The simple names that make up a domain may contain both upper and
   lower case letters (as well as digits and hyphen), but these names
   are not case sensitive.

   Hosts are generally known by names.  Sometimes a host is not known to
   the translation function and communication is blocked.  To bypass
   this barrier two forms of addresses are also allowed for host
   "names". One form is a decimal integer prefixed by a pound sign, "#".
   Another form, called "dotted decimal", is four small decimal integers
   separated by dots and enclosed by brackets, e.g., "[123.255.37.2]",
   which indicates a 32-bit ARPA Internet Address in four 8-bit fields.
   (Of course, these numeric address forms are specific to the Internet,
   other forms may have to be provided if this problem arises in other
   transport systems.)























 


RFC 819                                                     August 1982;


APPENDIX B

   An Aside on the Assignment of Simple Names

   In the following example, there are two naming hierarchies joining at
   the naming universe 'U'.  One consists of domains (S, R, N, J, P, Q,
   B, A); and the other (L, E, F, G, H, D, C, K, B, A). Domain B is
   assumed to have multiple parentage as shown.

                                U
                              /   \
                            /       \
                          J           L
                        /               \
                      N                   E
                    /   \               /   \
                  R       P           D       F
                /           \         | \      \
              S               Q       C  (X)     G
                                \   /   \          \
                                  B       K          H
                                /
                              A

                                Figure 3
    Illustration of Requirements for the Distinction of Simple Names

   Suppose someone at A tries to initiate communication with destination
   H.  The fully qualified destination name would be

      H.G.F.E.L.U

   Omitting common ancestors, the partially qualified name for the
   destination would be

      H.G.F

   To permit the case of partially qualified names, name server at A
   needs to resolve the simple name F, i.e., F needs to be distinct from
   all the other simple names in its database.

   To enable the name server of a domain to resolve simple names, a
   simple name for a child needs to be assigned distinct from those of
   all of its ancestors and their immediate children.  However, such
   distinction would not be sufficient to allow simple name resolution
   at lower-level domains because lower-level domains could have
   multiple parentage below the level of this domain.

      In the example above, let us assume that a name is to be assigned



 


RFC 819                                                     August 1982;