Wireshark packet capture illustration TCP three-way handshake/four waves details

Wireshark packet capture illustration TCP three-way handshake/four waves details

1. The link layer, also known as the data link layer or network interface layer, usually includes the device driver in the operating system and the network interface card corresponding to the computer. They work together with the physical interface details of the cable (or any other transmission medium.

2. The network layer, also known as the internet layer, Processes Group activities in the network, such as group routing. Network layer protocols include IP protocol (Internet Protocol), ICMP protocol (Internet control packet protocol), and IGMP protocol (Internet Group Management Protocol ).

3. The transport layer provides end-to-end communication for applications on two hosts. In the TCP/IP protocol family, there are two different transmission protocols: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol ). TCP provides high-reliability data communication for two hosts. His work includes dividing the data that an application has handed over to it into small pieces and handing it over to the network layer below, confirming the group received, and setting the timeout clock for sending the final confirmation group. Because the transport layer provides high-reliability end-to-end communication, the application layer can ignore all these details. On the other hand, UDP provides a very simple service for the application layer. It only sends a group called a datagram from one host to another, but it does not guarantee that the datagram can reach the other end. Any required reliability must be provided by the application layer.

4. The application layer is responsible for handling specific application details. Including Telnet (remote logon), FTP (file transfer protocol), SMTP (Simple Mail Transfer Protocol), and SNMP (Simple Network Management Protocol.

Shows the packets captured by wireshark and the corresponding protocol layer:

Wireshark packet capture illustration TCP three-way handshake/four waves details