1. Namespaces cs3353

2. Namespace Domain A computer system namespace domain is created and maintained to: –standardize the policy for names –prevent name collisions (same names with different meanings)

3. Namespace The namespace is used to create names for –User IDs –Individual computer systems –Other hardware –Other categories? Passwords

4. Namespace Policy Formula Theme –All names fit a theme like planet names, cartoon characters, star trek characters, etc. Function –The name describes the function: disk_server, main_printer, etc.

5. Namespace Policy Theme names for hardware are ok when there are only a few systems: –Server = hal9000 –Clients = uhura, checkov, sulu, spock, etc Managing a large number of systems this way is not advised.

6. Namespace Policy Function names: disk_server01, disk_server02, etc. Function names have their own maintenance problems: consider what happens when the disk_server is reassigned its role in the computing system to handle e- mail.

7. Namespace Policy: Formula Formula names are not interesting or personal, but are practical for large namespaces. Divide the name into fields. Fixed length fields make the names easier to learn. Keep the name to a reasonable length.

8. Namespace Policy: Formula Formula names can be used to obscure the function of named entities in the domain. Keep the names to a reasonable length unless long names serve a specific purpose. –Longer names tend to be used less frequently

9. Formula Policy User IDs, Passwords Machine names: clients & servers Miscellaneous hardware: –Printers, Fax-machine, etc Other?

10. Namespace Formula Policy Use any combination of: –Prefix: –Infix: –Postfix To construct a namespace.

11. Example: User ID Formula (Prefix) Prefix (one letter field) –Regular employee (e) –Consultant/Contractor (c) –Temp (t) –Vendor/Supplier (s | v) –Visitor/Guest (g) –Helpful for identification and access control

12. Example: User ID Formula (Infix,Postfix) Infix (three character field) –Three letters using name initials Postfix (two character field) –00 through 99 if two entities have the same first four characters.

13. Example: Namespace Policy (Hardware) Computer systems (6 to 8 characters) –Postfix –Infix –Prefix

14. Example: Namespace Policy (Hardware) Postfix –Server (s) –Client (c) –Experimental (e) –Printer (p) –Backup device (b) –Etc.

15. Example: Formula Namespace (Hardware) Infix – 3 character base-36 number: 000-zzz Postfix – 2 digits Year of purchase (09). Most hardware is retired within 10 years.

16. User ID name space Possible choices –Full name –Initials and digits –Anonymity of user IDs may be required. –Limit to 8 characters if possible.

17. User ID name space A centralized data base for User ID names is needed. A single authentication data base can be used to keep track of User ID name space.

18. Other Namespace Considerations Scope – what is the scope for your namespace. –What is the impact of growth or a merger? Security – do the names need to be obscure? Reuse – When is it appropriate to re-use a name, if ever?

19. Changes in the Namespace A name change policy is needed. A central database with a record of all names in the namespace is required for managing the namespace.

20. Class Exercise Create a formula policy for: –Hardware –User IDs –The formula method can be applied to passwords