The IESG has firmly rejected specifying security by alternate
scheme names (e.g., 'https:'). The working agreement within
the IPP WG is that the security is NOT discoverable by direct
examination of the URI, but is found through a directory service
(such as LDAP) or service location protocol (such as SLP)
by examining the attribute 'uri-security-supported' which is
an ordered attribute parallel to the 'printer-uri-supported'
attribute.
Several IETF-chartered working groups have already been shot
down trying to use either 'xxxs:' scheme names or mandatory
parameters appended to URI.
Embedding security info in URI has gone completely out of
favor with the IESG.
Also IPP/1.1 systems MUST use 'ipp:' for their URI, per
our Area Directors and other IESG members.
The SLP 'printer:' template (and its future translation
into an LDAP 'printer:' schema) already supports advertising
these two IPP Printer object attributes and makes such
advertisement MANDATORY.
Cheers,
- Ira McDonald (outside consultant at Xerox)
(editor of SLP 'printer:' template)