|UDP-Lite, Lightweight User Datagram Protocol|
|Protocol type:||Transport layer protocol.|
|Related protocols:||UDP, User Datagram Protocol.|
|SNMP MIBs:||iso.org.dod.internet.mgmt.mib-2.udpliteMIB (188.8.131.52.2.1.170)|
|Working groups:||tsvwg, Transport Area Working Group.|
UDP-Lite is similar to the UDP protocol but can also serve applications in error-prone network environments that prefer to have partially damaged payloads delivered rather than discarded. If this feature is not used, UDP-Lite is semantically identical to UDP.
|MAC header||IP header||UDP-Lite header||Data :::|
|Source Port||Destination Port|
The port number of the sender. Cleared to zero if not used.
The port number this packet is addressed to.
16 bits. 0 or 8+.
The number of bytes, counting from the first byte of the UDP-Lite header covered by the checksum. The UDP-Lite header MUST always be covered by the checksum. Despite this requirement, the Checksum Coverage is expressed in bytess from the beginning of the UDP-Lite header in the same way as for UDP. A Checksum Coverage of zero indicates that the entire UDP-Lite packet is covered by the checksum. A UDP-Lite packet with a Checksum Coverage value of 1 to 7 MUST be discarded by the receiver. Irrespective of the Checksum Coverage, the computed Checksum field MUST include a pseudo-header, based on the IP header. UDP-Lite packets with a Checksum Coverage greater than the IP length MUST also be discarded.
Computed as the 16-bit one's complement of the one's complement sum of a pseudo-header of information collected from the IP header, the number of bytes specified by the Checksum coverage field (starting at the first byte in the UDP-Lite header), virtually padded with a zero byte at the end if necessary to make a multiple of two bytes. Prior to computation, the checksum field MUST be cleared to zero. If the computed checksum is 0, it is transmitted as all ones (the equivalent in one's complement arithmetic).
[RFC 3828] The Lightweight User Datagram Protocol (UDP-Lite).
[RFC 4019] RObust Header Compression (ROHC): Profiles for User Datagram Protocol (UDP) Lite.