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VoIP and Number Portability: Perceived v. Real Problems

Explore the challenges of number portability in the VoIP industry, including addressing and portability on the internet, wireless data, H.323 and SIP, and more.

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VoIP and Number Portability: Perceived v. Real Problems

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  1. VoIP and Number Portability: Perceived v. Real Problems Tom Kershaw Vice President, VoIP VeriSign

  2. Agenda • Background • Circuit Switched Number Portability • Addressing and Portability on the Internet • Addressing and Portability for Wireless Data • A Parallel: H.323 and SIP • Key Portability Issues Today • Portability Architectures for VoIP • Portability Architectures for MMS • Recommendations, Bold Statements, Misc. Controversy

  3. Portability and the PSTN • Portability is based on regulatory mandate – Communications Act of 1996 • Technical Approach is based on “PSTN” concepts such as: • Rate centers • LATAs • Lines • Hence, the LRN • Mobile has followed this model in portability and roaming, which uses TLDNs in much the same way as LRNs • LRNs do little more than tell the network what trunk group to use to get to the subscriber • What if you don’t have trunk groups, rate centers and geography?

  4. Portability and the Internet • Internet addressing introduces clear separation between Name Space and “Address” • Users are identified by URLs and Domain Names • Hence, the DNS constellations that provides root addressing for the Internet: • Tree-based • Highly resilient • Segmented Address Structures: . tomkershaw verisign com @ Address space administered by Registrars; any unique address can be registered within each TLD Administered by the industry/go-vernment Address space controlled and administered by the name owner – you can have any unique address within this domain

  5. Portability and the Internet tomkershaw@verisign.com • Namespace on the Internet maps to a network address ie tomkershaw@verisign.com to 111.11.11.1 • Names are segmented: • If I want to change my name – tom@verisign.com, I have three choices: • Change the TLD ie tom@verisign.tv, assuming it is available • Change the domain to a new owner/name ie tom@tacobell.com • I can “port” my namespace into a new domain, assuming it’s available in that domain, but “tomkershaw” is not globally unique. • Address space is assumed to be infinite. • Names are fully geographic, Addresses Change Dynamically

  6. Protocol • Service Address • SIP • sip:tkershaw@VeriSign.com • SMTP • smtp:tkershaw@VeriSign.com 3 1 2 • TEL • tel:+17039483345 • HTTP • http://insite.VeriSign.com • Pager • page:18005551234 Portability and ENUM DNS 5.4.3.3.8.4.9.3.0.7.1.e164.arpa Service Application +1 703-948-3345 Set of NAPTR RRs ENUM uses DNS to resolve internet namespaces for VoIP To port this number, I can map the LRN to a SIP URI/:mailto:, or….. Change the domain space in the routing record…..

  7. The Fork in the Road PSTN Path 2: Create an Entire New System Optimized for IP Path 1: Adapt current PSTN system to IP VoIP

  8. The Fork in the Road PSTN • Slower to market • Built to last – not a corner cutter • Lacks features of original for some time • Wins in the End • Quickest path to market • Non-Disruptive • Phased Migration • Expensive • Difficult to Integrate with IP • “Voice is special….” SIP H.323 VoIP

  9. Portability Scenarios for VoIP

  10. Scenarios for Number Portability • 1) PSTN to PSTN (we have this sorted out) • 2) PSTN to IP • 3) IP to PSTN • 4) IP to IP • 5) MMS to MMS (MMSC to Handset) Bold Statement #1: Scenario 2 is the most important issue for VoIP operators today Bold Statement #2: Scenario #5 is the most important issue for mobile operators today Don’t Mix the Two Up

  11. Exec Summary (the Punch Line) • Currently, the biggest issue for VoIP Portability is introducing geographic portability • All other issues are minor in comparison • This must be addressed by the industry for VoIP to take off • Lack of geographic portability seriously hampers voip and also means most voip operators will not support portability at all • Until this is solved, other discussions are moot • The NPAC should be used for calls to or from the PSTN • IP addressing mechanisms such as ENUM and private trees should be used for IP to IP • I and P are the two most important letters in VoIP • Number portability should be implemented as a change to a resource record in ENUM/Location Server

  12. Key Points • Current industry discussions on “Implementing Portability for VoIP” have nothing to do with VoIP • VoIP operators did not ask for this • VoIP operators don’t benefit • VoIP operators need geographic portability, not URIs in the NPAC • The Real driver for these initiatives is MMS • When an MMS is received by an originating MMSC, it needs to find the terminating MMSC • In non-ported case, number is mapped to a carrier (easy) • In ported case, the LRN needs to map to a mailto: address • This is a very REAL problem that needs to be solved

  13. Geography and VoIP • VoIP separates the access network from the address • Access network can physically be anywhere; if you are on the network you are addressable • Similar structure to mobile – needs to have similar functionality • With recent FCC rulings, structure of telephone addressing will change • Rate Centers, City Codes, and NPAs will cease to be relevant • City Codes already losing relevance • DIDs will be available on demand, from anywhere, to anyone • Potential for anarchy…… • …..but that’s how the Internet works

  14. My “Address” in VoIP My Service Provider(Hawaii) Friend (Dallas) Family (Detroit) IP Network Office (Mt. View) Local (VA) Cable modem Home (VA) My URIs tom@verisign.com tkershaw@yahoo.com tck@voiprocks.com My Phone Numbers: 703-576-3287 650-834-8986 248-232-9534 214-989-4587

  15. The Geographic Portability Problem 1) Subscriber living in Washington DC (202-222-1234) ports her number to IPCarrier; also buys a second line with phone number 415 because her son has moved to San Francisco 3) Subscriber moves across the river to Virginia; changes DSL provider but keeps VoIP provider and same phone numbers 2) Calls from PSTN to 202-222-1234 are “local” under tarifing rules 5) Subscriber: Can’t port original number to new operator unless it has IMTs in the same rate center as 202-222-xxxx Can only port 408 number to a new carrier she does not even know 4) Subscriber is offered better deal by a mobile operator that combines fixed and mobile into one package

  16. Portability and VoIP to VoIP • When there are 10 million VoIP lines in North America, ¼% (.0025) of calls will be VoIP to VoIP • One of the big concerns of VoIP operators is reducing network round trips • Most peering architectures will map a phone number to: • A URI • An IP Address (typically of a proxy or border element) • The IP query will take place before a call is sent to the PSTN • The IP query may call out to an LNP resource • or the owner of the number will be up-to-date without querying the NPAC data • If a number is VoIP to VoIP, why call out to two databases when you can do portability and addressing in one?

  17. Simple Peering Architecture ASP Domain Directory SIP/ENUM Inter-Carrier Settlement (??) Applications/Services Subscriber Portal Service Broker Operator A Enterprise B Call Agent Call Agent Border Element Border Element IP Core CMTS DSLAM Call Agent Media Gateway PSTN

  18. An IP-to-IP Addressing Flow Or call out to an external directory Route Propagation: TGREP/TRIP/Manual Provisioning Port the number here External Callout Engine *LNP *CNAM *Carrier Select (ENUM or SIP) Route Engine TN To BE Route List Proportional Route Splay Route ToD/DoW Engine Class 4 Route Default (Trunk Group, PSTN Ctvty) TN Discovery TN Exists? Yes= BE RouteList External Callouts (SIP or ENUM) Number Analysis and Normalization (e.164 or URL) SIP Redirect Engine ENUM/DNS Interface to CCE

  19. Misc. IP Network Addressing in VoIP: The Internet Way Tier 1 ENUM Or Private Peering • IN NAPTR 10 10 "u" "E2U+sip" “!^.*$!sip:tkershaw@verisign.com!” • Ported to • IN NAPTR 10 10 "u" “E2U+mailto" “!^.*$!mailto:tkershaw@sprint.com Tier 2 ENUM Location Server/Registrar Call Control Call Control Call Control Call Control

  20. Protocol Service Address (NAPTR RRs) SIP sip:tkershaw@VeriSign.com SMTP Smtp:tkershaw@VeriSign.com TEL tel: +1 703 948 3258 HTTP http://www.VeriSign.com Page page:18009483258 Fax fax: +1703 421 8233 Porting in an ENUM Environment ENUM is a standard translation mechanism defined by the IETF that uses DNS to convert an E.164 telephone number into a set of addresses. Portability Request tkershaw@sprint.com; tkershaw@verisign.com Domain changed; Number “ported” ENUM DNS DNS/ENUM Resolver Interface RRP | EPP In: 8.5.2.3.8.4.9.3.0.7.1.e164.arpa Out: NAPTR RRs

  21. Option 1 Option 2 Option 3 Extending the Model: Whois for VoIP (IRIS) WhoIs? • IN NAPTR 10 10 "u" "E2U+sip" “!^.*$!sip:tkershaw@verisign.com!” • IN NAPTR 10 10 "u" “E2U+mailto" “!^.*$!mailto:tkershaw@verisign.com DNS Device Resources Tier 2 ENUM Location Server/Registrar Call Control Call Control Call Control Call Control Perimeter Security and Interop Resources

  22. Models for MMS • Mobile operators have a different problem: • Since endpoints do not have IP addresses, they will be ported with LRNs • When a discovery takes place, they want a mapping of the phone number or LRN to a mailto: address • Mailto address will correspond to an MMSC in the destination network • Using this method eliminates the overhead of using the SS7 network and makes delivery more efficient • Requires an up-to-date mail to address database • This problem space is small (100 mobile operators x 3000 LRNs x 2 mailtos • Private no/low cost solutions already out there for this

  23. Conclusions • Biggest portability issue for VoIP carriers is geographic portability • This will become an increasingly focal issue • VoIP operators do not benefit from extending LNP infrastructure to URIs or IP addresses in the immediate term • Requiring a second dip to an external directory does not make sense – support E.164 portability directly on the IP network • Mobile operators do have a strong need for an LRN to mailto solution – and there are solutions out there • We must be very careful in our architectural decisions – the impacts are far reaching and in some cases we are solving problems before they manifest themselves • In VoIP, E.164 is a NameSpace, not an Address – need to treat it accordingly

  24. Thank You! tkershaw@verisign.com 703-948-4509

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