UDP concept
User Datagram Protocol (User Datagram Protocol, UDP) is the Open Systems Interconnection model (Open System Interconnection, OSI) transport layer protocols in one, simple datagram-oriented protocol that reservation message boundaries. UDP does not provide error correction, queue management, deduplication, flow control and congestion control, but provides error detection. This protocol itself provides minimal functionality, so use it to do a lot of applications and processes on how to send datagrams control. Want to ensure that data is reliable delivery or correct sequencing, these applications must implement their own protection. The UDP datagram sent, but does not guarantee that they can reach their destination . In addition, there is no mechanism to prevent the negative impact of the agreement told UDP traffic to other network users. This lack of reliability required and the protective upper layer protocol UDP instead of complete, but because there is no connection characteristics UDP, which uses less expensive than other transport protocols.
Feature
1) UDP is a connectionless without establishing a connection before that transmit data, reducing overhead and delay before sending data
2) UDP use a best effort delivery, that does not guarantee reliable delivery, the host does not need to maintain complex connection status table.
3) UDP does not congestion control, network congestion does not invalidate the transmission rate of the source host is reduced
4) UDP to support one, one to many, and many-to-many interactive communication
5) UDP header overhead is small, only 8 bytes than the first 20 bytes of TCP shorter
wireshark UDP protocol analysis
Udp test using small tools, server open port 8888
8888 Port Services client connections through wireshark know, there is no information packets, UDP without establishing a connection
The client sends data
wireshark packets and UDP headers contrast control
View the trace stream transmission content
