e.
The application gets control classes either as part of a repertoire of
controls standardized through the IETF, or from directory vendors for
vendor-specific controls.  The request control classes should have
constructors that accept arguments in a type-safe and user-friendly
manner, while the response control classes should have access methods
for getting the data of the response in a type-safe and user-friendly
manner.  Internally, the request/response control classes deal with
encoding and decoding BER