[ibr-dtn] RFC for datagram CL for UDP-CL

Hello,

I am looking for a specification or a RFC for the datagram convergence layer which can be used with UDP- and LoWPAN-CL.

Where could I find a specification or is it an in-house development and there does not exist any RFC?

Is it correct that only using the UDP-CL without dgram is not reliable, too?

Greetings

Timo Wischer