nX.500 also added the concept that a sub-arc might
be identified by a pair of values (for example,
organisational unit and location), rather than just by a
single value.
nThis is the principal difference (apart from character
v binary representation) between the X.500 use of the
RH-name tree concept and the ASN.1 use of the RH-name tree
concept for the Object Identifier tree.