1. The physical layer is mainly used to send electrical signals.
2. Data link layer, Ethernet protocol (source mac, destination mac), used for data packets, the mac address table identifies the specific network card
3. The network layer (source IP, destination IP), used to represent the network segment.
4. Transport layer: Establish port-to-port communication, including TCP protocol and UDP protocol. Used to represent a specific application.
5、
6. The specific steps of sending the package:
1. Calculate whether it is in a broadcast domain
2. In the same broadcast domain, obtain the destination mac based on the arp protocol, and then send the data packet in the form of broadcast
3. If not in the same broadcast domain, obtain the gateway mac based on the arp protocol, and then send the data packet to the gateway by broadcasting