The Channel class is a "smart" object that implements a generic
interface to an IT Channel and hides differences in metadata
repositories (OMR and LDAP).
The connection factory throws a login exception when a connection request
cannot be granted because the connecting client cannot be authenticated
or authorized.
Interface describing service lookup policies that a local discovery
service should observe:
policy to retry to find services in the event that service(s) were
not available at the time a request was submitted.