2 Network Models and Encapsulation Free Online FlashCards

What is the OSI model used for?

The OSI model is a seven-layer reference framework for understanding and troubleshooting network functions.

What does the OSI Transport layer do?

The OSI Transport layer provides process-to-process delivery and may handle reliability and multiplexing. TCP and UDP are examples.

What are the four layers of the common TCP/IP model?

A common TCP/IP model has four layers: Application, Transport, Internet, and Link/network access. Some models split the bottom layer into physical and data-link layers, making five.

Which OSI layers roughly correspond to the TCP/IP Application layer?

The TCP/IP Application layer roughly corresponds to OSI layers 5–7: Session, Presentation, and Application.

What is network encapsulation?

Encapsulation is the process in which each lower layer adds control information, often a header, around the data it receives.

What does TCP add to application data to create a segment?

TCP adds a transport header to application data, creating a TCP segment. The header includes source and destination port numbers.

How do TCP’s delivery role and IP’s delivery role differ?

TCP provides a reliable, ordered byte stream and uses ports to deliver data to the appropriate process. IP addresses and delivers packets between networks but does not guarantee successful delivery.

What usually changes at a router as a packet crosses to the next link?

A router removes the incoming link-layer framing and puts the IP packet into a new frame for the next link. The source and destination IP addresses generally remain the same end-to-end.

What is the main function of the OSI Network layer?

The OSI Network layer addresses and routes packets between networks. IPv4 and IPv6 are examples.

What does the OSI Data Link layer transfer?

The OSI Data Link layer transfers frames across a local link. Ethernet, Wi-Fi, and PPP are examples.

What does the OSI Physical layer transmit?

The OSI Physical layer transmits signals and bits over a medium such as copper, fiber, or radio.

What happens during decapsulation?

Decapsulation occurs at the destination: each layer reads and removes its corresponding information in reverse order.