OSI and TCP/IP Models

Flashcards summarizing the OSI and TCP/IP models from the lecture notes.

What is the main purpose of the OSI 7 Layer Model?

Describes 7 layers that computer systems use to communicate over a network.

List the layers of the OSI model.

Application, Presentation, Session, Transport, Network, Datalink, Physical.

Name at least one advantage of the OSI Model.

Used to determine the hardware and software required to build the network, understand how each network node communicates and provides universal interoperability (non-vendor specific hardware).

In the OSI model, what is the main function of the Application Layer?

Human / computer interaction – applications!

In the OSI model, what does the Presentation Layer do?

Ensures data in a usable format, includes encryption, encoding and compression.

What is the responsiblity of the Session Layer in the OSI model?

Maintains connections, controls ports, opens, ensures and stops the session and sets checkpoints during a data transfer.

What are the functions of the Transport Layer in the OSI model?

Transmits data using protocols. Data is broken up into segments and reassembled. Ensures delivery of entire file / message and is responsible for flow and error control.

What are the two principal functions of the Network Layer?

Breaking segments into network packets (sender node) and reassembling the packets (receiving node) and discovering the best path across a physical network to route packets.

Explain the two distinct parts of the Data Link Layer.

Logical Link Control (LLC) identifies network protocols, performs error checking and frame synchronization. Media Access Control (MAC) MAC addresses connect devices and define permissions to receive and transmit data.

Describe the Physical Layer.

Defines the physical cable / wireless connection between network nodes and is responsible for transmission of raw data (series of 0s and 1s)

What is the TCP/IP model?

Transmission Control Protocol/Internet Protocol (TCP/IP) is not based on the OSI 7 layer model but is a functional model based on specific, standard protocols.

How does the TCP/IP model relate to the OSI model in terms of layers?

TCP/IP is simpler and several OSI layers are consolidated into one: OSI layers 5, 6, 7 combined into one Application Layer and OSI layers 1, 2 combined into one Network Layer

What are the layers of the TCP/IP model?

Application, Transport, Internet, and Link

What are some examples of Application Layer protocols in the TCP/IP model?

Domain Name System (DNS), Dynamic Host Control Protocol (DHCP), and Internet Message Access Protocol (IMAP).

Describe the two main protocols in the Transport Layer of the TCP/IP model.

Transmission Control Protocol (TCP) which is connection-orientated and User Datagram Protocol (UDP) which is connectionless.

What is the main function of the Internet Layer in the TCP/IP model?

Controls the flow of data including breaking up packets and reassembling them and ensures data is sent quickly and accurately.

What is the purpose of the Link Layer in the TCP/IP model?

Establishes and terminates a connection between two network nodes and packets are broken up into frames and sent from source to destination