Absolutely, let's continue with the explanation of the transport and application layers of the network model:

Transport Layer and Application Layer:

• The first three layers of the network model (Physical, Data Link, and Network layers) enable communication between nodes on a network, but they don't address how individual programs running on those nodes can communicate with each other.
• The transport and application layers step in to facilitate communication between specific applications running on different computers within a network.

Transport Layer's Role:

• The transport layer ensures that traffic is properly directed to the correct network applications.
• It deals with the segmentation, reassembly, and flow control of data to ensure reliable communication between applications.
• One key aspect of the transport layer is the concept of ports. Ports are used to identify specific network services or applications on a device.
• The transport layer also differentiates between two common protocols: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

Application Layer's Role:

• The application layer focuses on enabling communication between specific applications running on different computers.
• It provides a way for applications to understand each other's data and establish communication channels.
• Protocols at this layer include HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), SMTP (Simple Mail Transfer Protocol), and more.
• Each protocol defines rules for how data should be structured and exchanged between applications.

TCP Ports and Sockets:

• TCP ports are used to direct incoming data to the appropriate application.
• A socket is a combination of an IP address and a port number, providing a unique identifier for a network service.
• For example, web servers typically listen on port 80, while email servers use port 25.

TCP Header and Connection-Oriented Protocols: