1.5 Protocol Layering

• What are the purpose of layers?

  Each layer implements a service via its own internal-layer actions relying on services provided by layer below
• The presentation layer allows applications to interpret meaning of data and format it for the user. Examples: encryption, compression, machine-specific conventions
• The session layer is responsible for the communication between the client and the server.
• What layers do the OSI model have that the TCP/IP model doesn't?

  Presentation and Session
• The application layer handles the user's request and sends it to the appropriate server. It supports network applications such as FTP, SMTP, HTTP.
• The transport layer is responsible for host-host data transfer, ensuring data integrity, and managing flow control. Examples include TCP and UDP.
• The network layer manages addressing, routing, and logical connectivity in a network. Examples include IP and routing protocols.
• The link layer focuses on organizing bits into frames, ensuring reliable data transfer between directly connected network elements. Example: Ethernet
• The physical layer deals with the physical connection and transmission of individual bits over a physical medium(wire).