[Dundi] What requirements is DUNDi addressing?

[Ed Guy]

All,

As part of the DUNDi documentation and design effort, I'm trying to
identify the requirements that it is trying to address.

Below are my notes on the subject. (sorry, They're a little terse and rough
in
places - it is a work in progress.)

If you have any direction, feedback or comments... fire away!


/ed


---+  Terminology and Definitions

   * Service - The term "Service" refers to any voice-band communication
facility, e.g., telephone, fax, modem, etc.

   * Egress Gateway - The term "Egress Gateway" refers an Internet facility
that provides a communications path to a Service or Services that may not be
directly addressable via the Internet.

   * Routes - The term "Route" refers to an Internet address, policies, and
other characteristics associated with the Service, or the Egress Gateway
which provides access to the specified Service.

---+ Functions:

   Need a trusted system to register and locate telephone services and
Gateways
for the purposes of immediately setting up a voice call.

   * MUST provide method to Register Services and Egress gateways
      * Identifiers SHALL BE text and numeric

   * MUST provide Location service for Services and Egress Gateways in a
timely manner
      * TTL
      * minimal impact on PDD
      * Best Effort service.

   * MUST Scale to:
      * Large Enterprise
      * Cross enterprise
      * Not Global


---++ Identity

   * Need mechanism to represent services using phone numbers and names
      * identified by
         * E.164 numbers
         * Arbitrary Strings
         * private numbering plans
      * No central Authority
      * No assumed clustering of numbers
      * No assumed interconnect of services
      * duplicate routes may be provided -- caller to resolve.
      * cannot assume that services are unique.  (e.g., 700 numbers)

   * User Class of numbers must be represented
      * must be able to identify number class, if available.
         * residential
         * business
         * gov?
         * non profit?
         * Called-party pays (mobile)
         * toll free?
      * must be able to DND for unsolicited calls
      * must be able to DND for unsolicited calls from businesses


   * Must be able to represent routes to Internet-based services and Egress
Gateways
      * Routes in form of arbitrary URL/technology
         * multiple technologies available at same directory.
         * multiple routes available at same directory.
      * Relative Quality of route must be indicated.
      * Capacity of Egress Gateway must be indicated,
      * Source of route must be identified.

   * Need mechanism to Locate above services across a trusted collection of
servers.

   * Must be able to identify servers in network.


---++ Roles

   * Publisher
   * Consumers
   * Big/Small???  -- does it matter?

---+ Encoding

   * efficient & Compact transport
   * easy to parse, Minimize opportunity for errors (more specific)


---+ Transport

   * minimize network traffic
      * Avoid Querying nodes which do not have any related identities

   * Resiliency -  robust under multiple failures.

   * Partial Responses - need mechanism to deliver information as soon as
available.
       * must be able to identify complete and partial responses.
       * must be able to identify when responses are finished.

   * Network Loss/Load.
      * automatically recover from network partitions
      * retry with back off.

---+ Security

   * Limit queries/responses to a 'trust group'
      * nodes may be members of multiple trust groups
   * Encrypt Queries and responses
   * Privacy - no bulk publishing

---+ Caching

   * responses may be cached for appropriate lifetime.
      * TTL
   * certain classes of responses may not be cached.
   * mechanism to invalidate cache is recommended.
      * topology changes can invalidate cache.
   * SHOULD preload cache

What is nature of cache activity?  how are the
2-3 BHCAs distributed? does cache make sense?
Seems that there is probably a correlation between
caller/callee -- call backs are common.  may want to
cache caller as result of query.

---+ Maintenance

   * ability to 'whois' a location publisher/consumer.
   * ability to request an authoritative answer.
   * SHOULD have ability to identity all publishers in trust group.


---+ Out of scope ?
   * Caller determined service location.
      * Jurisdiction
      * ANI