sockets - What do you use when you need reliable UDP?

Question

If you have a situation where a TCP connection is potentially too slow and a UDP 'connection' is potentially too unreliable what do you use? There are various standard reliable UDP protocols out there, what experiences do you have with them?

Please discuss one protocol per reply and if someone else has already mentioned the one you use then consider voting them up and using a comment to elaborate if required.

I'm interested in the various options here, of which TCP is at one end of the scale and UDP is at the other. Various reliable UDP options are available and each brings some elements of TCP to UDP.

I know that often TCP is the correct choice but having a list of the alternatives is often useful in helping one come to that conclusion. Things like Enet, RUDP, etc that are built on UDP have various pros and cons, have you used them, what are your experiences?

For the avoidance of doubt there is no more information, this is a hypothetical question and one that I hoped would elicit a list of responses that detailed the various options and alternatives available to someone who needs to make a decision.

Answer 1

What about SCTP. It's a standard protocol by the IETF (RFC 4960)

It has chunking capability which could help for speed.

Update: a comparison between TCP and SCTP shows that the performances are comparable unless two interfaces can be used.

Update: a nice introductory article.