1 ENUM? “ ” Telephone Number Mapping (ENUM or Enum, from TElephone NUmber Mapping) is a suite of protocols to unify the telephone numbering system E.164 with the Internet addressing system DNS by using an indirect lookup method, to obtain NAPTR records. The records are stored at a DNS database.
1 ENUM? “ ” Telephone Number Mapping (ENUM or Enum, from TElephone NUmber Mapping) is a suite of protocols to unify the telephone numbering system E.164.
Dec 27, 2015
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ENUM?ENUM?
“
”
Telephone Number Mapping (ENUM or Enum, from TElephone NUmber Mapping) is a suite of protocols to unify the telephone numbering system E.164 with the Internet addressing system DNS by using an indirect lookup method, to obtain NAPTR records. The records are stored at a DNS database.
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AssumptionAssumption
Use of standard telephone numbers is not going away• PSTN/analog
terminals are going to be around
• IP phones use 12-button keypad
• Globally unique identifier that has established familiarity with end users
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Problem statementsProblem statements
How do network elements (gateways, SIP servers etc) find services on the Internet if you only have a telephone (E.164) number?
How can subscribers define their preferences for incoming communications?
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More Problem StatementsMore Problem Statements
How do you address an IP-based voice terminal from the PSTN?
For a call that starts out as VoIP, how do you know to keep the call on the IP-plane (as opposed to the PSTN) for a dialed telephone number if the customer is not yours?
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Today, Many AddressesToday, Many Addresses
tel:+46-8-971234
mailto:[email protected]
tel:+46-706051234
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With ENUM, Only OneWith ENUM, Only One
tel:+46-8-971234
mailto:[email protected]
tel:+46-706051234
tel:+46-706051234
Give this number to friends:+46-8-971234
ENUM
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Solution in shortSolution in short
Put domain names derived from telephone numbers in the global domain name system, DNS
IETF ENUM Working Group created to solve the problem of using the DNS for:
•domain name in
• [Numbers re-formatted as domain names]
•URI out
• [mailto, sip, tel, http or other URI scheme]
Solution: NAPTR records
Use the URI’s for the communication
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NAPTRNAPTR
• take phone number +46-8-6859131
• turn into domain name 1.3.1.9.5.8.6.8.6.4.e164.arpa.
• return list of URI’s sip:[email protected]
• ask the DNS mailto:[email protected]
NAPTR stands for Naming Authority Pointer and is a newer type of DNS record that supports regular expression based rewriting.
Several NAPTR records can be chained together creating fairly sophisticated URL rewriting rules. A record can go through any number of rewrites before reaching a terminal condition.
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NetworkNetwork
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Tier 0
Tier 1
Tier 2
DomainName
System
ApplicationServiceProvider
Registrar
Registry
ENUMEnabled
Applications
Provisioning
• voice• fax• messaging & presence• email• web pages
Authentication &
ValidationEntities
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The Public ENUM Infrastructure
The Public ENUM Infrastructure
$ORIGIN e164.arpa. 3.7.9.1 IN NS nsnanp.enum.com . 4.4 IN NS UK_enum.com .…
$ORIGIN 3.7.9.1.e164.arpa. 7.9.7.6.6.3.2 IN NS e164.att.net .8.9.7.6.6.3.2 IN NS e164.xyz.com .…
$ORIGIN 7.9.7.6.6.3.2.3.7.9.1.e164.arpa. IN NAPTR 100 10 "u" "sip+E2U" "!^.*$!sip:[email protected]!" .
e164.arpa
Tier 0 (Country Code Registry)
nsnanp.enum.com(3.7.9.1.e164.arpa)
Tier 1 (Telephone Number Registry)
e164.att.net
Tier 2 (Application Information)
International Implementation worked in IETF and ITU-T
National Implementation worked in ENUM Forum (US)
UK_enum.com(4.4.e164.arpa)
…
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Delegation of Country Codein Tier 0
Delegation of Country Codein Tier 0
Draft Recommendation E.A-ENUM in progress
Interim Procedures in place between IAB/ISOC and ITU-TSB• Use of e164.arpa pending outcome of
Recommendation• Country Code must be valid and assigned• Position of National Numbering Administrator
must be known and must opt-in
Similar situation for shared Network codes and codes for Groups of Countries (e.g., ETNS)
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Requirements DocumentRequirements Document
• Reference Architecture• Tier 1 Registry Operations, Security, & Admin• Tier 1 Performance Specifications• Privacy Considerations• Provisioning• Registrar Requirements• Authentication & Authorization• Tier 2 Requirements & Guidelines• Conflict Resolution• Issues Out of Scope
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Reference ArchitectureReference Architecture
Tier 1Registry
Tier 0
Root
Tier 2Provider
RegistrantRegistrant RegistrarRegistrar
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Reference ArchitectureReference Architecture
RegistrarRegistrantTier 1 Registry
o Does not address non geographic numbersTier 2 Service Provider
o Tier 2 contains the NAPTR records or delegations InterfacesIssue:
o One or More Tier 1 Providers– Delegation at Tier 0 by NPA
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Tier 1 AspectsTier 1 Aspects
Tier 1 Operationso Zone Information (aka zone files)o ContactInfo (aka WhoIs)o Reporting, backup, escrow & performance
requirementsPerformance Aspects
o DNS Performanceo EPP Interfaces
Tier 1 Security
Administrative Aspectso Dispute Resolutiono Data Collection and Privacy
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ProvisioningProvisioning
Tier 2Nameserver
RegistrarRegistrarTier 1
RegistryRegistrantRegistrant
Application ServiceProvider
Application ServiceProvider
Authentication & Validation Entities
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Provisioning AspectsProvisioning Aspects
Registrar Requirementso Registrant Validation & Authenticationo Dispute Resolutiono Registrar Infrastructure Requirementso Recommended Practices & Requirementso Various Scenarios
- Information Flows
Tier 2o Mostly Guidelines – SomeSome Requirementso Tier 2 may be self-provided or from a commercial 3rd
partyo Interfaces & Interactionso Performance Recommendations
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Future ActionsFuture Actions
Address implementation issues• Contracting model
• Integration/separation of North American countries
• Number of Tier 1 operators
Address Non-geographic numbers (specifically 8YY Toll Free)• Can’t be cleanly separated by North American
country
• Has unique provisioning requirements
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