name & directory services yang wang. outline why and what? some important terms. how to do?...
TRANSCRIPT
OutlineOutline
• Why and What?
• Some important Terms.
• How to do?
• History and Implementation.
• Example and Experiment
• References
Why We Need It?Why We Need It?
• Making a request to a service or accessing an object by means of inter-process communication requires that must one first locate the service or object.[1]
• Look-up operations.
• [1].Randy Chow,Theodore Johnson, “Distributed Operating Systems & Algorithms”, 1998
What Is It?What Is It?
• Name Service or Directory Service: Describing how a named object can be addressed and subsequently located by using its address.[1]
Resolution processResolution process
• The operation of locating an object.
• Two stages:
• Name resolution maps names to logical addresses. (who the object is.)
Address resolution that maps logical addresses to network routes.(where the object can be found.)[1]
PurposePurpose
• Enable user to reference network resources with short names instead of real addresses.
• Locate object by attributes.
• Provide a layer of transparency so that the network resources can be managed independently.[3]
OutlineOutline
• Why and What?
• Some important Terms.
• How to do?
• History and Implementation.
• Example and Experiment
• References
Name SpaceName Space
• Object attributes
• Focus on name and address.
• Collection of names ,with their corresponding attributes and addresses.
Name StructuresName Structures
• 1.flat structure <attributes> Physical
• 2.hierachical <name,attributes,address>
(DNS) Organizational
• 3.structure-free <name,type,attributes,address>
Functional
OutlineOutline
• Why and What?
• Some important Terms.
• How to do?
• History and Implementation.
• Example and Experiment
• References
Storage model(x.500)Storage model(x.500)
• X.500 DIB directory information base.• DIT Directory Information Tree.• Naming domain: a sub-name space for which
there is a single administrative authority for name management.
• Naming Context: basic units for distributing the info base to Directory Service Agents.
• DSA: The server for the name service.• DUA: directory user agent[1]
OutlineOutline
• Why and What?
• Some important Terms.
• How to do?
• History and Implementation.
• Example and Experiment
• References
History of Name ServiceHistory of Name Service
1. In 60s and early in 70s, hosts file and other files used to store parameters and information for locating.
Drawbacks: modify frequently, larger and larger.[7]
[7].Larry Gouthier, 1998, Directory-enabled computing: the directory's expanding role.
DNSDNS
• Domain Name Service replaced.
• Dynamic and based on server.
• The first standard directory and the most successful one.
• At the same time, people developed Directory for Novel Netware, MS LAN manager,SNA etc.[7]
X.500X.500
• DNS only contains host, domain and address, not enough.
• In the 80s, X.500
• Drawback: too complicated, not support by MS.Mainly In unix -> LDAP[7]
• [7].Larry Gouthier, 1998, Directory-enabled computing: the directory's expanding role.
ImplementationImplementation
• 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
OutlineOutline
• Why and What?
• Some important Terms.
• How to do?
• History and Implementation.
• Example and Experiment
• References
Name spaceName spaceRoot DomainRoot Domain
SubdomainsSubdomains
Second-Level DomainSecond-Level Domain
Top-Level DomainTop-Level Domain
FQDN:server1.sales.south.nwtraders.com
FQDN:server1.sales.south.nwtraders.com
southsouth
nwtradersnwtraders
comcom
salessales
westwest easteast
orgorgnetnet
Host: server1Host: server1
DNSDNS Locating ProcessLocating Process
Computer1Computer1
Local DNS Server
Local DNS Server
nwtraders.comnwtraders.com
Root Hint (.)Root Hint (.)
.com.com
Recu
rsive
que
ry fo
r
1.nw
trade
rs.co
m17
2.16
.64.
11
Iterative Query
Iterative Query
Iterative Query
Ask .com
Ask nwtraders.com
Authoritative Response33
22
11
Some new researchSome new research
• Load distribution.[6]
• Web Content distribution.[6]
• [6]. James E Kurose, Keith W.Ross, 2007,Computer Networking, 4th Edition.
ReferencesReferences
• 1.Randy Chow,Theodore Johnson, “Distributed Operating Systems & Algorithms”, 1998
• 2. Jeff Hodges,"Introduction to Directories and LDAP", June 1997
• 3. http://en.wikipedia.org/wiki/Directory_service • 4. http://en.wikipedia.org/wiki/X.500• 5.
http://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol
• 6. James E Kurose, Keith W.Ross, 2007,Computer Networking, 4th Edition.