OSI Model

Question 1

Layer 1

Answer 1

Physical - where bits travel in 1s and 0s over physical cables and satellite transmissions

Question 2

Layer 2

Answer 2

Data Link - responsible for data transferred between hosts on a LAN or WAN (Wide Area Network). This is also called the network interface layer. Data at this level is organized and grouped into frames.

Question 3

Layer 3

Answer 3

Network - responsible for the transfer of data outside of LAN or WAN, for example, between hosts on different networks. Data here is organized into packets and includes the source and destination IP (Internet Protocol) addresses of the sending and receiving hosts.

Question 4

Layer 4

Answer 4

Transport - where data is defined with more special service protocols and organized into segments. For example, the Transfer Control Protocol (TCP) assures that every segment or packet arrives at its destination. UDP does not ensure that each packet or segment arrives. Rather, it just streams data constantly.

Question 5

Layer 5

Answer 5

Session - provides the mechanism for opening, closing, and managing a session between end-user application processes

Question 6

Layer 6

Answer 6

Presentation - responsible for the formatting and delivery of information to the application layer for further processing or display (also called the syntax layer)

Question 7

Layer 7

Answer 7

Application - layer that connects software that users use with lower layers - HTTP is on this layer