Because tcp and udp are very basic. The only difference between the two transmissions is reliability. The same process can be transmitted through tcp or udp as needed.

With netstat -an, the IP header has a field called protocol, indicating whether the upper layer protocol is TCP, UDP or other P ..

TCP [::]:49 152 [::]:0 monitoring

TCP [::]:49 153 [::]:0 monitoring

TCP [::]:49 154 [::]:0 monitoring

Extended data:

The task of the transport layer is to maximize the use of network resources according to the characteristics of the communication subnet, provide the function of establishing, maintaining and canceling the transmission connection between the session layers of the two systems, and be responsible for end-to-end reliable data transmission. At this layer, the protocol data unit of information transmission is called segment or message.

The network layer only transmits the data packets sent by the source node to the destination node according to the network address, while the transport layer is responsible for reliably transmitting the data to the corresponding port. The resource subnet in the computer network is the initiator and receiver of communication, and each device in it is called an endpoint. Communication subnet provides communication services in the network, and the devices in it are called nodes. In the OSI reference model, the following four layers are used for communication control, but their control objects are different.

Baidu encyclopedia-transport layer