1. Name Services Johanna Hultin Carina Höglund

2. Name services Introduction General Terms Name Services Name Space Name Resolution Caching

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

4. Introduction Name service Translates a human-readable name into a system-internal identifier Ex human readable names: http://www.facebook.com URL www.facebook.comInternet Domain Name /etc/passwdFile name Ex system-internal name: 123.25.7.34IP address

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

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

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

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

9. Name Resolution Iterative navigation  DNS

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

11. Questions?

12. Thanks for listening!