Name Services Johanna Hultin Carina Hglund Name services

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Name Services Johanna Hultin Carina Höglund

Name Services Johanna Hultin Carina Höglund

Name services l Introduction l General Terms l Name Services l Name Space l

Name services l Introduction l General Terms l Name Services l Name Space l Name Resolution l Caching

Introduction Names l Fundamental in distributed systems Facilitates communication and resource sharing A consistent

Introduction Names l Fundamental in distributed systems Facilitates communication and resource sharing A consistent naming system is required l Adresses: locations of objects, not identifiers l l

Introduction l Name service l Translates a human-readable name into a system-internal identifier l

Introduction l Name service l Translates a human-readable name into a system-internal identifier l Ex human readable names: http: //www. facebook. com /etc/passwd l URL Internet Domain Name File name Ex system-internal name: 123. 25. 7. 34 IP address

General terms l Resolution ¡ l Binding ¡ l Set of bindings Attributes: value

General terms l Resolution ¡ l Binding ¡ l Set of bindings Attributes: value of property of an object ¡ l Association between an object and a name Context ¡ l Translation of a name into data Ex: address Ex Name Service: ¡ Domain Name System (DNS)

Name Service A name service stores the collection of one or more naming contexts

Name Service A name service stores the collection of one or more naming contexts l Major operation: Look at attributes of a given name l Other operations required l ¡ ¡ ¡ l Adding/deleting bindings Listing bound names Adding/deleting context Name management is separated from other services ¡ ¡ Unification: use the same naming scheme Integration: Openness

Ex: Reaching a file from URL address l Domain Name Server ¡ Name service

Ex: Reaching a file from URL address l Domain Name Server ¡ Name service used by webbrowsers to interpret URL and e-mail addresses

Name spaces l All valid names recognized in a particular service ¡ l DNS

Name spaces l All valid names recognized in a particular service ¡ l DNS name space ¡ l Ex: URL in DNS Hierarchical structure Alias ¡ Possible to use a simple name instead of a complicated one ¡ Provides for transparency. l www. example. net is an alias for www. johanna. example. net

Name Resolution l Iterative navigation ¡ DNS

Name Resolution l Iterative navigation ¡ DNS

Caching l Holds names that has previously been looked up l Consulted l Availability

Caching l Holds names that has previously been looked up l Consulted l Availability during name resolution

Questions?

Questions?

Thanks for listening!

Thanks for listening!