Written Lab 1.1: OSI Questions

Question 1

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

Answer 1

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

Question 2

Which layer is represented by frames?

Answer 2

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

Question 3

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

Answer 3

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 4

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

Answer 4

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

Question 5

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

Answer 5

Network

Question 6

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 6

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

Question 7

Which layer segments and reassembles data into a data stream?

Answer 7

Transport

Question 8

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

Answer 8

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

Question 9

Rearrange the following in order of encapsulation: 
Packets
Frames
Bits
Segments

Answer 9

Segments, packets, frames, bits

Question 10

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 10

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 11

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 11

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

Question 12

Which layer is represented by segments?

Answer 12

The Transport layer segments user data

Question 13

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

Answer 13

The Session layer creates sessions between different hosts’ applications.

Question 14

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

Answer 14

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

Question 15

Which layer is represented by packets?

Answer 15

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

Question 16

Which layer is represented by bits?

Answer 16

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

Question 17

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

Answer 17

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

Question 18

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

Answer 18

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

Question 19

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

Answer 19

Data Link

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