Chapter 1 - Internetworking

Question 1

Which layer chooses and determines the availability of communicating partners along with the resources necessary to make the connection, coordinates partnering applications, and forms a consensus on procedures for controlling data integrity and error recovery?

Answer 1

The Application layer is responsible for finding the network resources broadcast from a server and adding flow control and error control (if the application developer chooses).

Question 2

Which layer is responsible for converting data packets from the Data Link layer into electrical signals?

Answer 2

The Physical layer takes frames from the Data Link layer and encodes the 1s and 0s into a digital or analog (Ethernet or wireless) signal for transmission on the network medium.

Question 3

At which layer is routing implemented, enabling connections and path selection between two end systems?

Answer 3

The Network layer provides routing through an internetwork and logical addressing.

Question 4

Which layer defines how data is formatted, presented, encoded, and converted for use on the network?

Answer 4

The Presentation layer makes sure that data is in a readable format for the Application layer.

Question 5

Which layer is responsible for creating, managing, and terminating sessions between applications?

Answer 5

The Session layer sets up, maintains, and terminates sessions between applications.

Question 6

Which layer ensures the trustworthy transmission of data across a physical link and is primarily concerned with physical addressing, line discipline, network topology, error notification, ordered delivery of frames, and flow control?

Answer 6

PDUs at the Data Link layer are called frames and provide physical addressing plus other options to place packets on the network medium.

Question 7

Which layer is used for reliable communication between end nodes over the network and provides mechanisms for establishing, maintaining, and terminating virtual circuits; transport-fault detection and recovery; and controlling the flow of information?

Answer 7

The Transport layer uses virtual circuits to create a reliable connection between two hosts.

Question 8

Which layer provides logical addressing that routers will use for path determination?

Answer 8

The Network layer provides logical addressing, typically IP addressing and routing.

Question 9

Which layer specifies voltage, wire speed, and cable pinouts and moves bits between devices?

Answer 9

The Physical layer is responsible for the electrical and mechanical connections between devices.

Question 10

Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provides error detection?

Answer 10

The Data Link layer is responsible for the framing of data packets.

Question 11

Which layer is responsible for keeping the data from different applications separate on the network?

Answer 11

The Session layer creates sessions between different hosts’ applications.

Question 12

Which layer is represented by frames?

Answer 12

The Data Link layer frames packets received from the Network layer.

Question 13

Which layer is represented by segments?

Answer 13

The Transport layer segments user data.

Question 14

Which layer is represented by packets?

Answer 14

The Network layer creates packets out of segments handed down from the Transport layer.

Question 15

Which layer is represented by bits?

Answer 15

The Physical layer is responsible for transporting 1s and 0s (bits) in a digital signal.

Question 16

Rearrange the following in order of encapsulation:

Packets Frames Bits Segments

Answer 16

Segments , Packets, Frames, Bits

Question 17

Which layer segments and reassembles data into a data stream?

Answer 17

Transport

Question 18

Which layer provides the physical transmission of the data and handles error notification, network topology, and flow control?

Answer 18

Data Link

Question 19

Which layer manages logical device addressing, tracks the location of devices on the internetwork, and determines the best way to move data?

Answer 19

Network

Question 20

What is the bit length and expression form of a MAC address?

Answer 20

48 bits (6 bytes) expressed as a hexadecimal number

Question 21

Which of the following statements is/are true with regard to the device shown here? (Choose all that apply.)

Picture of small hub

A. It includes one collision domain and one broadcast domain.
B. It includes 10 collision domains and 10 broadcast domains.
C. It includes 10 collision domains and one broadcast domain.
D. It includes one collision domain and 10 broadcast domains.

Answer 21

A. The device shown is a hub and hubs place all ports in the same broadcast domain and the same collision domai

Question 22

With respect to the OSI model, which one of the following is the correct statement about PDUs?
A. A segment contains IP addresses.
B. A packet contains IP addresses.
C. A segment contains MAC addresses.
D. A packet contains MAC addresses.

Answer 22

B. The contents of a protocol data unit (PDU) depend on the PDU because they are created in a specific order and their contents are based on that order. A packet will contain IP addresses but not MAC addresses because MAC addresses are not present until the PDU becomes a frame.

Question 23

You are the Cisco administrator for your company. A new branch office is opening and you are selecting the necessary hardware to support the network. There will be two groups of computers, each organized by department. The Sales group computers will be assigned IP addresses ranging from 192.168.1.2 to 192.168.1.50. The Accounting group will be assigned IP addresses ranging from 10.0.0.2 to 10.0.0.50. What type of device should you select to connect the two groups of computers so that data communication can occur?
A. Hub
B. Switch C. Router D. Bridge

Answer 23

C. You should select a router to connect the two groups. When computers are in different subnets, as these two groups are, you will require a device that can make decisions based on IP addresses. Routers operate at layer 3 of the Open Systems Interconnect (OSI) model and make data-forwarding decisions based on layer 3 networking information, which are IP addresses. They create routing tables that guide them in forwarding traffic out of the proper interface to the proper subnet.

Question 24

The most effective way to mitigate congestion on a LAN would be to \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
A. Upgrade the network cards
B. Change the cabling to CAT 6
C. Replace the hubs with switches
D. Upgrade the CPUs in the routers

Answer 24

C. Replacing the hub with a switch would reduce collisions and retransmissions, which would have the most impact on reducing congestion.

Question 25

In the following work area, draw a line from the OSI model layer to its PDU. ``` Layer—————Description Transport Bits Data Link Segment Physical Packet Network Frame ```

Answer 25

In the following work area, draw a line from the OSI model layer to its PDU. ``` Layer—————Description Transport Bits Data Link Segment Physical Packet Network Frame ```

Question 26

What is a function of the WLAN Controller? A. To monitor and control the incoming and outgoing network traffic B. To automatically handle the configuration of wireless access points C. To allow wireless devices to connect to a wired network D. To connect networks and intelligently choose the best paths between networks

Answer 26

6. B. Wireless LAN Controllers are used to manage anywhere from a few access points to thousands. The AP's are completely managed from the controller and are considered lightweight or dumb AP's as they have no configuration on the AP itself.

Question 27

You need to provide network connectivity to 150 client computers that will reside in the same subnetwork, and each client computer must be allocated dedicated bandwidth. Which device should you use to accomplish the task? A. Hub B. Switch C. Router D. Bridge

Answer 27

B. You should use a switch to accomplish the task in this scenario. A switch is used to provide dedicated bandwidth to each node by eliminating the possibility of collisions on the switch port where the node resides. Switches work at layer 2 in the Open Systems Interconnection (OSI) model and perform the function of separating collision domains.

Question 28

In the following work area, draw a line from the OSI model layer definition on the left to its description on the right. Layer—————Description Transport Framing Physical End-to-end connection Data Link Routing Network Conversion to bits

Answer 28

In the following work area, draw a line from the OSI model layer definition on the left to its description on the right. Layer—————Description Transport Framing Physical End-to-end connection Data Link Routing Network Conversion to bits

Question 29

What is the function of a firewall? A. To automatically handle the configuration of wireless access points B. To allow wireless devices to connect to a wired network C. To monitor and control the incoming and outgoing network traffic D. To connect networks and intelligently choose the best paths between networks

Answer 29

C. Firewalls are used to connect our trusted internal network such as the DMZ, to the untrusted outside network—typically the internet.

Question 30

``` Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see whether enough resources exist for that communication? A. Transport B. Network C. Presentation D. Application ```

Answer 30

D. The Application layer is responsible for identifying and establishing the availability of the intended communication partner and determining whether sufficient resources for the intended communication exist.

Question 31

Which of the following correctly describe steps in the OSI data encapsulation process? (Choose two.) A. The Transport layer divides a data stream into segments and may add reliability and flow control information. B. The Data Link layer adds physical source and destination addresses and an FCS to the segment. C. Packets are created when the Network layer encapsulates a frame with source and destination host addresses and protocol-related control information. D. Packets are created when the Network layer adds layer 3 addresses and control information to a segment. E. The Presentation layer translates bits into voltages for transmission across the physical link.

Answer 31

A, D. The Transport layer segments data into smaller pieces for transport. Each segment is assigned a sequence number so that the receiving device can reassemble the data on arrival. The Network layer (layer 3) has two key responsibilities. First, this layer controls the logical addressing of devices. Second, the Network layer determines the best path to a particular destination network and routes the data appropriately.

Question 32

``` Which of the following layers of the OSI model was later subdivided into two layers? A. Presentation B. Transport C. Data Link D. Physical ```

Answer 32

C. The IEEE Ethernet Data Link layer has two sublayers, the Media Access Control (MAC) layer and the Logical Link Control (LLC) layer.

Question 33

What is a function of an access point (AP)? A. To monitor and control the incoming and outgoing network traffic B. To automatically handle the configuration of wireless access point C. To allow wireless devices to connect to a wired network D. To connect networks and intelligently choose the best paths between networks

Answer 33

C. Wireless AP's are very popular today and will be going away about the same time that rock n' roll does. The idea behind these devices (which are layer 2 bridge devices) is to connect wireless products to the wired Ethernet network. The wireless AP will create a single collision domain and is typically its own dedicated broadcast domain as well.

Question 34

A _____________ is an example of a device that operates only at the physical layer. A. Hub B. Switch C. Router D. Bridge

Answer 34

A. Hubs operate on the Physical Layer as they have no intelligence and send all traffic in all directions.

Question 35

Which of the following is not a benefit of using a reference model? A. It divides the network communication process into smaller and simpler components. B. It encourages industry standardization. C. It enforces consistency across vendors. D. It allows various types of network hardware and software to communicate.

Answer 35

C. While it is true that the OSI model's primary purpose is to allow different vendors' networks to interoperate, there is no requirement that vendors follow the model.

Question 36

Which of the following statements is not true with regard to routers? A. They forward broadcasts by default. B. They can filter the network based on Network layer information. C. They perform path selection. D. They perform packet switching.

Answer 36

A. Routers by default do NOT forward broadcasts.

Question 37

Switches break up ____________ domains, and routers break up ____________ domains. A. broadcast,broadcast B. collision,collision C. collision,broadcast D. broadcast,collision

Answer 37

C. Switches create separate collision domains within a single broadcast domain. Routers provide a separate broadcast domain for each interface.

Question 38

``` Which of the following is the only device that operates at all layers of the OSI model? A. Network host B. Switch C. Router D. Bridge ```

Answer 38

A. The following network devices operate at all seven layers of the OSI model: network management stations (NMSs), gateways (not default gateways), servers, and network hosts.