What transport services does udp provide?

udp provides "connectionless" transmission services. The Chinese name of UDP is User Datagram Protocol. It is a connectionless transport layer protocol in the OSI reference model. It provides simple and unreliable transaction-oriented information transmission services; UDP provides applications with a way to send encapsulated data without establishing a connection. IP packet method.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

UDP provides connectionless transmission service. It does not need to establish a connection with the other party and can send datagrams directly. UDP only encapsulates the data transmitted by the application to the IP layer into datagrams and then sends them out. There is no need to establish a connection, no connection management, and no handshake protocol before sending data, so it is much faster than TCP. However, UDP also has its own shortcomings. It cannot guarantee the reliability of data transmission, so if important data is transmitted, the unreliability of UDP must be taken into consideration.

udp protocol introduction

The Internet protocol set supports a connectionless transmission protocol called the User Datagram Protocol (UDP, User Datagram Protocol). UDP provides a way for applications to send encapsulated IP packets without establishing a connection. RFC 768 describes UDP.

UDP is the abbreviation of User Datagram Protocol. The Chinese name is User Datagram Protocol. It is a connectionless transport layer protocol in the OSI (Open System Interconnection) reference model that provides transaction-oriented Simple Unreliable Message Delivery Service, IETF RFC 768 is the official specification of UDP. The protocol number of UDP in IP packets is 17.

The UDP protocol is used to process data packets like the TCP protocol. In the OSI model, both are located at the transport layer, which is the upper layer of the IP protocol. UDP has the disadvantage of not providing data packet grouping, assembly, and inability to sort data packets. That is to say, after a message is sent, it is impossible to know whether it has arrived safely and completely. UDP is used to support network applications that need to transmit data between computers. Numerous client/server network applications, including network video conferencing systems, require the use of UDP protocol. The UDP protocol has been used for many years since its inception. Although its initial glory has been overshadowed by some similar protocols, UDP is still a very practical and feasible network transport layer protocol even today.

Content

UDP is a connectionless transport layer protocol in the OSI reference model. It is mainly used for packetization. In sequential arrival transmission, the checking and sorting of packet transmission order is completed by the application layer, providing a simple and unreliable transaction-oriented information transmission service. The UDP protocol is basically the interface between the IP protocol and the upper layer protocol. The UDP protocol is suitable for multiple applications running on the same device.

UDP provides connectionless communication and does not guarantee the reliability of transmitted data packets. It is suitable for transmitting a small amount of data at a time. The reliability of UDP transmission is responsible for the application layer. Commonly used UDP port numbers are: 53 (DNS), 69 (TFTP), and 161 (SNMP). UDP protocols include: TFTP, SNMP, NFS, DNS, and BOOTP.

UDP messages do not have reliability guarantee, sequence guarantee, flow control field, etc., and their reliability is poor. However, because the UDP protocol has fewer control options, it has small delay during data transmission and high data transmission efficiency. It is suitable for applications that do not require high reliability, or applications that can guarantee reliability, such as DNS, TFTP, and SNMP. wait.

Function

To identify multiple destination addresses on a given host, while allowing multiple applications to work on the same host and do so independently For the sending and receiving of data packets, the User Datagram Protocol UDP is designed.

UDP uses the underlying Internet protocol to transmit messages, and like IP provides unreliable connectionless packet transmission services. It does not provide functions such as packet arrival confirmation, sorting, and flow control.

UDP Helper can realize the relay and forwarding of broadcast messages of the specified UDP port, that is, convert the broadcast messages of the specified UDP port into unicast messages and send them to the specified server, playing the role of relay.

Extended knowledge:

The Internet's transport layer has two main protocols that complement each other. Connectionless is UDP, which does little in particular except give applications the ability to send packets and allow them to architect their own protocols at the required level. The connection-oriented one is TCP, which does almost everything.

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