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Network Working Group                                       Andy Bennett
INTERNET-DRAFT                                               Bernie Volz
                                                        Process Software

                                                       Andrea Westerinen
                                                               Microsoft

                                                            October 1999
                                                      Expires April 2000


                          DHCP Schema for LDAP
                     <draft-ietf-dhc-schema-01.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

Copyright Notice

   Copyright (C) The Internet Society (1999). All Rights Reserved.

Abstract

   This document presents an LDAP schema to represent the configuration
   of the DHCP protocol within a TCP/IP network.  It can be used to
   represent the configuration(s) of an entire enterprise network, a
   subset of the network, or even a single server.






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1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

   In places where different sets of terminology are commonly used to
   represent similar DHCP concepts, this schema uses the terminology of
   the Internet Software Consortium's DHCP server reference implementa-
   tion.  For more information see www.isc.org.

2.  Open Issues

   The following issues still need to be resolved:

   o The Policy Framework Mapping section is superficial and needs to be
     updated.

   o The CIM Mapping section is based on the object class definitions
     from the previous revision of this draft and needs to be updated.

3.  Design Considerations

   Some of the design considerations for this schema were:

   o Heterogeneous server environment - This schema is not designed to
     represent the configuration of a specific DHCP server implementa-
     tion.  The intent of this schema is to provide a basic framework
     for the representation of the most common elements used in the con-
     figuration of DHCP.  This should allow other network services to
     obtain and use basic DHCP configuration information in a server-
     independent way.  Also note that it is highly unlikely that this
     schema will be able to represent every feature of every implementa-
     tion (and it is not intended to do so).  It is expected that some
     implementations may need to extend the schema objects in order to
     fully implement all their features.

   o Use of the schema - This draft does not define any "minimal compli-
     ance criteria" for using the schema.  It is recommended that you
     use the object classes defined in this draft if you are represent-
     ing DHCP configuration information in an LDAP directory.  Some
     implementations may choose not to support all of the objects
     defined here.  In particular, the following two decisions are
     explicitly left up to the implementation:

     - it is up to the implementation to determine whether or not the
       lease information will be stored in the directory.  Some imple-
       mentations may choose not to store this information.



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     - it is up to the implementation to determine if the data in the
       directory is considered "authoritative", or if it is simply a
       copy of data from an authoritative source.

   o The schema is focused on the representation of configuration infor-
     mation.  It does not provide for the representation of statistical
     data, or historical lease data, only the current state of the DHC
     protocol's configuration.

   o The information in this schema will be used primarily by two types
     of applications:  DHCP servers (for loading their configuration)
     and Management Interfaces (for defining/editing configurations).
     The schema should must be efficient for the needs of both types of
     applications.

   o The schema is designed to allow objects managed by DHCP (such as
     computers, subnets, etc) to be present anywhere in a directory
     hierarchy (to allow those objects to be placed in the directory for
     managing administrative control and access to the objects).  How-
     ever, the schema also provides for the possibility that any given
     object may have multiple sets of configuration parameters defined
     for different servers.

   o The schema uses a few naming conventions - all object classes and
     attributes are prefixed with "dhcp" and there are no object classes
     and attributes that have the same name.  The schema also uses stan-
     dard naming attributes ("cn", "ou", etc) for all objects, though in
     some cases the "cn" may be the same as another attribute already
     defined on the object.

   o Relationship to DEN/DMTF - This document takes into consideration
     the object-oriented information model for representing Network
     information (including DHCP information) currently under develop-
     ment as part of the Common Information Model (CIM) activity in the
     Distributed Management Task Force (DMTF).  It should be noted that
     the CIM schema is still under development and subject to change.
     The DMTF efforts continue and draw upon the Directory-Enabled Net-
     works (DEN) specification.  The schema described in this Internet-
     Draft is intended to be an LDAP implementation of the appropriate
     objects in the DMTF model.  The DMTF schema was used as a source
     for defining certain terminology within this schema.  For more
     information see [DMTF] and [DEN].

   o Relationship to Policy Framework working group - Much of the infor-
     mation in this schema could be represented using the generalized
     schema being developed by the Policy Framework.  However, there
     were two issues that we felt would make this a very complex and
     most likely inefficient representation: (1) the complexity of the



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     inheritance relationships between the dhcp policy objects defined
     in this document and (2) the Policy Framework schema represents
     each of the conditions and actions of a policy as separate objects.
     However, it is still a fairly straightforward process to map the
     objects from this schema into the Policy Framework Core Schema
     objects.  For more information see [POLICY].

4.  Common Attributes

   Although DHCP manages several different types of objects, the config-
   uration of those objects is often very similar.  Consequently, most
   of these objects have a common set of attributes.

   The dhcpConfigurableObject class is an auxiliary class which can be
   used to associate the basic set of configuration attributes with
   another object.  Since some directories do not provide auxiliary
   classes we have also repeated these common attributes in the defini-
   tion of each of the DHCP object class definitions.

   An implementation of this schema is not required to provide this aux-
   iliary object class, but it SHOULD provide it if auxiliary classes
   are supported.  This is useful for associating DHCP configuration
   settings for objects that are not directly defined as part of this
   schema.

4.1.  dhcpConfigurableObject Object Class

   NAME                dhcpConfigurableObject
   DESCRIPTION         A class that provides attributes for configuring
                       options and server parameters for DHCP.
   TYPE                Auxiliary
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( )
   MUST CONTAIN        ( )
   MAY CONTAIN         ( dhcpOptionSetting dhcpParameterSetting
                         dhcpFieldSetting dhcpForcedOptions
                         dhcpIncludeOptionSet )

4.2.  Common Attribute Definitions

   NAME         dhcpOptionSetting
   DESCRIPTION  Encoded option values to be sent to clients.  Each value
                represents a single option and contains (OptionTag,
                Length, OptionValue) encoded in the 16-bit format used
                by DHCP.  For more information see [DHCPOPT].
   SYNTAX       OctetString MULTI-VALUE





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   NAME         dhcpParameterSetting
   DESCRIPTION  Encoded values of parameters that control server behav-
                ior.  Each value represents a single parameter setting
                in the form (ParameterName, ParameterValue) where the
                parameter name is a set of ASCII characters followed by
                a space followed by the parameter value as a string.
   SYNTAX       IA5String MULTI-VALUE

   NAME         dhcpFieldSetting
   DESCRIPTION  Encoded settings of fields (such as siaddr, file) in the
                DHCP message whose values may be configurable for send-
                ing back to a client.  For more information see
                [RFC951].  Encoded in the form (FieldName, FieldValue)
                where the field name is a set of ASCII characters fol-
                lowed by a space followed by the field value as a
                string.
   SYNTAX       IA5String MULTI-VALUE

   NAME         dhcpForcedOptions
   DESCRIPTION  This is a list of DHCP option tags that MUST be sent to
                clients.  If not specified, the server only sends the
                options back to the client which were requested.
   SYNTAX       Integer MULTI-VALUE

   NAME         dhcpIncludeOptionSet
   DESCRIPTION  The distinguished name(s) of dhcpNamedOptionSet objects
                whose settings should be included for this object.  If
                there are multiple option sets, the order is important
                so each value is preceded by it's precedence, followed
                by a colon as in "1:dn1", "2:dn2", etc.  Settings
                defined on the object take precedence over any settings
                found in an included option set.
   SYNTAX       IA5String MULTI-VALUE

5.  Configurations and Services

   The DHC working group is currently considering several proposals for
   failover and redundancy of DHCP servers.  These may require the shar-
   ing of configuration information between servers.  This schema pro-
   vides a generalized mechanism for supporting any of these proposals,
   by separating the definition of a server from the definition of the
   configuration being provided by the server.

   By separating these two concepts, a configuration may be provided by
   one or by several servers, and similarly, a server may provide one or
   more configurations. The schema does allow for a server to be config-
   ured as either a primary or secondary provider of a configuration.




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   Configurations are also defined so that one configuration can include
   some of the objects that are defined in another configuration (see
   "dhcpIncludeObjects" attribute).  This allows for sharing and/or a
   hierarchy of related configuration items.

5.1.  dhcpService Object Class

   A "dhcpService" is a single instance of DHC server software running
   on a computer system that provides the DHCP service defined by a
   "dhcpConfiguration".

   NAME                dhcpService
   DESCRIPTION         This represents a single DHCP server.
   TYPE                Structural
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( )
   MUST CONTAIN        ( cn )
   MAY CONTAIN         ( dhcpConfigurationDn dhcpImplementation )

5.1.1.  dhcpService Attribute Definitions

   NAME         cn
   DESCRIPTION  The "common name" of the server.  This does not have any
                significance to the server process that provides the
                DHCP service - it is simply a unique name used to refer
                to the server.  This attribute should be used as the
                naming attribute when constructing the dn.

   NAME         dhcpConfigurationDn
   DESCRIPTION  The distinguished name(s) of the configurations provided
                by the server.
   SYNTAX       DN MULTI-VALUE

   NAME         dhcpImplementation
   DESCRIPTION  This is a string value that identifies the hard-
                ware/software platform and version which is providing
                the service.
   SYNTAX       IA5String SINGLE-VALUE

5.2.  dhcpConfiguration Object Class

   A "dhcpConfiguration" is the collection of configuration information
   that represents everything a server would need to know to provide DHC
   service to some set of clients.

   From the perspective of the schema, it is basically a collection of
   objects.  This object class is used to capture information common to
   all the objects in a configuration.  The algorithm used to locate all



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   the objects in a configuration is discussed later.

   NAME                dhcpConfiguration
   DESCRIPTION         This represents a configuration, or a collection
                       of settings for related objects.  A single ser-
                       vice may have multiple configurations.  A config-
                       uration may be provided by multiple services, but
                       only one can be primary.
   TYPE                Structural
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( )
   MUST CONTAIN        ( cn )
   MAY CONTAIN         ( dhcpPrimaryService dhcpSecondaryService
                         dhcpIncludeObjects dhcpOptionSetting
                         dhcpParameterSetting dhcpFieldSetting
                         dhcpForcedOptions dhcpIncludeOptionSet )

5.2.1.  dhcpConfiguration Attribute Definitions

   NAME         cn
   DESCRIPTION  The "common name" of the configuration. This should be
                used as the naming attribute when constructing the dn.

   NAME         dhcpPrimaryService
   DESCRIPTION  The "dhcpService" which is the primary for the configu-
                ration.
   SYNTAX       DN SINGLE-VALUE

   NAME         dhcpSecondaryService
   DESCRIPTION  The "dhcpService(s)" which provide backup for the con-
                figuration.
   SYNTAX       DN MULTI-VALUE

   NAME         dhcpIncludeObjects
   DESCRIPTION  This attribute defines objects that are included in a
                configuration.  Each value is an LdapURL [RFC2255]
                (specifying search criteria) that is evaluated to find
                other objects that are included in this configuration.
                Note that in addition to these objects, all objects that
                are children of the configuration object in the direc-
                tory are automatically included in the configuration.
   SYNTAX       IA5String MULTI-VALUE

6.  Policy Objects

   Most of a DHCP configuration is the definition of policies that gov-
   ern the assignment of DHCP options and addresses to clients.  This
   schema defines a set of object classes which are common to most



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   server implementations for defining these policies.  All of these
   object classes are based on a higher level abstraction that repre-
   sents a dhcp policy.

   This is done for several reasons: it simplifies the organization of
   the data and it also facilitates a mapping of the dhcp schema into
   the work being developed in the Policy Framework working group.  This
   is discussed in more detail in a later section.

   This schema separates the definition of a policy for an object from
   the object itself.  This allows for the definition of multiple poli-
   cies for an object (possibly in multiple dhcp configurations).  How-
   ever, the policy object does maintain a link back to the original
   object (see the "dhcpSourceObject" attribute).

   The structure of a "source object" is not defined in this schema.  It
   can be any LDAP object, and it is not required to even exist.  How-
   ever, if it does exist that object can use the "dhcpConfigurableOb-
   ject" auxiliary class to directly associate dhcp configuration infor-
   mation with that object.  If an object is defined in this way, this
   information is used on every policy that references the object.

   Furthermore, the policy objects in the directory can be organized in
   a hierarchical fashion.  If objects are organized this way, the
   "child" policy object inherits settings from the "parent" policy
   object.  This can be done recursively.  Furthermore, the "child" pol-
   icy object inherits any conditions from the "parent" policy as well.
   This means that the "child" policy's settings will only be used when
   both sets of conditions are met.

   As an example, if a "dhcpClass" is a child of a "dhcpSubnet" then the
   settings for that class will only be used if the client request is a
   member of that class AND it is also from the specified subnet.

   The algorithm for resolving which option settings are applied for a
   policy object is defined in a later section.

6.1.  dhcpPolicy Object Class

   The "dhcpPolicy" class is an abstract class that defines attributes
   that are common to the DHCP configuration objects that define these
   policies.

   This class is the base class from which others are derived.  Also
   note that it includes all the attributes from the dhcpConfigurableOb-
   ject class.





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   NAME                dhcpPolicy
   DESCRIPTION         The base class for defining policies for address
                       and option assignment.
   TYPE                Abstract
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( )
   MUST CONTAIN        ( cn dhcpPolicyType )
   MAY CONTAIN         ( dhcpPoolName dhcpSubnetName
                         dhcpSharedNetworkName dhcpClientIdentifier
                         dhcpClassName dhcpVendorCondition
                         dhcpSourceObject dhcpOptionSetting
                         dhcpParameterSetting dhcpFieldSetting
                         dhcpForcedOptions dhcpIncludeOptionSet )

6.2.  dhcpPolicy Attribute Definitions

   NAME         cn
   DESCRIPTION  The "common name" of the policy. This should be used as
                the naming attribute when constructing the dn.

   NAME         dhcpPolicyType
   DESCRIPTION  The type of the policy.  This should be one of 'POOL',
                'SUBNET', 'SHAREDNETWORK', 'CLIENT', 'CLASS' unless the
                server implementation extends this with a new policy
                type.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpPoolName
   DESCRIPTION  A descriptive name of the pool for this policy.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpSubnetName
   DESCRIPTION  A descriptive name of the subnet for this policy.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpClientIdentifier
   DESCRIPTION  The DHCP client identifier for the client.  This is
                encoded in the binary format used for dhcp option 61 -
                the first octet is the ARP hardware type, followed by
                the link layer (or MAC) address.  If the value is an
                arbitrary identifier (instead of a MAC address) then the
                first octet is 0.  For more information see [RFC2132].
   SYNTAX       OctetString SINGLE-VALUE

   NAME         dhcpClassName
   DESCRIPTION  The name of the class for the policy.
   SYNTAX       IA5String SINGLE-VALUE




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   NAME         dhcpVendorCondition
   DESCRIPTION  If the server extends the policy types, this attribute
                MAY be used to specify the conditions under which the
                policy should be applied.  The content of this attribute
                is defined by the vendor/server implementation.
   SYNTAX       IA5String MULTI-VALUE

   NAME         dhcpSourceObject
   DESCRIPTION  If the policy applies to an object that is defined else-
                where in the directory, this attribute has the distin-
                guished name of that object.
   SYNTAX       DN SINGLE-VALUE

6.3.  dhcpPool Object Class

   A "dhcpPool" represents a policy for a collection of addresses speci-
   fied by one or more ranges of addresses.  If there are multiple
   ranges specified, they do not need to be contiguous, and it is not
   required that all the addresses be contained on the same IP subnet.

   The "dhcpPolicyType" attribute MUST be set to 'POOL', and the "cn"
   SHOULD be set to the value of the "dhcpPoolName" attribute".

   NAME                dhcpPool
   DESCRIPTION         This stores configuration information about one
                       (or more) ranges of addresses.
   TYPE                Structural
   DERIVED FROM        dhcpPolicy
   POSSIBLE SUPERIORS  ( OrganizationalUnit dhcpPolicy )
   MUST CONTAIN        ( cn dhcpPoolName dhcpAddressRange )
   MAY CONTAIN         ( )

6.3.1.  dhcpPool Attribute Definitions

   NAME         dhcpAddressRange
   DESCRIPTION  The starting & ending IP Addresses in the range (inclu-
                sive), separated by a hyphen.  Each range is defined as
                a separate value.
   SYNTAX       IA5String MULTI-VALUE

6.4.  dhcpSubnet Object Class

   A "dhcpSubnet" represents a policy for an IP subnet.

   The "dhcpPolicyType" attribute MUST be set to 'SUBNET', and the "cn"
   SHOULD be set to the value of the "dhcpSubnetName" attribute".





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   NAME                dhcpSubnet
   DESCRIPTION         This class defines a subnet.
   TYPE                Structural
   DERIVED FROM        dhcpPolicy
   POSSIBLE SUPERIORS  ( OrganizationalUnit dhcpPolicy )
   MUST CONTAIN        ( cn dhcpSubnetAddress dhcpSubnetMaskLength
                         dhcpSubnetName )
   MAY CONTAIN         ( )

6.4.1.  dhcpSubnet Attribute Definitions

   NAME         dhcpSubnetAddress
   DESCRIPTION  The network address for the subnet.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpSubnetMaskLength
   DESCRIPTION  The subnet mask length for the subnet.  The mask can be
                easily computed from this length.
   SYNTAX       Integer SINGLE-VALUE

6.5.  dhcpSharedNetwork Object Class

   A "dhcpSharedNetwork" represents a policy for multiple subnets on the
   same physical cabling.

   The "dhcpPolicyType" attribute MUST be set to 'SHAREDNETWORK', and
   the "cn" SHOULD be set to the value of the "dhcpSharedNetworkName"
   attribute".

   NAME                dhcpSharedNetwork
   DESCRIPTION         This represents multiple subnets on the same
                       physical cabling.
   TYPE                Structural
   DERIVED FROM        dhcpPolicy
   POSSIBLE SUPERIORS  ( OrganizationalUnit dhcpPolicy )
   MUST CONTAIN        ( cn dhcpSharedNetworkName )
   MAY CONTAIN         ( )

6.6.  dhcpClient Object Class

   The "dhcpClient" object class is used to store configuration informa-
   tion related to a specific host.

   The "dhcpPolicyType" attribute MUST be set to 'CLIENT', and the "cn"
   SHOULD be set to the value of the "dhcpClientIdentifier" attribute".






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   NAME                dhcpClient
   DESCRIPTION         This represents client-specific DHCP policies.
   TYPE                Structural
   DERIVED FROM        dhcpPolicy
   POSSIBLE SUPERIORS  ( OrganizationalUnit dhcpPolicy )
   MUST CONTAIN        ( cn dhcpClientIdentifier )
   MAY CONTAIN         ( dhcpClassMember )

6.6.1.  dhcpClient Attribute Definitions

   NAME         dhcpClassMember
   DESCRIPTION  This attribute indicates that the client is a member of
                the specified class(es).
   SYNTAX       IA5String MULTI-VALUE

6.7.  dhcpClass Object Class

   A "dhcpClass" represents information about a collection of clients.
   The DHC protocol provides 2 mechanisms for managing this information
   (User Class and Vendor Class).  The schema also provides 2 additional
   mechanisms for configuring groups of clients that are supported by
   some servers.  Clients may be explicitly added to a class by setting
   the "dhcpClassMember" attribute in the "dhcpClient" object class.
   Some servers also support forms of dynamic class membership beyond
   the User Class and Vendor Class mechanisms - setting the "dhcpVendor-
   Condition" attribute allows for the definition of dynamic classes.

   The "dhcpPolicyType" attribute MUST be set to 'CLASS', and the "cn"
   SHOULD be set to the value of the "dhcpClassName" attribute".

   NAME                dhcpClass
   DESCRIPTION         Represents information about a collection of
                       related clients.
   TYPE                Structural
   DERIVED FROM        dhcpPolicy
   POSSIBLE SUPERIORS  ( OrganizationalUnit dhcpPolicy )
   MUST CONTAIN        ( cn dhcpClassName )
   MAY CONTAIN         ( dhcpClassType )

6.7.1.  dhcpClass Attribute Definitions











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   NAME         dhcpClassType
   DESCRIPTION  This attribute indicates the type of the class.  It
                should be one of 'USERCLASS', 'VENDORCLASS', 'STATIC'
                (the only members of the class are enumerated clients),
                'DYNAMIC' (membership is determined by some vendor-spe-
                cific conditions).
   SYNTAX       IA5String SINGLE-VALUE

7.  Other Configuration objects

   Many server implementations provide other objects that simplify the
   configuration of the DHCP protocol.  One example is the ability to
   assign a name to a group of option settings and then to refer to the
   entire group of settings by referencing the name.  This is addressed
   by the "dhcpNamedOptionSet" object class.

   It is also fairly common for server implementations to allow users to
   extend the default set of options with site specific option defini-
   tions.  This is addressed by the "dhcpDictionary" object class.  This
   object class is also used to define the implementation-specific
   parameters (and their values) that can be specified in the "dhcpPa-
   rameterSetting" attribute.

7.1.  dhcpNamedOptionSet Object Class

   A "dhcpNamedOptionSet" is an object class for associating a name with
   a collection of option settings.  The entire set of options can be
   associated with a DHCP object by referring to the name.  This allows
   a common set of option settings to be re-used without repeating the
   option settings on each configured object.  To see how an option set
   is referenced, see the "dhcpIncludeOptionSet" attribute.

   NAME                dhcpNamedOptionSet
   DESCRIPTION         This is a named collection of settings for
                       options and/or server parameters.
   TYPE                Structural
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( OrganizationalUnit )
   MUST CONTAIN        ( cn )
   MAY CONTAIN         ( dhcpOptionSetting dhcpParameterSetting
                         dhcpFieldSetting dhcpForcedOptions
                         dhcpIncludeOptionSet )

7.1.1.  dhcpDictionary Object Class

   "dhcpDictionary" objects define the options and/or parameters that
   can be set when configuring various DHCP entities.




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   NAME                dhcpDictionary
   DESCRIPTION         This class defines an option or parameter that
                       can have a value.
   TYPE                Structural
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( OrganizationalUnit )
   MUST CONTAIN        ( cn )
   MAY CONTAIN         ( dhcpKeyword dhcpTag dhcpDataType dhcpDefault
                         dhcpMultiValued dhcpDescription dhcpLegalValues
                         dhcpTypeRestriction dhcpImplementation )

7.2.  dhcpDictionary Attribute Definitions

   NAME         cn
   DESCRIPTION  The "common name" of the option or parameter.  This will
                usually be the same as the "dhcpKeyword" attribute.
   SYNTAX       Integer SINGLE-VALUE

   NAME         dhcpKeyword
   DESCRIPTION  This is a string tag (or keyword) that is used to iden-
                tify the option or parameter.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpTag
   DESCRIPTION  The numeric tag that identifies an option.  This MUST be
                defined for options, but is not required for parameters.
   SYNTAX       Integer SINGLE-VALUE

   NAME         dhcpDataType
   DESCRIPTION  The data type for values of this option.  The set of
                valid data types are defined by the DHCP protocol.  For
                more information see [RFC2131].
   SYNTAX       Integer SINGLE-VALUE

   NAME         dhcpDefault
   DESCRIPTION  Indicates the default value of a parameter or option
                definition in a dictionary object.  This is  encoded as
                it would be in the "dhcpOptionSetting" or "dhcpParame-
                terSetting" attribute.
   SYNTAX       OctetString SINGLE-VALUE

   NAME         dhcpMultiValued
   DESCRIPTION  Indicates whether the parameter or option can have more
                than one value.
   SYNTAX       Boolean SINGLE-VALUE






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   NAME         dhcpDescription
   DESCRIPTION  A textual description of an object.
   SYNTAX       String SINGLE-VALUE

   NAME         dhcpLegalValues
   DESCRIPTION  The list of allowed values for the option or parameter.
                Each "legal value" is stored as a separate value for the
                attribute, and each one is encoded as it would be in the
                "dhcpOptionSetting" or "dhcpParameterSetting" attribute.
   SYNTAX       OctetString MULTI-VALUE

   NAME         dhcpTypeRestriction
   DESCRIPTION  This attribute is used to specify that the option or
                parameter should only be used with specific types of
                policies.  This is restricted to the same set of values
                as the "dhcpPolicyType" attribute.
   SYNTAX       IA5String MULTI-VALUE

   NAME         dhcpImplementation
   DESCRIPTION  This attribute is used to specify that the option or
                parameter should only be used with specific server
                implementations.
   SYNTAX       IA5String MULTI-VALUE

8.  Tracking Addresses

   The behavior of a DHCP server is influenced by two factors - it's
   configuration and the current state of the addresses that have been
   assigned to clients.  This schema defined a set of objects for stor-
   ing the configuration of the server, and the following object class
   provides the ability to record how addresses are used.

8.1.  dhcpAddress Object Class

   This class represents an IP address.  It may or may not be leaseable,
   and the object may exist even though a lease is not currently active
   for the associated IP address.

   Note that this object class has some of the "Settings" attributes
   that are defined for the "dhcpConfigurableObject", but they are not
   used for configuration - only for tracking the settings that were
   assigned to the client.  It is not required that the server implemen-
   tation record options that were offered to the client.








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   NAME                dhcpAddress
   DESCRIPTION         This class represents an IP Address, which may or
                       may not have been leased.
   TYPE                Structural
   DERIVED FROM        Top
   POSSIBLE SUPERIORS  ( )
   MUST CONTAIN        ( cn dhcpAddressType dhcpAddressState )
   MAY CONTAIN         ( dhcpExpirationTime dhcpStartTimeOfState
                         dhcpLastTransactionTime dhcpBootpFlag
                         dhcpDomainName dhcpDnsStatus
                         dhcpRequestedHostName dhcpAssignedHostName
                         dhcpReservedForClient dhcpAssignedToClient
                         dhcpRelayAgentInfo dhcpOptionSetting
                         dhcpParameterSetting dhcpFieldSetting )

8.2.  dhcpAddress Attribute Definitions

   NAME         cn
   DESCRIPTION  The IP address, as a string.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpAddressType
   DESCRIPTION  This describes how the address is to be assigned to a
                client.  One of 'UNKNOWN', 'DYNAMIC', 'FIXED', 'UNAS-
                SIGNED', 'NOTASSIGNABLE'.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpAddressState
   DESCRIPTION  This stores information about the current binding-status
                of an address, using the states defined in the safe-
                failover draft.  For more information see [FAILOVR].
   SYNTAX       Integer SINGLE-VALUE

   NAME         dhcpExpirationTime
   DESCRIPTION  This is the time the current lease for an address
                expires.
   SYNTAX       DateTime SINGLE-VALUE

   NAME         dhcpStartTimeOfState
   DESCRIPTION  This is the time of the last state change for a leased
                address.
   SYNTAX       DateTime SINGLE-VALUE

   NAME         dhcpLastTransactionTime
   DESCRIPTION  This is the last time a valid DHCP packet was received
                from the client.
   SYNTAX       DateTime SINGLE-VALUE




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   NAME         dhcpBootpFlag
   DESCRIPTION  This indicates whether the address is assigned via BOOTP
   SYNTAX       Boolean SINGLE-VALUE

   NAME         dhcpDomainName
   DESCRIPTION  This is the name of the domain assigned to the client by
                the server.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpDnsStatus
   DESCRIPTION  This indicates which resource records were added to the
                domain on behalf of the client by the DHCP server.  The
                allowed values are: "No DNS Activity", "Update A
                Records", "Update PTR Records", and "Update Both A and
                PTR Records"
   SYNTAX       Integer SINGLE-VALUE

   NAME         dhcpRequestedHostName
   DESCRIPTION  This is the hostname that was requested by the client.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpAssignedHostName
   DESCRIPTION  This is the actual hostname that was assigned to a
                client. It may not be the name that was requested by the
                client.  The fully qualified domain name can be deter-
                mined by appending the value of "dhcpDomainName" (with a
                dot separator) to this name.
   SYNTAX       IA5String SINGLE-VALUE

   NAME         dhcpReservedForClient
   DESCRIPTION  The distinguished name of a "dhcpClient" that an address
                is reserved for.  This may not be the same as the "dhc-
                pAssignedToClient" attribute if the address is being
                reassigned but the current lease has not yet expired.
   SYNTAX       DN SINGLE-VALUE

   NAME         dhcpAssignedToClient
   DESCRIPTION  This is the distinguished name of a "dhcpClient" that an
                address is currently assigned to.  This only has a value
                when the address is leased.
   SYNTAX       DN SINGLE-VALUE










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   NAME         dhcpRelayAgentInfo
   DESCRIPTION  If the client request was received via a relay agent,
                this contains information about the relay agent that was
                available from the DHCP request.  This is a hex-encoded
                option value.  For more information see [RELAY].
   SYNTAX       OctetString SINGLE-VALUE

9.  Object Containment

   These diagrams depict the containment hierarchy of the objects.
   <Administrative-Container> can be any LDAP object.

   <Administrative-Container>
      |
      +---dhcpConfiguration
          |
          +--- ou = OptionDictionary
          |  |
          |  +---dhcpDictionary
          |
          +--- ou = ParameterDictionary
          |  |
          |  +---dhcpDictionary
          |
          +--- ou = NamedOptionSets
          |  |
          |  +---dhcpNamedOptionSet
          |
          +--- ou = Policies
          |  |
          |  +---dhcpPolicy
          |      |
          |      +---dhcpPolicy . . .
          |
          +--- ou = Addresses
             |
             +---dhcpAddress


   <Administrative-Container>
      |
      +---dhcpService


10.  Object Class Inheritance

   The following diagram shows the inheritance hierarchy of the classes:




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   Top
      |
      +---dhcpDictionary
      |
      +---dhcpService
      |
      +---dhcpConfiguration (aux: dhcpConfigurableObject)
      |
      +---dhcpNamedOptionSet (aux: dhcpConfigurableObject)
      |
      +---dhcpAddress (aux: dhcpConfigurableObject)
      |
      +---dhcpPolicy (aux: dhcpConfigurableObject)
             |
             +---dhcpClass
             |
             +---dhcpClient
             |
             +---dhcpPool
             |
             +---dhcpSharedNetwork
             |
             +---dhcpSubnet


11.  Determining Policy settings

   This section of the document defines the algorithm that should be
   used for determining the settings for options and/or parameters for a
   policy.  Most DHCP server implementations provide for some degree of
   inheritance of options between configuration objects.  This algorithm
   is both flexible enough to allow server implementations to represent
   their existing behavior.

   The option settings directly associated with a "dhcpPolicy" object
   MUST take precedence over all other option settings.  The policy also
   inherits options from the following objects (in order of precedence):
   - options from one or more included "dhcpNamedOptionSet" objects, as
     defined in the "dhcpIncludeOptionSet" attribute.  If there is more
     than one option set, the attribute values define the order in which
     the option sets should be included.
   - options from the "dhcpSourceObject" for the policy.
   - options from "dhcpNamedOptionSet" objects associated with the
     "dhcpSourceObject" for the policy.
   - options from the "parent" policy (only if the object's parent in
     the directory is also a "dhcpPolicy" object.
   - options from "dhcpNamedOptionSet" objects associated with the "par-
     ent" policy.



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   - options from walking up the directory hierarchy inheriting from
     ancestor policies until the "dhcpConfiguration" object is reached.

12.  Policy Framework Schema Mapping

   This section of the document provides a mapping to the Policy Frame-
   work Core schema being developed by the Policy Framework working
   group.

   The Policy Framework Core schema provides a general representation of
   policies.  Mapping the "dhcpPolicy" objects in this schema to that
   general model is a fairly straightforward exercise.  For the most
   part each "dhcpPolicy" maps directly into a "policyRule" object from
   the Core schema.

   When a dhcpPolicy has a value for any of the following attributes: {
   "dhcpPoolName", "dhcpSubnetName", "dhcpSharedNetworkName", "dhcpCli-
   entIdentifier", "dhcpClassName", "dhcpVendorCondition" } this would
   be mapped into a "policyCondition" object.  Values for the { "dhcpOp-
   tionSetting", "dhcpParameterSetting", "dhcpFieldSetting", "dhcpForce-
   dOptions", "dhcpIncludeOptionSet" } attributes would be mapped into
   "policyAction" objects.


13.  CIM Mapping

   This section of the document provides a mapping to the CIM (Common
   Information Model) DHCP Schema defined by the DMTF.

13.1.  dhcpConfigurableObject

   The DMTF Schema maps the setting and parameter data in the dhcpCon-
   figurableObject class using instances of CIM_Setting classes and
   associations.

   The individual dhcpOption, Parameter and Field Settings are instances
   of the CIM_DHCPSetting class (derived from CIM_Setting).  The
   CIM_DHCPSetting class defines key properties and an octet string to
   hold the OptionData. The CIM_DHCPSetting instances are associated
   with the various subclasses of dhcpConfigurableObject using the
   CIM_ElementSetting, CIM_SettingContext or CIM_CollectionSetting rela-
   tionships. (Which association is used depends on the derivation of
   the dhcpConfigurableObject in the CIM class hierarchy.)

   The individual dhcpConfigurations and dhcpIncludeOptionSets are
   instances of the CIM_DHCPConfiguration class or of its subclass,
   CIM_DHCPOptionConfiguration (both classes were discussed earlier in
   this document).  The  CIM_DHCPConfiguration instances are associated



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   with the various subclasses of dhcpConfigurableObject using the
   CIM_ElementConfiguration, CIM_ConfigurationComponent or CIM_Collec-
   tionConfiguration relationships. (As above, the association that to
   be used depends on the derivation of the dhcpConfigurableObject in
   the CIM class hierarchy.)

   dhcpForcedOptions is mapped to the CIM_DHCPForcedOptions class
   (derived from CIM_Setting).  CIM_DHCPForcedOptions defines key prop-
   erties and an integer array to hold the option tags being "forced".
   It is associated with the various subclasses of dhcpConfigurableOb-
   ject using the CIM_ElementSetting, CIM_SettingContext or CIM_Collec-
   tionSetting relationships. (As above, the association that is used
   depends on the derivation of the dhcpConfigurableObject in the CIM
   class hierarchy.)

   Since the CIM_DHCPSetting and CIM_DHCPForcedOptions classes were not
   discussed previously, a brief overview of their properties is needed.
   Both classes contain only key properties for identification, plus one
   additional property in each object.  The CIM_DHCPSetting class has an
   octet string to hold the option, parameter or field data.  The
   CIM_DHCPForcedOptions class has an integer array holding option tags.

   The key properties of CIM_DHCPSetting and CIM_DHCPForcedOptions are:
     - ConfiguredObject, a string identifying the entity to which the
       Setting or ForcedOptions applies
     - SettingID, a string identifier for the instance
     - For CIM_DHCPSetting only, a SettingType enumerated integer defin-
       ing whether an option, parameter or field setting is specified.
   These string properties taken together form the objects' key and con-
   ceptually are a DN.

13.2.  Configurations and Services

13.2.1.  dhcpService

   The DMTF Schema specifies a CIM_DHCPService object (derived from
   CIM_Service) that corresponds to dhcpService.  In CIM, Services are
   defined and named relative to the System that hosts them.  Therefore,
   the keys of CIM_DHCPService are defined as:
     - The hosting System's CreationClassName (for example, CIM_Uni-
       taryComputerSystem) and Name.
     - The Service's CreationClassName (= "CIM_DHCPService") and Name.
   These string properties taken together form the object's key and con-
   ceptually are a DN.

   That CIM_DHCPService is named and scoped by a CIM_System is consis-
   tent with the definition of a <Computer> as a "possible superior" of
   dhcpService. In CIM, this relationship is described using the



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   CIM_HostedService association.

   CIM_DHCPService also contains the following properties:
     - Description and Caption strings (inherited from CIM_ManagedSys-
       temElement)
     - ImplementationMatchingStrings, an array of strings
     - Numerous other properties defining runtime characteristics of the
       DHCP Service.  For example, whether or not the Service provides
       ProxyDNSSupport (a boolean) or the BootPLeaseLength (a uint32)
       are properties of CIM_DHCPService.
   The dhcpServiceName string can be mapped into the CIM_DHCPService
   class' Name property, if the uniqueness characteristics of CIM naming
   are satisfied.  Otherwise, it should be mapped into the Caption
   string.  And, the dhcpImplementation multi-valued string can be
   mapped into the ImplementationMatchingStrings property.

   The dhcpConfiguration property is mapped to an association, CIM_Ser-
   viceForDCHPConfiguration, in the DMTF Schema.  This association was
   explained above.

13.2.2.  dhcpConfiguration

   The DMTF Schema defines a CIM_DHCPConfiguration object (derived from
   CIM_Configuration) that corresponds to dhcpConfiguration.  The CIM
   class has the following properties:
     - A Name string that is the object's key, and conceptually is a DN
     - Description and Caption strings
   The dhcpConfigurationName string is mapped into the CIM_DHCPConfigu-
   ration class' Name property, if it satisfies the uniqueness charac-
   teristics of CIM naming.  Otherwise, it should be mapped into the
   Caption property.

   The remainder of the dhcpConfiguration properties are mapped to asso-
   ciations in the DMTF Schema.  The correspondence is as follows:
     - dhcpPrimaryService and dhcpSecondaryService map to the CIM_Ser-
       viceForDHCPConfiguration association.  This association ties
       together a CIM_DHCPConfiguration and a CIM_DHCPService, and
       includes a boolean property to identify the PrimaryService.
     - dhcpParentConfiguration (subsetted by the dhcpIncludeFromParent
       property) is defined by instantiating various CIM_DHCPConfigura-
       tion objects and then grouping them using the CIM_Configura-
       tionComponent relationship. The aggregation in CIM defines the
       parts or components of the parent, as opposed to the LDAP DHCP
       Schema which defines the parent and then subsets it.

   The dhcpLocator property is unique to the LDAP Schema and has no CIM
   correspondence.




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13.3.  Policy Objects

13.3.1.  dhcpPool

   Different than the LDAP schema, the DMTF Schema defines a CIM_IPAd-
   dressRange entity to uniquely identify and manipulate ranges.  The
   key properties of the class are its start and end addresses.
   CIM_IPAddressRanges can be aggregated into CIM_RangeGroups using the
   CIM_CollectionOfRanges association.

   Regarding dhcpSubnet being a "possible superior" of dhcpPool, this is
   mapped in the DMTF Schema using the CIM_RangeGroupInSubnet aggrega-
   tion association.

13.3.2.  dhcpSubnet

   The DMTF Schema specifies a CIM_IPSubnet object (derived from
   CIM_LogicalNetwork) that corresponds to the dhcpSubnet class.  The
   property correspondence is as follows:
     - dhcpIpAddress = CIM_IPSubnet.SubnetNumber
     - dhcpSubnetMaskLength = (mapping is not 1 to 1 in that CIM_IPSub-
       net specifies the complete mask, as the SubnetMask property)
     - dhcpSubnetName = CIM_IPSubnet.Name, inherited from CIM_Logical-
       Network and part of the key structure for the class

   The dhcpSubnetName string can be mapped into the CIM_DHCPService
   class' Name  property, only if the uniqueness characteristics of CIM
   naming are satisfied.  Otherwise, it should be mapped into the Cap-
   tion property.

   Participation in a SharedNetwork (indicated by the dhcpSharedNetwork
   attribute in the LDAP Schema) is indicated by the CIM_SubnetInShared-
   Network aggregation.  This association would relate an instance of
   CIM_IPSubnet and an instance of CIM_SharedNetwork.

   Regarding dhcpSubnet being a "possible superior" of another Subnet,
   this is mapped in the DMTF Schema using the CIM_SubnetInSubnet aggre-
   gation association.

13.3.3.  dhcpSharedNetwork

   CIM_SharedNetwork (subclassed from CIM_CollectionOfMSEs) is defined
   in the DMTF Schema to correspond to the dhcpSharedNetwork class.  A
   property of the CIM_SharedNetwork class, Name (its key), maps the
   dhcpSharedNetworkName information. This mapping is allowed if the
   dhcpSharedNetworkName satisfies the uniqueness characteristics of CIM
   naming.  Otherwise, the Name data should be mapped into the
   CIM_SharedNetwork.Caption property, inherited from



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   CIM_CollectionOfMSEs.

13.3.4.  dhcpClient

   The DMTF Schema defines a CIM_DHCPClientEndpoint object (derived from
   CIM_ProtocolEndpoint) that corresponds to dhcpClient.  The CIM class
   maps the LDAP Schema properties as follows:
     - dhcpClientIdentifier = DHCPClientID string
     - dhcpUserClass = UserClass string array
     - dhcpVendorClass = VendorClass string
     - dhcpCharacteristics = Characteristics string array
     - dhcpCreatedByServer = CreatedForUnlistedClient boolean

   The remainder of the dhcpClient properties are mapped to associations
   in the DMTF Schema.  The correspondence is as follows:
     - Information in dhcpAssignedAddress is mapped to the CIM_DHCPAd-
       dressAssignment association,  relating CIM_DHCPClientEndpoint and
       CIM_DHCPAllocatedEndpoint (as discussed in Section 3.2.1)
     - Information in dhcpMemberOfGroup is mapped to the CIM_DHCPEnd-
       pointCollection association, relating CIM_DHCPClientEndpoint and
       CIM_DHCPClientCollection (as discussed in Section 3.3

   To identify instances of CIM_DHCPClientEndpoint, key (naming) proper-
   ties are needed. Names are defined relative to the System that hosts
   the Endpoints. So, the keys of any CIM_ProtocolEndpoint are specified
   as:
     - The hosting System's CreationClassName (for example, CIM_Uni-
       taryComputerSystem) and Name,
     - The ProtocolEndpoint's CreationClassName (= "CIM_DHCPClientEnd-
       point") and Name.
   These string properties taken together form the object's key and con-
   ceptually are a DN.

13.3.5.  dhcpClass

   The DMTF Schema defines CIM_DHCPClientCollection (derived from
   CIM_CollectionOfMSEs) to correspond to dhcpClass. In the CIM_DHCP-
   ClientCollection object, UserClass and VendorClass information is
   individually called out (addressing the DHC protocol mechanisms for
   determining a collection of clients).  Also, it is permissible to
   define other membership Characteristics, as well as to specify
   explicit membership.  In CIM, properties can be left unde-
   fined/unspecified.  Therefore, if the UserClass, VendorClass or other
   Characteristics are not applicable, they can be left NULL (unde-
   fined).

   The mapping of properties from dhcpClass to CIM_DHCPClientCollection
   is straightforward.



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     - dhcpClassName corresponds to the CIM_DHCPClientCollection's Name
       property ( if CIM naming requirements for uniqueness are met).
       Otherwise, dhcpClassName should be mapped into the Caption prop-
       erty, inherited from CIM_CollectionOfMSEs.
     - dhcpClassType is mapped to the CollectionType enumeration.
     - dhcpClassCharacteristics corresponds to the Characteristics
       string array property.
     - dhcpUserClass and dhcpVendorClass map to the UserClass and Ven-
       dorClass string arrays, respectively.

   Explicit membership by a client in a particular instance of CIM_DHCP-
   ClientCollection is specified using the CIM_DHCPEndpointCollection
   aggregation association.  (In the LDAP Schema, this is defined by
   placing the DN of the dhcpClass in the client's dhcpMemberOfGroup
   attribute.)  CIM_DHCPEndpointCollection is also useful when enumerat-
   ing the client members of a Collection, after evaluation of the User-
   Class, VendorClass and Characteristics requirements.

   Regarding dhcpConfiguration as a "possible superior" for dhcpClass,
   this is mapped in the DMTF Schema as an instance of the CIM_Collec-
   tionConfiguration association.  The association would be instantiated
   to reference the CIM_DHCPClientCollection and the appropriate
   CIM_DHCPConfiguration.

13.4.  Other Configuration Objects

13.4.1.  dhcpNamedOptionSet

   In the DMTF Schema, the CIM_DHCPOptionConfiguration object corre-
   sponds to the dhcpNamedOptionSet class. dhcpOptionSetName is mapped
   into the Name property (a key property) of the CIM class.  This is
   acceptable if dhcpOptionSetName meets CIM's requirements for unique-
   ness.  Otherwise, its data should be placed into the Caption prop-
   erty, inherited from CIM_Configuration.

   If the instance of CIM_DHCPOptionConfiguration is part of a higher
   level CIM_DHCPConfiguration, this is indicated by instantiating the
   CIM_ConfigurationComponent association and referencing both Configu-
   rations.

13.4.2.  dhcpDictionary

   The DMTF Schema defines a CIM_DHCPOptionDictionary object (derived
   from CIM_Setting) that corresponds to dhcpOptionDictionary.
   Instances of CIM_DHCPOptionDictionary may be grouped by CIM_DHCPCon-
   figurations using the CIM_SettingContext association.  This associa-
   tion aggregates one or more Settings into a Configuration, and corre-
   sponds to the definition of dhcpConfiguration as a "possible



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   superior" of dhcpOptionDictionary.  It also is the mapping for the
   dhcpConfigurationName string attribute.

   The property values of the CIM_DHCPOptionDictionary class map one-to-
   one to those of dhcpOptionDictionary. The explicit mapping is:
     - dhcpOptionName = OptionName string
     - dhcpOptionTag = OptionTag uint32
     - dhcpDataType = DataType enumeration
     - dhcpMultiValued = MultiValued boolean
     - dhcpDefault = DefaultValue octet string
     - dhcpVendorClass = VendorClass string
     - dhcpDescription = Description string, inherited from CIM_Setting
     - dhcpLegalValues = LegalValues octet string
     - dhcpTypeRestriction = RestrictedTo enumerated integer array

   To identify instances of CIM_DHCPOptionDictionary, one or more key
   (naming) properties are needed. The key of CIM_DHCPOptionDictionary
   is specified as its SettingID (a string). This property conceptually
   is a DN.

13.5.  Tracking Addresses

13.5.1.  dhcpAddress

   The DMTF Schema defines a CIM_DHCPAllocatedEndpoint (a subclass of
   CIM_ProtocolEndpoint) that corresponds to the dhcpAddress class.
   However, in CIM, to obtain all the data for an IP address, one must
   examine several classes.  These are:
     - CIM_DHCPAllocatedEndpoint containing lease specific information
     - CIM_IPProtocolEndpoint containing address specific data, such as
       address type and IP version support
     - CIM_EndpointIdentity, an association instantiated between the
       CIM_DHCPAllocatedEndpoint and CIM_IPProtocolEndpoint, to tie
       together these different aspects of the same address
     - CIM_DHCPAddressAssignment, an association relating a CIM_DHCPAl-
       locatedEndpoint with a DHCP client

   Mapping the dhcpAddress properties into the DMTF Schema results in
   the following list:
     - dhcpIPAddress = CIM_DHCPAllocatedEndpoint.Address string
     - dhcpAddressType = CIM_DHCPAllocatedEndpoint.DHCPAddressType enu-
       meration
     - dhcpAddressState = CIM_DHCPAllocatedEndpoint.AddressState enumer-
       ation
     - dhcpDomainName = CIM_DHCPAllocatedEndpoint.DomainName string
     - dhcpLastTransactionTime = CIM_DHCPAllocatedEndpoint.LastTransac-
       tionTime datetime




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     - dhcpExpirationTime = CIM_DHCPAllocatedEndpoint.Expiration date-
       time
     - dhcpStartTimeOfState = CIM_DHCPAllocatedEndpoint.TimeOfLastState-
       Change datetime
     - dhcpRequestedHostName = CIM_DHCPAllocatedEnd-
       point.RequestedDNSName string
     - dhcpBootpFlag = CIM_DHCPAllocatedEndpoint.BootPAddress boolean
     - dhcpAssignedHostName = CIM_DHCPAllocatedEndpoint.AssignedDNSName
       string
     - dhcpDnsStatus = CIM_DHCPAllocatedEndpoint.DNSStatus enumeration
     - dhcpReservedForClient = An instance of the CIM_DHCPAddressAssign-
       ment association with the Reserved boolean set to TRUE
     - dhcpAssignedToClient = An instance of the CIM_DHCPAddressAssign-
       ment association indicating the current lease assignment
     - dhcpRelayAgentInfo = CIM_DHCPAllocatedEndpoint.RelayAgent octet
       string

   To identify CIM_IPProtocolEndpoint or CIM_DHCPAllocatedEndpoint
   instances, key (naming) properties are needed. Names are defined rel-
   ative to the System that hosts the Endpoints. So, the keys of any
   CIM_ProtocolEndpoint are specified as:
     - The hosting System's CreationClassName (for example, CIM_Uni-
       taryComputerSystem) and Name.
     - The ProtocolEndpoint's CreationClassName (= "CIM_IPProtocolEnd-
       point" or "CIM_DHCPAllocatedEndpoint") and Name.
   These string properties taken together form the object's key and con-
   ceptually are a DN.

   Any instances of CIM_ProtocolEndpoints (or instances of its sub-
   classes) can be members of CIM_LogicalNetworks.  This is specified
   using the CIM_InLogicalNetwork association.  Using this association,
   one can relate  CIM_DHCPAllocatedEndpoints and CIM_IPProtocolEnd-
   points to a CIM_IPSubnet. The InLogicalNetwork association becomes
   the mapping for the dhcpSubnet "possible superior" relationship to
   dhcpAddress.

14.  References

   [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
             March 1997.

   [RFC2132] Alexander, S., Droms, R., "DHCP Options and BOOTP Vendor
             Extensions", RFC 2132, March 1997.

   [DMTF]    Distributed Management Task Force, "Common Information
             Model (CIM) Specification", Version 2.0, Mar 1998.





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   [DEN]     Strassner, J., "Directory-Enabled Networks, Information
             Model and Base Schema", DEN Specification v3.0c, July 1998.

   [MSDHCP]  Gu, Y., Vyaghrapuri, R., "An LDAP Schema for Dynamic Host
             Configuration Protocol Service", Internet Draft
             <draft-gu-dhcp-ldap-schema-00.txt>, August 1998.

   [NOVDHCP] Miller, T., Patel, A., Rao, P., "Lightweight Directory
             Access Protocol (v3): Schema for Dynamic Host Configuration
             Protocol (DHCP)", Internet Draft
             <draft-miller-dhcp-ldap-schema-00.txt>, June 1998.

   [FAILOVR] Droms, R., Rabil, G., Dooley, M., Kapur, A., Gonczi, S.,
             Volz, B., "DHCP Failover Protocol", Internet Draft
             <draft-ietf-dhc-failover-03.txt>, November 1998.

   [RELAY]   Patrick, M., "DHCP Relay Agent Information Option", Inter-
             net Draft <draft-ietf-dhc-agent-options-05.txt>, November
             1998.

   [DHCPOPT] Carney, M., "New Option Review Guidelines and Additional
             Option Namespace", Internet Draft
             <draft-ietf-dhc-option_review_and_namespace-00.txt>, June
             1999.

   [POLICY]  Strassner, J., Elleson, E., Moore, B., "Policy Framework
             LDAP Core Schema", Internet Draft
             <draft-ietf-policy-core-schema-05.txt>, October 1999.

   [RFC2251] Wahl, M., Howes, T., Kille, S., "Lightweight Directory
             Access Protocol (v3)", RFC 2251, December 1997.

   [RFC2252] Wahl, M., Coulbeck, A., Howes, T., Kille, S., "Lightweight
             Directory Access Protocol (v3) Attribute Syntax Defini-
             tions", RFC 2252, December 1997.

   [RFC2255] Howes, T., Smith, M., "The LDAP URL Format", RFC 2255,
             December 1997.

   [RFC951]  Croft, B., Gilmore, J., "Bootstrap Protocol (BOOTP)", RFC
             951, September 1985.

   [RFC2119] Bradner, S. "Key words for use in RFCs to Indicate Require-
             ment Levels", RFC 2119, March 1997.







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15.  Acknowledgements

      This document is closely aligned with the work being done in the
      Distributed Management Task Force (DMTF) Networks working group.

      Design ideas included in this document are primarily based on dis-
      cussions during two meetings with some members of the IETF DHC
      Working Group and the DMTF Networks working group.  The contribu-
      tions of these individuals is gratefully acknowledged.

      Special thanks to Lee Rafalow, Steve Gonczi, Steve Chirokas, Kim
      Kinnear, Ellen Stokes, Tom Miller, Ye Gu, Glenn Waters, Mike Car-
      ney, Ralph Droms, Greg Rabil and Steve Bazyl for their contribu-
      tions.

      Thanks also to Ester Burwell, Andy Sudduth, Fred Hunter, Paul Rai-
      son, Josh Littlefield, Peter Heitman, Neil Russell and Linda Scobo
      for their participation in these meetings.

16.  Author information

      Andy Bennett
      Bernie Volz
      Process Software Corporation
      959 Concord St.
      Framingham, MA 01701
      Phone: (508) 879-6994
      Email: bennett@process.com
      Email: volz@process.com

      Andrea Westerinen
      Microsoft Corporation
      One Microsoft Way
      Redmond, WA  98052
      Phone:  +1 425-705-2553
      Email:  andreawe@microsoft.com

17.  Full Copyright Statement

      Copyright (C) The Internet Society (1999). All Rights Reserved.

      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



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      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 lan-
      guages 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 ENGI-
      NEERING 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.



































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