Chapter 2

Question 1

The OSI model has 7 layers what are they?

30

Answer 1

Application- layer 7
Presentation- layer 6
Session-layer 5
Transport- layer 4
 Network- layer 3
Data Link- layer 2
Physical - layer 1

Question 2

The application layer.

31

Answer 2

The application layer serves as the window ( interface ) for users and application processes to access network services.

Question 3

The presentation layer.

33

Answer 3

The presentation layer formats the data to be presented to the application layer. It can be viewed as the translator for the network. This layer may translate data from a format used by the application layer into a common format at the sending station, then translate the common format to a format known to the application layer at the receiving station.

Question 4

The Session layer

33

Answer 4

The session layer allows session establishment between processes running on different stations. It provides:

1- Session establishment, maintenance and termination: allows two application processes on different machines to establish, use and terminate a connection, called a session.
2- Session support: performs the functions that allow these processes to communicate over the network, performing security, name recognition, logging, and so on.

Question 5

The transport layer.

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Answer 5

The transport layer ensures that messages are delivered error-free, in sequence, and with no losses or duplications. It relieves the higher layer protocols from any concern with the transfer of data between them and their peers.

Question 6

The Network layer.

39

Answer 6

The network layer controls the operation of the subnet, deciding which physical path the data should take based on network conditions, priority of service, and other factors

Question 7

The data link layer

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Answer 7

The data link layer provides error-free transfer of data frames from one node to another over the physical layer, allowing layers above it to assume virtually error-free transmission over the link.

Question 8

The physical layer.

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Answer 8

The physical layer consists of the basic networking hardware transmission technologies of a network.

Question 9

in which layer are the frames encoded from 1s and 0s into digital signal?
44

Answer 9

Physical layer

Question 10

Connection oriented communication.

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Answer 10

Connection-oriented communication is a network communication computer networking, where a communication session or a semi-permanent connection is established before any useful data can be transferred, and where a stream of data is delivered in the same order as it was sent.