Is UDP Considered to be a "Best-Effort" Service?

Question

I would like to know if UDP is considered to be a "best-effort" service?

The reason I ask is because there are no guarantees that any of the packets will reach their destination/s at all. Therefore, could UDP be classed as "best-effort" or is there another term which is deemed the "correct" way of describing this?

Thanks.

Answer 1

One word answer: yes, best-effort is the way to describe it.

Longer answer...

From RFC 768 - User Datagram Protocol...

This protocol  provides  a procedure  for application  programs  to send
messages  to other programs  with a minimum  of protocol mechanism.  The
protocol  is transaction oriented, and delivery and duplicate protection
are **not guaranteed**. (emphasis mine)

Answer 2

It's not really best effort, more fire and forget. Although the term "best effort" is actually used IMHO it's incorrect, since in non-telecoms usage it implies at least a modicum of effort beyond default behaviour, and often somewhat more than that.

No part of the network makes any special allowances for any IP packet except when there's Quality of Service in place, and even then that's really hop-by-hop rather than end-to-end.