ENUM Overview Richard Shockey IETF ENUM WG Co-Chair Director – Member of Technical Staff NeuStar, Inc Center Oak Plaza Sterling VA USA ENUM will it pay? PULVER.COM VON Europe Stockholm

VoIP has won..like duh Because the Internet WON !!!!!! –The IP model has proven better, cheaper and faster for most applications and has been universally embraced –Behavior patterns have shifted to a desire for ubiquitous access to full media, content, applications and communications services, any time, any place, and to or from anywhere –Services and applications are being dis- intermediated from network ownership and management –VoIP independent of transport layer Wireline, Cable, Wireless Vint Cerf - Google “IP on Everything”

ENUM has won the signaling argument VoIP Peering and interconnection is the #1 technical subject among Service Providers. You have to translate the phone number to do anything –Phone number in URI out. DNS based ENUM is faster than SIP Redirect by a factor of 10 Commercial Private ENUM services have exploded RFC 3761 is central to all NGN architectures –IMS – 3GPP –MMS SMS

IMS call flow overview w / ENUM IMS theory claims that the future core infrastructure includes 40+ functional entities & interfaces String theory claims that the universe is comprised of 6 or more dimensions of time space. Which is more far-fetched? ENUM DB CSCF SIP Proxy

ENUM in the IMS Architecture ( really simplified) 1.End-user dials E.164 to initiate service. 2.(S)erving-CSCF [Call Session Control Function] issues ENUM service discovery query to on-site or hosted ENUM DNS server for a SIP-URI of the destination CMS. 3.S-CSCF resolves host name within SIP URI using on-site or hosted private DNS infrastructure. 4.S-CSCF sends SIP Invite to destination (I)nterrogating-CSCF. 5.Destination I-CSCF queries Home Subscriber Server to get address of Destination S-CSCF. 6.I-CSCF proxies Invite to destination S-CSCF. 7.Standard SIP/SDP session negotiation follows

ENUM WG still in business Explosion in Enumservice Registrations – – – – – –Will anyone actually use them ? Infrastrructure ENUM Requirements – Infrastructure ENUM Root –ie164.arpa Treaty of Dallas –Agreement that their should be a single apex e164i.arpa –Use of BLR is interim aka i.4.4.e164.arpa –Political process starts all over again SPEERMING WG on Peering / Interconnection

Public ENUM RFC 3761 Public ENUM is generally defined as the administrative policies and procedures surrounding the use of the domain for TN to URI resolution. –By ITU-IAB agreement all portions of the tree are nation state issues –All records are visible on the Internet US - UK – Canadian Govt policy has been to encourage consumer OPT- IN. Which is generally assumed to be the number holder as opposed to the carrier of record is the only entity permitted to create records in e164.arpa. How do you register the Phone Number? –Registration Model much like Domain Names… –Might be a Service Provider or Telecom Equipment Vendor or Independent “Registrar” such as in the Domain Name Industry

Public ENUM Status - What about the US? US ENUM LLC Trials Beginning this June 1.e164.arpa United States Government has reiterated its support for RFC 3761 and endorses moving forward with ENUM based on the concept of a Industry Managed LLC – Aug 9, 2004 United States ENUM Forum - United States ENUM LLC – Participants include MCI, ATT, Sprint, SBC, Verizon, NeuStar, Cox, Comcast, Cisco, Telcordia Canada too..

Carrier/Infrastructure ENUM Carrier ENUM is generally regarded now as the use of a separate domain to permit service providers to exchange phone number to URI data in order to find points of interconnection. – – Only the service provider of record for a particular TN is permitted to provision data for that FQDN. Service providers are looking for NGN signaling infrastructures Carrier ENUM is to be assumed as authoritative for all endpoints service providers choose to exchange data for.

Questions about ie164.arpa Why would any service provider place information into the global DNS that resolves to points of network interconnection? –Security implications staggeriing - DDOS Why would any service provider ASK for Government intervention and regulation in the critical signaling infrastructure? –Choice of ie164.arpa requires Govt approval and delegation –Isn't the telecom industry moving to deregulation?

Private ENUM is the solution for VoIP Peering Private ENUM is generally regarded as one or more technologies that permit service providers to exchange phone number to URI data to find points of interconnection in private secure manner. –any mutually specified domain –VPN –Subnets –Private Root Private ENUM is to be assumed as authoritative for all endpoints service providers choose to exchange data for. –Maintains essential bilateral agreement for interconnection Potential PSTN as well as IP data. –All Call query on call origination.

The Business Case for Private ENUM Peering Inter-Carrier Compensation is driving the VoIP Peering issue $20 Billion US per year SS7 signaling costs impossible to estimate. VoIP/NGN Peering is IMPOSSIBLE without Telephone Number Translation.. aka ENUM in some form Industry’s Conclusion : Working towards public ENUM in the future (very important), deploying Private ENUM now. Public and Private ENUM are Orthogonal to each other, they serve different markets for different reasons.

Market Realities driving NGN signaling adoption Flat Rate Pricing ( all you can call ) beginning to dominate –variable costs unacceptable –predictable costs for signaling IS acceptable Carriers beginning to demand bill and keep vs inter- carrier compensation for interconnection –current accounting costs outrageous The Internet model of Transit and Peering is about to be applied to Voice traffic as well SS7/C7 dip charges and infrastructure OPEX are as bad as Reciprocal Comp charges for Termination

How do you get the data? Classic ENUM - Pull Model 1. The caller dials the person’s telephone number Query e164.arpa? 2. Calling party proxy UAC queries DNS for endpoint location Dial ENUM DNS Service 3. DNS returns NAPTR record containing SIP URL to Calling Party UA Response Sip Sip Proxy 4. Calling party UA connects the call Sip Proxy “Call Setup”

How does a SP get its signaling data? A Different ENUM paradigm - Carrier PUSH Model SS /CMS/ Proxy PUSH Model queries a fully cached copy of the ENUM Signaling DB internally PULL Model ( classic ENUM) queries external signaling databases

The Classic Class 5 signaling - Pull Model Service Control Point Class 5 Switch Tandem Access Switch TCAP Query Response Inter Machine Trunking (IMT)

The New NGN = Where is the number translation done ? Push or Pull from the “IP-SCP” IP SCP Internal SIP Proxy / SS / CSCF Media Gateway ENUM DB External All call query on call origination DNS or SIP Redirect Query Response déjà vu all over again DNS vs TCAP

The Emerging IP SCP

Use URI / NAPTR Records can define any endpoint PSTN or IP, Internal or External URI’s = Uniform Resource Indicator – The naming and addressing scheme for Internet services $ORIGIN mso.net Output ord pr fl service regexp IN NAPTR "u" “E2U+sip" and IN NAPTR "u" “E2U+sip:contact" and IN NAPTR "u" "E2U+pstn:tel" "!^.*$!tel: ;npdi;rn= " and IN NAPTR "u" "E2U+pstn:cnam:data" "!^.*$!data:Richard%Shockey!"

Using ENUM for LNP $ORIGIN sipix.nsr.foo. NAPTR "u" "E2U+pstn:tel“ "!^.*$!tel: ;npdi;rn= !“ Or NAPTR "u" "E2U+pstn:sip“ “ In this example, a Routing Number (rn) and a Number Portability Dip indicator (npdi) are used as shown in "Number Portability Parameters for the “tel” URI” ; draft-ietf-iptel-tel-np-09.txt. The ‘npdi’ field is included in order to prevent subsequent lookups in legacy-style PSTN databases. See: “IANA Registration for an Enumservice Containing PSTN Signaling Information”; draft-ietf-enum-pstn-04.txt; Author(s) : J. Livingood, R. Shockey

Using ENUM for CNAM $ORIGIN cnam1.mso.foo. NAPTR "u" "E2U+pstn;cnam:data “"!^.*$!data:Richard%Shockey!“ See: IANA Registration for an Enumservice for Calling Name (CNAM) Information; draft-ietf-enum-cnam-01.txt; Author(s) : R. Shockey, editor J. Livingood, et al.

ENUM is the core signaling technology for the NGN-Network to Network Interface DNS Caching Servers are the NGN IP-SCP All Call Query - Query on Call Origination All data associated with a call delivered at call set up. So What’s Next