1.3.6 Practice Questions

In the OSI model, which of the following functions are performed at the Application layer? (Select all that apply.)

Enabling communication between network clients and services Integrating network functionality into the host operating system The Application layer enables network services and integrates network functionality into the host operating system. Applications actually run above the OSI Application layer. Conversation identification is accomplished at the Session layer through connection or transaction ID numbers. Data translation is performed at the Presentation layer.

Which of the following functions are performed at the Physical layer of the OSI model?

Moving data across network cables The Physical layer is concerned with how to transmit data and how to connect network hosts.

Which OSI model layer is responsible for guaranteeing reliable message delivery?

Transport The Transport layer is responsible for connection services that provide reliable message delivery through error detection and correction mechanisms. Specifically, the TCP protocol provides these services. The Application layer integrates network functionality into the host operating system and enables network services. The Session layer's primary function is managing the sessions in which data is transferred. The Data Link layer defines the rules and procedures for hosts as they access the Physical layer.

Match the networking function or device on the left with its associated OSI model layer on the right.

Application HTTP Presentation ASCII Session Session ID number Transport Port Numbers Network Router Data Link Switch Physical Modem

Which of the following tasks is associated with the Session layer?

Connection establishment Connection establishment is controlled through Session layer protocols.

Which of the following are included as part of Data Link layer specifications? (Select two.)

Controlling how messages are propagated through the network. Identifying physical network devices. The Data Link layer controls device identification on networks, as well as how messages travel through the network (the logical topology). The other functions listed here are performed by the Physical layer.

What is the basic purpose of the OSI Physical layer?

Coordinates rules for transmitting bits. The OSI Physical layer coordinates rules for transmitting bits.

In the OSI model, which of the following functions are performed at the Presentation layer? (Select two.)

Encrypt and compress data Specify data format (such as file formats) The Presentation layer encrypts data, changes and converts character sets, and compresses data. File formats (such as .jpg, .wmv, and .wav) are part of the Presentation layer. The Application layer provides network services. The Session layer maintains separate client connections through session IDs and maintains those sessions. Flow control and error detection are provided at both the Transport layer and the Data Link layer. Frame transmission occurs at the Physical layer.

The Data Link Layer of the OSI model is comprised of two sublayers. What are they? (Select two.)

LLC MAC The Data Link layer is split into the following sublayers: The Logical Link Control (LLC) Sublayer, which provides the operating system link to the device driver. The Media Access Control (MAC) Sublayer, which translates generic network requests into device-specific terms.

Which of the following are functions of the MAC sublayer? (Select two.)

Letting devices on the network have access to the LAN Defining a unique hardware address for each device on the network The MAC sublayer defines a unique MAC or data-link address for each device on the network. This address is usually assigned by the manufacturer. The MAC sublayer also provides devices with access to the network media.

Match each layer of the TCP/IP model on the left with the corresponding layer of the OSI model on the right. Each option on the left can be used more than once.

Presentation Application Data Link Network Access Application Application Session Application Network Internet Transport Host-to-Host The TCP/IP networking model maps to the OSI networking model as follows: TCP/IP Model Layer - OSI Model Layer Application - Application, Presentation, Session Host-to-Host Transport - Transport Internet - Network Network Access - Data Link (Hardware) - Physical

Which of the following functions are performed by the OSI Transport layer? (Select three.)

Reliable message delivery Data segmentation and reassembly End-to-end flow control The Transport layer is responsible for breaking upper-layer data into segments and allowing reliable communications through end-to-end flow control, error detection, and error correction. Message transmission through media is performed at the Physical layer. Media access, logical topology, and device identification occurs at the Data Link layer. Path identification and selection is a function of the Network layer. Data formatting is performed at the Presentation layer.

In the OSI model, what is the primary function of the Network layer?

Routes messages between networks The Network layer is responsible for routing messages between networks.

During TCP/IP communications between two network hosts, information is encapsulated on the sending host and decapsulated on the receiving host using the OSI model. Match the information format on the left with the appropriate layer of the OSI model on the right. (Not all layers have a matching information format.)

Session Layer *BLANK* Transport Layer Segments Network Layer Packets Data Link Layer Frames Physical Layer Bits Encapsulation is the process of breaking a message into packets, adding control and other information, and transmitting the message through the transmission media. The following is the five-step data encapsulation/decapsulation process used by the OSI model: > Upper layers prepare the data to be sent through the network. > The Transport layer breaks the data into pieces called segments, adding sequencing and control information. > The Network layer converts the segments into packets, adding logical network and device addresses. > The Data Link layer converts the packets into frames, adding physical device addressing information. > The Physical layer converts the frames into bits for transmission across the transmission media