		Mastering Intranet and Internet Technology

Directory Comparison

A directory should provide the services required by the organisation. Any one of the directories discussed will provide the basic facilities. However, some are more versatile than others.

Depending on your organisation's IT environment, some may provide a better service than others.

Parameter Description Relevance

Scalability

Partitioning Where and how backup/secondary copies of the directory are or can be stored. Having the ability to place a copy of the directory or a part of it on a particular (usually remote) computer makes it possible for those remote users to authenticate using that computer rather than connectiong to one further away. It also provides redundancy, which increases reliability.

Replication The facility whereby redundant copies of the directory information are kept up to date.

The ablity to quickly propagate changes to the directory means that remote systems can be used (almost) as soon as a change is committed. Can be event driven or polled. Polled systems generate more network traffic than event driven systems.

Network Traffic

Maximum Object Count

Extensible

Object Oriented?

Relational

Referential Integrity The facility that ensures that relationships are maintained when data values are changed or data is inserted, moved or deleted. When an object is deleted, all references to that object in any container are removed. If and object is moved, references to that object in other containers are adjusted to point to the new location.

Hierarchical

Backup Options

Management Requirements

Mainyenance Requirements

Maintainability

Remote Access

LDAP Support and Version

DirXML Support

Multiplatform Whether the service runs on more than one hardware/software platform. Heterogenous networks ae the norm these days. For best manageability, the directory service should be able to run on all the platforms in your organisation.

X.500 Compatible

Segmentation Whether parts of the directory tree may be replicated separately. It makes good sense to replicate only that part of the tree that needs to be accessed from a remote location. This reduces WAN traffic to a minimum.

Administration Rights and Privileges

Policy Management

Role Based Administration

Local Authentication Whether logins are authenticated to the nearest replica of the directory or are forced to access one specific authentication machine. On WANs local authentication reduces traffic considerably. This is especialy important in an itinerant work force.

Community Support The creation and support of "groups" that span the hierarcy of the tree. E.g. a airline's directory might be structured (vertically) on regional lines. However, the pilots scattered across the regions could be addressed as a community. Privileges could be applied to the community as one rather than applying to each group or organisational unit in each leg of the tree.

Parameter	Description	Relevance
Scalability
Partitioning	Where and how backup/secondary copies of the directory are or can be stored.	Having the ability to place a copy of the directory or a part of it on a particular (usually remote) computer makes it possible for those remote users to authenticate using that computer rather than connectiong to one further away. It also provides redundancy, which increases reliability.
Replication	The facility whereby redundant copies of the directory information are kept up to date.	The ablity to quickly propagate changes to the directory means that remote systems can be used (almost) as soon as a change is committed. Can be event driven or polled. Polled systems generate more network traffic than event driven systems.
Network Traffic
Maximum Object Count
Extensible
Object Oriented?
Relational
Referential Integrity	The facility that ensures that relationships are maintained when data values are changed or data is inserted, moved or deleted.	When an object is deleted, all references to that object in any container are removed. If and object is moved, references to that object in other containers are adjusted to point to the new location.
Hierarchical
Backup Options
Management Requirements
Mainyenance Requirements
Maintainability
Remote Access
LDAP Support and Version
DirXML Support
Multiplatform	Whether the service runs on more than one hardware/software platform.	Heterogenous networks ae the norm these days. For best manageability, the directory service should be able to run on all the platforms in your organisation.
X.500 Compatible
Segmentation	Whether parts of the directory tree may be replicated separately.	It makes good sense to replicate only that part of the tree that needs to be accessed from a remote location. This reduces WAN traffic to a minimum.
Administration Rights and Privileges
Policy Management
Role Based Administration
Local Authentication	Whether logins are authenticated to the nearest replica of the directory or are forced to access one specific authentication machine.	On WANs local authentication reduces traffic considerably. This is especialy important in an itinerant work force.
Community Support	The creation and support of "groups" that span the hierarcy of the tree. E.g. a airline's directory might be structured (vertically) on regional lines. However, the pilots scattered across the regions could be addressed as a community. Privileges could be applied to the community as one rather than applying to each group or organisational unit in each leg of the tree.

	Web Author: Geoff May	Last Update: 23/11/2001
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