draft-ietf-asid-ldapv3ext-01.txt   draft-ietf-asid-ldapv3ext-02.txt 
ASID Working Group Y. Yaacovi ASID Working Group Y. Yaacovi
INTERNET-DRAFT Microsoft INTERNET-DRAFT Microsoft
M. Wahl M. Wahl
Critical Angle Inc. Critical Angle Inc.
K. Settle K. Settle
Microsoft Microsoft
T. Genovese T. Genovese
Microsoft Microsoft
Expires in six months from 10 September 1996 Expires in six months from 14 October 1996
Intended Category: Standards Track Intended Category: Standards Track
Lightweight Directory Access Protocol: Lightweight Directory Access Protocol:
Extensions for Dynamic Directory Services Extensions for Dynamic Directory Services
<draft-ietf-asid-ldapv3ext-01.txt> <draft-ietf-asid-ldapv3ext-02.txt>
1. Status of this Memo 1. Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and documents of the Internet Engineering Task Force (IETF), its areas,
its working groups. Note that other groups may also distribute working and its working groups. Note that other groups may also distribute
documents as Internet-Drafts. working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material time. It is inappropriate to use Internet-Drafts as reference
or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
To learn the current status of any Internet-Draft, please check the To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
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ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim).
2. Abstract 2. Abstract
This document defines the requirements for dynamic directory services This document defines the requirements for dynamic directory services
and specifies the format of request and response extended operations for and specifies the format of request and response extended operations
supporting client-server interoperation in a dynamic directories for supporting client-server interoperation in a dynamic directories
environment. environment.
The Lightweight Directory Access Protocol (LDAP) [1] supports The Lightweight Directory Access Protocol (LDAP) [1] supports
lightweight access to static directory services, allowing relatively lightweight access to static directory services, allowing relatively
fast search and update access. Static directory services store fast search and update access. Static directory services store
information about people that persists in its accuracy and value over information about people that persists in its accuracy and value over
a long period of time. a long period of time.
Dynamic directory services are different in that they store information Dynamic directory services are different in that they store
about people that only persists in its accuracy and value while people information about people that only persists in its accuracy and value
are online. Though the protocol operations and attributes used by while people are online. Though the protocol operations and
dynamic directory services are similar to the ones used for static attributes used by dynamic directory services are similar to the ones
directory services, clients that are bound to a dynamic directory used for static directory services, clients that are bound to a
service need to periodically refresh their presence at the server to dynamic directory service need to periodically refresh their presence
keep directory entries from getting stale in the presence of client at the server to keep directory entries from getting stale in the
application crashes. presence of client application crashes.
A flow control mechanism from the server is also described that allows In addition, static directories may include dynamic information, in
a server to inform clients how often they should refresh their presence. the form of dynamic attributes in an otherwise static entry. Such
information needs to be refreshed periodically in the same manner.
A flow control mechanism from the server is also described that
allows a server to inform clients how often they should refresh
their presence.
3. Requirements 3. Requirements
The protocol extensions must allow accessing dynamic directories in a The protocol extensions must allow accessing dynamic directories in a
standard LDAP manner, to allow clients to access static and dynamic standard LDAP manner, to allow clients to access static and dynamic
directories in the same way. directories in the same way.
By nature of dynamic directories, entries are not persistent and clients By definition, dynamic entries or dynamic attributes are not
may go away gracefully or not. The proposed extensions must offer a persistent and clients may go away gracefully or not. The proposed
way for server to tell if entries are still valid, and to do this in a extensions must offer a way for a server to tell if entries or
way that will scale for a relatively large number of users. There also attributes are still valid, and to do this in a way that will scale
must be a mechanism for clients to reestablish their entry with the for a relatively large number of users. There also must be a
server. mechanism for clients to reestablish their entry or attributes with
the server.
Finally, to allow clients to broadly use the dynamic extensions, they Finally, to allow clients to broadly use the dynamic extensions,
need to be registered as standard LDAP extended operations. the extensions need to be registered as standard LDAP extended
operations.
4. Description of Approach 4. Description of Approach
The Lightweight Directory Access Protocol (LDAP) [1] permits additional The Lightweight Directory Access Protocol (LDAP) [1] permits
operation requests and responses to be added to the protocol. The additional operation requests and responses to be added to the
support for dynamic directories takes advantage of these to establish protocol. The support for dynamic directories takes advantage of
a mechanism to support dynamic directories which is fully integrated these to establish a mechanism to support dynamic directories
with LDAP. which is fully integrated with LDAP.
A dynamic entry is an object in the directory tree which has a time-to-live The approach described in this proposal defines dynamic entries and
associated with it. This time-to-live is set when the entry is created. dynamic attributes in order to allow implementing directories with
The time-to-live is automatically decremented, and when it expires the dynamic information. An implementation of dynamic directories, must
dynamic entry disappears. By invoking the refresh extended operation be able to support both dynamic directory entries and dynamic
(defined below) to re-set the time-to-live, a client can cause the entry attributes.
to remain present a while longer.
A dynamic entry is created by including the objectClass value given in 4.1. Dynamic Entries and the dynamicObject object class
section 6 in the list of attributes when adding an entry. This method
is subject to standard access control restrictions. A dynamic entry is an object in the directory tree which has a
time-to-live associated with it. This time-to-live is set when the
entry is created. The time-to-live is automatically decremented, and
when it expires the dynamic entry disappears. By invoking the
refresh extended operation (defined below) to re-set the time-to-live, a
client can cause the entry to remain present a while longer.
A dynamic entry is created by including the objectClass value given
in section 6 in the list of attributes when adding an entry. This
method is subject to standard access control restrictions.
The extended operation covered here, allows a client to refresh a The extended operation covered here, allows a client to refresh a
dynamic entry by invoking at intervals refresh operations containing dynamic entry by invoking at intervals refresh operations containing
that entry's name. Dynamic entries will be treated the same as that entry's name. Dynamic entries will be treated the same as
non-dynamic entries when processing search, compare, add, delete, non-dynamic entries when processing search, compare, add, delete,
modify and modifydn operations. However if clients stop sending modify and modifydn operations. However if clients stop sending
refresh operations for an entry, then the server will automatically refresh operations for an entry, then the server will automatically
and without notification remove that entry from the directory. and without notification remove that entry from the directory. This
This removal will be treated the same as if the client had issued a removal will be treated the same as if the entry had been deleted by
delete operation on that entry. an LDAP protocol operation.
There is no way to change a static entry into a dynamic one and vice- There is no way to change a static entry into a dynamic one and vice-
versa. If the client is using Modify with an objectClass of dynamicObject versa. If the client is using Modify with an objectClass of
on a static entry, the server must return a service error either dynamicObject on a static entry, the server must return a service
"objectClassModsProhibited" (if the server does not allow objectClass error either "objectClassModsProhibited" (if the server does not
allow objectClass modifications at all) or "objectClassViolation"
(if the server does allow objectClass modifications in general).
modifications at all) or "objectClassViolation" (if the server does allow A dynamic entry may be removed by the client using the delete
objectClass modifications in general). operation. This operation will be subject to access control
restrictions.
A dynamic entry may be removed by the client using the delete operation. A non-dynamic entry cannot be added subordinate to a dynamic entry:
This operation will be subject to access control restrictions. the server must return an appropriate update or service error if this
is attempted.
A non-dynamic entry cannot be added subordinate to a dynamic entry: the 4.2. Dynamic Attributes
server must return an appropriate update or service error if this is
attempted. A similar concept is dynamic attributes. These attributes behave the
same as ordinary user attributes to Search, Compare and Modify
requests, except that if they time out they disappear from the entry
in which they are located. (Unlike the dynamicObject class, the
entry itself does not disappear, and non-dynamic attributes are
unaffected). Like dynamic entries, a static entry with dynamic
attributes must have the entryTtl attribute which is described
in section 6 below.
Dynamic attributes do not necessarily introduce a new set of
attributes in the schema. Any static attribute in the schema can be
made dynamic by including the ;dynamic attribute modifier with the
typename. It is allowed to introduce new dynamic attributes which
are not useful in the static domain. Such attributes will still require
including the ;dynamic attribute modifier with the typename to define
them as dynamic.
A dynamic attribute may be a subtype of a non-dynamic attribute, ]
but a non-dynamic attribute must not be a subtype of a dynamic attribute.
Operational attributes and collective attributes must not be dynamic.
All dynamic attributes are considered to be user attributes, however
they are not guaranteed to be present in shadow copies of entries.
A client may introduce dynamic attributes into an entry by using a
Modify request to add them, or by including them in the attribute
list of an Add Request. If the attribute type is permitted in the entry
then the dynamic attribute is also permitted. The client would
specify that the attribute is dynamic by including the tag ";dynamic"
with the typename. Dynamic values may be changed, and the attributes
removed, by using the Modify request as normal. If the entry is
deleted, dynamic attributes disappear immediately along with all the
non-dynamic. A ;dynamic modifier on an attribute may not be used in
a compare request, or in a search request (either in the filter or
attributes requested for return). This is in keeping with the
philosophy that dynamic attributes be indistinguishable from static
attributes as much as possible.
The granularity of a dynamic attribute is the entire attribute
including all values. Dynamic and static values may not be mixed
within a single attribute. For example, suppose an existing static
entry had an attribute called "ipAddress" with the value "1.2.3.4".
A modification of the entry to add the value "5.4.3.2" to the attribute
"ipAddress;dynamic" would fail with a "constraintViolation" error.
The addition and modification of dynamic attributes are subject to
schema and access control restrictions, as with non-dynamic
attributes. Thus unless the extensibleObject object class is
present, generally an object class or content rule must be defined
to permit those attributes to be present in an entry. If their presence
is controlled by an object class, then just as with non-dynamic
attributes, the object class value must have already been added
before the attributes are added. The dynamicObject object class
described in section 4.1 does not itself permit any particular
dynamic attributes.
Dynamic attributes in a particular entry are refreshed using the
Refresh extended operation. All of the entry's dynamic attributes
are refreshed by a single refresh request. The TTL given in the refresh
response applies to all of the entry's dynamic attributes. There is
no way to refresh particular dynamic attributes within an entry at
different times, or to have different TTLs apply to different dynamic
attributes.
If not refreshed, all dynamic attributes in an entry time out
simultaneously. All the attributes which are dynamic with all their
values disappear atomically, as if the server had done a ModifyEntry
specifying that all the dynamic types were to be deleted from that
entry. The client must not expect any dynamic attributes to be
present in an entry after the time-to-live for that entry has reached
zero. However the attributes may not disappear immediately as
servers may only process timing out attributes at intervals
(e.g. every few minutes).
Note that if an object class definition references a dynamic
attribute as a mandatory attribute, the entry will still time out,
but a schema inconsistency will be present in that entry.
(The objectClass attribute and its values always remain
since objectClass is not a dynamic attribute.) Thus it is
strongly recommended that designers not specify dynamic
attributes as anything other than optional attributes
of auxiliary classes.
Dynamic attributes may be used within dynamic entries (i.e., entries
containing object class "dynamicObject", defined below), but since
all of such an entry's attributes are implicitly dynamic, such use
is superfluous.
5. Protocol Additions 5. Protocol Additions
5.1 Refresh Request 5.1 Refresh Request
Refresh is a protocol operation sent by a client to tell the server that Refresh is a protocol operation sent by a client to tell the server
the client is still alive and the directory entry is still accurate and that the client is still alive and the dynamic directory entry or the
valuable. The client sends a Refresh request periodically based on the dynamic attributes of the entry are still accurate and valuable. The
value of the client refresh period (CRP). The server can request that client sends a Refresh request periodically based on the value of the
the client change this value. As long as the server receives a Refresh client refresh period (CRP). The server can request that the client
request within the timeout period, the directory entry is guaranteed change this value. As long as the server receives a Refresh request
to persist on the server. Clients implementors should be aware that within the timeout period, the directory entry is guaranteed to
persist on the server. Clients implementers should be aware that
since the intervening network between the client and server is since the intervening network between the client and server is
unreliable, a Refresh request packet may be delayed or lost while in unreliable, a Refresh request packet may be delayed or lost while in
transit. If this occurs, the entry may disappear, and the client will transit. If this occurs, the entry or the dynamic attributes may
need to detect this and re-add the entry. disappear, and the client will need to detect this and re-add the
entry or the attributes.
A client may request this operation by transmitting an LDAP PDU containing A client may request this operation by transmitting an LDAP PDU
an ExtendedRequest. An LDAP ExtendedRequest is defined as follows: containing an ExtendedRequest. An LDAP ExtendedRequest is defined as
follows:
ExtendedRequest ::= [APPLICATION 23] SEQUENCE { ExtendedRequest ::= [APPLICATION 23] SEQUENCE {
requestName [0] LDAPOID, requestName [0] LDAPOID,
requestValue [1] OCTET STRING } requestValue [1] OCTET STRING }
The requestName field must be set to the string The requestName field must be set to the string
"1.3.6.1.4.1.1466.101.119.1". "1.3.6.1.4.1.1466.101.119.1".
The requestValue field will contain as a value the DER-encoding of the The requestValue field will contain as a value the DER-encoding of
following ASN.1 data type: the following ASN.1 data type:
SEQUENCE { SEQUENCE {
entryName [0] LDAPDN, entryName [0] LDAPDN,
requestTtl [1] INTEGER requestTtl [1] INTEGER
} }
The entryName field is the UTF-8 string representation of the name of the The entryName field is the UTF-8 string representation of the name of
dynamic entry [3]. This entry must already exist. the dynamic entry or the entry containing dynamic attributes [3].
This entry must already exist.
The requestTtl is a time in seconds (between 1 and 31557600) that the The requestTtl is a time in seconds (between 1 and 31557600) that the
client requests that the entry exists in the directory before it is client requests that the entry or the dynamic attributes exists in
automatically removed. Servers are not required to accept this value the directory before being automatically removed. Servers are not
and might return a different TTL value to the client. Clients must be required to accept this value and might return a different TTL value
to the client. Clients must be able to use this server-dictated
able to use this server-dictated value as their CRP. value as their CRP.
5.2 Refresh Response 5.2 Refresh Response
If a server implements this extension, then when the request is made it If a server implements this extension, then when the request is made
will return an LDAP PDU containing an ExtendedResponse. An LDAP it will return an LDAP PDU containing an ExtendedResponse. An LDAP
ExtendedResponse is defined as follows: ExtendedResponse is defined as follows:
ExtendedResponse ::= [APPLICATION 24] SEQUENCE { ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
responseName [0] LDAPOID OPTIONAL, responseName [0] LDAPOID OPTIONAL,
response [1] OCTET STRING OPTIONAL, response [1] OCTET STRING OPTIONAL,
standardResponse [2] LDAPResult } standardResponse [2] LDAPResult }
The responseName field contains the same string as that present in the The responseName field contains the same string as that present in
request. the request.
The response field will contain as a value the DER-encoding of the The response field will contain as a value the DER-encoding of the
following ASN.1 data type: following ASN.1 data type:
SEQUENCE { SEQUENCE {
responseTtl [1] INTEGER responseTtl [1] INTEGER
} }
The responseTtl field is the time in seconds which the server chooses The responseTtl field is the time in seconds which the server chooses
to have as the time-to-live field for that entry. It must not be any to have as the time-to-live field for that entry. It must not be any
smaller than that which the client requested, and it may be larger. smaller than that which the client requested, and it may be larger.
Please note that for the case of a static entry with dynamic
attributes, this time-to-live applies to all the dynamic attributes
in this entry.
If the operation was successful, the errorCode field in the If the operation was successful, the errorCode field in the
standardResponse part of an ExtendedResponse will be set to success. standardResponse part of an ExtendedResponse will be set to success.
In case of an error, the responseTtl field will have the value 0, In case of an error, the responseTtl field will have the value 0, and
and the errorCode field will contain an appropriate value, as follows: the errorCode field will contain an appropriate value, as follows: If
If the entry named by entryName could not be located, the errorCode the entry named by entryName could not be located, the errorCode
field will contain "noSuchObject". field will contain "noSuchObject". If the entry is not dynamic, or
If the entry is not dynamic, the errorCode field will contain does not have dynamic attributes, the errorCode field will contain
"objectClassViolation". "objectClassViolation". If the requester does not have permission to
If the requestor does not have permission to refresh the entry, refresh the entry, the errorCode field will contain
the errorCode field will contain "insufficientAccessRights". "insufficientAccessRights". If the requestTtl field is too large,
If the requestTtl field is too large, the errorCode field will contain the errorCode field will contain "sizeLimitExceeded".
"sizeLimitExceeded".
If a server does not implement this extension, it will return an LDAP If a server does not implement this extension, it will return an LDAP
PDU containing an ExtendedResponse, which contains only the PDU containing an ExtendedResponse, which contains only the
standardResponse element (the responseName and response elements standardResponse element (the responseName and response elements will
will be absent). The LDAPResult element will indicate the protocolError be absent). The LDAPResult element will indicate the protocolError
result code. result code.
This request is permitted to be invoked when LDAP is carried by a This request is permitted to be invoked when LDAP is carried by a
connectionless transport. connectionless transport.
When using a connection-oriented transport, there is no requirement that When using a connection-oriented transport, there is no requirement
this operation be on the same particular connection as any other. A client that this operation be on the same particular connection as any
other. A client may open multiple connections, or close and then
may open multiple connections, or close and then reopen a connection. reopen a connection.
6. Schema Additions 6. Schema Additions
All dynamic entries must have the dynamicObject value in their All dynamic entries must have the dynamicObject value in their
objectClass attribute. This object class is defined as follows objectClass attribute. This object class is defined as follows
(using the ObjectClassDescription notation of [2]): (using the ObjectClassDescription notation of [2]):
( 1.3.6.1.4.1.1466.101.119.2 NAME 'dynamicObject' ( 1.3.6.1.4.1.1466.101.119.2 NAME 'dynamicObject'
DESC 'This class, if present in an entry, indicates that this entry has DESC 'This class, if present in an entry, indicates that this entry
a limited lifetime and may disappear automatically when its has a limited lifetime and may disappear automatically when
time-to-live has reached 0. There are no mandatory attributes of its time-to-live has reached 0. There are no mandatory
this class, however if the client has not supplied a value for attributes of this class, however if the client has not
the entryTtl attribute, the server will provide one.' supplied a value for the entryTtl attribute, the server will
provide one.'
SUP top AUXILIARY ) SUP top AUXILIARY )
Furthermore, the dynamic entry must have the following operational Furthermore, the dynamic entry or the static entry with dynamic
attribute. It is described using the AttributeTypeDescription notation attributes must have the following operational attribute. It is
of [2]: described using the AttributeTypeDescription notation of [2]:
( 1.3.6.1.4.1.1466.101.119.3 NAME 'entryTtl' ( 1.3.6.1.4.1.1466.101.119.3 NAME 'entryTtl'
DESC 'This operational attribute is maintained by the server and appears DESC 'This operational attribute is maintained by the server and
to be present in every dynamic entry. The attribute is not present appears to be present in every dynamic entry or an entry that
when the entry does not contain the dynamicObject object class. contains dynamic attributes. The attribute is not present
The value of this attribute is the time in seconds that the entry when the entry does not contain the dynamicObject object
will continue to exist before it disappears from the directory. class or dynamic attributes. The value of this attribute is the
In the absence of intervening refresh operations, the values time in seconds that the entry or the dynamic attributes in a
returned by reading the attribute in two successive searches static entry will continue to exist before disappearing from
are guaranteed to be nonincreasing. The smallest permissible value the directory. In the absence of intervening refresh
is 0, indicating that the entry may disappear without warning. operations, the values returned by reading the attribute in
The attribute is marked NO-USER-MODIFICATION since it may only be two successive searches are guaranteed to be nonincreasing.
changed using the refresh operation.' The smallest permissible value is 0, indicating that the
entry may disappear without warning. The attribute is marked
NO-USER-MODIFICATION since it may only be changed using the
refresh operation.'
SYNTAX 'Integer' SINGLE-VALUE NO-USER-MODIFICATION USAGE dSAOperation ) SYNTAX 'Integer' SINGLE-VALUE NO-USER-MODIFICATION USAGE dSAOperation )
7. Client and Server Requirements 7. Client and Server Requirements
7.1 Client Requirements 7.1 Client Requirements
Once a dynamic entry has been created, clients are responsible for Once a dynamic entry has been created, clients are responsible for
invoking the refresh extended operation, in order to keep that entry invoking the refresh extended operation, in order to keep that entry
present in the directory. present in the directory. The same holds true for keeping dynamic
attributes present on a static entry.
Clients must not expect that the entry will be present in the DIT after Clients must not expect that a dynamic entry will be present in the
it has timed out, however it must not either require that the server DIT after it has timed out, however it must not either require that
remove the entry immediately (some servers may only process timing out the server remove the entry immediately (some servers may only
entries at intervals). If the client wishes to ensure the entry process timing out entries at intervals). If the client wishes to
does not exist it should issue a RemoveRequest for that entry. ensure the entry does not exist it should issue a RemoveRequest for
that entry. Again, dynamic attributes behave the same: they will not
be present in the DIT after they timed out, but the client should not
require their immediate removal.
Initially, a client needs to know how often it should send refresh Initially, a client needs to know how often it should send refresh
requests to the server. This value is defined as the CRP (Client Refresh requests to the server. This value is defined as the CRP (Client
Refresh Period) and is set by the server based on the entryTtl.
Period) and is set by the server based on the entryTtl. Since the Since the AddRequest is left unchanged and is not modified in this
AddRequest is left unchanged and is not modified in this proposal to proposal to return this value, a client must issue a Refresh extended
return this value, a client must issue a Refresh extended operation operation immediately after an Add that created a dynamic entry.
immediately after an Add that created a dynamic entry. The Refresh The Refresh Response will return the CRP (in responseTtl) to the client.
Response will return the CRP (in responseTtl) to the client.
Clients must not refresh dynamic entries which they have not created. Clients must not issue the refresh request for dynamic entries which
they have not created or for static entries to which they did not add
dynamic attributes. Please note that when a client refreshes a
static entry to which it added dynamic attribute(s), it refreshes ALL
the dynamic attributes in this entry, including ones added by other
clients. Also note that servers which allow anonymous clients to
create and refresh dynamic entries and attributes will not be able to
enforce the above.
Clients should always be ready to handle the case in which their entry Clients should always be ready to handle the case in which their
timed out. In such a case, the Refresh operation will fail with entry or dynamic attributes timed out. In such a case, the Refresh
an error code such as noSuchObject, and the client is expected to operation will fail with an error code such as noSuchObject, and the
re-create its entry. client is expected to re-create its entry or re-add the dynamic
attributes.
Clients should be prepared to experience refresh operations failing Clients should be prepared to experience refresh operations failing
with protocolError, even though the add and any previous refresh with protocolError, even though the add and any previous refresh
requests succeeded. This might happen if a proxy between the client requests succeeded. This might happen if a proxy between the client
and the server goes down, and another proxy is used which does not and the server goes down, and another proxy is used which does not
support the Refresh extended operation. support the Refresh extended operation.
7.2 Server Requirements 7.2 Server Requirements
Servers are responsible for removing dynamic entries when they time out. Servers are responsible for removing dynamic entries and dynamic
Server are not required to do this immediately. attributes when they time out. Servers are not required to do this
immediately.
Servers must enforce the structural rules listed in above section 4. Servers must enforce the structural rules listed in above section 4.
Servers must ensure that the operational attribute described in section 6 Servers must ensure that the operational attribute described in
is present in dynamic entries. section 6 is present in dynamic entries or in static entries that
contain dynamic attributes.
Servers are permitted to check the authentication of the client invoking Servers are permitted to check the authentication of the client
a refresh extended operation, and only permit the operation if it invoking a refresh extended operation, and only permit the operation
matches that of the client which created the dynamic entry. Servers may if it matches that of the client which created the dynamic entry or
permit anonymous users to refresh entries. added dynamic attributes to this entry (please see a note about that
in section 7.1). Servers may permit anonymous users to refresh
entries.
Servers may require that a client which attempts to create a dynamic entry Servers may require that a client which attempts to create a dynamic
have remove permission for that entry. entry have a remove permission for that entry.
Servers which implement this extension must have the OBJECT Servers which implement this extension must have the OBJECT
IDENTIFIERs, described above in section 5 for the request and response, IDENTIFIERs, described above in section 5 for the request and
present as values of the supportedExtension field in the root DSE. They response, present as values of the supportedExtension field in the
must also have as values in the attributeTypes and objectClasses attributes root DSE. They must also have as values in the attributeTypes and
of their subschema subentries, the AttributeTypeDescription and objectClasses attributes of their subschema subentries, the
ObjectClassDescription from section 6. AttributeTypeDescription and ObjectClassDescription from section 6.
An implementation of dynamic directories, must be able to support
both dynamic directory entries and dynamic attributes.
8. Implementation issues 8. Implementation issues
8.1 Storage of dynamic information 8.1 Storage of dynamic information
Dynamic information is expected to change very often. In addition, Dynamic information is expected to change very often. In addition,
Refresh requests are expected to arrive at the server very often. Refresh requests are expected to arrive at the server very often.
Disk-based databases that static directory services often use are Disk-based databases that static directory services often use are
likely inappropriate for storing dynamic information. We recommend likely inappropriate for storing dynamic information. We recommend
that server implementations store dynamic entries in memory sufficient that server implementations store dynamic entries in memory
to avoid paging. This is not a requirement. sufficient to avoid paging. This is not a requirement.
We expect LDAP servers to be able to store static and dynamic entries. We expect LDAP servers to be able to store static and dynamic
If an LDAP server does not support dynamic entries, it should respond entries. If an LDAP server does not support dynamic entries,
with an error code such as objectClassViolation it should respond with an error code such as objectClassViolation.
Such a server might still support setting dynamic attributes
on a static entry.
8.2 Client refresh behavior 8.2 Client refresh behavior
In some cases, the client might not get a Refresh response. This In some cases, the client might not get a Refresh response. This may
may happen as a result of a server crash after receiving the Refresh happen as a result of a server crash after receiving the Refresh
request, the TCP/IP socket timing out in the connection case, or request, the TCP/IP socket timing out in the connection case, or the
the UDP packet getting lost in the connection-less case. UDP packet getting lost in the connection-less case.
It is recommended that in such a case, the client will retry the It is recommended that in such a case, the client will retry the
Refresh operation immediately, and if this Refresh request does Refresh operation immediately, and if this Refresh request does not
not get a response as well, it will resort to its original Refresh get a response as well, it will resort to its original Refresh cycle,
cycle, i.e. send a Refresh request at its Client Refresh Period i.e. send a Refresh request at its Client Refresh Period (CRP).
(CRP).
9. Localization 9. Localization
The are no localization issues for this extended operation. The are no localization issues for this extended operation.
10. Security Considerations 10. Security Considerations
Security issues are not addressed in this document. Please note, though, Security issues are not addressed in this document. Please note,
that anonymous clients are able to refresh entries which they did not though, that anonymous clients are able to refresh entries which they
create. did not create.
11. Acknowledgements Also, Care should be taken in making use of information obtained from
directory servers that has been supplied by client, as it may now be
out of date. In many networks, for example, IP addresses are
automatically assigned when a host connects to the network, and may
be reassigned if that host later disconnects. An IP address obtained
from the directory may no longer be assigned to the host that placed
the address in the directory. This issue is not specific to LDAP or
dynamic directories.
Design ideas included in this document are based on those 11. Acknowledgments
discussed in ASID and other IETF Working Groups.
Design ideas included in this document are based on those discussed
in ASID and other IETF Working Groups.
12. Authors Addresses 12. Authors Addresses
Yoram Yaacovi Yoram Yaacovi
Microsoft Microsoft
One Microsoft way One Microsoft way
Redmond, WA 98052 Redmond, WA 98052
USA USA
Phone: +1 206-936-9629 Phone: +1 206-936-9629
skipping to change at page 8, line 28 skipping to change at line 535
Microsoft Microsoft
One Microsoft way One Microsoft way
Redmond, WA 98052 Redmond, WA 98052
USA USA
Phone: +1 206-703-0852 Phone: +1 206-703-0852
EMail: tonyg@microsoft.com EMail: tonyg@microsoft.com
13. Bibliography 13. Bibliography
[1] M.Wahl, T. Howes, S. Kille, "Lightweight Directory Access Protocol [1] M.Wahl, T. Howes, S. Kille, "Lightweight Directory Access
(Version 3)". INTERNET DRAFT <draft-ietf-asid-ldapv3-protocol-01.txt> Protocol (Version 3)". INTERNET DRAFT
<draft-ietf-asid-ldapv3-protocol-01.txt>
[2] M.Wahl, A.Coulbeck, T. Howes, S. Kille, "Lightweight Directory Access [2] M.Wahl, A.Coulbeck, T. Howes, S. Kille, "Lightweight Directory
Protocol Standard and Pilot Attributes". INTERNET DRAFT Access Protocol Standard and Pilot Attributes". INTERNET DRAFT
<draft-ietf-asid-ldapv3-attributes-02.txt> <draft-ietf-asid-ldapv3-attributes-02.txt>
[3] M.Wahl, S.Kille, "Lightweight Directory Access Protocol UTF-8 String [3] M.Wahl, S.Kille, "Lightweight Directory Access Protocol UTF-8
Representation of Distinguished Names". INTERNET DRAFT String Representation of Distinguished Names". INTERNET DRAFT
<draft-ietf-asid-ldapv3-dn-00.txt> <draft-ietf-asid-ldapv3-dn-00.txt>
Expires on 10 March 1996. Expires on six months from the post date (see top).
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