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Oracle Directory Server Enterprise Edition Reference 11 g Release 1 (
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Document Information


1.  Directory Server Enterprise Edition File Reference

Software Layout for Directory Server Enterprise Edition

Directory Server Instance Default Layout

Directory Proxy Server Instance Default Layout

Part I Directory Server Reference

2.  Directory Server Overview

3.  Directory Server LDAP URLs

4.  Directory Server LDIF and Search Filters

5.  Directory Server Security

6.  Directory Server Monitoring

7.  Directory Server Replication

8.  Directory Server Data Caching

9.  Directory Server Indexing

10.  Directory Server Logging

11.  Directory Server Groups and Roles

12.  Directory Server Class of Service

About CoS

CoS Definition Entries and CoS Template Entries

CoS Definition Entry

CoS Template Entry

Pointer CoS, Indirect CoS, and Classic CoS

Pointer CoS

Indirect CoS

Classic CoS

Managing Attributes With Class of Service

Using CoS When Many Entries Share the Same Value

Using CoS When Entries Have Natural Relationships

Avoiding Excessive CoS Definitions

CoS Priorities

CoS Limitations

13.  Directory Server DSMLv2

14.  Directory Server Internationalization Support

Part II Directory Proxy Server Reference

15.  Directory Proxy Server Overview

16.  Directory Proxy Server Load Balancing and Client Affinity

17.  Directory Proxy Server Distribution

18.  Directory Proxy Server Virtualization

19.  Connections Between Directory Proxy Server and Backend LDAP Servers

20.  Connections Between Clients and Directory Proxy Server

21.  Directory Proxy Server Client Authentication

22.  Security in Directory Proxy Server

23.  Directory Proxy Server Logging

24.  Directory Proxy Server Alerts and Monitoring


About CoS

Imagine a directory containing thousands of entries that all have the same value for the facsimileTelephoneNumber attribute. Traditionally, to change the fax number, you would update each entry individually, a time consuming job for administrators. Using CoS, the fax number is stored in a single place, and the facsimileTelephoneNumber attribute is automatically generated on every entry as it is returned.

To client applications, a CoS attribute is generated in the same ways as any other attribute. However, directory administrators now have only a single fax value to manage. Also, because there are fewer values stored in the directory, the database uses less disk space. The CoS mechanism also allows entries to override a generated value or to generate multiple values for the same attribute.

Note - Because CoS virtual attributes are not indexed, referencing them in an LDAP search filter may have an impact on performance.

Generated CoS attributes can be multivalued. Specifiers can designate several template entries, or there can be several CoS definitions for the same attribute. Alternatively, you can specify template priorities so that only one value is generated from all templates.

Roles and classic CoS can be used together to provide role-based attributes. These attributes appear on an entry because it possesses a particular role with an associated CoS template. You could use a role-based attribute to set the server look through limit on a role-by-role basis, for example.

CoS functionality can be used recursively; you can generate attributes through CoS that depend on other attributes generated through CoS. Complex CoS schemes can simplify client access to information and ease administration of repeated attributes, but they also increase management complexity and degrade server performance. Avoid overly complex CoS schemes; many indirect CoS schemes can be redefined as classic or pointer CoS, for example.

You should also avoid changing CoS definitions more often than necessary. Modifications to CoS definitions do not take effect immediately, because the server caches CoS information. Although caching accelerates read access to generated attributes, when changes to CoS information occur, the server must reconstruct the cache. This task can take some time, usually in the order of seconds. During cache reconstruction, read operations may still access the old cached information, rather than the newly modified information, which means that if you change CoS definitions too frequently, you are likely to be accessing outdated data.