User Datagram Protocol (UDP)

Introduced

A User Datagram protocol is a protocol that defines the communication of a computer to provide packet switching in an interconnected network environment. This protocol defaults to the network Protocol (IP) as its underlying protocol. This protocol provides the simplest protocol mechanism for sending information to another user program. This Protocol is action-oriented and does not provide submit and copy protection. If your application requires reliable data transfer, you should use Transmission Control Protocol (TCP). The datagram format is as follows:

User Data Header Format

Domain

The source port is an optional domain, and when it is meaningful, it refers to the port on which the process is sent, which also assumes where the return information should be sent without additional information. If you do not use it, fill in 0 in this field. The destination port is meaningful when there is a specific destination network address. Length refers to the octal representation of the length of this user datagram. (This indicates that the minimum datagram length is 8.) The checksum code has 16 digits, is to the IP head, the UDP header and the data in the information header's digit to take opposite and then obtains.

The header is conceptually based on the UDP header information, which includes the active address, the destination address, the protocol used, and the UDP length. This information does not allow information to be received incorrectly. This validation process is consistent with the process used in TCP.

If the computed checksum code is zero, it will be sent all 0. A full zero checksum means that the sender does not produce a checksum code.

User interface

The user interface should allow the creation of a new receive port, where the receive operation on the receiving port has: should return a octal number indicating the source port and the source address, allowing datagram routing, specifying data, source and destination ports, and destination addresses.

IP Layer Interface

The UDP module must be able to determine the network address of the source and destination, and must be able to know the protocol used from the header. A possible interface way is to return the entire datagram, including the header returned by the receive operation. Such an interface should also allow UDP to transmit full packet headers to IP for transmission. The IP determines the consistency and calculates the checksum code.

Protocol Application

The most important uses of this protocol are the Internet name server and the small file Transfer protocol.

Agreement Number

When used in IP, its protocol number is 17 (octal is 21).