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Lightweight User Datagram Protocol

What Does Lightweight User Datagram Protocol Mean?

Lightweight User Datagram Protocol (UDP-Lite) is a connectionless protocol similar to User Datagram Protocol (UDP).


However, it also may serve applications in error-prone network environments where partially damaged payloads are preferred to be delivered rather than discarded by the station receiving it.
This saves on bandwidth and time since data does not need to be sent again and decisions about data integrity are left to the receiving application or codec.

Aside from this feature, it is functionally and semantically similar to regular UDP.

Techopedia Explains Lightweight User Datagram Protocol

UDP-Lite is, as the name suggests, based on UDP.

However, there is a key difference: Unlike UDP, which either protects none or all of a packet with a checksum, UDP-Lite allows implementation of partial checksums that cover only a part of the datagram, and therefore delivers partially corrupted packets.

This protocol was meant for multimedia functions such as streamed video or VoIP where receiving partially corrupted or damaged packets are beneficial compared with not receiving any at all.

When using conventional UDP, an error in a single bit will cause a different or bad checksum and will invalidate and then discard the packet. In this scheme, no error is considered minor so even if the error is trivial, the packet is still discarded, which then requires resending that packet from the source, taking up time and bandwidth.

The checksum algorithm for both types of UDP is the same, but for Lite, it is only implemented partially starting from the UDP-Lite header which must always be covered by the checksum.

This does not mean that some UDP-Lite packets are not discarded. For example, packets with a checksum coverage value of 1-7 must be discarded (it must be 0 or 8+) and those with coverage greater than the IP length also must be discarded.


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