Next-Generation Communications Services: Issues and Opportunities

John C Klensin, Ph.D.

TWNIC Conference, 2004 March

2004.03.31 2

Looking Two Steps Ahead

• Talk is less aboutWhat is happening today or

what one should do next

• But, instead, about What to start looking at now for the steps after

the next one.

2004.03.31 3

New Services or Simulation of Old Ones in New Medium

• Is the Internet a good telephone?– VoIP in closed networks

• Equipment savings ?• Still simulating SS7 ?

– Internet Telephony• Service quality, customer support, and

expectations• Economics and tariff arbitrage

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Internet Telephony as a Substitution Service

• Dubious long-term economics

• Good short-term

• Very good for equipment providers

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Tariff Arbitrage

• Very good short-term business• In the long term, one of several things happens

– Regulators impose comparable tariffs on new activities

– Tariffs are abolished, reducing or eliminating price advantage

– New activities are prohibited– New activities are ignored; old, tariffed, way of doing

things disappears

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Terminal Signaling Capability as a Defining Characteristic

• Service models determined by twelve buttons (or worse)

• Consequences– Smart Central Switches– Intelligent Network– Menus and VRUs to increase call setup

bandwidth

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The History of Distance Communications

• Low bandwidth – High speed– Signal fires, drums, telegraph, telex– Telephone ?

• High bandwidth – Low speed– Packets of letters carried by horse or coach– Bags of letters carried by train– Tapes in the back of an automobile– Fax or other images of paper ?

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Reviewing “Convergence”

• Carry the torch onto the coach ?

• Load the horse onto the train ?

• Tapping on the telephone handset ?

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The Actual Pattern

• Parallel use until

One technology drops off

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Advanced Services in the PSTN Paradigm

• “Integrated Messaging”– Voice, voicemail, fax, pager to one phone

number– Remote pickup and intercept

• Call forwarding and similar routing

• The Instant Messaging problem

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What Are You Trying to Reach

• Surrogate for a copper pair leading to a specific terminal device?

• A person or function?

Almost always the second

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Specifying a Target

• Preferred medium ?

• Person or alternative ?

• How important ?

• Interruption levels and tracking/ forwarding

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Permitting a Source

• Receiving a connection should be a negotiation…

• Do you want to be reached? By the caller?

• With what priority ? How much are you willing to be followed around?

• What do you think of the caller’s priorities?

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Example: Phone call with forwarding and roaming

• Colleague places a call to US “office number” at 2PM.

• Phone rings at 3 am in Singapore• Obvious questions…

– Would it have been placed if destination and time were known?

– Should it be received without knowing its importance?– How does one guess at time of recipient when

country and city codes are meaningless?

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Example: Whom am I calling?

• Number reaches a terminal or surrogate. People may be widely distributed.

• Long VRU menus seem to be our best solution, but cannot be the right answer.

• So– Call person or function, not a number– If we are to number people for convenience,

E.164 phone numbers are probably the wrong model

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Can This be Done in the PSTN?

• Maybe

• Big scaling problem, high complexity

• Very difficult authentication problems– Current “four digit PIN” strategy in many

countries not good enough– Limit to setting from “home” phone provides

poor service.

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ENUM itself may be the wrong model

• E.164 is not only tied to phone system semantics but to complex regulatory politics

• While the routing environment tied to E.164 is implemented by bilateral agreements, ENUM creates the first global telephony regulation opportunity for ITU.

• Should it have been– Number.CityCode.3166-country-code.enum… ?– For example: 23411313.2.tw.enum… or even

23411313.2.886.enum… ?

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Who Needs “Internet Telephony”?

• Internet → PSTN– Yes, but for how long and at what rates?

• Internet → Internet– Not needed; use NAPTR records with names

• PSTN → Internet– Not for Central Office switches: better ways– Not for dual mode phones: Internet → Internet

or POTs → POTs devices– Smart-routing PBX switches? Maybe.

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Networks: Central Control and Edge Control

• Edge-based networks permit distribution of control functions– “My server”, “my agent”… not tied to CO

switch– Different people/ organizations can get

different functions– Lots of competitive business opportunities

• Avoid both “one size fits all” and option-complexity problems

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A Different Communications Model – Initiator

• Specifies preferences– Person or function to be reached– Preferred/ ranked contact medium

• Simultaneous voice, voicemail, fax, email, assistant,…

– Priority/ importance– Conditions

• E.g., “don’t interrupt if…”

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A Different Communications Model – Receiver

• Specifies rules for people/ groups/ defaults– Preferred/ ranked contact medium

• Simultaneous voice, voicemail, fax, email, assistant,…

– Assessment of priority/ importance statements• More priority from some people than they specify• Less for others

– Relationship between• Derived priority and• Acceptable medium

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Generalization

• Extensions are almost trivial for– Multiparty communications

“conference calls” and group discussions

– Multimedia connectionsImages, text, sound, interactive remote whiteboards

– Asynchronous and semi-asynchronous communications

Email, fax, instant messages, “push” voicemail

• The special case– Two party, not prearranged, fully synchronous, audio-

only,…

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Some Lessons from Instant Messaging

• Is being interrupted a good thing?– Maybe better than by the telephone– More choices:

• Identification of caller, not calling number• Ability to delay response somewhat, not pure real-time

• Controlled access to interrupt– Need more than

• Available or not• Friend or not

• How to divert to email, or…

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Could we do this?

• Technology basically exists• Changing styles of thinking

moving away from “make it look like a telephone”

may be harder

• Designing a rule-specifying system that is• Sophisticated enough to be useful• Simple enough for consumers to use

– Is not trivial. But not impossible either.

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What Next?

• If we build it, will anyone come?

• How bad does – information overload– Interruption overload

need to get before we do something real about it?