The Handle System: and its role in a Digital Object Architecture

1. The Handle System:and its role in a Digital Object Architecture Robert E. Kahn CNRI Workshop on Frontiers in Distributed Information Systems Presidio of San Fransisco July 31 – August 1, 2003

2. Objective of the Framework Heterogeneous Networks Information Systems Information Systems Networks Seamless Whole Internet objective Best-effort Packet Delivery Seamless Interoperability Federating Heterogeneous Systems

3. Internet Comparison • IP Addresses  Machines • Gateways (now routers) help with access • TCP handles end-end issues • Remove duplicate packets • Restructure the arriving fragmented stream • Perform end-end error detection & retransmission • Provide flow control

4. Further Scoping the Problem Time to Resolve Query Complexity of Query Initial Focus on Queries with Complexity = Zero

5. Global Identifier Interoperability Cross-Industry Resolution Literary Music Video Financial Grid Enum RFID Some Existing Approaches “SimpleLookup URL IPaddresses “Unfederated Databases”

6. Basic Attributes of the Approach • Digital Objects (i.e. Data Structures) • Unique Identifiers Digital Objects • Resolution & Administration Mechanism • Maintains Uniqueness of Ids  DOs as long as they persist • Maps Ids  Useful State Information • Is distributed and scaleable • Does not involve complete search

7. Digital Object • Set of elements, each of <Type, Value> • Parsable across heterogeneous platforms • One element must be the unique identifier • Properties Record contains metadata • Transaction Record records usage • Most users wish to access its Essence • Key Metadata is part of the Essence

8. Object-Oriented Programming Digital Object Model Disseminators Methods Internal Data Structure Digital Object The internal data structure is not directly accessible by the programmer Access to the object is subject to control by the owner. For example, a market in disseminators is possible.

9. Purposely Silent about • What Types • What Type of Types • What Values • What metadata or metadata schema • What state information in Handle Records • Policies and Procedures in general • There are policies for Global, however

10. A Range of Possibilities • Identifiers are persistent – e.g. DOIs • Identifiers are transient – e.g. Grid • Identifiers are resolvable • Resolution information is not accessible • Digital Objects are fixed, unchangeable • Access to Digital Objects is fixed, even if DOs are changeable

11. Repository Notion Logical External Interface Any Hardware & Software Configuration RAP

12. Nesting of Repositories Core Structure Aggregation & De-aggregation Content Core Interface must be present at each level Other levels could be separately defined later

13. Federated Repositories • Key issue is commonality of interests in accessing information from multiple repositories. • Financial Information is prime applications area • Metadata Registries allow for searching based on “user-supplied” inputs. The use of handles (however branded) can simplify access. • Access via local repositories is an operational desirable capability.

14. MetaObjects & Metadata Registries • MetaObjects provide a structural basis for indirection and for organizing information • Metadata is used to characterize digital objects, to access their identifiers and to assist in cross referencing • Metadata Registries provide uniform access to metadata.

15. Handle Format 2304568.40/12345678 Naming Authority Item ID (any format) Suffix Prefix In use, a Handle is an opaque string. Corporation For National Research Initiatives

16. Handle Data type Handle data URL http://www.loc.gov/..... 2304568.40/12345678 URL http://www.loc2.gov/.. Extensible Data Types RAP XYZ loc/repository 1001110011110 Handles Resolve to Typed Data Just one example - also looks like a digital object Handle Record Handles can also have semantics but we frown on it! Resolution is independent of semantics in every instance

17. Allocation of Prefixes • - System Uses • - High Fan in/out Organizations • “ • - Businesses and formal organizations • “ • - Individuals and anything that cant fit above • “ • “

18. Creating & Resolving Type Information Dynamically • Prefixes of the form 0.X are reserved for defining resolvable “system information” such as types and naming authorities • 0.type/<type> is a handle for the type in brackets • 0.na/<na> is a handle for a particular na • Non-system types can also be created by individual users

19. Global Handle Resolution HANDLE ADMINISTRATION HS1 HS2 HPS3 HS4 Multiple Handle Servers Handle Servers HANDLE RESOLUTION (Handles are uniformly spread by hashing)

20. Global & Local Handle Resolution HANDLE ADMINISTRATION HS1 HS2 HPS3 HS4 Global Handle Servers HANDLE RESOLUTION Local HANDLE RESOLUTION

21. How do handles resolve... 1. Where is 1895.22/1011? GHR Two steps to resolve a handle - - • Client queries GHR: “Which Handle Service has 1895.22/1011?” • GHR responds with a “map” showing the client which servers within the responsible LHS it can query for that handle . LHS C Map of LHS B LHS A LHS ..n LHS D Handle Client LHS B 2. Give me all data for 1895.22/1011 Handle Data Handle System

22. Administration of Handle Records univ/thesis.txt 1217/4913527 univ/4913527 1217/thesis.txt (the handles shown above identify digital objects) univ 1217 1217.34 univ.csl univ.csl.17 1217.34.1 univ.csl.17.2

23. The Global Handle Registry Global Handle Registry MIT Handle Service • The GHR is a unique handle service used to store the identity and location of all local handle services (LHS), and tells a handle client which service to query to resolve a handle. • All handle clients (for resolution or administration) know how to contact and query the GHR. Twin Bays Handle Service DOI Handle Service Korean Ctrl Lib Handle Service LOC Handle Service CMU Handle Service Liqid Krystal Handle Service Nat’l Lib Australia Handle Service DTIC Handle Service

24. Groups of Handle Servers P S S Group A Group B S S Group C Group D

25. Handle Clients Administration Use the Java™ Handle Client Tool provided in the distribution for creating or updating handles one-at-a-time or via a batch. or Develop your own administration client.

26. Handle Clients Resolution Download web browser plug-in which enables browsers to recognize the handle protocol. or Append a handle to proxy server e.g http://hdl.handle.net/<handle>) which understands both HTTP and HDL protocols. or Develop your own resolution client.

27. Setting up a Local Handle Service... • Download the software from http://www.handle.net. • Follow the instructions in the installation script. • Send your “site bundle”, containing the IP address of your server and your administrator information, to the Global Handle Registry (GHR) administrator.

28. Organization of the International DOI Foundation Members are Mostly Book & Journal Publishers  Membership Dues IDF • Policies & Procedures • Licensing the DOI TM • Qualifying RAs • Marketing the DOI brand Registration Agencies (RA) CDD IDF is a non-profit organization with offices in Washington, DC (AAP) Geneva, Switzerland (IPA) 4¢ per DOI on deposit – 1X; min $20K/yr 1¢ per DOI in CDD on 12/31 – annual ½¢ per DOI in CDD after $50K per RA

29. Business Potential • Enabling new forms of Creativity • New forms of expression • Representing value as Digital Objects • Selling infrastructure technology & services • Enabling Third Party value-added capabilities • Helping organizations manage their own information better & offer new types of services • Stimulating access to “surface information” and “embedded information” with appropriate access controls and conditions of use

30. Evolution of Policy for Global • Original Policy • Best efforts service; run in-house • Cost paid by the Government • Available to the research community for free • Current Policy (still in flux) • Best efforts service; run 7x24 with backup • Free to the research community; commercial users pay after a period of experimentation • Handle System Advisory Committee oversees costs and evolution.

31. Cost of Global Services • IPv4  several million addresses; about 50M TLDs (excluding CCs) • At say $20 per year per TLD, the cost of global registration and resolution services is about $1B per year – this is inefficient, very profitable or both • The handle system is almost as large as DNS (there are over 10M DOIs alone) and costs about $250K per year at present. • The DNS can be run within the handle system, if desired; but the handle system can support IPv4 and IPv6 without DNS

32. Applications of the Technology • Identity Management (DHS) • PKI Infrastructure • Personal Locator Information • Efficient Communications • Steganography • Managing Digital Cash • Managing Business Transactions (e.g. email) • Learning of more up to date Publications • Cataloguing and Indexing