RFC 2167 (rfc2167) - Page 3 of 69

Referral Whois (RWhois) Protocol V1

RFC 2167                    RWhois Protocol                    June 1997


2. Architecture

2.1 Overview

   As a directory service, RWhois is a distributed database, where data
   is split across multiple servers to keep database sizes manageable.
   The architecture portion of this document details the concepts upon
   which the protocol is based and describes its structural elements.
   Specifically, the architecture is concerned with how the data is
   split across the different servers. The basis of this splitting is
   the lexically hierarchical label (or tag), which is a text string
   whose position in a hierarchy can be determined from the structure of
   the string itself.

   All data can follow some sort of hierarchy, even if the hierarchy
   seems somewhat arbitrary. For example, person names can be arranged
   into hierarchical groups via geography. If all the people in
   particular towns are grouped into town groups, then all of the town
   groups can be grouped into state (or province) groups, and then all
   of the state groups can be grouped into a country group. Then, a
   particular name would belong in a town group, a state group, and a
   country group. However, just given a name, it would be impossible to
   determine where in the hierarchy it belongs.  Therefore, a person
   name is not lexically hierarchical.

   However, there are certain types of data whose position in the
   hierarchy can be determined by deciphering the data itself, for
   example, phone numbers. A phone number is grouped according to
   country code, area code, local exchange, and local extension. By
   looking at a phone number, it is possible to determine to which of
   all these groups the number belongs:  1-303-555-2367 is in country
   code 1, area code 303, local exchange 555, and has a local extension
   of 2367. Therefore, a phone number is lexically hierarchical.

   On the Internet, two such types of data are widely used: domain names
   and IP networks. Domain names are organized via a label-dot system,
   reading from a more specific label to a more general label left to
   right; for example, war.west.netsol.com is a part of west.netsol.com,
   which is a part of netsol.com, which is a part of com. IP networks
   are also lexically hierarchical labels using the Classless Inter-
   Domain Routing (CIDR) notation, but their hierarchy is not easily
   determined with simple text manipulation; for example, 198.41.0.0/22
   is a part of 198.41.0.0/16, which is a part of 198.40.0.0/15.
   Instead, an IP network's hierarchy is determined by converting the
   network to binary notation and applying successively shorter bit
   masks.





Williamson, et. al.          Informational