[1] RFC 5050 - Bundle Protocol Specification ( ( 版)) <http://tools.ietf.org/html/rfc5050#section-4.4>
[2] RFC 5050 - Bundle Protocol Specification ( 版) <https://tools.ietf.org/html/rfc5050>
o The "dtn" scheme, which is used at minimum in the representation
of the null endpoint ID "dtn:none". The forwarding of a bundle to
the null endpoint is never contraindicated, and the minimum
reception group for the null endpoint is the empty set.