2.2.6 Section Quiz

Question 1

In the OSI model, which of the following functions are performed at the Application Layer (Select two)

1. Device control for data transmission rates.
2. Enabling of communication between network clients and services.
3. Standard setting for sending and receiving signals.
4. Communication setup, maintenance, and teardown.
5. Integration of network functionality into the host operating system.

Answer 1

2. Enabling of communication between network clients and services.
3. Integration of 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.

The setup, maintenance, and teardown of communication happens at the Session layer.

The Data Link layer controls the rate of data transmission between hosts (flow control).

The Physical layer sets standards for sending and receiving electrical signals between devices.

Question 2

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

1. Digital data conversion
2. Physical topology
3. Physical network device identification
4. Cable and connector specifications
5. Data transmission between hosts

Answer 2

3. Physical network device identification
4. Data transmission between hosts

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.

Question 3

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

1. Transmit data frames
2. Ensure that packets are delivered with no loss or duplication
3. Enable communication between network clients and services
4. Route messages between networks

Answer 3

4. Route messages between networks

The Network later is responsible for routing messaged between networks.

The Transport layer provides a transition between the upper and lower layers of the OSI model.

The Data Link layer defines how to verify that data received from the Physical layer is error free (using parity and cyclic redundancy checks {CRC}).

Question 4

What is the purpose of the OSI Physical layer?

1. Maintain a list of known networks and neighboring routers.
2. Define when devices have access to the LAN
3. Define how physical network devices are identified on the network.
4. Coordinate rules for sending and receiving electrical signals.

Answer 4

4. Coordinate rules for sending and receiving electrical signals.

The OSI Physical layer sets standards for sending and receiving electrical signals between devices.

The Data Link layer defines how physical networks devices are identified on a network and when devices have access to the LAN.

The Network layer maintains a list of known networks and neighboring routers.

Question 5

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

1. Network services
2. Data encryption and compression
3. Data frame transmission
4. End-to-end flow control
5. Data format specifications

Answer 5

2. Data encryption and compression
3. Data format specifications

The Presentation layer encrypts data, changes and converts character sets, and compresses data. File formats (such as .jpg, .wmv, .wav) are part of the Presentation layer.

The Application layer provides network services.

End-to-end flow control is provided by the Transport layer.

Frame transmission occurs at the Physical layer.

Question 6

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

1. IP address assignment
2. Data block breakdown
3. Port number assignment
4. Connection establishment

Answer 6

4. Connection establishment

Connection establishment is controlled through Session layer protocols.

The Transport layer breaks down data into blocks called segments. It then appends a port number to identity which top-layer application needs to receive the data on the destination device.

One very important thing that happens at the Network layer is IP address assignment.

Question 7

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

1. End-to-end flow control
2. Media access control, logical topology, and device identification
3. Consistent data formatting between dissimilar systems
4. Path identification and selection
5. Data segmentation and reassembly
6. Reliable message delivery
7. Packet formatting for delivery through the medium

Answer 7

1. End-to-end flow control
2. Data segmentation and reassembly
3. Reliable message delivery

The Transport layer is responsible for breaking upper-layer data into segments and allowing reliable communication through end-to end flow control, error detection, and error correction.

Message transmission through a medium is performed at the Physical layer.

Media access, logical topology, and device identification occur at the Data Link layer.

path identification and selection is a function of the Network layer.

Data formatting is performed at the Presentation layer.