In addition, comment from Russ Housley

"> >   Figure 2 shows TLS being used over UDP.  DTLS can be used with UDP,
> >   but that dos not seem to be needed here.  UDP seems to be used for
> >   D-mode, and D-mode is used when security is not needed.  C-mode is
> >   used when security is needed.

[snip]

Would 'Transport Layer Security (TLS or DTLS)'  be better?"