User Datagram Protocol
Just a simple wrapper around a basic IP packet. UDP packets are not guaranteed to arrive, yet in most cases they do. Especially when talking to localhost or local area network.
Losing UDP packets within your LAN or localhost means your machine has some much more serious trouble than whatever you are trying to get through.
Advantages of UDP are:
- you only need one socket to talk with everyone in the world
- you don't have to wait for handshakes for transmission to start.
PSYC supports both TCP and UDP. UDP SHOULD be used by default when only a _notice is about to be sent, and a circuit hasn't been created yet. Notice thus is a not 100% reliable method family.
Wikinotify is an example of a PSYC application that uses UDP rather than TCP.
It is not stupid to also implement an in-between thing between the two. See UDP circuits for that. No, it is not re-inventing the wheel. Only a bit. ;°)
Techie details on Wikipedia:User Datagram Protocol.