I don't think there is a problem vis-a-vis multiple
entries in a directory. The truth is, these services
are distinct. A client which can use one protocol wants
to find a server to use. It doesn't care that the server
supports a bunch of other access protocols.
There is merit in the approach of registering a server once
if it represents a constellation of features, instead of
many URIs. In this case, the client would request the
service by listing its requirements in a service request:
This will return only services which support daa and http
access protocols, say:
This doesn't give you the actual printer uri though!
Unfortunately, you then have to do an attribute request for
service URL: service:printer://someserver
This would return the entire http URL, for instance:
As Jim indicated, this would require two requests instead of one.