RFC 2651 (rfc2651) - Page 2 of 19

The Architecture of the Common Indexing Protocol (CIP)

RFC 2651                  The CIP Architecture               August 1999


   The indexing part of Whois++ is integrated with the data access
   protocol. The goal in designing CIP is to extract the indexing
   portion of Whois++, while abstracting the index objects to apply more
   broadly to information retrieval. In addition, another kind of
   technology reuse has been undertaken by converting the ad-hoc data
   representations used by Whois++ into structures based on the MIME
   specification for structured Internet mail.

   Whois++ used a version number field in centroid objects to facilitate
   future growth. The initial version was "1". Version 1 of CIP (then
   embedded in Whois++, and not referred to separately as CIP) had
   support for only ISO-8895-1 characters, and for only the centroid
   index object type.

   Version 2 of the Whois++ centroid was used in the Digger software by
   Bunyip Information Systems to notify recipients that the centroid
   carried extra character set information. Digger's centroids can carry
   UTF-8 encoded 16-bit Unicode characters, or ISO-8859-1 characters,
   determined by a field in the headers.

   This specification is for CIP version 3.  Version 3 is a major
   overhaul to the protocol.  However, by using of a short negotiation
   sequence, CIP version 3 servers can interoperate with earlier servers
   in an index-passing mesh.

   For unclear terms the reader is referred to the glossary in Appendix
   A.

1.2 CIP's place in the Information Retrieval world

   CIP facilitates query routing. CIP is a protocol used between servers
   in a network to pass hints which make data access by clients at a
   later date more efficient. Query routing is the act of redirecting
   and replicating queries through a distributed database system towards
   the servers holding the actual results via reference to indexing
   information.

   CIP is a "backend" protocol -- it is implemented in and "spoken" only
   among network servers. These same servers must also speak some kind
   of data access protocol to communicate with clients. During query
   resolution in the native protocol implementation, the server will
   refer to the indexing information collected by the CIP implementation
   for guidance on how to route the query.

   Data access protocols used with CIP must have some provision for
   control information in the form of a referral. The syntax and
   semantics of these referrals are outside the scope of this
   specification.



Allen & Mealling            Standards Track