ENUM Overview

Richard ShockeyIETF ENUM WG Co-Chair

Director – Member of Technical StaffNeuStar, Inc.

46000 Center Oak PlazaSterling VA 20166 USA

richard.shockey@neustar.com richard@shockey.us+1 571.434.5651

ENUMIts about the NGN Registry

London 2007

Why we are here. Bye Bye PSTN. Well, eventually.

• Deutsche Telecom said it will shut down the PSTN in 2019

• British Telecom said it will have the 21CN fully in place 2015

• KPN talks about 2010

• GSM-A ongoing discussion about IPX

• North American Cable Operators are already there.

– They WILL optimize VoIP session termination strategies by routing directly from one SP to another in 2007

Is there a DMS / 5ESS bone yard ready?

For the 6,332 time : “Islands of VoIP” problem

• The PSTN is used as the inter-VOIP “default” network– Service is degraded as it must transverse multiple networks

• Every VOIP network is an Island (apologies to John Donne!)– Enterprise or carrier VOIP dial plans cannot be remotely accessed by

other VOIP gateways

• Clash between flat-rate calling and variable network costs– PSTN termination, settlement, and management

• Demand to differentiate services in market– Higher quality, presence, usage communities

$$ $$

VoIP Peering: It’s not just VoIP and it’s not just Peering

• Reduce complexity and costs– PSTN termination, settlement, and

management – Efficient, scalable business and

technology models – Secure, high performance

infrastructure

• Drive higher-level feature sets– Presence, location, communities and

quality– Seamless inter-working of SIP and IMS

applications across domains– Reliable call setup and service delivery

Cross platform InteroperabilityAny IP session from any device on any network to any device on any network

TCAP SS7/C7 avoidance is still a significant business driver.

• It just costs too much money.• Fixed revenue services models

variable costs are unacceptable.• LNP per dip charges major driver of

Private ENUM applications in US. RFC 4769– CNAM dip avoidance

The NGN Signaling Architecture is not fully in place

• You HAVE to translate phone numbers into efficient routing information.

• SS7/C7 Network cannot be sustained any more than managing 2 networks TDM and IP

• There is no new service creation in TDM based networks.

• Confusion about the 3 flavors of ENUM– Public - e164.arpa– Infrastructure – ie164.arpa– Private – industry lead or private consortiums

• Confusion about the role of a root/apex– Who controls the apex– Is a APEX needed

• Confusion about the delegation models.– Do you need Tier 2’s?– Carrier vs Nation State

• Enterprises are changing the game as well by demanding IP trunking.

The SIPconnect Reference Architecture – Direct trunking of VoIP to SP Networks

U.S. PBX Revenue Forecast

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Legacy PBXIP-PBXLegacy PBXIP-PBX

http://www.sipforum.org/sipconnect

ENUM query technology is winning the NNI Interconnection Signaling Protocol argument

• DNS based ENUM is faster than SIP Redirect by a factor of 10

• DNS Queries integrates neatly with SIP URI resolution

• Commercial - Private ENUM services have exploded

• RFC 3761 is central to all NGN architectures– IMS – 3GPP– MMS/SMS on IP– PacketCable 1.5

Its not about ENUM roots. Its about Registries.

• Its about how operators exchange data to enable interoperable services

• How the data is queried is irrelevant

• NGN Registries can enable services beyond voice

• Mobile IM • Presence

• Enable Law Enforcement Requirements

The existing SS7/C7 signaling networks cannot accommodate NGN IP services.The real solution for the industry are stand-alone, neutral National Telephone Number Registries, (databases)

The NGN TN Registry is not ENUM Tier 1

• We’ve brainwashed ourselves into thinking this is about the DNS

– Delegation is not the issue

• Using ENUM Query technology does not mean you have to use the Global DNS

• The NGN Registry could populate ENUM services Public, Private or Infrastructure.

• The NGN Registry insures Open Competition– Open choice of Registrar for Provisioning– Open choice of Query Model [Hosted/Cached

vs per dip]– Open choice of Query Type

• DNS vs SIP Redirect vs ???

• The Registry should NEVER own the data.

• The Registry only shows you where to go not how to get there.

The Registry is the enabler of Metcalfe’s Law

• No single service provider lives on an island. They must interconnect in order to provide global services. “Coase Theorem”

– http://www.itu.int/ITU-D/treg/Events/Seminars/GSR/GSR07/discussion_papers/JScott_Marcus_Interconnection_IP-based.pdf

• The integrity of this registry data is too vital to depend on multiple, direct SP-to-SP connections.

• One Registry avoids the “spider-web” created by N (Squared) or more direct SP-to-SP connections.

• One Registry provides for more efficient auditing, trouble shooting, and problem resolution.

• In short the single registry model is simply more efficient distribution of the registry data.

There can only be one …per country.

You can’t route if you can’t trust the data.

• ENUM is about how you query the data ..not how you create it.• The registry must have a Authentication and Validation model that

insures the data is accurate.– Example LNP

• A NGN TN Registry broadcasts routing and administrative data to all carriers simultaneously upon record activation or change.• Independent vendors can establish per dip query models.

• A NGN TN Registry ensures that routing information is current and in sync, and that appropriate business processes have been followed prior to accepting any provisioning changes in accordance with national law and regulatory proceedings.

• Registry Governance should be a partnership between industry andregulators.

Operational Principals of a National NGN TN Registry

• Not require telecommunications carrier to rely on databases, other network facilities, or service provided by other telecommunications carriers to route calls to proper termination point

• Support existing and future network services, features and capabilities using IP transport

• Efficiently use E.164 numbering resources for new service delivery and interoperability– Not require end users to change their telecommunications numbers

• Not result in unreasonable degradation in service quality or network reliability when implemented

• Capable implementing number portability if required• Be flexible enough to accommodate a variety of Query Response

mechanisms and Data distribution models. “Be Future Proof”– SPID/DPC

What examples exist ? (shameless plug)

• North American Number Portability Administration Center -NPAC-[NeuStar] + LERG [Telcordia]

– In service since 1996 managed by NeuStar / LERG by Telcordia– Open Choice of Registrar’s – Open Choice of Query Operator– NPAC NGN initiatives

• NANC 399– Define 2 new Service Provider Identification fields ( Service Type - ALT-SPID)

• NANC 400– Put Service URI’s in the NPAC– http://www.nanc-chair.org/docs/nowg/Apr05_NeuStar_Joint_FoN_LNPA_Presentation.ppt

• COIN ( COmmunications INfrastructure in The Netherlands )– ADD URI data to COIN and Infrastructure ENUM would be in place.

• http://isoc.nl/files/ScriptieLennartMaris.pdf

• OFCOM Study Review of General Condition 1- Number Portability• Concludes that “ present analysis appears to favor transition from current onward routing solution

for routing of calls to ported numbers to an All-Call-Query of a common database of numbers (“ACQ/CDB”) aka I-ENUM

• http://www.ofcom.org.uk/consult/condocs/gc18/

• The real issues are administrative polices and procedures carriers use to interact with each other and the cost recovery model for managing the NGN TN Registry.

Push data to the “IP-SCP” or Pull from external source

IP SCPInternal

Cache DNS

SIP Proxy / SS /CSCF

Media Gateway

External ENUM Service

All call query on call origination

DNS or SIP Redirect Query Response

NGN Registry

Provisioning

Public DNS will never work for service providers

• The Public DNS is not secure and probably never will be (DNSSEC is not going to happen)

• Why would any service provider place information into the global DNS that resolves to points of network interconnection?

– Security implications staggering – DDOS– SPIT

• UK CRUE proposal is IMHO completely unworkable.

• National NGN TN Registries can be linked in ways similar to existing Global Tidal Translation without resorting to a heircharcial tree.

• All service provider relationships have been and will IMHO continue to be bi-lateral.

GSM-A Private Infrastructure ENUM Details

• Private and Closed - "Carrier ENUM" for the IPX network• For use by operators only• Single private domain• Not connected to Public DNS• Totally closed• Ultimately Intended to be available for global use by any operator,

mobile or fixed, who wishes to connect– We’ll see.

• Will be primarily used by IMS and MMS services• Documented in IR.67 DNS Guidelines

• But again ..where is the data coming from….!!– IMHO Delegation should be at nation-state level not operator level– Use the NGN TN Registries to populate the system– Must support Multi-Service applications

So what about Public ENUM?

• Its time will come…

• We have not seen interest from Enterprises …yet• New applications may yet be developed• May be a platform for Identity management (SAML)

ENUM WG still in business, but not for much longer.

• Ready to declare Victory

• Advance RFC 3761 to Draft Standard

• Develop Standard Template for Enumservice Registrations

• WG Approved lots of Enumservice Registrations– http://www.ietf.org/internet-drafts/draft-ietf-enum-iax-01.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-vcard-05.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-im-service-01.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-calendar-service-00.txt

• Lots of work defining Infrastructure ENUM services that replace TCAP queries– None of them will use the Public DNS

Using ENUM for LNP

$ORIGIN 3.1.8.7.1.8.9.5.1.2.1.sipix.nsr.foo.

NAPTR 10 100 "u" "E2U+pstn:tel“"!^.*$!tel:+1-215-981-7813;npdi;rn=+1-215-981-7600!“ Or

NAPTR 10 100 "u" "E2U+pstn:sip“"!^.*$!sip:+1-215-981-7813;npdi;rn=+1-215-981-7600@network.us;user=phone! “

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”; RFC 4769 Author(s) : J. Livingood, R. Shockey

There is still work to do.

• SPEERMINT WG on Peering / Interconnection

• Proposed PEPPERMINT BOF on Registry Provisioning issues.

– “ ENUM is specifically chartered to develop protocols that involve the translation of E.164 numbers to URI's. SPEERMINT has been chartered to develop best current practicesamong real-time application service providers and how such services interconnect across domain boundaries. It is clear from discussions in both working groups that Multi-Media Interconnection will require address of record data to be provisioned among administrative domains outside the normal scope of establishing a SIP session.”

• Provisioning goes to the heart of the issue “ How do you trust the data you are using to route?”

• Build on RFC 4114 and RFC 4414 ???• Probably settle on SOAP/XML interfaces• Working to formalize BOF in at IETF 69 in Chicago.

MEMO on Infrastructure ENUM

• WG chairs sent memo to IAB/IETF.– http://www1.ietf.org/mail-archive/web/enum/current/msg05529.html

• IETF Community concerned that existing agreements with ITU could not be preserved if IETF attempted to define a Infrastructure ENUM apex. [ ie164.arpa ]

• IETF Community concerned it should not define business roles and structures for carriers only protocols

• IF there is a need for a new apes the ITU-T should take responsibility for "Infrastructure ENUM" where goals are resolve the issues described in draft-ietf-enum-infrastructure-04.txt.

• IAB/IESG to send Liaison Memo to ITUT-SG2 outlining these issues.

• Relevant Texts– http://www.ietf.org/internet-drafts/draft-ietf-enum-infrastructure-enum-reqs-03.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-branch-location-record-02.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-combined-04.txt– http://www.ietf.org/internet-drafts/draft-ietf-enum-infrastructure-05.txt

In Conclusion ….

ENUM is about signaling …not necessarily about the DNS.