OSI And TCP/IP

Question 1

OSI: Application Layer

Answer 1

HTTP, provides network services directly to users. Web browsers are network applications which are dependent on this layer’s protocols to function. Response handling and network access.

Question 2

OSI: Presentation Layer

Answer 2

Concerns the data format between peers. It translates, compresses, encrypts/ decrypts data so other applications can understand it. Sender side encrypts the data and the receiver side decrypts the data.

Question 3

OSI: Session Layer

Answer 3

Ties different transport streams that are part of same app. (EX: audio and video streams for zoom). Does session management, authentication, and authorization.

Question 4

OSI: Transport Layer

Answer 4

Implements a process to process channel. Controls the reliability of communication through segmentation, flow control, and error control.

Question 5

OSI: Network Layer

Answer 5

Handles routing among nodes in a packet switched network. It’s data delivery, routing for moving a data packet to source from destination, logical addressing for assigning unique identifiers, and path determination where computer can be on internet or server.

Question 6

OSI: Data Link

Answer 6

Collects a stream of bits into frames, network adaptors and device drivers. Ensures reliable frame transmission. LLC does error detection and flow control but MAC assigns addresses and manages access to physical mediums.

Question 7

OSI: Physical Layer

Answer 7

Handles transmission of raw bits over a communication link. (EX: Ethernet, WiFi, fiber optics)

Question 8

OSI vs TCP/IP

Answer 8

OSI has 7 layers, TCP/IP has 4.
OSI is conceptual (for learning) and TCP/IP is used for IRL networking.
OSI is mainly for reference but TCP/IP powers the internet.

Question 9

Transport Layer of IP

Answer 9

TCP: reliable, connection oriented
UDP: best effort delivery, connectionless.