What is the difference between RUDP and UDP?

Question

Which is better and why ??

Answer 1

RUDP the name implies that it is more reliable than UDP.

1. Main features added is in sequence delivery which was not there with UDP,But in TCP it was there But the header for handing this facility was with high overhead.But in RUDP with less overhead this is added.
2. But still it is connection less as UDP.
3. As here ACK bit is present so it supports Packet Re transmission like TCP.
4. Hero also packet contains the sequence number so that we can aware of Packet loss too.

see the RUDP packet header I found in RFC

    0 1 2 3 4 5 6 7 8            15
   +-+-+-+-+-+-+-+-+---------------+
   |S|A|E|R|N|C|T| |    Header     |
   |Y|C|A|S|U|H|C|0|    Length     |
   |N|K|K|T|L|K|S| |               |
   +-+-+-+-+-+-+-+-+---------------+
   |  Sequence #   +   Ack Number  |
   +---------------+---------------+
   |            Checksum           |
   +---------------+---------------+

The complete and easy reference is present at http://www.ietf.org/proceedings/44/I-D/draft-ietf-sigtran-reliable-udp-00.txt