6. The arrangement of claim 5 wherein: the defining means further define the network numbering plan such that the individual symbol strings each comprise alphabetic symbols or numeric symbols within a predefined digital alphabet and said string being a member either of a natural human language or of a proper name so that said symbol string has a logical meaning outside of the network numbering plan.
5. The arrangement of claim 3 wherein: the defining means further define the network numbering plan such that the symbol strings of individual types have variable lengths in terms of numbers of symbols that make up individual symbol strings of the individual type.