ENUM Overview

1
ENUM Overview
ENUM will it pay? PULVER.COM VON
Europe Stockholm

• Richard Shockey
• IETF ENUM WG Co-Chair
• Director Member of Technical Staff
• NeuStar, Inc.
• 46000 Center Oak Plaza
• Sterling VA 20166 USA
• richard.shockey_at_neustar.com richard_at_shockey.us
  
• 1 571.434.5651

2
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

IP on Everything
Vint Cerf - Google
3
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

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IMS call flow overview w / ENUM
CSCF SIP Proxy
ENUM DB

• 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?

5
ENUM in the IMS Architecture ( really simplified)

• End-user dials E.164 to initiate service.
• (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.
• S-CSCF resolves host name within SIP URI using
  on-site or hosted private DNS infrastructure.
• S-CSCF sends SIP Invite to destination
  (I)nterrogating-CSCF.
• Destination I-CSCF queries Home Subscriber Server
  to get address of Destination S-CSCF.
• I-CSCF proxies Invite to destination S-CSCF.
• Standard SIP/SDP session negotiation follows

6
ENUM WG still in business

• Explosion in Enumservice Registrations
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-iax-00.txt
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-vcard-00.txt
• http//www.ietf.org/internet-drafts/draft-reiching
  er-enum-foaf-00.txt
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-im-service-00.txt
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-calendar-service-00.txt
• Will anyone actually use them ?
• Infrastrructure ENUM Requirements
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-infrastructure-enum-reqs-01.txt
• 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

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Public ENUM RFC 3761

• Public ENUM is generally defined as the
  administrative policies and procedures
  surrounding the use of the lte164.arpagt 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

8
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 - http//www.enum-forum.o
  rg
• United States ENUM LLC http//www.enumllc.com
• Participants include MCI, ATT, Sprint, SBC,
  Verizon, NeuStar, Cox , Comcast, Cisco, Telcordia
• Canada too .. http//www.enumorg.ca

9
Carrier/Infrastructure ENUM

• Carrier ENUM is generally regarded now as the use
  of a separate domain lt ie164.arpagt to permit
  service providers to exchange phone number to URI
  data in order to find points of interconnection.
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-infrastructure-enum-reqs-02.txt
• http//www.ietf.org/internet-drafts/draft-ietf-enu
  m-infrastructure-00.txt
• 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.

10
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?

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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.

12
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
• Industrys 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.

13
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

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How do you get the data?Classic ENUM - Pull
Model
ENUM DNS Service
3. DNS returns NAPTR record containing SIP URL to
Calling Party UA
2. Calling party proxy UAC queries DNS for
endpoint location
Responsesipname_at_domain.com
Query4.3.2.1.5.5.2.0.2.1.e164.arpa?
Call Setup
1. The caller dials the persons telephone number
Sipsipname_at_domain.com
4. Calling party UA connects the call
Dial 1-202-555-1234
Sip Proxy
Sip Proxy
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How does a SP get its signaling data?A Different
ENUM paradigm - Carrier PUSH Model
PUSH Model queries a fully cached copy of the
ENUM Signaling DB internally
PULL Model ( classic ENUM) queries external
signaling databases
SS /CMS/ Proxy
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The Classic Class 5 signaling - Pull Model
Tandem Access Switch
Class 5 Switch
Inter Machine Trunking (IMT)
TCAP Query Response
Service Control Point
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The New NGN Where is the number translation
done ?Push or Pull from the IP-SCP
ENUM DB External
déjà vu all over again
All call query on call origination
Media Gateway
SIP Proxy / SS / CSCF
DNS or SIP Redirect Query Response
DNS vs TCAP
IP SCP Internal
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The Emerging IP SCP
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Use URI / NAPTR Records can define any endpoint
PSTN or IP, Internal or External

• URIs Uniform Resource Indicator The naming
  and addressing scheme for Internet services
• ORIGIN. 1.5.6.5.4.3.4.1.7.5.1.mso.net
• Output
• ord pr fl service
  regexp
  
• IN NAPTR 20 10 "u" E2Usip"
  "!.!sip15714345651_at_proxy4.mso.netuserphon
  e!" .
• and
• IN NAPTR 10 10 "u" E2Usipcontact"
  "!.!sip15714345651_at_240.67.89.124!" .
• and
• IN NAPTR 30 10 "u" "E2Upstntel"
  "!.!tel[phone]npdirn15712768933"
  
• and
• IN NAPTR 40 10 "u" "E2Upstncnamdata"
  "!.!dataRichardShockey!"

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Using ENUM for LNP

• ORIGIN 3.1.8.7.1.8.9.5.1.2.1.sipix.nsr.foo.
• NAPTR 10 100 "u" "E2Upstntel
• "!.!tel[phone]npdirn1-215-981-7600
  ! Or
• NAPTR 10 100 "u" "E2Upstnsip
• "!.!sip1-215-981-7813npdirn1-215-981-760
  0_at_network.ususerphone!
• 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  

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Using ENUM for CNAM

• ORIGIN 3.1.8.7.1.8.9.5.1.2.1.cnam1.mso.foo.
• NAPTR 10 100 "u" "E2Upstncnamdata
  "!.!dataRichardShockey!
• 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.
•        

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So Whats Next

• 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.