2. Feb. 2005Future of Telecommunications Re-Inventing the Phone System Henning Schulzrinne Dept. of Computer Science Columbia University (Brooklyn Poly)

3. Feb. 2005 Future of Telecommunications Overview Predictions – some plausible outcomes Internet – from research dominance to consumer- driven Interconnection vs. islands peer-to-peer vs. server-based The end of phone tag? The future of telephone numbers Challenges: setup and configuration reliability unsolicited communications creating new services emergency services (911)

4. Feb. 2005 Future of Telecommunications Lifecycle of technologies militarycorporateconsumer traditional technology propagation: opex/capex doesn’t matter; expert support capex/opex sensitive, but amortized; expert support capex sensitive; amateur Can it be done? Can I afford it? Can my mother use it?

5. Feb. 2005 Future of Telecommunications Cause of death for the next big thing QoSmulti- cast mobile IP active networks IPsecIPv6 not manageable across competing domains  not configurable by normal users (or apps writers)  no business model for ISPs  no initial gain  80% solution in existing system  (NAT) increase system vulnerability 

6. Feb. 2005 Future of Telecommunications Evolution of VoIP “amazing – the phone rings” “does it do call transfer?” “how can I make it stop ringing?” 1996-2000 2000-20032004- catching up with the digital PBX long-distance calling, ca. 1930 going beyond the black phone

7. Feb. 2005 Future of Telecommunications (Early) Adulthood “fully developed and mature” Not quite yet, but no longer a teenager probably need another 6 years to be grown up… Responsibilities: Dealing with elderly relatives  POTS Financial issues  payments, RADIUS Family emergencies  911

8. Feb. 2005 Future of Telecommunications PSTN vs. Internet Telephony Signaling & Media Signaling Media PSTN: Internet telephony: China Belgian customer, currently visiting US Australia

9. Feb. 2005 Future of Telecommunications Evolution: disaggregation All devices are nomadic new location, but same identifier Telephone companies are no longer needed there are still carriers for DSL and cable “IP dial tone” but unaware of type of data carried (voice, web, IM, …) VSP may be in another state or country anybody can be their own “VSP” Corporations and universities don’t have email carriers, either voice service provider [VSP] (TCP, RTP, SIP) ISP (IP, DHCP) dark fiber provider (λ) Yahoo MCI NYSERNET

10. Feb. 2005 Future of Telecommunications Alternative evolution: duopoly ILEC voice ILEC ISP ILEC DSL ILEC VoD web MSO voice MSO ISP MSO cable modem MSO VoD web block port 25 (email) reduce QoS for UDP restrictive (symmetric) NATs QoS only through application negotiation

11. Feb. 2005 Future of Telecommunications Internet evolution alternatives IPv6 stacked NATs SBC ISP#1 ISP#2 ISP#3 vs.

12. Feb. 2005 Future of Telecommunications Technology evolution of PSTN SS7: 1987-1997

13. Feb. 2005 Future of Telecommunications The end of the beginning and the beginning of the end Already, most large PBX  VoIP but interconnect largely via PSTN development of digital switches has ceased Large fraction of international traffic VoIP most prepaid calling cards Japan: BB Phone 3.85m (4/2004) US: Vonage 400,000 (1/2005) Likely PSTN for residential/SOHO users for decade+ maybe forced upgrade: residential gateway at line termination

14. Feb. 2005 Future of Telecommunications Challenges and Opportunities User-visible complexity and reliability Will there be telephone numbers? Peer-to-peer vs. server-based Presence as service enabler Spam 911 Service creation

15. Feb. 2005 Future of Telecommunications User-visible complexity Lots of obscure configuration parameters trivial mistakes cause silent failures NATs and firewalls strange failures: one-way voice, interrupted calls Reliability user has no clue whether malfunction is due to software/phone or operating system voice service provider Internet service provider Callee service provider

16. Feb. 2005 Future of Telecommunications Does it have to be that complicated? highly technical parameters, with differing names inconsistent conventions for user and realm made worse by limited end systems (configure by multi-tap) usually fails with some cryptic error message and no indication which parameter out-of-box experience not good

17. Feb. 2005 Future of Telecommunications NAT and VPN troubles Unplanned transition from Internet = one global address space to clouds (“realms”) of unknown scope Can’t know without help whether directly reachable Any number of concentric spaces There is no universally workable NAT solution always problems with inbound calls may need to maintain and refresh permanent connections to globally routable entity may need relay agent for media (TURN) ? ? ? home NAT ISP NAT Internet

18. Feb. 2005 Future of Telecommunications Server-based vs peer-to-peer Server-based Cost: maintenance, configuration Central points of failures Managed SIP infrastructure Controlled infrastructure (e.g., DNS) Peer-to-peer Robust: no central dependency Self organizing, no configuration Scalability ? C C C C C S P P P P P

19. Feb. 2005 Future of Telecommunications Will there be telephone numbers? Yes: Some locality (shorter) Easy to convey orally There are lots of them… No: Hard to keep when moving Becoming 10/12-digit random number Already have email address Prediction: slow fade, with ENUM as bridge DNS NAPTR +1 212 555 1234 sip:bob@example.com

20. Feb. 2005 Future of Telecommunications P2P-SIP Differences to proprietary Skype architecture Robust and efficient lookup using DHT Interoperability DHT algorithm uses SIP protocol messages Hybrid architecture First try DNS NAPTR/SRV if no SIP server there, then lookup in SIP+P2P Unlike file-sharing applications Data storage, caching, delay, reliability Disadvantages Lookup delay and security

21. Feb. 2005 Future of Telecommunications (SIP) unsolicited calls and messages Possibly at least as large a problem as spam more annoying (ring, pop-up) Bayesian content filtering unlikely to work  identity-based filtering PKI for every user unrealistic Use two-stage authentication SIP identity work home.com Digest mutual PK authentication (TLS)

22. Feb. 2005 Future of Telecommunications Domain Classification Classification of domains based on their identity instantiation and maintenance procedures plus other domain policies. Admission controlled domains Strict identity instantiation with long term relationships Example: Employees, students, bank customers Bonded domains Membership possible only through posting of bonds tied to a expected behavior Membership domains No personal verification of new members but verifiable identification required such as a valid credit card and/or payment Example: E-bay, phone and data carriers Open domains No limit or background check on identity creation and usage Example: Hotmail Open, rate limited domains Open but limits the number of messages per time unit and prevents account creation by bots Example: Yahoo

23. Feb. 2005 Future of Telecommunications Reputation service Alice Bob Carol David Emily Frank has sent email to has sent IM to is this a spammer?

24. Feb. 2005 Future of Telecommunications Traditional Emergency Calling Basic 911: just route to local PSAP based on local switch no location delivery Enhanced 911: route + location delivery (90%+?) multiple PSAPs per PSTN switch multiple switches per PSAP location delivered out-of-band via caller number Phase I wireless (70%) call delivery based on cell tower and face no location delivery Phase II wireless (30%) call delivery based on geo address geo location delivery to PSAP

25. Feb. 2005 Future of Telecommunications Core problems PSTN: approximate routing often works same switch based on cell tower based on caller number PSTN: relatively few, regionally-limited telecom providers (carriers) IP: carrier = bobs-bakery.com IP: no such approximations (usually) application layer (e.g., SIP) has no clue as to location L1—L3 may know about location (at least approximately), but don’t know about emergency calls

26. Feb. 2005 Future of Telecommunications 911: Location-based call routing – UA knows its location GPS 48° 49' N 2° 29' E INVITE sips:sos@ DHCP outbound proxy server 48° 49' N 2° 29' E  Paris fire department

27. Feb. 2005 Future of Telecommunications Presence as communication facilitator

28. Feb. 2005 Future of Telecommunications The role of presence Guess-and-ring high probability of failure: “telephone tag” inappropriate time (call during meeting) inappropriate media (audio in public place) current solutions: voice mail  tedious, doesn’t scale, hard to search and catalogue, no indication of when call might be returned automated call back  rarely used, too inflexible  most successful calls are now scheduled by email Presence-based facilitates unscheduled communications provide recipient-specific information only contact in real-time if destination is willing and able appropriately use synchronous vs. asynchronous communication guide media use (text vs. audio) predict availability in the near future (timed presence) Prediction: almost all (professional) communication will be presence-initiated or pre-scheduled

29. Feb. 2005 Future of Telecommunications Basic presence Role of presence initially: “can I send an instant message and expect a response?” now: “should I use voice or IM? is my call going to interrupt a meeting?” Yahoo, MSN, Skype presence services: on-line & off-line useful in modem days – but many people are (technically) on-line 24x7 thus, need to provide more context + simple status (“not at my desk”) entered manually  rarely correct does not provide enough context for directing interactive communications

30. Feb. 2005 Future of Telecommunications Context-aware communication context = “the interrelated conditions in which something exists or occurs” anything known about the participants in the (potential) communication relationship both at caller and callee timeCPL capabilitiescaller preferences locationlocation-based call routing location events activity/availabilitypresence sensor data (mood, bio)privacy issues similar to location data

31. Feb. 2005 Future of Telecommunications Presence and event notification Presence = special case of event notification “user Alice is available for communication” Human users: multiple contacts per presentity device (cell, PDA, phone, …) service (“audio”) activities, current and planned surroundings (noise, privacy, vehicle, …) contact information composing (typing, recording audio/video IM, …) Events in multimedia systems: REFER (call transfer) message waiting indication conference floor control conference membership push-to-talk system configuration General events: emergency alert (“reverse 911”) industrial sensors (“boiler pressure too high”) business events (“more than 20 people waiting for service”)

32. Feb. 2005 Future of Telecommunications IETF efforts SIP, SIPPING and SIMPLE working groups but also XCON (conferencing) Define SIP methods PUBLISH, SUBSCRIBE, NOTIFY GEOPRIV: geospatial privacy location determination via DHCP information delivery via SIP, HTTP, … privacy policies SIMPLE: architecture for events and rich presence configuration (XCAP) session-oriented IM ( ↔ page mode) filtering, rate limiting and authorization

33. Feb. 2005 Future of Telecommunications Presence data model “calendar”“cell”“manual” alice@example.com audio, video, text r42@example.com video person (presentity) (views) services devices

34. Feb. 2005 Future of Telecommunications Presence data architecture raw presence document create view (compose) privacy filtering draft-ietf-simple-presence-data-model composition policy privacy policy presence sources XCAP (not defined yet) depends on watcher select best source resolve contradictions PUBLISH

35. Feb. 2005 Future of Telecommunications Presence data architecture candidate presence document watcher filter raw presence document post-processing composition (merging) final presence document difference to previous notification SUBSCRIBE NOTIFY remove data not of interest watcher

36. Feb. 2005 Future of Telecommunications RPID: rich presence

37. Feb. 2005 Future of Telecommunications Rich presence: time information Presence is currently about here and now but often only have (recent) past – e.g., calendar or future “will be traveling in two hours” “will be back shortly” allows watcher to plan communication timed-status time RPID fromuntil now

38. Feb. 2005 Future of Telecommunications Privacy rules Conditions identity, sphere time of day current location identity as or + Actions watcher confirmation Transformations include information reduced accuracy User gets maximum of permissions across all matching rules privacy-safe composition: removal of a rule can only reduce privileges Extendable to new presence data rich presence biological sensors mood sensors

39. Feb. 2005 Future of Telecommunications Example rules document user@example.com allow sip mailto true bare

40. Feb. 2005 Future of Telecommunications User service creation Old model: “Killer application” small set of applications created by experts ISDN CLASS application: caller ID, call forward, speed dial New model: web model: end-user and entrepreneur-created applications based on open platforms (ASP, PHP+mysql, …) often, hosted by content-neutral computation + network providers blogs, RSS, Wiki, podcasting, …

41. Feb. 2005 Future of Telecommunications Service creation programmer, carrier end user network servers SIP servlets, sip-cgi CPL end systemVoiceXMLVoiceXML (voice), LESS Tailor a shared infrastructure to individual users traditionally, only vendors (and sometimes carriers) learn from web models

42. Feb. 2005 Future of Telecommunications Program location-based services

43. Feb. 2005 Future of Telecommunications Location-based service language false true NOTIFY action alert conditions proximity occupancy time IM actions alert message log call transfer join events incoming outgoing notify message subscription

44. Feb. 2005 Future of Telecommunications Automating media interaction – service examples If call from my boss, turn off the stereo  call handling with device control As soon as Tom is online, call him  call handling with presence information Vibrate instead of ring when I am in movie theatre  call handling with location information At 9:00AM on 09/01/2005, find the multicast session titled “ABC keynote” and invite all the group members to watch  call handling with session information When incoming call is rejected, send email to the callee  call handling with email

45. Feb. 2005 Future of Telecommunications LESS: Decision tree  No loops  Limited variables  Not necessarily Turing-complete

46. Feb. 2005 Future of Telecommunications When Tom is online, … ………

47. Feb. 2005 Future of Telecommunications

48. Feb. 2005 Future of Telecommunications Tracking

49. Feb. 2005 Future of Telecommunications Conclusion At inflection point from trials to widespread deployment legacy will fade except for access Risks to competition duopoly of access  tying access to applications Risks to usability