1. Introduction to Name and Directory Services
Gang Shen (Bruce)
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2. Introduction What is What for Standard How does it work Example
References
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3. What is Name or Directory Services
Look-up operations. Given the name or some attributes of an object entity, more attribute information is obtained. Name service and Directory service are interchangeable. They all describe how a named object can be addressed and located by using its address.[1]
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4. What is Name or Directory Services
A directory service is a software application — or a set of applications — that stores and organizes information about a computer network's users and network resources, and that allows network administrators to manage users' access to the resources. Additionally, directory services act as an abstraction layer between users and shared resources.[3]
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5. Purpose of Directory Service
Enable user to reference network resources with short names instead of real addresses
Locate object by attributes
Provide a layer of abstraction so that the network resources can be managed independently without service interruption
Added value, such as security,etc.
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6. Implementation Active Directory for Windows 2000, Server 2003
Apple Open Directory in Mac OS X Server
Novell eDirectory - formerly called Novell Directory Services (NDS) for Novell NetWare version 4.x-5.x
OpenLDAP
Sun Directory Services
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7. Standard
X.500 defined by CCITT(Comité Consultatif International Téléphonique et Télégraphique) Now ITU-T (Telecommunication Standardization Sector of the International Telecommunications Union).
Includes[4]
DAP (Directory Access Protocol)
DSP (Directory System Protocol)
DISP (Directory Information Shadowing Protocol)
DOP (Directory Operational Bindings Management Protocol)
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8. Standard
LDAP, Lightweight Directory Access Protocol, is a networking protocol for querying and modifying directory services running over TCP/IP.[5]
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9. How does it work Object resolution process has two steps.
Name resolution: Map name to logical address. More interesting. Example, Locate a server. Retrieve a user object..
Address resolution: map logical address to physical address/network route. It’s a network function.
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10. Ways to name an object
<attribute>,<name,attributes,address>,<name, type, attributes, address>
Flat,hierarchy structure, structure-free name, value pairs
Physical, organizational, functional
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11. Storage
DIB (directory information base) from X.500. It’s a tree structure.
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13. Access Mode DSA—Directory Service Agent DUA–- Directory User Agent
Client Server Based model
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15. LDAP
Latest technology on directory service. Client server architecture, based on TCP (vs. OSI), less operations, only support string type (vs. more data types), faster and easier to use. [6]
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16. LDAP Server
It’s a fast read, slow update database. It organized in a very shallow tree fashion for read performance. All or nothing updates. It can return multiple result objects. It only return success search result or failure. It retrieve result from other servers on clients behalf.
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17. Terms Domain component – dc Organizational unit – ou
Distinguished name (fully qualified name) – dn
Common name – cn
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18. Example
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19. Query LDAP Combination of DN, filter, and scope…[2]
a base DN indicates where in the hierarchy to begin the search
a filter specifies attribute types, assertion values, and matching criteria
scope indicates what to search:base DN,one level below the base DN, subtree rooted at the base DN
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20. Query base DN: dc = edu scope: entire subtree
filter: objectClass = person
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21. Opportunities Performance, cache, replication Reliability, replication
Security
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22. Extent ions and Questions
Cache
Security
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23. References
1.Randy Chow,Theodore Johnson, “Distributed Operating Systems & Algorithms”, 1998
2. Jeff Hodges,"Introduction to Directories and LDAP", June 1997 3. 4. 5.
6. Timothy A. Howes, "The Lightweight Directory Access Protocol: X.500 Lite", July 27, 1995, CITI Technical Report 95-8
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