Network Working Group
Request for Comments: 2654
Category: Experimental

R. Hedberg
Catalogix
B. Greenblatt
Directory Tools and Application Services, Inc.
R. Moats
AT&T
M. Wahl
Innosoft International, Inc.
August 1999

A Tagged Index Object for use in the Common Indexing Protocol

Status of this Memo

This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.

Copyright Notice

Abstract

This document defines a mechanism by which information servers can exchange indices of information from their databases by making use of the Common Indexing Protocol (CIP). This document defines the structure of the index information being exchanged, as well as the appropriate meanings for the headers that are defined in the Common Indexing Protocol. It is assumed that the structures defined here can be used by X.500 DSAs, LDAP servers, Whois++ servers, CSO Ph servers and many others.

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2. Background  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3. Object  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   4. The Tagged Index Object . . . . . . . . . . . . . . . . . . . . 5
   4.1. The Agreement . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.2. Content Type  . . . . . . . . . . . . . . . . . . . . . . . . 8
   4.3 Tagged Index BNF . . . . . . . . . . . . . . . . . . . . . . . 9
   4.3.1. Header Descriptions . . . . . . . . . . . . . . . . . . . .10
   4.3.2. Tokenization types  . . . . . . . . . . . . . . . . . . . .11
   4.3.3. Tag Conventions . . . . . . . . . . . . . . . . . . . . . .11
   4.4. Incremental Indexing  . . . . . . . . . . . . . . . . . . . .12
   
   5. Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . .13
   5.1 The original database  . . . . . . . . . . . . . . . . . . . .13
   5.1.1 "complete" consistency based full update . . . . . . . . . .14
   5.1.2 "tag" consistency based full update  . . . . . . . . . . . .14
   5.1.3 "unique" consistency based full update . . . . . . . . . . .15
   5.2 First update . . . . . . . . . . . . . . . . . . . . . . . . .16
   5.2.1 "complete" consistency based incremental update  . . . . . .16
   5.2.2 "tag" consistency based incremental update   . . . . . . . .17
   5.2.3 "unique" consistency based incremental update  . . . . . . .17
   5.3 Second update  . . . . . . . . . . . . . . . . . . . . . . . .18
   5.3.1 "complete" consistency based incremental update  . . . . . .18
   5.3.2 "tag" consistency based incremental update . . . . . . . . .19
   5.3.3 "unique" consistency based incremental update  . . . . . . .20
   6. Aggregation . . . . . . . . . . . . . . . . . . . . . . . . . .21
   6.1 Aggregation of Tagged Index Objects  . . . . . . . . . . . . .21
   7. Security Considerations . . . . . . . . . . . . . . . . . . . .21
   8. References  . . . . . . . . . . . . . . . . . . . . . . . . . .22
   9. Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . .23
   Full Copyright Statement . . . . . . . . . . . . . . . . . . . . .24

1. Introduction

The Common Indexing Protocol (CIP) as defined in [1] proposes a mechanism for distributing searches across several instances of a single type of search engine to create a global directory. CIP provides a scalable, flexible scheme to tie individual databases into distributed data warehouses that can scale gracefully with the growth of the Internet. CIP provides a mechanism for meeting these goals that is independent of the access method that is used to access the data that underlies the indices. Separate from CIP is the definition of the Index Object that is used to contain the information that is exchanged among Index Servers. One such Index Object that has already been defined is the Centroid that is derived from the Whois++ protocol [2].

The Centroid does not meet all the requirements for the exchange of index information amongst information servers. For example, it does not support the notion of incremental updates natively. For information servers that contain millions of records in their database, constant exchange of complete dredges of the database is bandwidth intensive. The Tagged Index Object is specifically designed to support the exchange of index update information. This design comes at the cost of an increase in the size of the index object being exchanged. The Centroid is also not tailored to always be able to give boolean answers to queries. In the Centroid Model, "an index server will take a query in standard Whois++ format, search its collections of centroids and other forward information, determine which servers hold records which may fill that query, and then notifies the user's client of the next servers to contact to submit the query." [2] Thus, the exchange of Centroids amongst index servers allows hints to be given about which information server actually contains the information. The Tagged Index Object labels the various pieces of information with identifiers that tie the individual object attributes back to an object as a whole. This "tagging" of information allows an index server to be more capable of directing a specific query to the appropriate information server. Again, this feature is added to the Tagged Index Object at the expense of an increase in the size of the index object.

2. Background

The Lightweight Directory Access Protocol (LDAP) is defined in [3], and it defines a mechanism for accessing a collection of information arranged hierarchically in such a way as to provide a globally distributed database which is normally called the Directory Information Tree (DIT). Some distinguishing characteristics of LDAP servers are that normally, several servers cooperate to manage a common subtree of the DIT. LDAP servers are expected to respond to requests that pertain to portions of the DIT for which they have data, as well as for those portions for which they have no information in their database. For example, the LDAP server for a portion of the DIT in the United States (c=US) must be able to provide a response to a Search operation that pertains to a portion of the DIT in Sweden (c=se). Normally, the response given will be a referral to another LDAP server that is expected to be more knowledgeable about the appropriate subtree. However, there is no mechanism that currently enables these LDAP servers to refer the LDAP client to the supposedly more knowledgeable server. Typically, an LDAP (v3) server is configured with the name of exactly one other LDAP server to which all LDAP clients are referred when their requests fall outside the subtree of the DIT for which that LDAP server has knowledge. This specification defines a mechanism whereby LDAP server can exchange index information that will allow referrals to point towards a clearly accurate destination.

The X.500 series of recommendations defines the Directory Information Shadowing Protocol (DISP) [4] which allows X.500 DSAs to exchange information in the DIT. Shadowing allows various information from various portions of the DIT to be replicated amongst participating DSAs. The design point of DISP is improved at the exchange of entire portions of the DIT, whereas the design point of CIP and the Tagged Index Object is optimized at the exchange of structural index information about the DIT, and improving the performance of tree navigation amongst various information servers. The Tagged Index Object is more appropriate for the exchange of index information than is DISP. DISP is more targeted at DIT distribution and fault tolerance. DISP is thus more appropriate for the exchange of the data in order to spread the load amongst several information servers. DISP is tailored specifically to X.500 (and other hierarchical directory systems), while the Tagged Index Object and CIP can be used in a wide variety of information server environments.

While DISP allows an individual directory server to collect information about large parts of the DIT, it would require a huge database to collect all the replicas for a significant portion of the DIT. Furthermore, as X.525 states: "Before shadowing can occur, an agreement, covering the conditions under which shadowing may occur is required. Although such agreements may be established in a variety of ways, such as policy statements covering all DSAs within a given DMD ...", where a DMD is a Directory Management Domain. This is owing to the case that the data in the DIT is being exchanged amongst DSA rather than only the information required to maintain an Index. In many environments such an agreement is not appropriate, and to collect information for a meaningful portion of the DIT, many agreements may need to be arranged.

3. Object

What is desired is to have an information server (or network of information servers) that can quickly respond to real world requests, like:

   -    What is Tim Howes's email address?  This is much harder than;
        What email address does Tim Howes at Netscape have ?
   
   -    What is the X.509 certificate for Fred Smith at compuserve.com?
        One certainly doesn't want to search CompuServe's entire
        directory tree to find out this one piece of information.  I
        also don't want to have to shadow the entire CompuServe
        directory subtree onto my server.  If this request is being made
        because Fred is trying to log into my server, I'd certainly want
        to be able to respond to the BIND in real time.
   
   -    Who are all the people at Novell that have a title of
        programmer?

all these requests can reasonably be translated into LDAP or Whois++, and other directory access protocol queries. They can also be serviced in a straightforward way by the users home information server if it has the appropriate reference information into the database that contains the source data. Here, the first server would be able to "chain" the request for the user. Alternatively, a precise referral could be returned. If the home information server wants to service (i.e chain) the request based on the index information that it has on hand, this servicing could be done several different means:

      -    issuing LDAP operations to the remote directory server
      
      -    issuing DSP operations to the remote directory server
      
      -    issuing DAP operations to the remote directory server
      
      -    issuing Whois++ operations to the remote Whois++ server
      
      -     ...

4. The Tagged Index Object

This section defines a Tagged Index Object that can be exchanged by Information Servers using CIP. While often it is acceptable for Information Servers to make use of the Centroid definition (from [2]) to exchange index information, the goals in defining a new construct are multi-pronged:

   -    When the Information Server receives a search request that
        warrants that a referral be returned, allow the server to return
        a referral that will point client to a server that is most
        likely able to answer the request correctly.  False positive
        referrals (the search turns up hits in the index object that
        generate referrals to servers that don't hold the desired
        information) can be reduced, depending on the choice of
        attribute tokenization types that are used.
   
   -    Potentially allow incremental updates that will then consume
        substantially less bandwidth then if full updates always had to
        be used.

4.1. The Agreement

Before a Tagged Index Object can be exchanged, the organization that administers the object supplier and the organization that administers the object consumer must reach an agreement on how the servers will communicate. This agreement contains the following:

   -    "index-type": This specification describes the index type "x-
        tagged-index-1"
   
   -    "dsi": An OID that uniquely identifies the subtree and scope.
        This field is not explicitly necessary, as it may not provide
        information beyond what is contained in the "base-uri" below.
   
   -    "base-uri": One or more URI's that will form the base of any
        referrals created based on the index object that is governed by
        this agreement.  For example, in the LDAP URL format [8] the
        base-uri would specify (among other items): the LDAP host,  the
        base object to which this index object refers (e.g. c=SE), and
        the scope of the index object (e.g. single container).
   
   -    "supplier": The hostname and listening portnumber of the
        supplier server, as well as any alternative servers holding that
        same naming contexts, if the supplier is unavailable.
   
   -    "consumeraddr": This is a URI of the "mailto:" form, with the
        RFC 822 email address of the consumer server.  Further versions
        of this draft allow other forms of URI, so that the consumer may
        retrieve the update via the WWW, FTP or CIP.
   
   -    "updateinterval": The maximum duration in seconds between
        occurances of the supplier server generating an update.  If the
        consumer server has not received an update from the supplier
        server after waiting this long since the previous update, it is
        likely that the index information is now out of date.  A typical
        value for a server with frequent updates would be 604800
        seconds, or every week.  Servers whose DITs are only  modified
        annually could have a much longer update interval.
   
   -    "attributeNamespace": Every set of index servers that together
        wants to support a specific usage of indeces, has to agree on
        which attributenames to use in the index objects. The
        participating directory servers also has to agree on the mapping
        from local attributenames to the attributenames used in the
        index. Since one specific index server might be involved in
        several such sets, it has to have some way to connect a update
        to the proper set of indexes. One possible solution to this
        would be to use different DSIs.
   
   -    "consistencybase": How consistency of the index is maintained
        over incremental updates:

"complete" - every change or delete concerning one object has to contain all tokens connected to that object. This method must be supported by any server who wants to comply with this standard.

"tag" - starting at a full update every incremental update refering back to this full updated has to maintain state- information regarding tags, such that a object within the original database is assigned the same tagnumber every time. This method is optional.

"unique" - every object in the Dataset has to have a unique value for a specific attribute in the index. A example of such a attribute could be the distinguishedName attribute. This method is also optional.

   -    "securityoption": Whether and how the supplier server should
        sign and encrypt the update before sending it to the consumer
        server.  Options for this version of the specification are:

"none" - the update is sent in plaintext

"PGP/MIME": the update is digitally signed and encrypted using PGP [9]

"S/MIME": the update is digitally signed and encrypted using S/MIME [10]

"SSLv3": the update is digitally signed and encrypted using an SSLv3 connection [11]

"Fortezza": the update is digitally signed and encrypted using Fortezza [5]

It is recommended that the "PGP/MIME" option be used when exchanging sensitive information across public networks, and both the supplier and consumer have PGP keys. The "Fortezza" option is intended for use in environments where security protocols are based on Fortezza- compatible devices. The "S/MIME" option can be used with both the supplier and consumer have RSA keys and can make use of the PKCS protocols defined in the S/MIME specification. The "SSLv3" option can be used when both the supplier and consumer have access to SSL services, have server certificates, and can mutually authenticate each other.

   -    Security Credentials: The long-term cryptographic credentials
        used for key exchange and authentication of the consumer and
        supplier servers, if a security option was selected.  For
        "PGP/MIME," this will be the trusted public keys of both
        servers.  For "Fortezza," this will be the certificate paths of
        both servers to a common point of trust. For "S/MIME" and
        "SSLv3" these will be the certificates of the supplier and
        consumer.

Note that if the index server maintains the information that would appear in the agreement in a directory according to the definitions in [7], then no real formal agreement between the two parties needs to be put in place, and the information that is required for communication between the two index servers is derived automatically from the directory.

4.2. Content Type

The update consists of a MIME object of type application/cip-index- object. The parameters are:

"type":

this has value "application/index.obj.tagged".

"dsi":

the DSI (if any) from the agreement.

"base-uri". A set of URIs, separated by spaces. In each URI, the hostname/portno must be distinct, and based on the "supplier" part of the agreement.

The payload is mostly textual data but may include bytes with the high bit set. The originating information server should set the content-transfer-encoding as appropriate for the information included in the payload.

This object may be encapsulated in a wrapper content (such as multipart/signed) or be encrypted as part of the security procedures. The resulting content can the distributed, for example via electronic mail. For example,

   From: supplier@sup.com Date: Thu, 16 Jan 1997 13:50:37 -0500
   Message-Id: <199701161850.NAA29295@sup.com>;
   To: consumer@consumer.com       <<-- from consumer server address
   
   Reply-to: supplier-admin@sup.com
   MIME-Version: 1.0
   Content-Type: application/index.obj.tagged;
   dsi=1.3.6.1.4.1.1466.85.85.1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16;
   base-uri="ldap://sup.com/dc=sup,dc=com ldap://alt.com/dc=sup,dc=com"

The payload is series of CRLF-terminated lines. The payload is UTF-8. Some supplier servers may only be able to generate the printable US- ASCII subset of UTF-8, but all consumer servers must be able to handle the full range of Unicode characters when decoding the attribute values (in the "attr-value" field in the BNF below).

4.3. Tagged Index BNF

The Tagged Index object has the following grammar, expressed in modified BNF format:

   index-object = 0*(io-part SEP) io-part
   io-part      = header SEP schema-spec SEP index-info
   header       = version-spec SEP update-type SEP this-update SEP
                   last-update context-size name-space SEP
   version-spec = "version:" *SPACE "x-tagged-index-1"
   update-type  = "updatetype:" *SPACE ( "total" |
                  ( "incremental" [*SPACE "tagbased"|"uniqueIDbased" ] )
   this-update  = "thisupdate:" *SPACE TIMESTAMP
   last-update  = [ "lastupdate:" *SPACE TIMESTAMP SEP]
   context-size = [ "contextsize:" *SPACE 1*DIGIT SEP]
   schema-spec  = "BEGIN IO-Schema" SEP 1*(schema-line SEP)
                  "END IO-Schema"
   schema-line  = attribute-name ":" token-type
   token-type   = "FULL" | "TOKEN" | "RFC822" | "UUCP" | "DNS"
   index-info   = full-index | incremental-index
   full-index   = "BEGIN Index-Info" SEP 1*(index-block SEP)
                  "END Index-Info"
   incremental-index = 1*(add-block | delete-block | update-block)
   add-block    = "BEGIN Add Block" SEP 1*(index-block SEP)
                  "END Add Block"
   delete-block = "BEGIN Delete Block" SEP 1*(index-block SEP)
                  "END Delete Block"
   update-block = "BEGIN Update Block" SEP
                  0*(old-index-block SEP)
                  1*(new-index-block SEP)
                  "END Update Block"
   old-index-block = "BEGIN Old" SEP 1*(index-block SEP)
                  "END Old"
   new-index-block = "BEGIN New" SEP 1*(index-block SEP)
                  "END New"
   index-block  = first-line 0*(SEP cont-line)
   first-line   = attr-name ":" *SPACE taglist "/" attr-value
   cont-line    = "-" taglist "/" attr-value
   taglist      = tag 0*("," tag) | "*"
   tag          = 1*DIGIT ["-" 1*DIGIT]
   attr-value   = 1*(UTF8)
   attr-name    = 1*(NAMECHAR)
   TIMESTAMP    = 1*DIGIT
   NAMECHAR     = DIGIT | UPPER | LOWER | "-" | ";" | "."
   SPACE        = <ASCII space, %x20>;
   SEP          = (CR LF) | LF
   CR           = <ASCII CR, carriage return, %x0D>;
   LF           = <ASCII LF, line feed, %x0A>;
   DIGIT        = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
                  "8" | "9"
   
   UPPER        = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" |
                  "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" |
                  "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" |
                  "Y" | "Z"
   LOWER        = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" |
                  "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" |
                  "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" |
                  "y" | "z"
   
   US-ASCII-SAFE  = %x01-09 / %x0B-0C / %x0E-7F
                   ;; US-ASCII except CR, LF, NUL
   UTF8           = US-ASCII-SAFE / UTF8-1 / UTF8-2 / UTF8-3
                             / UTF8-4 / UTF8-5
   UTF8-CONT      = %x80-BF
   UTF8-1         = %xC0-DF UTF8-CONT
   UTF8-2         = %xE0-EF 2UTF8-CONT
   UTF8-3         = %xF0-F7 3UTF8-CONT
   UTF8-4         = %xF8-FB 4UTF8-CONT
   UTF8-5         = %xFC-FD 5UTF8-CONT

The set of characters allowed to appear in the attr-name field is limited to the set of characters used in LDAP and WHOIS++ attribute names. For other services that have attribute name character sets that are larger than these, those services should create a profile that maps the names onto object identifiers, and the sequence of digits and periods is used by those services in creating the attr- name fields for their Tagged Index Objects.

It is worth mentioning that updates to a index based in tagged index objects MUST be performed in the order specified by the tagged index object itself.

4.3.1. Header Descriptions

The header section consists of one or more "header lines". The following header lines are defined:

"version": This line must always be present, and have the value "x-tagged-index-1" for this version of the specification.

"updatetype": This line must always be present. It takes as the value either "total" or "incremental". The first update sent by a supplier server to a consumer server for a DSI must be a "total" update.

"thisupdate": This line must always be present. The value is the number of seconds from 00:00:00 UTC January 1, 1970 at which the supplier constructed this update.

"lastupdate": This line must be present if the "updatetype" list has the value "incremental". The value is the number of seconds from 00:00:00 UTC January 1, 1970 at which the supplier constructed the previous update sent to the consumer. This field allows the consumer to determine if a previous update was missed

"contextsize": This line may be present at the supplier's option. The value is a number, which is the approximate total number of entries in the subtree. This information is provided for statistical purposes only.

4.3.2. Tokenization Types

The Tagged Index Object inherits the "TOKEN" scheme for tokenization as specified in [2]. In addition, there are several other tokenization schemes defined for the Tagged Index Object.
The following table presents these schemes and what character(s) are used to delimit tokens.

        Token Type      Tokenization Characters
        FULL    none
        TOKEN   white space, "@"
        RFC822  white space, ".", "@"
        UUCP    white space, "!"
        DNS     any character note a number, letter, or "-"

4.3.3. Tag Conventions

In the tag list, multiple consecutive tags may be shortened by using "#-#". For example, the list "3,4,5,6,7,8,9,10" may be shortened to "3-10". Tags are to be applied to the data on a per entry level. Thus, if two index lines in the same index object contain the same tag, then those two lines always refer to the same "record" in the directory. In LDAP terminology, the two lines would refer to the same directory object. Additionally if two index lines in the same index object contain different tags, then it is always the case that those two lines refer back to different records in the directory. The meaning of '*' in the tag position is that that specific token apears in every record in the directory.

The tag applied to the same underlying record in two separate transmissions of a full-index may be different. Thus, receiving index servers should make no assumptions about the values of the tags across index object boundaries.

4.4. Incremental Indexing

The tagged index object format supports the ability of information servers to distribute only delta index data, rather than distributing total index information each time. This scenario, known as incremental indexing supports three basic types of operations: add, delete and replace. If the incremental updatetype is specified in the tagged index object, then the index object contains a snapshot of only the changes that have been made since the index object specified in the lastupdate header was distributed. If the receiving index server did not receive that index object, it should request a total index object. If the CIP protocol supports it, the index server may request the specific index object that it missed.

If the tagged index object contains an Add Block, then the lines in the Add Block refer to new records that were added to the information base of the transmitting index server. It can be guaranteed that those records did not exist in any previously received tagged index object, and the receiving index server can insert this index information in the index that it already maintains for the transmitting index server.

If the tagged index object contains a Delete Block, then the structure of the Delete Block depends on how the consistency is maintained;

"completeRecord": all the tokens connected to the record to be deleted has to be included, the tag used to connect tokens in this message has no relation to tags used in previously sent tagged index objects.

"uniqueIDBased": only the unique identifier has to be defined.

"tagBased": all the tokens connected to the record has to be included but then preceded by the tag used for this specific record in the preceding set of the last full update and the there on following incremental updates.

If the tagged index object contains an Update Block, then the lines in the Update Block refer to records that were changed in the information base of the transmitting index server. Again the specific content of the block depends on how the consistency is maintained.

"completeRecord": All the tokens representing the old version of the record as well as the new ones has to be included.

"uniqueIDBased": The unique ID has to be included together with the tokens that have changed.

"tagBased": Only the changed tokens are included, but then both the old version, if there was one, as well as the new one, if there is one.

The Update Block also supports the idea of indexing new attributes that were not previously included in the tagged index object. For example, if the transmitting index server began including index information on postal addresses, then it could include an Update Block in the index object that included all the index information on postal addresses for all records in its information base, and indicate that nothing else has changed.

5. Examples

In the following sections, for each different consistencybase type, the tagged index object is represented for the following scenario; The examples starts with one full update and following that a set of updates. The underlying information is presented in the LDIF [6] format.

5.1 The original database

dn: cn=Barbara Jensen, ou=Product Development, o=Ace Industry, c=US objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Barbara Jensen
cn: Barbara J Jensen
cn: Babs Jensen
sn: Jensen
uid: bjensen
dn: cn=Bjorn Jensen, ou=Accounting, o=Ace Industry, c=US objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Bjorn Jensen
sn: Jensen
title: Accounting manager
dn: cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Gern Jensen
cn: Gern O Jensen
sn: Jensen
title: testpilot
dn: cn=Horatio Jensen, ou=Product Testing, o=Ace Industry, c=US objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Horatio Jensen
cn: Horatio N Jensen
sn: Jensen
title: testpilot

5.1.1 "Complete" consistency based full update

   version: x-tagged-index-1
   updatetype: total
   thisupdate: 855938804
   BEGIN IO-Schema
   cn: TOKEN
   sn: FULL
   title: TOKEN
   END IO-Schema
   BEGIN Index-Info
   cn: 1/Barbara
   -1/J
   -1/Babs
   -*/Jensen
   -2/Bjorn
   -3/Gern
   -3/O
   -4/Horatio
   -4/N
   sn: */Jensen
   title: 1/product
   -1-2/manager
   -1/accounting
   -3,4/testpilot
   END Index-Info

5.1.2 "tag" consistency based full update

   version: x-tagged-index-1
   updatetype: total
   thisupdate: 855938804
   BEGIN IO-Schema
   cn: TOKEN
   sn: FULL
   title: TOKEN
   END IO-Schema
   BEGIN Index-Info
   cn: 1/Barbara
   -1/J
   -1/Babs
   -*/Jensen
   -2/Bjorn
   -3/Gern
   -3/O
   -4/Horatio
   -4/N
   sn: */Jensen
   
   title: 1/product
   -1-2/manager
   -1/accounting
   -3,4/testpilot
   END Index-Info

5.1.3 "unique" consistency based full update

   version: x-tagged-index-1
   updatetype: total
   thisupdate: 855938804
   BEGIN IO-Schema
   dn: FULL
   cn: TOKEN
   sn: FULL
   title: TOKEN
   END IO-Schema
   BEGIN Index-Info
   dn: 1/cn=Barbara Jensen, ou=Product Development, o=Ace Industry, c=US
   -2/cn=Bjorn Jensen, ou=Accounting, o=Ace Industry, c=US
   -3/cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US
   -4/cn=Horatio Jensen, ou=Product Testing, o=Ace Industry, c=US
   cn: 1/Barbara
   -1/J
   -1/Babs
   -*/Jensen
   -2/Bjorn
   -3/Gern
   -3/O
   -4/Horatio
   -4/N
   sn: */Jensen
   title: 1/product
   -1-2/manager
   -1/accounting
   -3,4/testpilot
   END Index-Info

5.2 First update

Gern Jensen's entry above changes to:

dn: cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Gern Jensen
cn: Gern O Jensen
sn: Jensen
title: chiefpilot

5.2.1 First update using "complete"

   version: x-tagged-index-1
   updatetype: incremental
   lastupdate: 855940000
   thisupdate: 855938804
   BEGIN IO-schema
   cn: TOKEN
   sn: FULL
   title: FULL
   END IO-Schema
   BEGIN Update Block
   BEGIN Old
   cn: 1/Gern
   cn: 1/O
   cn: 1/Jensen
   sn: 1/Jensen
   title: 1/testpilot
   END Old
   BEGIN New
   cn: 1/Gern
   cn: 1/O
   cn: 1/Jensen
   sn: 1/Jensen
   title: 1/chiefpilot
   END New
   END Update Block

5.2.3 First update using "unique" ID's

   version: x-tagged-index-1
   updatetype: incremental
   lastupdate: 855940000
   thisupdate: 855938804
   BEGIN IO-schema
   cn: TOKEN
   sn: FULL
   title: FULL
   END IO-Schema
   BEGIN Update Block
   BEGIN Old
   dn: 1/cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US
   title: 1/testpilot
   END Old
   BEGIN New
   dn: 1/cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US
   title: 1/chiefpilot
   END New
   END Update Block

5.3 Second update

# Add a new entry
dn: cn=Bo Didley, ou=Marketing, o=Ace Industry, c=US changetype: add
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Bo Didley
sn: Didley
title: Policy Maker
# Delete an existing entry
dn: cn=Bjorn Jensen, ou=Accounting, o=Ace Industry, c=US changetype: delete
# Modify all other entries: adding an additional locality value dn: cn=Barbara Jensen, ou=Product Development, o=Ace Industry, c=US changetype: modify
add: locality
locality: New Jersey
dn: cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US changetype: modify
add: locality
locality: New Orleans
dn: cn=Horatio Jensen, ou=Product Testing, o=Ace Industry, c=US changetype: modify
add: locality
locality: New Caledonia

5.3.1 "complete"

   version: x-tagged-index-1
   updatetype: incremental
   lastupdate: 855938804
   thisupdate: 855939525
   BEGIN IO-schema
   cn: TOKEN
   sn: FULL
   title: FULL
   locality: TOKEN
   END IO-Schema
   BEGIN Add Block
   cn: 1/Bo
   -1/Didley
   sn: 1/Didley
   title: 1/Policy
   -1/maker
   locality: 1/New
   -1/York
   END Add Block
   BEGIN Delete Block
   cn: 1/Bjorn
   -1/Jensen
   sn: 1/Jensen
   title: 1/Accounting
   -1/Manager
   END Delete Block
   BEGIN Update Block
   BEGIN Old
   cn: 1/Barbara
   -1/J
   -1-3/Jensen
   -2/Gern
   -2/O
   -3/Horatio
   sn: 1-3/Jensen
   title: 1/Production
   -1/Manager
   -2/Testpilot
   -3/Chiefpilot
   END Old
   BEGIN New
   cn: 1/Barbara
   -1/J
   -1-3/Jensen
   -2/Gern
   -2/O
   -3/Horatio
   
   sn: 1-3/Jensen
   title: 1/Production
   -1/Manager
   -2/Testpilot
   -3/Chiefpilot
   locality: 1/Jersey
   -2/Orleans
   -3/Caledonia
   -1-3/New
   END New    END Update Block

5.3.2 "tag"

   version: x-tagged-index-1
   updatetype: incremental
   lastupdate: 855938804
   thisupdate: 855939525
   BEGIN IO-schema
   cn: TOKEN
   sn: FULL
   title: FULL
   locality: TOKEN
   END IO-Schema
   BEGIN Add Block
   cn: 5/Bo
   -5/Didley
   sn: 5/Didley
   title: 5/Policy
   -5/maker
   locality: 5/New
   -5/York
   END Add Block
   BEGIN Delete Block
   cn: 2/Bjorn
   -2/Jensen
   sn: 2/Jensen
   title: 2/Accounting
   -2/Manager
   END Delete Block
   BEGIN Update Block
   BEGIN New
   locality: 1/Jersey
   -2/Orleans
   -4/Caledonia
   -1,2,4/New
   END New
   END Update Block

5.3.3 "unique"

   version: x-tagged-index-1
   updatetype: incremental
   lastupdate: 855938804
   thisupdate: 855939525
   BEGIN IO-schema
   cn: TOKEN
   sn: FULL
   title: FULL
   locality: TOKEN
   END IO-Schema
   BEGIN Add Block
   dn: 1/cn=Bo Didley, ou=Marketing, o=Ace Industry, c=US
   cn: 1/Bo
   -1/Didley
   sn: 1/Didley
   title: 1/Policy
   -1/maker
   locality: 1/New
   -1/York
   END Add Block
   BEGIN Delete Block
   dn: 1/cn=Bjorn Jensen, ou=Accounting, o=Ace Industry, c=US
   END Delete Block
   BEGIN Update Block
   BEGIN New
   dn: 1/cn=Barbara Jensen, ou=Product Development, o=Ace Industry, c=US
   -2/cn=Gern Jensen, ou=Product Testing, o=Ace Industry, c=US
   -3/cn=Horatio Jensen, ou=Product Testing, o=Ace Industry, c=US
   locality: 1/Jersey
   -2/Orleans
   -3/Caledonia
   -1-3/New
   END New
   END Update Block

6. Aggregation

6.1. Aggregation of Tagged Index Objects

Aggregation of two tagged index objects is done by merging the two lists of values and rewriting each tag list. The tag list rewriting process is done so that the resulting index object appears as if it came from a single source. An index server that aggregates tagged index objects for export MUST ensure that the export URL (i.e. the base-uri of the CIP object) for the aggregate index object will route all queries that have "hits" on the index object to that server (otherwise, query routing will not succeed).

7. Security Considerations

This specification provides a protocol for transferring information between two servers. The information transferred may be protected by laws in many countries, so care must be taken in the methods used to tokenize the data to ensure that protected data may not be reconstructed in full by the receiving server. This protocol does not have any inherent protection against spoofing or eavesdropping. However, since this protocol is transported in MIME messages (as are all CIP index objects), it inherits all the security capabilities and liabilities of other MIME messages. Specifically, those wanting to prevent eavesdropping or spoofing may use some of the various techniques for signing and encrypting MIME messages.

Information Server administrators must decide what portions of their databases are appropriate for inclusion in the Tagged Index Object.

For distribution of information outside the enterprise, information server developers are encouraged to allow for facilities that hide the organizational structure when generating the Tagged Index Object from the underlying information database. To allow for the secure transmission of Tagged Index Objects across the Internet, Index Servers should make use of SSL when completing the connection. In order to strongly verify the identity of the peer index server on the other side of the connection, SSL version 3 certificate exchange should be implemented, and the identity in the peer's certificate verify with the Public Key Infrastructure. If electronic mail is used to exchange the Tagged Index Objects, then a secure messaging facility, such as PGP/MIME or S/MIME should be used to sign or encrypt (or both) the information.

8. References

   [1]  Allen, J. and M. Mealling, "The Architecture of the Common
        Indexing Protocol (CIP)," RFC 2651, August 1999.
   
   [2]  Weider, C., Fullton, J. and S. Spero, "Architecture of the
        Whois++ Index Service", RFC 1913, February 1996.
   
   [3]  Wahl, M., Howes, T. and S. Kille, "Lightweight Directory Access
        Protocol (v3)", RFC 2251, December 1997.
   
   [4]  ITU, "X.525 Information Technology - Open Systems
        Interconnection - The Directory: Replication", November 1993.
   
   [5]  "FORTEZZA Application Implementors  Guide for the FORTEZZA
        Crypto Card (Production Version)", Document #PD4002102-1.01,
        SPYRUS, 1995.
   
   [6]  Good, G., "The LDAP Data Interchange Format (LDIF) - Technical
        Specification", Work in Progress.
   
   [7]  Hedberg, R., "LDAPv2 Client vs. the Index Mesh", RFC 2657,
        August 1999.
   
   [8]  Howes, T. and M. Smith, "The LDAP URL Format", RFC 2255,
        December 1997.
   
   [9]  Elkins, M., "MIME Security with Pretty Good Privacy (PGP)", RFC
        2015, October 1996.
   
   [10] Ramsdell, B., Editor, "S/MIME Version 3 Message Specification",
        RFC 2633, June 1999.
   
   [11] Allen, C. and T. Dierks, "The TLS Protocol Version 1.0", RFC
        2246, January 1999.

9. Authors' Addresses

Roland Hedberg
Catalogix
Dalsveien 53
0387 Oslo
Norway

   EMail:  roland@catalogix.ac.se

Bruce Greenblatt
Directory Tools and Application Services, Inc.
6841 Heaton Moor Drive
San Jose, CA 95119
USA

   Phone: +1-408-224-5349
   EMail: bgreenblatt@directory-applications.com

Ryan Moats
AT&T
15621 Drexel Circle
Omaha, NE 68135-2358
USA

   Phone:  +1 402 894-9456
   EMail:  jayhawk@att.com

Mark Wahl
Innosoft International, Inc.
8911 Capital of Texas Hwy, Suite 4140
Austin, TX 78759
USA

   Phone +1 626 919 3600
   EMail  Mark.Wahl@innosoft.com

10. Full Copyright Statement

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.

The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

Funding for the RFC Editor function is currently provided by the Internet Society.