Roles of TCP and UDP protocols in the Communication System

Adding Internet applications to communication applications suddenly expands the communication space. The vast transmission space of the Internet has made communication a huge step forward. Now let's take a look at the basic principles and usage of TCP and UDP protocols in GPRS. GPRS is used in personal business networks, mainly for webpage access, sending and receiving mails, and various applications have fixed protocols. However, in industrial data transmission and other industries, users face optional TCP and UDP transmission, there is no clear standard, the owner, equipment suppliers, and system integrators often choose which transmission protocol to use on the GPRS network for a long time to discuss and test. This article compares the two Protocols, the applicability of the two data transmission protocols in different application fields is discussed in depth in terms of reliability, applicability, and charges ｡

1. GPRS industry applications

Currently, GPRS is widely used in power supply, Oilfield, industrial control, transportation, finance, securities, commerce, public security, weather forecasting, and real-time traffic information release. Its application features small data volumes, high Transmission Interval or irregular transmission. Data Transmission Through GPRS network is advantageous in low cost, fast and flexible networking, wide range, and professional team maintenance ｡

In applications, you can select TCP and UDP protocols on the GPRS network. Because there is no clear standard, the protocol used allows the owner, equipment suppliers, and system integrators to discuss the protocol for a long time and conduct a large number of tests. Almost every project requires small-scale tests, the process of GPRS application in the industry is affected. In addition to the protocol selection, the system running effect is also affected by the network quality, usage, and peripheral devices. The results of many tests are inconsistent, the results of TCP and UDP protocol selection cannot be accurately reflected, so that TCP and UDP choices are re-entered into a new round of discussion and testing process ｡

2. Definitions of the two transmission protocols and comparison of Main Features

For more information about the TCP and UDP protocols, see relevant materials. Here we will describe the characteristics of industrial applications ｡

UDP is a simple datagram-oriented transport layer protocol. Each output operation of a process generates a UDP datagram and assembles it into an IP datagram to be sent ｡

UDP does not provide reliable connections: it sends data from applications to the IP layer, but it does not guarantee that the data can reach the destination ｡

Both TCP and UDP use the same network layer (IP). TCP provides a reliable connection-oriented byte stream transport layer service ｡

TCP provides a completely different service to the application layer than UDP. TCP provides a connection-oriented and reliable byte stream service. TCP packages user data to form a packet segment; it starts a timer after sending data, waiting for confirmation of the peer data; the other end confirms the received data, sorts the data in the out of order, and discards the duplicate data; TCP provides end-to-end traffic control, and calculates and verifies a mandatory end-to-end test ｡

Connection orientation means that two applications that use TCP (usually a customer and a server) must establish a TCP connection before exchanging data with each other. This process is similar to making a call, dial the ring tone and wait for the other party to say "Hello" Before explaining who it is ｡

TCP transmission protocol connection process:

First, establish a connection. TCP uses three packet segments to establish the connection. This process is also called three-way handshake )｡

It takes four handshakes to terminate a connection ｡

Data transmission must be confirmed by the receiver and guaranteed by timeout retransmission, which is the root cause of TCP transmission ｡

We can see that TCP provides reliable communication protection during transmission, so that the transmitted data will not be lost for various reasons ｡

The TCP and UDP protocols provide different transmission modes and different transmission quality. TCP provides transmission assurance by increasing the network overhead. In the actual test of the GPRS network, when the network is normal, from the gprs dtu-> GPRS network-> Internet-> User Data Center path, UDP transmission is more effective than 99%, and TCP transmission is more effective than 100%. TCP basically guarantees reliable transmission ｡