Small footprint clock synchronization without NTP

Question

I\'m looking for a simple clock synchronization protocol that would be easy to implement with small footprint and that would work also in the absence of internet connection,

Answer 1

Might using http://www.ietf.org/rfc/rfc5905.txt be appropriate?

Even if it is much more than what you need, you could certainly implement a "compatible" client that works with an NTP server (even if you run your own NTP server), but where the client implementation is purposely naive?

Eg, if you don't care about small time adjustments, don't implement them. If you don't care about bidirectional synchronisation, don't implement that, etcetera.

(Be warned: Most of the functionality present in that RFC is there for a reason - Accurate time synchronisation has many pitfalls - including the fact that many OS's do not like it if the time suddenly changes)