255.0.
B. The hosts must be reconfigured to use private IP addresses for direct connections of this type.
C. A default gateway needs to be set on each host.
D. A rollover cable should be used in place of the straight-through cable
E. A crossover cable should be used in place of the straight-through cable.
F. The subnet masks should be set to 255.255.255.192.
Answer: A, E
Explanation:
This problem is due to the misconfiguration of subnet mask as well as the fact that a straight-through cable is used to connect the two devices. To ensure connectivity, the correct subnet mask needs to be used so that the two devices are in the same subnet and when connecting two PC's back to back a crossover cable should be used.

QUESTION 96
Assuming you build networks to exact specifications, what is the recommended maximum length a 10BaseT cable can be before it has to be segmented or repeated?
A. 100 meters
B. 100 feet
C. 100 yards
D. 200 meters
E. None of the above
Answer: A
Explanation:
The distance standards are in meters and 10BaseT has a distance restriction of 100 meters. If you go further then that, you compromise data integrity. 10BastT is the predominant cable type used in Ethernet networks.

QUESTION 97
Exhibit:

You need to connect the network devices in a new Certkiller office. What types of cables should you use to make the connections that are shown?
A.
A-rollover
B-straight-through
C-straight-through
D-rollover
E-crossover
B.
A-straight-through
B-straight-through
C-rollover
D-straight-through
E-straight-through
C.
A-straight-through
B-crossover
C-rollover
D-straight-through
E-straight-through
D.
A-crossover
B-straight-through
C-crossover
D-straight-through
E-crossover
E.
A-crossover
B-straight-through
C-rollover
D-straight-through
E-straight-through
Answer: E
Explanation:
Crossover Cables are Used to Connect :
Host to Host (Peer to Peer) Networking
Switch to Switch
Hub to Hub
Computer to Router's Ethernet Port
Straight through Cable:
Host to Switch
Host to Hub
Switch to Router
Serial Cable:
Router's Serial Port to Serial Port
Rollover Cable :
To connect Router/Switch Console port.

QUESTION 98
Exhibit:

Host Certkiller A has just been added to the network. Which type of cable should be used between Switch Certkiller 2 and host Certkiller A?
A. Crossover cable
B. Rollover cable
C. Straight-through cable
D. Console cable
E. Fiber optic cable
F. None of the above
Answer: C
Explanation:
Straight-through cables are used to connect hosts to a switch (or hub) and routers to a switch (or hub). See the table below:

QUESTION 99
The Certkiller LAN is upgrading all devices to operate in full duplex. Which statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?
A. Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive
B. Full-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet provides a point-to-point link
C. Full-duplex Ethernet can provide higher throughout than can half-duplex Ethernet of the same bandwidth
D. Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex ethernet uses a jam signal
E. None of the above
Answer: C

QUESTION 100
A network administrator wants to control which user hosts can access the network based on their MAC address. What will prevent workstations with unauthorized MAC addresses from connecting to the network through a switch?
A. BPDU
B. Port security
C. RSTP
D. STP
E. VTP
F. Blocking mode
Answer: B
Explanation:
Understanding How PortSecurity Works: You can use port security to block input to an Ethernet, Fast Ethernet, or Gigabit Ethernet port when the MAC address of the station attempting to access the port is different from any of the MAC addresses specified for that port. Alternatively, you can use port security to filter traffic destined to or received from a specific host based on the host MAC address. When a secure port receives a packet, the source MAC address of the packet is compared to the list of secure source addresses that were manually configured or autoconfigured (learned) on the port. If a MAC address of a device attached to the port differs from the list of secure addresses, the port either shuts down permanently (default mode), shuts down for the time you have specified, or drops incoming packets from the insecure host. The port's behavior depends on how you configure it to respond to a security violation. If a security violation occurs, the Link LED for that port turns orange, and a link-down trap is sent to the Simple Network Management Protocol (SNMP) manager. An SNMP trap is not sent if you configure the port for restrictive violation mode. A trap is sent only if you configure the port to shut down during a security violation.

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QUESTION 81
While troubleshooting a network connectivity problem, a Certkiller technician observes steady link lights on both the workstation NIC and the switch port to which the workstation is connected. However, when the ping command is issued from the workstation, the output message "Request timed out." is displayed. At which layer of the 7-layer OSI model does the problem most likely exist?
A. The data link layer
B. The application layer
C. The protocol layer
D. The access layer
E. The session layer
F. The network layer
G. None of the above
Answer: F
Explanation:
Network Layer:
The Network layer (also called layer 3) manages device addressing, tracks the location of devices on the network, and determines the best way to move data, which means that the Network layer must transport traffic between devices that aren't locally attached. Routers (layer 3 devices) are specified at the Network layer and provide the routing services within an internetwork. Request Time out, Destination Unreachable etc error comes from Network Layer problem.

QUESTION 82
A host is connected to the Certkiller network as displayed below:

The two connected ports on the switch are not turning orange or green. What would be the most effective steps to troubleshoot this physical layer problem? (Choose three)
A. Ensure that the Ethernet encapsulations match on the interconnected router and switch ports.
B. Ensure that cables A and B are straight-through cables.
C. Ensure cable A is plugged into a trunk port.
D. Ensure that switch has power.
E. Reboot all of the devices.
F. Reseat all cables.
Answer: B, D, F
Explanation:
Straight-through cables are used to connect hosts to a switch (or hub) and routers to a switch (or hub). See the table below:

Incorrect Answers:
A: This would mean that there was a layer 2 issue, not layer 1. If the problem was related to the encapsulation, the lights on the switch would indicate layer 1 activity.
C: A trunk port is not required, and again if this was the problem the link lights on the
switch would be on.
E: This should only be used as a last resort, as this will affect all users on the switch.

QUESTION 83
Which line from the output of the show ip interface command indicates that there is a Layer 1 problem?
A. Serial0/1 is up, line protocol is down
B. Serial0/1 is down, line protocol is down
C. Serial0/1 is up, line protocol is up
D. Serial0/1 is administratively down, line protocol is down
E. None of the above
Answer: B
Explanation:
When the physical interface itself is down, then the problem is related to layer 1. When it is up, but the line protocol is down, then the problem is related to layer 2.

QUESTION 84
At which layer of the OSI model does the protocol that provides the information displayed by the "show cdp neighbors" command operate?
A. Transport
B. Physical
C. Application
D. Data link
E. Network
Answer: D
Explanation:
CDP is a device discovery protocol that runs over Layer 2 (the data link layer) on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network management applications to discover Cisco devices that are neighbors of already known devices. With CDP, network management applications can learn the device type and the Simple Network Management Protocol (SNMP) agent address of neighboring devices running lower-layer, transparent protocols.

QUESTION 85
Which three of the protocols below belong to the application layer? (Select three answer choices)
A. ARP
B. HTTPS
C. SMTP
D. CDP
E. TFTP
F. ICMP
Answer: B, C, E
Explanation:
The application layer is the highest OSI layer, and protocols at this layer are end-user oriented. HTTPS so people can get information on the internet, SMTP so people can manage networks, and TFTP so people can download files.
Incorrect Answers:
A, D, F. ARP, CDP, ICMP are protocols that equipment like routers and switches use to communicate with themselves, and belong to lower levels on the model.

QUESTION 86
Exhibit:

A Cisco router and a Catalyst switch are connected as shown. The Certkiller network administrator is working on a computer that is connected to the management console of the switch. In order to configure the default gateway for the switch, the administrator needs to learn the IP address of the attached router interface. Which IOS command will provide this information in the absence of Layer 3 connectivity?
A. ping router_ip_address
B. show ip rarp
C. ping switch_ip_address
D. show cdp neighbors detail
E. show dhcp-config
F. show ip neighbors
G. None of the above
Answer: D
Explanation:
To display detailed information about neighboring devices discovered using Cisco Discovery Protocol (CDP), use the show cdp neighbors privileged EXEC command. Detail - (Optional) Displays detailed information about a neighbor (or neighbors) including network address, enabled protocols, hold time, and software version. The following is sample output for the show cdp neighbors detail command.
router#show cdp neighbors detail
Device ID: lab-7206
Entry address(es):
IP address: 172.19.169.83
Platform: cisco 7206VXR, Capabilities: Router
Interface: Ethernet0, Port ID (outgoing port): FastEthernet0/0/0 Holdtime : 123 sec
Version :
Cisco Internetwork Operating System Software
IOS (tm) 5800 Software (C5800-P4-M), Version 12.1(2) Copyright (c) 1986-2002 by Cisco Systems, Inc.
advertisement version: 2
Duplex: half

QUESTION 87
You want to upgrade the Certkiller LAN so that all ports operate in full duplex mode. Which statement is true about full-duplex Ethernet when comparing to half-duplex Ethernet?
A. Full-duplex Ethernet consists of a shared cable segment. Half-duplex provides a point-to-point link
B. Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive
C. Full-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of the same bandwidth
D. Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet uses a jam signal
E. None of the above
Answer: C
Explanation:
Full-duplex Ethernet uses two pairs of wires instead of one wire pair like half duplex. And full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device. This means that with full-duplex data transfer, you get a faster data transfer compared to half duplex.

QUESTION 88
What are two characteristics of "store and forward" switching? (Select two answer choices)
A. Latency fluctuates regardless of frame size.
B. The switch receives the complete frame before beginning to forward it.
C. Latency through the switch varies with frame length.
D. The switch checks the destination address upon receipt of headers.
Answer: B, C
Explanation:
With store-and-forward, the entire frame is received by the switch before the first bit of the frame is forwarded. As soon as the incoming switch port receives enough of the frame to see the destination MAC address, the forwarding decision is made and the frame is transmitted out the appropriate outgoing port to the destination device. So, each frame might experience slightly less latency. Store and forward switching may add latency when compared to other switching methods such as cut through, but it can reduce the amount of errors that become forwarded through a network.
Incorrect Answers:
A. The amount of latency that is introduced with this method of switching is dependent on the size of the frame, as the switch must wait to receive the entire frame before sending it.
D. The switch must wait for the entire frame before forwarding it on, and not just the headers.

QUESTION 89
Split horizon has been enabled within the Certkiller routed network. Which one of the following statements best explains the split horizon rule?
A. Only routers can split boundaries (horizons) between networks in separate AS numbers.
B. Each AS must keep routing tables converged to prevent dead routes from being advertised across boundaries.
C. Once a route is received on an interface, advertise that route as unreachable back out the same interface.
D. Information about a route should never be sent back in the direction from which the original update came.
E. None of the above
Answer: D
Explanation:
The split horizon rule states:
* Never advertise a route out of the interface through which you learned it. For instance, in Figure 4a below, if Router One is connected to Routers Two and Three through a single multipoint interface (such as Frame Relay), and Router One learned about Network A from Router Two, it will not advertise the route to Network A back out the same interface to Router Three. Router one assumes that Router Three would learn about Network A directly from Router Two.

Incorrect Answers:
A: There is no such requirement
B: Distance vector protocols updates routing table at regular intervals instead of Topology changes
C: This is the definition of the poison reverse rule, not the split horizon rule.
Reference: Wendell Odom. CISCO CCNA Certification Guide (2000 Press) Page 369.

QUESTION 90
Which of the following commands would be applied to a WAN interface, but not on LAN Interface? (Choose all that apply)
A. IP address
B. encapsulation PPP
C. no shutdown
D. authentication CHAP
E. Speed
F. None of the above
Answer: B, D
Explanation:
PPP encapsulation can be used in ISDN interfaces, Asynchronous serial interfaces, and point to point serial WAN connections. PPP is not an option for LAN interfaces. CHAP authentication is a PPP 3 way authentication method. CHAP authentication can only be used on PPP encapsulated interfaces and is not a LAN interface configuration option.
Incorrect Answers:
A, C. This command can be applied to both LAN and WAN interface types.
E. The speed command is used on LAN interfaces, and is not used on WAN interface types.

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QUESTION 71

Part of the Certkiller network is shown below:

In this network segment, host Certkiller A sends data to Host Certkiller B. As packets travel from host Certkiller A to host Certkiller B, which three devices will use the destination MAC address of the packet to determine a forwarding path? (Choose three)
A. Hub Certkiller 0
B. Switch Certkiller 1
C. Router Certkiller 5
D. Router Certkiller 4
E. Switch Certkiller 2
F. Switch Certkiller 3
Answer: B, E, F
Explanation:
Switches use the destination MAC address information for forwarding traffic, while routers use the destination IP address information. Local Area Networks employ Layer 2 Switches and Bridges to forward and filter network traffic. Switches and Bridges operate at the Data Link Layer of the Open System Interconnect Model (OSI). Since Switches and Bridges operate at the Layer 2 they operate more intelligently than hubs, which work at Layer 1 (Physical Layer) of the OSI. Because the switches and bridges are able to listen to the traffic on the wire to examine the source and destination MAC address. Being able to listen to the traffic also allows the switches and bridges to compile a MAC address table to better filter and forward network traffic. To accomplish the above functions switches and bridges carry out the following tasks:
1. MAC address learning by a switch or a bridge is accomplished by the same method. The switch or bridge listens to each device connected to each of its ports and scan the incoming frame for the source MAC address. This creates a MAC address to port map that is cataloged in the switches/bridge MAC database. Another name for the MAC address table is content addressable memory or CAM table.
2. When a switch or bridge is listening o the network traffic, it receives each frame and compares it to the MAC address table. By checking the MAC table the switch/ bridge are able o determine which port the frame came in on. If the frame is on the MAC table the frame is filtered or transmitted on only that port. If the switch determines that the frame is not on the MAC table, the frame is forwarded out to all ports except the incoming port.

QUESTION 72
Exhibit:

You work as a network technician at Certkiller .com. Please study the exhibit carefully. Host Certkiller A is communicating with the server. What will be the source MAC address of the frames received by Host Certkiller A from the Certkiller B server?
A. The MAC address of Certkiller 2 router interface e1
B. The MAC address of Certkiller 2 router interface e0
C. The MAC address of the Certkiller B server network interface
D. The MAC address of host Certkiller A
E. None of the above
Answer: B
Explanation:
Whereas switches can only examine and forward packets based on the contents of the MAC header, routers can look further into the packet to discover the network for which a packet is destined. Routers make forwarding decisions based on the packet's network-layer header (such as an IPX header or IP header). These network-layer headers contain source and destination network addresses. Local devices address packets to the router's MAC address in the MAC header. After receiving the packets, the router must perform the following steps:
1. Check the incoming packet for corruption, and remove the MAC header . The router checks the packet for MAC-layer errors. The router then strips off the MAC header and examines the network-layer header to determine what to do with the packet.
2. Examine the age of the packet. The router must ensure that the packet has not come too far to be forwarded. For example, IPX headers contain a hop count. By default, 15 hops is the maximum number of hops (or routers) that a packet can cross. If a packet has a hop count of 15, the router discards the packet. IP headers contain a Time to Live (TTL) value. Unlike the IPX hop count, which increments as the packet is forwarded through each router, the IP TTL value decrements as the IP packet is forwarded through each router. If an IP packet has a TTL value of 1, the router discards the packet. A router cannot decrement the TTL value to 1 and then forward the packet.
3. Determine the route to the destination. Routers maintain a routing table that lists available networks, the direction to the desired network (the outgoing interface number), and the distance to those networks. After determining which direction to forward the packet, the router must build a new header. (If you want to read the IP routing tables on a Windows 95/98 workstation, type ROUTE PRINT in the DOS box.)
4. Build the new MAC header and forward the packet. Finally, the router builds a new MAC header for the packet. The MAC header includes the router's MAC address and the final destination's MAC address or the MAC address of the next router in the path.
Figure 5 shows the contents of a packet before and after it has been forwarded by a router. Figure 5 also shows the contents of the router's routing tables.
Figure 5: Routers forward packets based on the network address.

QUESTION 73
The Certkiller network is displayed in the diagram shown below:

The Certkiller network consists of a small office with twenty-five employees that has one connection to the Internet through the CK1 router. What routing configurations are recommended on the CK1 and ISP routers?
A. BGP on both the routers.
B. RIP on both the routers.
C. Default routes on both routers.
D. BGP on the ISP router and a static route on CK1 .
E. A default route on CK1 and a static route on the ISP router.
F. None of the above
Answer: E
Explanation:
Since private network use RFC 1918 IP address ranges internally, and because of security reasons, it is generally not possible to use an interior routing protocol with the ISP. This eliminates choice B. When connecting to an ISP, usually only BGP or static routes are supported. In this case, since there is only one connection to the Internet, BGP is not needed so choices A and D can be eliminated. A static default route would be needed on router CK1 to route to the Internet. In turn, the ISP only needs a specific static route to reach the LAN of the Certkiller network.
Incorrect Answers:
A. D: BGP is not needed on networks that contain only a single link to the Internet.
B. Interior routing protocols are generally not supported with an ISP.
C. A default route on the ISP router would send all of their customers Internet traffic to the Certkiller network, and not the Internet.

QUESTION 74
A new point to point circuit is installed, connecting Certkiller 1 to Certkiller 2 as shown below:

Users at Certkiller 1 wish to utilize the existing Internet connection at Certkiller 2. To do this, a gateway of last resort needs to be set. What is the command to do this?
A. Certkiller 1(config)# ip route 172.16.4.2 0.0.0.0 0.0.0.0
B. Certkiller 1(config)# ip route 0.0.0.0 0.0.0.0 S1
C. Certkiller 1(config)# ip route 172.16.4.1 0.0.0.0 0.0.0.0
D. Certkiller 1(config)# ip route S0 0.0.0.0 0.0.0.0
E. Certkiller 1(config)# ip route 0.0.0.0 0.0.0.0 172.16.4.2
F. None of the above
Answer: E
Explanation:
Setting the default gateway is done by issuing either the "ip route 0.0.0.0 0.0.0.0 serial 0" or the "ip route 0.0.0.0 0.0.0.0 172.16.4.2" command. The following excerpt provides some additional information:

Incorrect Answers:
A, C. The IP address of the next hop needs to go after the route, not before.
B. This would have been acceptable if the interface specified was S0, not S1.
C. The interface used to forward packets for the route should be placed after the route, not before.

QUESTION 75
The network associate is configuring OSPF on the Core router shown below. All the connections to the branches should be participating in OSPF. The link to the ISP should NOT participate in OSPF and should only be advertised as the default route. What set of commands will properly configure the Core router?

A. Core(config-router)# default-information originate
Core(config-router)# network 10.0.0.0 0.255.255.255 area 0 Core(config-router)# exit
Core(config)# ip route 0.0.0.00.0.0.010.10.2.14
B. Core(config-router)# default-information originate
Core(config-router)# network 10.10.2.32 0.0.0.31 area 0 Core(config-router)# exit
Core(config)# ip route 0.0.0.00.0.0.0 10.10.2.14
C. Core(config-router)# default-information originate
Core(config-router)# network 10.10.2.13 0.0.0.242 area 0 Core(config-router)# exit
Core(config)# ip route 0.0.0.00.0.0.010.10.2.14
D. Core(config-router)# default-information originate
Core(config-router)# network 10.10.2.16 0.0.0.15 area 0 Core(config-router)# exit
Core(config)# ip route 0.0.0.00.0.0.010.10.2.14
Answer: D
Explanation:
There are two ways to inject a default route into a normal area.
1. If the ASBR already has the default route in its routing table, you can advertise the existing 0.0.0.0/0 into the OSPF domain with the default-information originate router configuration command.
2. If the ASBR doesn't have a default route, you can add the keyword always to the default-information originate command (default-information originate always). This command will advertise a default route into the OSPF domain, regardless of whether it has a route to 0.0.0.0. Another benefit of adding always keyword is that it can add stability to the internetwork. For example, if the ASBR is learning a default route from another routing domain such as RIP and this route is flapping, then without the always keyword, each time the route flaps, the ASBR will send a new Type 5 LSA into the OSPF domain causing some instability inside the OSPF domain. With the always keyword, the ASBR will advertise the default inside the OSPF domain always, and thus the flapping of the default route from the RIP domain will not cause any instability inside the OSPF domain. In the example shown here, only choice D is correct as the wildcard mask correctly specifies the 10.10.2.16 0.0.0.15 networks, which include all IP addresses in the 10.10.2.16-10.10.2.31 range. In this question we were told that the ISP link should NOT be configured for OSPF, making choice A incorrect.
Reference: http://www.cisco.com/warp/public/104/21.html

QUESTION 76
A new Internet T1 is being added to the Certkiller network as shown:

The ISP assigned you the class CIP address 207.134.6.0/30 for this Internet connection. A default route to the Internet should be set up. Which of the following are acceptable ways to configure this on the Gateway router? (Select all that apply)
A. Gateway(config)# ip route 0.0.0.0 0.0.0.0 207.134.6.1.
B. Gateway(config)# router rip
Gateway(config-router)# network 207.134.6.0 default
C. Gateway(config)# ip route 207.134.6.0 255.255.255.0 Serial0/0
D. Gateway(config)# router OSPF
Gateway(config-router)# network 207.134.6.0
E. Gateway(config)# ip default-network 207.134.6.0
Answer: A, E
Explanation:
This question only involves the configuration of the gateway router to the ISP, nothing else. You have two choices to accomplish this: the command "ip route" or the command "ip default-network". Both of these methods will configure a default route to the ISP as desired.
Incorrect Answers:
B, D: RIP and OSPF are interior routing protocols. The T1 Internet connection that is being set up here is between two different Autonomous Systems. The only routing protocol that could be potentially used is BGP, but that is not an option.
C: This command will only set up a static route to the 207.134.6.0/24 network. We wish to set up a static default route.

QUESTION 77
Router Certkiller 2 is connected to an ISP as shown below:

In the ISP link to the WAN shown above, you must complete the connection between the Certkiller 2 router to the service provider. To accomplish this task, which two devices could be installed at the Certkiller site to provide a connection through the local loop to the CO of the provider? (Choose two)
A. Multiplexer
B. WAN switch
C. ATM switch
D. CSU/DSU
E. PVC
F. Modem
G. LMI
Answer: D, F

QUESTION 78
Part of the Certkiller network is shown below:

Study the exhibit shown above. A problem with network connectivity has been observed. It is suspected that the cable connected to switch port Fa0/9 on Switch Certkiller 1 is disconnected. What would be an effect of this cable being disconnected?
A. Communication between VLAN3 and the other VLANs would be disabled
B. Host Certkiller B would not be able to access the server in VLAN9 until the cable is reconnected
C. For less than a minute, Host Certkiller B would not be able to access the server in VLAN9. Then normal network function would resume
D. The transfer of files from Host Certkiller B to the server in VLAN9 would be significantly slower
E. None of the above
Answer: C
Explanation:
Spanning-Tree Protocol (STP) is a Layer 2 protocol that utilizes a special-purpose algorithm to discover physical loops in a network and effect a logical loop-free topology. STP creates a loop-free tree structure consisting of leaves and branches that span the entire Layer 2 network. The actual mechanics of how bridges communicate and how the STP algorithm works will be discussed at length in the following topics. Note that the terms bridge and switch are used interchangeably when discussing STP. In addition, unless otherwise indicated, connections between switches are assumed to be trunks. STP keeps the port either in block or in forward states, when forward port disconnect then within the less then a minute blocked port comes into forward state so packets starts to go through new forward port. The Spanning Tree Protocol (STP) would identify the best path as well as alternate path to reach in proper destination. In a redundant link, if the primary link fails then the secondary links will automatically start after few minutes. If port Fa0/9 became disconnected, then the packets would be re-routed automatically using the Certkiller A- Certkiller 2- Certkiller 3 path.

QUESTION 79
You are logged into a router and wish to view the layer 3 information about your neighboring Cisco routers. What IOS command gives layer 3 information for of the directly connected router interfaces?
A. show ip links
B. show cdp neighbor
C. show cdp neighbor detail
D. show ip clients
E. show ip route
F. None of the above
Answer: C
Explanation:
To display detailed information about neighboring devices discovered using Cisco Discovery Protocol (CDP), use the show cdp neighbors privileged EXEC command. Detail - (Optional) Displays detailed information about a neighbor (or neighbors) including network address, enabled protocols, hold time, and software version.
Incorrect Answers:
A, D. These are invalid commands.
B. The "show cdp neighbor" command, without the "detail" keyword will not display the additional layer 3 protocol information.
E. This will show all routes from all other routers within the domain. We wish to see information from just the direct interface neighbors.

QUESTION 80
A Certkiller technician is troubleshooting connectivity problems between two routers that are directly connected through the serial line. The technician notices that the serial line is up but cannot see any neighbors displayed in the output of the show cdp neighbors command. In which OSI layer is the problem most likely occurring?
A. Physical
B. Data link
C. Network layer
D. Transport layer
E. Application layer
Answer: B
Explanation:
As the question states that serial line is up, it means the problem is not on the Network layer. The administrator cannot see any output by issuing the show cdp neighbors command. It means that CDP is disabled and CDP is a protocol that runs over Layer2 (the data link layer) on all Cisco routers, bridges, access servers, and switches.

CCNA 640-802 Ver 22-09-2008 page7

2009-03-07T08:11:00.000-08:00

QUESTION 61
Which IOS user EXEC command will allow a network technician to determine which router in the path to an unreachable network host should be examined more closely for the cause of the network failure?
A. Certkiller B> telnet
B. Certkiller B > ping
C. Certkiller B > trace
D. Certkiller B > show ip route
E. Certkiller B > show interface
F. Certkiller B > show cdp neighbors
Answer: C
Explanation:
This can perform the trace command. It sends the ping packets to each of the routers on the way to the receiver. The router which doesn't respond will be a potential failure place in this network.

QUESTION 62
A Certkiller office's network topology is shown in the diagram below:

Host Certkiller A needs to communications with the e-mail server shown above. What address will be placed on the destination address field of the frame when it leaves host Certkiller A?
A. The MAC address of Certkiller A
B. The MAC address of switch Certkiller 1
C. The MAC address of the E0 interface of the Certkiller 3 router.
D. The MAC address of the E1 interface of the Certkiller 3 router.
E. The MAC address of switch Certkiller 2
F. The MAC address of the email server
Answer: C
Explanation:
If the destination host is in the remote segment than the router will change the MAC address of the source to its own. The inverse ARP protocol is by default on. Remember that IP address is not changed after forwarding. The MAC address is changed after crossing each broadcast domain.

QUESTION 63
The Certkiller network topology is shown below:

You work as a network engineer at Certkiller .com. The topology of the Certkiller .com network is displayed in the exhibit. Host Certkiller 1 has established a connection with the HTTP server attached to interface E0 of the Certkiller B router. Which of the following statements describe the information contained in protocol data units sent from host Certkiller 1 to this server? (Select three)
A. The destination port number in a segment header will have a value of 80.
B. The destination port number in a segment header will have a unique value greater than or equal to 1023.
C. The destination address of a frame will be the MAC address of the HTTP server interface.
D. The destination address of a frame will be the MAC address of the E0 interface of the Certkiller A router.
E. The destination IP address of a packet will be the IP address of the E0 interface of the Certkiller A router.
F. The destination address of a packet will be the IP address of the HTTP-Server
Answer: A, D, F
Explanation:
HTTP uses TCP port 80, making choice A correct. The source port will be chosen randomly, but not the destination TCP port. The destination IP address will be left unchanged, and since HTTP server is on a remote network, the destination MAC address will be the MAC address of the default gateway ( E0 on Certkiller A).

QUESTION 64
The Certkiller network is shown belod:

In this network, host Certkiller 1 is able to send data to Host Certkiller 2. How will Router Certkiller D handle the data frame received from Host Certkiller 1? (Choose three)
A. Router Certkiller D will strip off the source MAC address and replace it with the MAC address on the forwarding Fast Ethernet interface
B. Router Certkiller D will strip off the source IP address and replace it with the IP address on the forwarding Fast Ethernet interface
C. Router Certkiller D will strip off the destination MAC address and replace it with the MAC address of Host Certkiller 2
D. Router Certkiller D will strip off the destination IP address and replace it with the IP address of Host B
E. Router Certkiller D will forward the data frame out interface Fast Ethernet0/1
F. Router Certkiller D will forward the data frame out interface FastEthernet0/2
Answer: A, C, F
Explanation:
Whereas switches can only examine and forward packets based on the contents of the MAC header, routers can look further into the packet to discover the network for which a packet is destined. Routers make forwarding decisions based on the packet's network-layer header (such as an IPX header or IP header). These network-layer headers contain source and destination network addresses. Local devices address packets to the router's MAC address in the MAC header. After receiving the packets, the router must perform the following steps:
1. Check the incoming packet for corruption, and remove the MAC header . The router checks the packet for MAC-layer errors. The router then strips off the MAC header and examines the network-layer header to determine what to do with the packet.
2. Examine the age of the packet. The router must ensure that the packet has not come too far to be forwarded. For example, IPX headers contain a hop count. By default, 15 hops is the maximum number of hops (or routers) that a packet can cross. If a packet has a hop count of 15, the router discards the packet. IP headers contain a Time to Live (TTL) value. Unlike the IPX hop count, which increments as the packet is forwarded through each router, the IP TTL value decrements as the IP packet is forwarded through each router. If an IP packet has a TTL value of 1, the router discards the packet. A router cannot decrement the TTL value to 1 and then forward the packet.
3. Determine the route to the destination. Routers maintain a routing table that lists available networks, the direction to the desired network (the outgoing interface number), and the distance to those networks. After determining which direction to forward the packet, the router must build a new header. (If you want to read the IP routing tables on a Windows 95/98 workstation, type ROUTE PRINT in the DOS box.)
4. Build the new MAC header and forward the packet. Finally, the router builds a new MAC header for the packet. The MAC header includes the router's MAC address and the final destination's MAC address or the MAC address of the next router in the path.
Figure 5 shows the contents of a packet before and after it has been forwarded by a router. Figure 5 also shows the contents of the router's routing tables.

Figure 5: Routers forward packets based on the network address.

QUESTION 65
Two Certkiller hosts are shown below:

Refer to the exhibit above. Host A is communicating with host B. How will the data be addressed when it leaves host A?
A. Source MAC=000A.8A47.E612
Destination MAC=000B.DC04.12F4
Source IP=192.168.23.4
Destination IP=192.168.23.1
B. Source MAC=000A.8A47.E612
Destination MAC=0010.7BE7.FAEF
Source IP=192.168.23.4
Destination IP=192.168.127.7
C. Source MAC=000A.8A47.E612
Destination MAC=000B.DC04.12F4
Source IP=192.168.23.4
Destination IP=192.168.127.7
D. Source MAC=000A.8A47.E612
Destination MAC=0010.7BE7.FAEF
Source IP=192.168.23.4
Destination IP=192.168.23.1
E. None of the above
Answer: B
Explanation:
When packets leave from the host, the packets contains the source MAC and IP of the host address. The source and destination IP address will not change (if it did, the router devices would not know where to send the data). Because the host knows that the destination is on another subnet, it will forward the packet to the default gateway device, so the destination MAC address will be of the default gateway, which is the LAN interface of router Certkiller 1.

QUESTION 66
Exhibit:

Please study the exhibit above carefully. If host Certkiller A sends an IP packet to host Certkiller B, what will the OSI Layer 3 source address be in the packet when it reaches host B?
A. B2:B2:B2:B2:B2:B2
B. A1:A1:A1:A1:A1:A1
C. 10.168.10.99
D. 10.168.11.65
E. C3:C3:C3:C3:C3:C3
F. 10.168.11.88
G. None of the above
Answer: C
Explanation:
When packets transfer from one host to another across a routed segment, the source IP address always remains the same source IP address, and the physical (MAC) address will be the existing router's interface address. Similarly, the destination IP address always remains the same and the destination physical (MAC) address is the destination router's interface address.

QUESTION 67
Exhibit:

Please study the exhibit carefully. If host Certkiller A sends an IP packet to host Certkiller B, what will the source physical (MAC) address be in the frame when it reaches host Certkiller B?
A. A1:A1:A1:A1:A1:A1
B. D4:D4:D4:D4:D4:D4
C. B2:B2:B2:B2:B2:B2
D. 10.168.11.88
E. 10.168.10.99
F. C3:C3:C3:C3:C3:C3
Answer: F
Explanation:
When packets transfer from one host to another across a routed segment, the source IP address always remains the same source IP address, and the source physical (MAC) address will be the existing router's interface address. Similarly, the destination IP address always remains the same and the destination physical (MAC) address is the destination router's interface address.

QUESTION 68
In the network below, host Certkiller A is transferring a file to the FTP server. Point A represents the frame as it goes toward the Certkiller 1 router. What will the Layer 2 destination address be at this point?

A. 192.168.7.17
B. abcd.1123.0045
C. aabb.555.2222
D. 192.168.1.1
E. abcd.2246.0035
Answer: E
Explanation:
For packets destined to a host on another IP network, the destination MAC address will be the LAN interface of the router. Since the FTP server lies on a different network, the host will know to send the frame to it's default gateway, which is Certkiller 1.

QUESTION 69
Part of the Certkiller network is shown below:

Host Certkiller 1 needs to communicate with the email server shown above. What address will be placed in the destination address field of the frame when it leaves Host Certkiller 1?
A. The MAC address of Host Certkiller 1
B. The MAC address of E0 of the router Certkiller C
C. The MAC address of Switch Certkiller B
D. The MAC address of E1 of the router Certkiller C
E. The MAC address of Switch Certkiller A
F. The MAC address of the email server Certkiller D
G. None of the above
Answer: B
Explanation:
Since the email server resides on a different IP subnet than the host Certkiller 1, the host will send the frame to its default gateway. In this case, the router Certkiller C is acting as the default gateway for all hosts on the LAN, so the frame will be sent to its Ethernet interface so that it can be routed to the email server.

QUESTION 70
Part of the Certkiller network is shown below:

In this Certkiller network segment, host Certkiller A needs to send data to Host Certkiller B. Which Layer 2 and Layer 3 destination addresses will be used in this session to send the data from Host Certkiller A to Host Certkiller B?
A. 192.168.60.5 and 0007.0e56.ab2e
B. 192.168.24.2 and 0007.0e84.acef
C. 192.168.24.1 and 0007.0e56.ab2e
D. 192.168.60.5 and 0011.43da.2c98
E. None of the above
Answer: A
Explanation:
When packets leave from the host, the packets contains the source MAC and IP of the host address. The source and destination IP address will not change. Because the host knows that the destination is on another subnet, it will forward the packet to the default gateway device, so the destination MAC address will be of the default gateway, which is the FA0/0 interface of router Certkiller 2.

CCNA 640-802 Ver 22-09-2008 page6

2009-03-05T02:17:00.000-08:00

QUESTION 51

You work as a network technician at Certkiller .com. You have been assigned the task of designing a new Certkiller internetwork. The main priority is the achieve the highest reliability available, however not at all costs. Certkiller .com is willing to spend more dollars to avoid downtime caused by link failure. Which of the following four designs would provide some redundancy and increase reliability for all four sites, but would cost less than a fully redundant topology?

A. Design Certkiller A
B. Design Certkiller B
C. Design Certkiller C
D. Design Certkiller D
Answer: B
Explanation:
You can think of the partial mesh Frame Relay design as the compromise between network administrators and cost-saving managers.
Example:

QUESTION 52
You work as a network technician at Certkiller .com. You have been assigned the task of designing a new Certkiller internetwork. The main priority is to minimize the link costs and at the same time wants to ensure the branch offices with direct connectivity to the main site. Which of the following four designs is to be preferred?

A. Design Certkiller A
B. Design Certkiller B
C. Design Certkiller C
D. Design Certkiller D
Answer: C
Explanation:
Every network looks for cost efficiency. Redundancy is often sacrificed on the altar of monthly cost. Thus, the hub and spoke Frame Relay network design is one of the more common. In this configuration, you pick a centralized location (most likely, your largest, most connected office) as the "hub" of the network. All other locations are considered "spokes" and have a single virtual circuit connection back to the hub. The major advantage of this configuration is the cost. It offers the cheapest monthly price tag, which cost-cutting corporations enjoy. The disadvantages are beginning to mount against this design, however. The redundancy is sorely lacking. If a single router (the central router) loses connectivity for any reason (if the router crashes, if a trenching company cuts through the line), your entire WAN goes down. The other disadvantage of this design is beginning to eclipse even redundancy. It is the disadvantage of tandem switching. Any time the spoke offices need to reach each other, they must go through the hub office.
Example:

QUESTION 53
A Certkiller network is shown in the exhibit below:

The routers in this network are running RIPv2. Which addressing scheme would satisfy the needs of this network yet waste the fewest addresses?
A. Network 1: 192.168.10.0/26Network 2: 192.168.10.64/26Network 3:
192.168.10.128/26Serial link 1: 192.168.20.0/24Serial link 2: 192.168.30.0/24
B. Network 1: 192.168.10.0/26Network 2: 192.168.10.64/28Network 3:
192.168.10.80/29Serial link 1: 192.168.10.88/30Serial link 2: 192.168.10.96/30
C. Network 1: 192.168.10.0/26Network 2: 192.168.10.64/27Network 3:
192.168.10.96/28Serial link 1: 192.168.10.112/30Serial link 2: 192.168.10.116/30
D. Network 1: 192.168.10.0/27Network 2: 192.168.10.64/28Network 3:
192.168.10.96/29Serial link 1: 192.168.10.112/30Serial link 2: 192.168.10.116/30
Answer: C
Explanation:
Network 1
Required Number of hosts :50
When We use the 26 bits for Network : 11111111.11111111.11111111.11000000 so 62 usable host can be in one network. 50 host for now and remaining hosts address for further growth.
Network 2
Required Number of Hosts: 20
When we use the 27 bits for Network: 11111111.11111111.1111111.11100000 so 30 usable hosts can be in one network.
Network 3
Required Number of Hosts: 10
When we use the 28 bits for Network: 11111111.11111111.11111111.11110000 so 14 usable hosts can be in one network.
Connection between CK1 , CK2 and CK3 is WAN so when you use 30 bits network IP, you will not lose any IP addresses from network since this subnet allows for only 2 host addresses.

QUESTION 54
The Certkiller network is shown below:

A technician is investigating a problem with the network shown above. These symptoms have been observed:
1. All of the user hosts can access the Internet.
2. None of the user hosts can access the server in VLAN9
3. All of the hosts can ping each other.
What could cause the symptoms?
A. Interface S0/0 on the router is down.
B. Interface Fa1/0 on the router is down.
C. Interface Fa0/5 on Certkiller 3 is down.
D. Interface Fa0/4 on Certkiller 3 is down.
E. Certkiller 2 is turned off.
F. Trunking is not enabled on the link between Certkiller 1 and Certkiller 3.
Answer: D
Explanation:
Since all user hosts have access to internet, link to router has to be up. Therefore, router interface (Fa0/1 - believe it is labeled incorrectly on diagram as Fa1/0) must be up. Since all hosts can ping each other, but none can get to VLAN 9 which is through single interface Fa0/4, this interface must be down.
Choice A: incorrect, S0/0 must be up if internet access available.
Choice B: incorrect, Fa0/1 must be up if internet access (through router) available. Choice C: incorrect, would not prevent access to VLAN9 via other routes (i.e Fa0/7, Fa0/9, Fa0/4)
Choice D: correct
Choice E: incorrect: Certkiller 2 must be up if internet access (through switch and then router) available
Choice F: incorrect: Disabled trunking on link between Certkiller 1 and Certkiller 3 would not prevent access to VLAN9 via other routes

QUESTION 55
Refer to the graphic shown below:

What symbol represents a type of device that is connected to interface FastEthernet 0/23 of the 2960 switch Sw1-2960?
A. Picture A
B. Picture B
C. Picture C
D. Picture D
Answer: D
Explanation:
Some of the common Cisco symbols are shown below:

Note: Choice B in this question represents an ATM switch, which is not pictured above. From the output shown in this question, we can see that there a numerous different MAC addresses associated with port Fa 0/23. This can only mean that a device with multiple hosts attached to it is plugged into this port, such as a hub or another switch.

QUESTION 56
Part of the Certkiller network topology is shown below:

Entry exhibit:

Host Certkiller A pings Host Certkiller B, which entry will be in the ARP cache of Host Certkiller A to support this transmission?
A. A
B. B
C. C
D. D
E. E
Answer: C

QUESTION 57
The Certkiller network is shown in the following exhibit:

Certkiller uses EIGRP as the routing protocol. Based on the info shown above, what path will packets take from a host on the 192.168.10.192/26 network to a host on the LAN attached to router Certkiller 1?
A. The path of the packets will be Certkiller 3 to Certkiller 2 to Certkiller 1
B. The path of the packets will be Certkiller 3 to Certkiller 1 to Certkiller 2
C. The path of the packets will be both Certkiller 3 to Certkiller 2 to Certkiller 1 AND Certkiller 3 to Certkiller 1
D. The path of the packets will be Certkiller 3 to Certkiller 1
E. None of the above
Answer: D
Explanation:
Based on the routing table of Certkiller 3, the best path to the Certkiller 1 LAN is shown on the first routing entry (192.168.10.64). Certkiller 3 will use the Serial 0/0 interface to route traffic to this destination, with the next hop IP address of 192.168.10.9, which is the network used between Certkiller 3 and Certkiller 1, making choice D correct. Note that there is only one routing entry for this destination. If traffic were load balancing over both paths, then both would be displayed in the routing table.

QUESTION 58
Refer to the following exhibit:

Based on the diagram shown above, what is the correct addressing for a frame and packet received by Host Certkiller B from Host Certkiller A?
A. Destination MAC: 0011.43da.2c98
Source MAC: 0070.0e8f.088a
Destination IP: 192.168.60.5
Source IP: 192.168.60.1
B. Destination MAC: 0011.43da.2c98
Source MAC: 0070.0e8f.088a
Destination IP: 192.168.60.5
Source IP: 192.168.24.5
C. Destination MAC: 0011.43da.2c98
Source MAC: 00b0.d0ef.5f6a
Destination IP: 192.168.60.5
Source IP: 192.168.24.5
D. Destination MAC: 0011.43da.2c98
Source MAC: 0070.0e97.af4e
Destination IP: 192.168.60.5
Source IP: 192.168.60.2
E. None of the above
Answer: B
Explanation:
When packets leave from the host, the packets contains the source MAC and IP of the host address. The source and destination IP address will not change. Because the host knows that the destination is on another subnet, it will forward the packet to the default gateway device, so the destination MAC address will be of the default gateway, which is the FA0/0 interface of router Certkiller 3.

QUESTION 59
Exhibit #1:

Please study the two exhibits carefully.
The partial frame shown above displays select header information as it arrives at the destination host. Of the following choices shown below, which one represents the correct header information in the responding frame returned to the remote host?
A. A
B. B
C. C
D. D
E. E
Answer: A

QUESTION 60 The Certkiller network is shown below:

Based on the diagram above, which destination addresses will Host A use to send data to Host B? (Choose two.)
A. The IP address of Certkiller 1
B. The IP address of Certkiller A Fa0/0
C. The IP address of Host B
D. The MAC address of Certkiller 1
E. The MAC address of Certkiller A Fa0/0
F. The MAC address of Host B
Answer: C, E
Explanation:
When sending data from one host to another, destination information will be added to every packet's header. The destination information will be the IP and MAC Address of destination host. If the destination is found outside the subnet the MAC address of the router is used. Note: The destination IP address will never change, unless NAT is
involved.

E-BOOK CISCO EXAM

2009-03-03T05:16:00.000-08:00

CCNA 640-802 Ver 22-09-2008 page5

2009-03-03T03:18:00.000-08:00

QUESTION 41
Which of the following services use TCP? (Choose three)
A. DHCP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. TFTP
Answer: B, D, E
Explanation:
TCP (Transmission Control Protocol) is a reliable mechanism for data delivery. SMTP, FTP and HTTP services use TCP via ports 25, 20/21, and 80, respectively.
QUESTION 42
Which of the following are types of flow control? (Choose three)
A. Buffering
B. Cut-through
C. Windowing
D. Congestion avoidance
E. Load balancing
Answer: A, C, D
Explanation:
Data transmission flow control occurs at layer 4 with the help of buffering, windowing and congestion avoidance.
QUESTION 43
Which Layer 4 protocol is used for a Telnet connection between two Certkiller routers?
A. IP
B. ICMP
C. DNS
D. TCP
E. UDP
F. RTP
Answer: D
Explanation:
TCP is a reliable connection-oriented protocol. TCP uses acknowledgments, sequencing, and flow control to ensure reliability. Telnet uses TCP port 23.

QUESTION 44
FTP, Telnet, DNS, and SMTP are all protocols being used in the Certkiller network. Of these, which uses both TCP and UDP ports?
A. Telnet
B. FTP
C. DNS
D. SMTP
E. None of the above
Answer: C
Explanation:
The following port numbers for the protocols listed above are as follows: FTP: TCP Port 20 and 21
SMTP: TCP Port 25
Telnet: TCP Port 23
DNS: both TCP and UDP Port 53

QUESTION 45
Although TCP segments are similar to UDP segments, TCP packets contains some additional fields. Which of theNfollowing are found in a TCP header, but not in a UDP header? (Choose three)
A. Checksum
B. Sequence number
C. Destination port
D. Window size
E. Acknowledgment number
F. Source port
Answer: B, D, E
Explanation:
The Figure below illustrates the fields and overall format of a TCP packet. Twelve fields comprise a TCP packet.

TCP Packet Field Descriptions
The following descriptions summarize the TCP packet fields illustrated in Figure 30-10:

Source Port and Destination Port-Identifies points at which upper-layer source and destination processes receive TCP services.
Sequence Number-Usually specifies the number assigned to the first byte of data in the current message. In the connection-establishment phase, this field also can be used to identify an initial sequence number to be used in an upcoming transmission.
Acknowledgment Number-Contains the sequence number of the next byte of data the sender of the packet expects to receive.
Data Offset-Indicates the number of 32-bit words in the TCP header.
Reserved-Remains reserved for future use.
Flags-Carries a variety of control information, including the SYN and ACK bits used for connection establishment, and the FIN bit used for connection termination.
Window-Specifies the size of the sender's receive window (that is, the buffer space available for incoming data).
Checksum-Indicates whether the header was damaged in transit.
Urgent Pointer-Points to the first urgent data byte in the packet.
Options-Specifies various TCP options.
Data-Contains upper-layer information.

User Datagram Protocol (UDP)
The User Datagram Protocol (UDP) is a connectionless transport-layer protocol (Layer 4) that belongs to the Internet protocol family. UDP is basically an interface between IP and upper-layer processes. UDP protocol ports distinguish multiple applications running on a single device from one another. Unlike the TCP, UDP adds no reliability, flow-control, or error-recovery functions to IP. Because of UDP's simplicity, UDP headers contain fewer bytes and consume less network overhead than TCP. UDP is useful in situations where the reliability mechanisms of TCP are not necessary, such as in cases where a higher-layer protocol might provide error and flow control. UDP is the transport protocol for several well-known application-layer protocols, including Network File System (NFS), Simple Network Management Protocol (SNMP), Domain Name System (DNS), and Trivial File Transfer Protocol (TFTP). The UDP packet format contains four fields, as shown in the figure below. These include source and destination ports, length, and checksum fields. A UDP packet consists of four fields.

Source and destination ports contain the 16-bit UDP protocol port numbers used to demultiplex datagrams for receiving application-layer processes. A length field specifies the length of the UDP header and data. Checksum provides an (optional) integrity check on the UDP header and data.

QUESTION 46
DRAG DROP
You work as a network administrator at Certkiller .com. Your boss, Mrs. Certkiller, is interested in the OSI layers. Match the items with the appropriate layers. Note that not all options are used.

Answer:

QUESTION 47
Certkiller is installing IP phones in a new office. The phones and office computers connect to the same device. To ensure maximum throughout for the phone data sessions, the company needs to make sure that the phone traffic is on a different network from that of the office computer data traffic. What is the best network device to which to directly connect the phones and computers and what technology should be implemented on this device? (Choose two)
A. VLAN
B. Subinterface
C. STP
D. Hub
E. Switch
F. Router
G. Wireless Access Point
H. VTP
Answer: A, E

QUESTION 48
The corporate head office of Certkiller has a teleconferencing system that uses VOIP (voice over IP) technology. This system uses UDP as the transport for the data transmissions. If these UDP datagrams arrive at their destination out of sequence, what will happen?
A. UDP will send an ICMP Information Request to the source host.
B. UDP will pass the information in the datagrams up to the next OSI layer in the order that they arrive.
C. UDP will drop the datagrams.
D. UDP will use the sequence numbers in the datagram headers to reassemble the data in the correct order.
E. UDP will not acknowledge the datagrams and wait for a retransmission of the datagrams.
Answer: B
Explanation:
VOIP systems utilize UDP because it is faster and uses less overhead. In addition, the reliable transport mechanism used in TCP is useless to VOIP because if a packet gets dropped and needs to be resent, it will be already too late. UDP provides a service for applications to exchange messages. Unlike TCP, UDP is connectionless and provides no reliability, no windowing, and no reordering of the received data. However, UDP provides some functions of TCP , such as data transfer, segmentation, and multiplexing using port numbers, and it does so with fewer bytes of overhead and with less processing required. UDP data transfer differs from TCP data transfer in that no reordering or recovery is accomplished. Applications that use UDP are tolerant of lost data, or they have some application mechanism to recover data loss.

QUESTION 49
Part of the Certkiller network is shown below:

You work as a network technician for Certkiller and are responsible for this network. Based on the diagram shown above, how many collision domains are there?
A. Six
B. Fourteen
C. Four
D. Two
E. Three
F. One
G. Eight
Answer: D
Explanation:
The multi-segment configuration guidelines apply only to a single Ethernet "collision domain." A collision domain is formally defined as a single CSMA/CD network in which there will be a collision if two computers attached to the system transmit at the same time. An Ethernet system composed of a single segment or multiple segments linked with repeaters is a network that functions as a single collision domain.

FIGURE 1 Repeater hubs create a single collision domain
The figure shows two repeater hubs connecting three computers. Since only repeater connections are used between segments in this network, all of the segments and computers are in the same collision domain. In the next figure, the repeaters and DTEs are instead separated by a router (packet switch) and are therefore in separate collision domains, since routers do not forward collision signals from one segment to another. Routers contain multiple Ethernet interfaces and are designed to receive a packet on one Ethernet port and transmit the data onto another Ethernet port in a new packet.

FIGURE 2 Routers creates separate collision domains
Instead of propagating collision signals between Ethernet segments, routers interrupt the collision domain and allow the Ethernets they link to operate independently. Therefore, you can use packet switching hubs to build larger network systems by interconnecting individual Ethernet systems.

QUESTION 50
You work as a network technician at Certkiller .com. You have been assigned the task of designing a new Certkiller internetwork. The main priority is to achieve the highest reliability available. Certkiller .com is willing to spend more dollars to avoid downtime caused by link failure. Which of the following four designs is to be preferred?

A. Design Certkiller A
B. Design Certkiller B
C. Design Certkiller C
D. Design Certkiller D
Answer: A Explanation:
A network topology that is set up so that each device is directly connected to every other device on the network. This connection method has built-in redundancy. If one link goes down, the device will transmit via another link.
Example:
If the partial mesh design is a compromise between the network administrators and managers, then the full mesh design implies that the network administrators won. This design is every Cisco network administrator's picture of perfection over a Frame Relay cloud. It gives every site a direct virtual circuit to every other site, as shown in Figure This design gives maximum redundancy and minimum packet latency (latency describes how long it takes a packet to reach each location).

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QUESTION 31

As a CCNA candidate, you will be expected to know the OSI model very well. Which of the following are associated with the application layer (layer 7) of the OSI model? (Choose two)
A. TCP
B. Telnet
C. FTP
D. Ping
E. IP
F. UDP
Answer: B, C
Explanation:
The application layer is the top layer of the OSI model and is used to describe the end user applications that can be used over a network.
Layer Name Examples
Application (layer 7) Telnet, HTTP, FTP, WWW browsers, NFS, SMTP gateways,
SNMP
Incorrect Answers:
A. TCP resides at layer 4.
D. ARP is a function of the data link layer, which is layer 2.
E. IP is used at layer 3 (network layer).

QUESTION 32
As the Certkiller network administrator, you are required to have a firm understanding of the OSI model. Why does the data communication industry use the layered OSI reference model? (Choose two)
A. It enables equipment from different vendors to use the same electronic components, thus saving research and development funds
B. It encourages industry standardization by defining what functions occur at each layer of the model
C. It divides the network communication process into smaller and simpler components; thus aiding component development, design and troubleshooting
D. It provides a means by which changes in functionality in one layer require changes in other layers
E. It supports the evolution of multiple competing standards and thus provides business opportunities for equipment manufacturers
Answer: B, C
Explanation:
The OSI (Open System Interconnection) reference model was created as a reference point for communications devices. A layered approach is used to segment the entire telecommunications process into a series of smaller steps. A is correct because it encourages a level of standardization by encouraging that functions be compared to known layers. D is also correct because it allows engineers to focus on the development, refining, and perfection of simpler components.

QUESTION 33
You need to describe the various types of flow control to your co-workers. Which of the following are types of flow control that can be used in a network? (Choose three)
A. Congestion avoidance
B. Windowing
C. Cut-through
D. Buffering
E. Load Balancing
F. Fast Forward
Answer: A, B, D

QUESTION 34
Which of the protocols below use TCP at the transport layer? (Select four)
A. TFTP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. HTTPS
Answer: B, D, E, F
Explanation:
SMTP (Simple Mail Transfer Profile for email), FTP (File Transfer Protocol), and HTTP/HTTPS (Hyper Text Transfer Protocol for internet) all use TCP because of the reliable delivery mechanism. SMTP uses TCP port 25, FTP uses TCP ports 20 and 21, HTTP uses TCP port 80, and HTTPS uses TCP port 443.
Incorrect Answers:
A, C: SNMP and TFTP use UDP as the transport mechanism. Generally speaking, protocols that use the keywords "trivial" or "simple" uses UDP, since connectionless, best effort delivery mechanism usually suffice.

QUESTION 35
Exhibit:

The exhibit above displays the partial contents of an encapsulation header. Which of the following are true of the network traffic represented in this diagram? (Select three)
A. This is a UDP header
B. This is an OSI layer 4 header.
C. This is traffic from an FTP server.
D. This is traffic from an Telnet client.
E. The last PDU received in this session had a sequence number of 292735.
Answer: B, C, E
Explanation:
As the header contains the sequence number and ACK number fields, it represents a TCP header. Choice B is correct as TCP works on Layer 4 i.e. Transport Layer. Source Port mentioned in the header is 21 which indicate it is FTP Traffic because FTP uses port 20 and 21 for data and control. So choice C is correct. The acknowledgment number refers to the sequence number of the last PDU received, which is 292735, making choice E also correct.

QUESTION 36
Which fields are included in the TCP header? (Choose three).
A. Source Port
B. Acknowledgement Number
C. Request Number
D. Destination Address
E. Window
F. Data
Answer: A, B, E
Explanation:
TCP header:

Source Port: 16 bits.
Destination Port: 16 bits.
Sequence Number: 32 bits.
The sequence number of the first data byte in this segment. If the SYN bit is set, the sequence number is the initial sequence number and the first data byte is initial sequence number + 1.
Acknowledgment Number: 32 bits.
If the ACK bit is set, this field contains the value of the next sequence number the sender of the segment is expecting to receive. Once a connection is established this is always sent.
Data Offset: 4 bits.
The number of 32-bit words in the TCP header. This indicates where the data begins. The length of the TCP header is always a multiple of 32 bits.
Reserved: 3 bits.
Must be cleared to zero.
ECN, Explicit Congestion Notification: 3 bits.
Added in RFC 3168.
Control Bits: 6 bits.
Window: 16 bits, unsigned. The number of data bytes beginning with the one indicated in the acknowledgment field which the sender of this segment is willing to accept.
Checksum: 16 bits.
This is computed as the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the TCP header, and the data, padded as needed with zero bytes at the end to make a multiple of two bytes.
Urgent Pointer: 16 bits, unsigned.
If the URG bit is set, this field points to the sequence number of the last byte in a sequence of urgent data.
Options: 0 to 44 bytes.
Options occupy space at the end of the TCP header. All options are included in the checksum. An option may begin on any byte boundary. The TCP header must be padded with zeros to make the header length a multiple of 32 bits.
Data: Variable length.

QUESTION 37
Acknowledgements, sequencing, and flow control are functions that are handled by which layer of the OSI model?
A. Layer 5
B. Layer 4
C. Layer 7
D. Layer 6
E. Layer 3
F. Layer 2
G. Layer 1
Answer: B

QUESTION 38
A receiving host has failed to receive all of the segments that it should acknowledge. What can the host do to improve the reliability of this communication session?
A. Start a new session using UDP
B. Obtain a new IP address from the DHCP server
C. Use a different source port for the session
D. Decrease the sequence number
E. Decrease the window size
Answer: E
Explanation:
A TCP window the amount of outstanding (unacknowledged by the recipient) data a sender can send on a particular connection before it gets an acknowledgment back from the receiver that it has gotten some of it. For example if a pair of hosts are talking over a TCP connection that has a TCP window size of 64 KB (kilobytes), the sender can only send 64 KB of data and then it must stop and wait for an acknowledgment from the receiver that some or all of the data has been received. If the receiver acknowledges that all the data has been received then the sender is free to send another 64 KB. One way to improve the reliability of the TCP connection is to reduce the window size that the receiver needs to receive before sending an acknowledgement. However, this will reduce throughput as more segments and acknowledgements will need to be sent in order to transfer the same amount of data.

QUESTION 39
You have set up an Internet based FTP server, where people can upload and download files. In terms of the OSI model, what is the highest layer used during the FTP sessions.
A. Application
B. Presentation
C. Session
D. Transport
E. Internet
F. Data Link
G. Physical
Answer: A
Explanation:
The application layer is the highest layer (layer 7) of the OSI model, and is reserved for end user applications. Since FTP is itself an application, layer 7 is the highest layer used.
Incorrect Answers:
B, C, D, E, F, G. In any given FTP session, all of these layers will be used at some point
but they are incorrect because the question asked for the highest layer used by FTP.

QUESTION 40
ICMP is often used in troubleshooting and verifying network. What statements are true regarding ICMP packets? (Choose two)
A. They acknowledge receipt of TCP segments.
B. They guarantee datagram delivery.
C. They can provide hosts with information about network problems.
D. They are encapsulated within IP datagrams.
E. They are encapsulated within UDP datagrams.
F. They are encapsulated within TCP datagrams.
Answer: C, D
Explanation:
ping may be used to find out whether the local machines are connected to the network or whether a remote site is reachable. This tool is a common network tool for determining the network connectivity which uses ICMP protocol instead of TCP/IP and UDP/IP. This protocol is usually associated with the network management tools which provide network information to network administrators, such as ping and traceroute (the later also uses the
UDP/IP protocol). ICMP is quite different from the TCP/IP and UDP/IP protocols. No source and destination ports are included in its packets. Therefore, usual packet-filtering rules for TCP/IP and UDP/IP are not applicable. Fortunately, a special "signature" known as the packet's Message type is included for denoting the purposes of the ICMP packet. Most commonly used message types are namely, 0, 3, 4, 5, 8, 11, and 12 which represent echo reply, destination unreachable, source quench, redirect, echo request, time exceeded, and parameter problem respectively. In the ping service, after receiving the ICMP "echo request" packet from the source location, the destination.
Incorrect Answers
ICMP is an IP protocol so A and E are incorrect.
ICMP doesn't guarantee datagram delivery so B is wrong as well.

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QUESTION 21

Which OSI layer is associated with the following: The acknowledgement of transmissions, sequencing, and flow control across a network?
A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5
E. Layer 6
F. Layer 7
Answer: C
Explanation:
The Transport layer (Layer 4) defines several functions, including the choice of protocols. The most important Layer 4 functions are error recovery and flow control. The transport layer may provide for retransmission, i.e., error recovery, and may use flow control to prevent unnecessary congestion by attempting to send data at a rate that the network can accommodate, or it might not, depending on the choice of protocols. Multiplexing of incoming data for different flows to applications on the same host is also performed. Reordering of the incoming data stream when packets arrive out of order is included. Examples include: TCP, UDP, and SPX.

QUESTION 22
Which OSI layer header contains the address of a destination host that is on another network?
A. Application
B. Presentation
C. Session
D. Transport
E. Network
F. Data link
G. Physical
Answer: E
Explanation:
Only network address contains this information. To transmit the packets the sender uses network address and datalink address. But the layer 2 address represents just the address of the next hop device on the way to the sender. It is changed on each hop. Network address remains the same.

QUESTION 23
Which of the following correctly describe steps in the OSI data encapsulation process? Choose two)
A. The presentation layer translates bits into voltages for transmission across the physical link.
B. The transport layer divides a data stream into segments and adds reliability and flow control information.
C. Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
D. The data link layer adds physical source and destination addresses and an FCS to the segment.
E. Packets are created when the network layer encapsulates a frame with source and destination host addresses and protocol-related control information.
Answer: B, C
Explanation:
The Transport Layer:
You can think of the transport layer of the OSI model as a boundary between the upper and lower protocols. The transport layer provides a data transport service that shields the upper layers from transport implementation issues such as the reliability of a connection.
The transport layer provides mechanisms for:
Segmenting upper layer application
The establishment, maintenance, and orderly termination of virtual circuits information flow control and reliability via TCP
Transport fault detection and recovery
The Network Layer:
Layer three of the OSI model is the network layer.
The network layer creates and sends packets from source network to destination network. it provides consistent end-to-end packet delivery service and control information it creates and uses layer3 addresses for use in path determination and to forward packets.
Incorrect Answers:
A: This correctly describes the physical layer, not the presentation layer.
D: Although the data link layer adds physical (MAC) source and destination addresses, it adds it to a frame, not a segment.
E: Packets are encapsulated, not frames.

QUESTION 24
When files are transferred between a host and an FTP server, the data is divided into smaller pieces for transmission. As these pieces arrive at the destination host, they must be reassembled to reconstruct the original file. What provides for the reassembly of these pieces into the correct order?
A. The sequence number in the TCP header
B. The Start Frame Delimiter in the 802.3 Preamble
C. The TTL in the IP header
D. The acknowledgement number in the segment header
E. The frame check sequence in the Ethernet frame trailer
Answer: A
Explanation:
The Transport layer can provide reliable networking via acknowledgments, sequencing, and flow control. Acknowledgments Delivered segments are acknowledged to the sender. If they are not acknowledged, the sender will retransmit. Sequencing Data segments are sequenced into their original order when they arrive at the destination. Flow Control Provides buffer controls that prevent packet flooding to the destination host. Buffers store bursts of data for processing when the transmission is complete. Layer 4 protocols include the following:
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
Sequenced Packet Exchange (SPX) A reliable communications protocol created by Novell NetWare

QUESTION 25
DRAG DROP
You work as a network administrator at Certkiller .com.
Your boss, Mrs. Certkiller, is interested in the OSI layers. Match the terms with the appropriate layer. Some options are not used.

Answer :

Explanation:
The Transport layer segments and reassembles data into a data stream. Services located
in the Transport layer segment and reassemble data from upper-layer applications and
unite it into the same data stream. They provide end-to-end data transport services and
can establish a logical connection between the sending host and destination host on an
internetwork.
TCP and UDP transport protocol lies on Transport Layer, which break down the data coming from upper layer into segment.
Windows are used to control the amount of outstanding, unacknowledged data segments that is also on Transport Layer.
Network Layer:
The Network layer (also called layer 3) manages device addressing, tracks the location of devices on the network, and determines the best way to move data, which means that the Network layer must transport traffic between devices that aren't locally attached. Routers (layer 3 devices) are specified at the Network layer and provide the routing services within an internetwork. Protocol Data Packets (PDU) on Network Layer is known as Packets. Routing and Routed protocols are lies on Network Layer.
Routing Protocol: RIP, IGRP, EIGRP, OSPF, BGP
Routed Protocol: IP, IPX

QUESTION 26
Refer to the following exhibit:

What data structure is described in the exhibit shown above?
A. IP datagram
B. TCP segment
C. Ethernet frame
D. UDP datagram
E. FDDI frame
F. Token Ring frame
G. None of the above
Answer: B
Explanation:
The Figure below illustrates the fields and overall format of a TCP packet. Twelve fields comprise a TCP packet.

The following descriptions summarize the TCP packet fields illustrated above.

SourcePort and DestinationPort-Identifies points at which upper-layer source and destination processes receive TCP services.
Sequence Number-Usually specifies the number assigned to the first byte of data in the current message. In the connection-establishment phase, this field also can be used to identify an initial sequence number to be used in an upcoming transmission.
Acknowledgment Number-Contains the sequence number of the next byte of data the sender of the packet expects to receive.
Data Offset-Indicates the number of 32-bit words in the TCP header.
Reserved-Remains reserved for future use.
Flags-Carries a variety of control information, including the SYN and ACK bits used for connection establishment, and the FIN bit used for connection termination.
Window-Specifies the size of the sender's receive window (that is, the buffer space available for incoming data).
Checksum-Indicates whether the header was damaged in transit.
Urgent Pointer-Points to the first urgent data byte in the packet.
Options-Specifies various TCP options.
Data-Contains upper-layer information.

QUESTION 27
Network equipment supporting the use of flow control mechanisms has been recently installed in the Certkiller network. What is the purpose of flow control in a data network?
A. It ensures that data is retransmitted if an acknowledgment is not received.
B. It reassembles segments in the correct order on the destination device.
C. It provides a mechanism for the receiver to control the transmission speed.
D. It regulates the size of each datagram segment.
E. All of the above are functions of flow control
Answer: C
Explanation:
Flow control paces the transmission of data between a sending device and a receiving device. Flow control ensures that the receiving device can absorb the data sent to it before the sending device sends more. When the buffers on the receiving device are full, a message is sent to the sending device to suspend transmission until the data in the buffers has been processed.
Incorrect Answers:
A. Data retransmission mechanisms are not handled by control. They are most often handled by transport layer protocols such as TCP.
B. This describes the reassembly portion of the segmentation and reassembly (SAR) function of network equipment.
D. The maximum transmission unit (MTU) handles the regulation of maximum frame
sizes.

QUESTION 28
Part of the Certkiller network is displayed below:

Study the exhibit shown above. Host Certkiller A has established a connection with the Certkiller II server attached to interface E0 of the Certkiller 2 router. Which of the following statements describe the information contained in protocol data units sent from Host Certkiller to Certkiller II? (Choose three)
A. The destination port number in a segment header will have a value of 80
B. The destination IP address of a packet will be the IP address of the E0 interface of the Certkiller 1 router
C. The destination IP address of a packet will be the IP address of the network interface of the Certkiller II server
D. The destination address of a frame will be the MAC address of the E0 interface of Certkiller 1 router
Answer: A, C, D

QUESTION 29
You have just installed a new web server on the Certkiller network. You are required to ensure that the web server is accessible from the Internet. The network uses private addressing, so an IP-to-registered address mapping is required. To do this, you enter the following command:

Certkiller (config)# ip nat inside source static 192.168.2.1 198.18.1.254
You unsuccessfully try to ping the Internet from a PC host on the LAN. During the troubleshooting process, you enter the "show ip nat translations" command but the output is blank.
What is the most likely cause of the problem?
A. The keyword overload is missing from the command.
B. The NAT pool must be defined first.
C. An access list must be defined to create static NAT translations.
D. The interfaces must be configured for NAT.
E. None of the above
Answer: D
Explanation:
In order to successfully configure a static NAT translation, the interfaces must be configured for NAT, in addition to the global NAT command that was entered. The router interface that lies on the inside part of the network must be defined using the "ip nat inside" command. Similarly, the WAN interface that is being used for the Internet connection must be defined using the "ip nat outside" command.
Incorrect Answers:
A. In order to make an internal server reachable from the Internet, a static one to one NAT entry must be configured for the server. The keyword "overload" is used to configure many to one NAT, or PAT.
B, C. This need not be done in order to create a static NAT entry. These steps are
typically done in setting up NAT so that inside LAN users can access the Internet via
NAT.

QUESTION 30
Which protocol below uses TCP port 443 at layer 4?
A. HTML
B. HTTPS
C. TFTP
D. Telnet
E. SMTP
F. None of the above
Answer: B
Explanation:
HTTPS is the secured version of the HTTP application, which normally uses 128 bit SSL encryption to secure the information sent and received on a web page. An example is a banking web site, or a trustworthy shopping web site that takes credit card information. It is an application layer protocol which uses TCP port 443.
Incorrect Answers:
A. HTML is not a protocol.
C. TFTP uses UDP port 69.
D. Telnet uses TCP port 23.
E. SMTP uses TCP port 25.

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QUESTION 11
CDP is running between two Certkiller devices. What information is supplied by CDP? (Select three)
A. Device Identifiers
B. Capabilities list
C. Platform
D. Route identifier
E. Neighbor traffic data
Answer: A, B, C
Explanation:

QUESTION 12

Two buildings on the London campus of a the Certkiller corporation must be
connected to use Ethernet with a bandwidth of at least 100 Mbps. Certkiller is
concerned about possible problems from voltage potential differences between the two buildings. Which media type should be used for the connection?
A. Coaxial cable
B. Fiber optic cable
C. UTP cable
D. STP cable
E. None of the above
Answer: B
Explanation:
Current Ethernet technology typically comes via either copper UTP or fiber cables. In this scenario the distance between the buildings is only 55 meters so either copper or fiber could be used, as the distance limitation for 100M UTP Ethernet is 100 meters. However, fiber would be a better fit as it is not prone to errors that could occur due to the voltage potential differences. Because fiber is a dielectric material, it's not susceptible to electrical interference. FO-product vendors also claim that fiber systems make secure communications easier. Interference immunity and lack of emissions are givens in FO systems and in the fiber medium itself.

QUESTION 13
Refer to the Certkiller network shown below:

You work as a network technician at Certkiller .com. Please study the exhibit carefully. Based on the information shown above, what is needed to allow host Certkiller 1 to ping host Certkiller 2?
A. a crossover cable connecting the switches
B. a backbone switch connecting the switches with either fiber optic or straight-through cables
C. a straight-through cable connecting the switches
D. a CSU/DSU connected to the switches with straight-through cables
E. a router connected to the switches with straight-through cables
Answer: E
Explanation:
Routers are Layers 3 devices used for inter-network communication. In this scenario there are two different networks, so both switches need to connect to a router using straight-through cables.
A straight-through cable is used to connect two different devices like, switch to router,
host to switch. Since we need to insert a router for communication between the two
switches, straight through cables will be used between the switches and the router.

QUESTION 14
Exhibit:

A new Certkiller office is opening, and a network device needs to be installed in the place of the icon labeled Network Device to accommodate a leased line T1 to the Internet. Which network device and interface configuration meets the minimum requirements for this installation?
A. A switch with two Ethernet interfaces
B. A router with two Ethernet interfaces
C. A switch with one Ethernet and one serial interface
D. A router with one Ethernet and one serial interface
E. A router with one Ethernet and one modem interface
F. None of the above
Answer: D
Explanation:
Only a router can terminate a leased line T1 access circuit, and only a router can connect
two different IP networks. Here, we will need a router with two interfaces, one serial
connection for the T1 and one Ethernet interface to connect to the switch on the LAN.

QUESTION 15
As a CCNA candidate, you must know the various layers of the OSI model. At which layers of the OSI Model do Wide Area Networks operate in? (Choose two)
A. Physical Layer
B. Datalink Layer
C. Network Layer
D. Session Layer
E. Transport Layer
F. Presentation Layer
G. Application Layer
Answer: A, B
Explanation:
A WAN is a data communications network that covers a relatively broad geographic area
and that often uses transmission facilities provided by common carriers, such as
telephone companies. WAN technologies generally function at the lower two layers of
the OSI reference model: the physical layer and the data link layer as shown below.

Note: Occasionally WAN's would also be considered to operate at layer 3, but since this question asked for only 2 choices layers 1 and 2 are better choices.

QUESTION 16
While troubleshooting a connectivity problem on the network, you issue the ping
command from your PC command prompt, but the output shows "request times
out."
At which OSI layer is this problem associated with?
A. The data link layer
B. The application layer
C. The access layer
D. The session layer
E. The network layer
Answer: E
Explanation:
TCP/IP includes ICMP, a protocol designed to help manage and control the operation of a TCP/IP network. The ICMP protocol provides a wide variety of information about a
network's health and operational status. Control message is the most descriptive part of a name. ICMP helps control and manage IP's work and therefore is considered part of
TCP/IP's network layer.

QUESTION 17
You download a file from an FTP site on the Internet. What is the highest layer in the OSI model used in this FTP operation?
A. Application
B. Presentation
C. Session
D. Transport
E. Internet
F. Data Link
G. Physical
Answer: A
Explanation:
Layer 7 is the application layer, which is the highest layer in the OSI model. This layer
describes the use of end user applications, such as opening movie files (avi, mpeg, etc)
used Microsoft Office applications, using WWW browsers, using Telnet, and using FTP.

QUESTION 18
A host computer has been correctly configured with a static IP address, but the default gateway is incorrectly set. Which layer of the OSI model will be first affected by this configuration error?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 5
F. Layer 6
E. Layer 7
Answer: C
Explanation:
IP Addressing and IP routing resides on the OSI Network layer, which is layer 3.

QUESTION 19
Which layer of the OSI reference model is responsible for ensuring reliable end-to-end delivery of data?
A. Application
B. Presentation
C. Session
D. Transport
E. Network
F. Data-Link
Answer: D
Explanation:
A key function of the transport layer is to provide connection services for the protocols and applications that run at the levels above it. These can be categorized as either connection-oriented services or connectionless services. Some protocol suites, such as TCP/IP, provide both a connection-oriented and a connectionless transport layer
protocol, to suit the needs of different applications. The transport layer is also the place in the layer stack where functions are normally included to add features to end-to-end data transport. Where network layer protocols are
normally concerned with just "best effort" communications, where delivery is not guaranteed. Transport layer protocols are given intelligence in the form of algorithms that ensure that reliable and efficient communication between devices takes place. This encompasses several related jobs, including lost transmission detection and handling, and managing the rate at which data is sent to ensure that the receiving device is not overwhelmed. Transmission quality, meaning ensuring that transmissions are received as sent, is so important that some networking references define the transport layer on the basis of reliability and flow-control functions. However, not all transport layer protocols provide these services. Just as a protocol suite may have a connection-oriented and a connectionless transport layer protocol, it may also have one that provides reliability and data management services, and one that does not. Again, this is the case with TCP/IP: there is one main transport layer protocol; TCP, that includes reliability and flow control features, and a second, UDP, that doesn't.

QUESTION 20
At which OSI layer is a logical path created between two host systems named CK1 and CK2 on the Certkiller LAN?
A. Physical
B. Session
C. Data link
D. Transport
E. Network
F. Application
G. Presentation
Answer: E
Explanation:
The Network layer (also called layer 3) manages device addressing, tracks the location of devices on the network, and determines the best way to move data, which means that the Network layer must transport traffic between devices that aren't locally attached. Routers (layer 3 devices) are specified at the Network layer and provide the routing services
within an internetwork.

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QUESTION 1
Both switches and hubs are being utilized within the Certkiller network. Which of the following is true regarding the use of switches and hubs for network connectivity in this network?
A. Switches take less time to process frames than hubs take
B. Hubs can filter frames
C. Switches do not forward broadcasts
D. Switches increase the number of collision domains in the network
E. Using hubs can increase the amount of bandwidth available to hosts
F. None of the above
Answer: D
Explanation:
The biggest benefit of using switches instead of hubs in your internetwork is that each switch port is actually its own collision domain. (Conversely, a hub creates one large collision domain.) But even armed with a switch, you still can't break up broadcast domains. Neither switches nor bridges will do that. They'll typically simply forward all broadcasts instead. Switch creates the collision domain per port, so we can say switch increase the number of collision domains.

QUESTION 2
Which one of the following characteristics is true regarding the use of hubs and switches?
A. Hubs can have their ports be configured with VLANs
B. Using hubs is costly with regard to bandwidth availability.
C. Switches can not forward broadcasts.
D. Switches are more efficient than hubs in processing frames.
E. Switches increase the number of collision domains in the network.
Answer: E
Explanation: Switches increases the number of collisions domains in the network. Switches that are configured with VLANs will reduce the size of the collision domains by increasing the number of collision domains in a network, but making them smaller than that of one big, flat network.
Incorrect Answers:
A. Switches are capable of VLAN configurations, but hubs are not.
B. Hubs are generally the least costly method possible to connect multiple devices together in a network.
C. Switches forward broadcasts and multicasts, by default, to all ports within the same VLAN. Only routers block all broadcast traffic by default.
D. Switches and hubs can be equally efficient in processing frames, in theory. In practice, switches are generally more efficient as they usually have more CPU and memory
allocated to them, and are generally much more expensive than a simple hub.

QUESTION 3
When comparing and contrasting the similarities and differences between bridges and switches, which of the following are valid statements? Choose all the valid answer choices)
A. Bridges are faster than switches because they have fewer ports.
B. A switch is a multiport bridge,
C. Bridges and switches learn MAC addresses by examining the source MAC address of each frame received.
D. A bridge will forward a broadcast but a switch will not.
E. Bridges and switches increase the size of a collision domain.
F. None of the above statements are true.
Answer: B, C
Explanation:
Both bridges and switches build the bridge table by listening to incoming frames and examining the source MAC address in the frame. Switches are multiport bridges that allow you to create multiple broadcast domains. Each broadcast domain is like a distinct virtual bridge within a switch.
Incorrect Answers:
A. Switches are generally faster than bridges. Bridges also do not necessarily have fewer ports than switches.
D. Both bridges and switches will forward broadcast and multicast traffic, assuming that the traffic remains in the same VLAN.
E. The use of VLANs in a switch can decrease the size of the collision domain, by creating additional, smaller collision domains.

QUESTION 4
Which of the following correctly describe the various functions and virtues of a router? (Select all valid answer choices)
A. Packet switching
B. Collision prevention on a LAN segment.
C. Packet filtering
D. Broadcast domain enlargement
E. Broadcast forwarding
F. Internetwork communication
G. None of the above
Answer: A, C, F
Explanation:
The main function of a router is to connect different, separated networks together. In doing so, switching packets from one network to another is a primary function, along with providing for communication between networks. As an additional feature, routers are capable of providing filtering on a network address and application port level, so choice C is also correct.
Incorrect Answers:
B. Routers can indeed be used to segment a network separate a collision domain, since routers do not forward LAN broadcasts and multicasts to other interfaces. However, routers alone can not prevent all collisions from occurring on any given LAN segment. D. Routers actually segment LANs into smaller broadcast domains. E. Routers do not forward broadcast and multicast traffic out the additional interfaces by default. Unless bridging or IP helpers are configured on the router, LAN broadcasts are blocked at the router level.

QUESTION 5
The LAN needs are expanding at the Certkiller corporate office, which is quickly growing. You are instructed to enlarge the area covered by a single LAN segment on the Certkiller network. Which of the following are layer 1 devices that you can use? (Choose all that apply.)
A. A switch
B. A router
C. A network adapter card
D. A hub
E. A repeater
Answer: D, E
Explanation:
A hub simply repeats the electrical signal and makes no attempt to interpret the electrical
signal (layer 1) as a LAN frame (Layer 2). So, a hub actually performs OSI layer 1
functions, repeating an electrical signal, whereas a switch performs OSI layer 2
functions, actually interpreting Ethernet header information, particularly addresses, to
make forwarding decisions. Hubs can be used to increase the number of stations that can
be supported on a LAN. Because the repeater does not interpret what the bits mean, but does examine and generate electrical signals, a repeater is considered to operate at Layer 1. Repeaters can be used to physically extend the LAN to greater distances.

QUESTION 6
Cisco is the leader in the router market space. What basic functions do their routers perform in a network? (Choose two)
A. The microsegmentation of broadcast domains
B. Path selection
C. Packet switching
D. Bridging between LAN segments
E. Access layer security
F. VLAN membership assignment
G. Application optimization
Answer: B, C
Explanation:
The primary functions of a router are: Packet Switching and Path Selection. It is the routers job to determine the best method for delivering the data, and switching that data as quickly as possible.

QUESTION 7
Both bridges are switches are being used throughout the Certkiller LAN. Which of the following statements are true regarding bridges and switches in this network? (Choose 3)
A. Switches are primarily software based while bridges are hardware based.
B. Switches usually have a higher number of ports than most bridges.
C. Bridges are frequently faster than switches.
D. Bridges define broadcast domains while switches define collision domains.
E. Both bridges and switches forward Layer 2 broadcasts.
F. Both bridges and switches make forwarding decisions based on Layer 2 addresses.
Answer: B, E, F

QUESTION 8
As a network administrator, you will need to decide on the appropriate network devices to use. Which of the following correctly describes the roles of devices in a WAN? (Choose three)
A. A CSU/DSU terminates a digital local loop.
B. A router is commonly considered a DCE device.
C. A modem terminates an analog local loop.
D. A router is commonly considered a DTE device.
E. A modem terminates a digital local loop.
F. A CSU/DSU terminates an analog local loop.
G. A modem is used to terminate a T1
Answer: A, C, D
Explanation:
Layer 2 switching is considered hardware-based bridging because it uses specialized hardware called an application-specific integrated circuit (ASIC). ASICs can run up to gigabit speeds with very low latency rates. Switches usually have higher port number then bridge. Generally bridges have two ports. Both operates on Data link layer.

QUESTION 9
The Certkiller network administrator needs to determine what LAN devices to install on the Certkiller network. What are two advantages of using Layer 2 Ethernet switches over hubs? (Choose two)
A. Allowing simultaneous frame transmissions
B. Increasing the size of broadcast domains
C. Increasing the maximum length of UTP cabling between devices
D. Filtering frames based on MAC addresses
E. Decreasing the number of collision domains
Answer: A, D
Explanation:
A: A half duplex connection is where only one device can send or receive at a time. A full duplex connection is where both devices can send and receive at the same time. Thus, if you have a 100Mb half duplex connection, only sending at 100Mb OR receiving at 100Mb can happen at the same time. If you have a 100Mb full duplex connection, you can effectively get 200Mb out of the link because you could be sending 100Mb and receiving 100Mb at the same time. D: Switches are capable of filtering frames based on any Layer 2 fields. For example, a switch can be programmed to reject (not forward) all frames sourced from a particular network. Because link layer information often includes a reference to an upper-layer protocol, switches usually can filter on this parameter. Furthermore, filters can be helpful in dealing with unnecessary broadcast and multicast packets.

QUESTION 10
CDP is being used throughout the Certkiller network. What are two reasons why the Certkiller network administrator would use CDP? (Choose two)
A. To determine the status of network services on a remote device
B. To obtain the IP Address of a connected device in order to telnet to the device
C. To verify the type of cable interconnecting two devices
D. To verify Layer 2 connectivity between two devices when Layer 3 fails
E. To obtain VLAN information from directly connected switches
F. To determine the status of the routing protocols between directly connected routers
G. To support automatic network failover during outages
Answer: B, D
Explanation:
Cisco Discovery Protocol (CDP) is a proprietary protocol designed by Cisco to help administrators collect information about both locally attached and remote devices. By using CDP, you can gather hardware and protocol information about neighbor devices, which is useful info for troubleshooting and documenting the network.
You can use:
Show cdp neighbor
Show cdp neighbor details
Commands to gather the information of connected neighbors.