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

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

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

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

Literary Music Video Financial Grid Enum RFID “SimpleLookup URL IPaddresses “Unfederated Databases”

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

Digital Object Set of elements, each of 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

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

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

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

Repository Notion Any Hardware & Software Configuration Logical External Interface RAP

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

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.

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.

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

Handles Resolve to Typed Data Handle data / URLhttp:// HandleData type RAPloc/repository URLhttp:// Extensible Data Types XYZ Just one example - also looks like a digital object Handles can also have semantics but we frown on it! Resolution is independent of semantics in every instance Handle Record

Allocation of Prefixes 1- System Uses 2- High Fan in/out Organizations 3 “ 4- Businesses and formal organizations 5 “ 6- Individuals and anything that cant fit above 7 “ 8 “

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/ is a handle for the type in brackets 0.na/ is a handle for a particular na Non-system types can also be created by individual users

Global Handle Resolution HS1HS2HPS3HS4 HANDLE ADMINISTRATION HANDLE RESOLUTION Handle Servers (Handles are uniformly spread by hashing) Multiple Handle Servers

Global & Local Handle Resolution HS1HS2HPS3HS4 HANDLE ADMINISTRATION HANDLE RESOLUTION Handle Servers Global Local HANDLE RESOLUTION

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

Administration of Handle Records univ/thesis.txt1217/ univ/ /thesis.txt univ.csl.17.2 (the handles shown above identify digital objects) univ1217 univ.csl.17 univ.csl

The Global Handle Registry 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. Global Handle Registry DOI Handle Service LOC Handle Service CMU Handle Service DTIC Handle Service Korean Ctrl Lib Handle Service Nat’l Lib Australia Handle Service Twin Bays Handle Service Liqid Krystal Handle Service MIT Handle Service

Groups of Handle Servers P S S S S Group AGroup B Group CGroup D

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. Develop your own administration client. or

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 ) which understands both HTTP and HDL protocols. or Develop your own resolution client.

Setting up a Local Handle Service... Download the software from 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.

Organization of the International DOI Foundation IDF IDF is a non-profit organization with offices in Washington, DC (AAP) Geneva, Switzerland (IPA) Members are Mostly Book & Journal Publishers  Membership Dues - Policies & Procedures - Licensing the DOI TM - Qualifying RAs - Marketing the DOI brand 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 CDD

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

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.

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

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