Endpoint vs. Network VoIP Services

1. Endpoint vs. Network VoIP Services Henning Schulzrinne (with Xiaotao Wu) Columbia University FCC Technical Advisory Council III Washington, DC – October 20, 2003

2. What are services? • Call routing services  subset of CLASS services • name/number translation • terminal, user mobility • call forward busy/no answer • call forward conditional (time-of-day, call center) • Directory services • white and yellow pages • global and corporate • Media services • media encoding translation for bandwidth • media type conversion: language, speech-to-text • media combining: conferencing • Identity services • identity assertion (“Columbia attests that Joe Smith, an employee, is calling”) • identity hiding (“agent42@anonymizer.com is calling”) • configuration repository • media preferences • address book and speed dial

3. PSTN vs. Internet Telephony Internet Telephony end system PSTN Number of lines or pending calls is virtually unlimited More (per-user) processing power than most network servers Single line, 12 buttons and hook flash to signal

4. PSTN vs. Internet Telephony PSTN: Signaling & Media Signaling & Media can be far away from either user Internet Telephone: Signaling Signaling Media

5. PSTN vs. VoIP • PSTN: only carriers can get full signaling functionality (SS7) • UNI vs. NNI signaling • VoIP: same signaling, same functionality

6. Network vs. end system services • Really two meanings: • services implemented in user agent (instead of proxy) • services implemented in server run by end user (instead of carrier)  • business • residential • Variation on old Centrex vs. PBX argument • except that media routing no longer an issue • Often, services require or can use both: • e.g., the history of speed dial • CLASS service: translation in CO • (semi)intelligent end systems: locally, possibly with hotsync to PC • intelligent end system, but network-synchronized

7. End system vs. network trade-offs

8. Network services PSTN gateway multiplexing gain SS7 access Backup services e.g., no answer from enterprise due to failure no permanent connectivity for residential users Large-scale conferences for residential users bandwidth availability End system/user services media processing distinctive ringing programmable services user control but: security maintenance End system vs. Network services – the easier cases

9. Call routing services • Outsourcing allows temporarily disconnected end users • Staged service: carrier proxy user proxy personal preferences basic call routing

10. Identity management • Identity assertion (notary) services • best done by larger organization • server certificates • name recognition • recourse • Anonymity services • needs to have large user population to provide effective hiding • Portable services • high availability and universal reachability

11. Service architectureProgramming language model

12. Service location examples (*) = with information provided by end system

13. Analogies • False either/or choice • See email and web for precedent • carrier-provided (ISPs) • basic service • name portability issues • enterprise • provide and manage own infrastructure • only purchase “raw bits” • home user • albeit actively discouraged • hosting companies = bandwidth + service • shared and dedicated facilities • but not an ISP in the traditional sense • service-only companies • web mail • mail forwarding

14. The vanishing phone • Old model: • explicit, user-visible signaling  dialing, ringing • small number of phone lines, (mostly) each with one E.164 identifier • New model: • session initiation from • IM session  no dialing and ringing • game session  proximity triggers conversation • event based  connect if event occurs • no notion of lines • teenager (or telemarketer…) may have dozens of chat windows open • some identifiers may make no PSTN calls at all • from monthly service  calling card-like • any number of identifiers • one per wire or device  multiple per person (role-based)

15. Example: VoIP embedded in VR

16. The impact of regulations • Phone (service) companies are not required any more, but may be useful • don’t have (many) email companies, either • Regulation should not bias technical and business decisions on in-house vs. out-sourcing • Avoid conflicts of interest for ISPs that provide phone service: • no port blocking except by user request • traffic neutrality  provide differentiated services to all • provide externally routable addresses • address shortage excuse  NAT  difficult to have inbound connections • distinguish residential / business via application-neutral measures, e.g., bandwidth or availability • Goal: • ensure “transparent Internet” + service providers for added value • encourages service innovation • encourages service competition

17. Impact of regulations: E911 • Traditional notion: small number of phone companies (often, one) do selective routing of 911 calls to PSAPs • PSAP information tightly guarded • public information, but hard/$$$ to get • For service competition: • should be able to route to PSAP from my home proxy • open access to PSAP information • See my ex-parte filing for details

18. Conclusions • VoIP enables, but does not force, end point services • Move service location decision to end user, with trade-offs in • cost • control • availability • functionality • technical sophistication needed • Regulatory framework should • ensure this user choice • prevent network operators from stifling service competition • Consumer protection  define service rules for effective monopoly & oligopoly providers • goal of transparent (end-to-end) Internet