Transcript Mr. Vincent Humphries

Use and
Administration of
ENUM
Vince Humphries
European Radiocommunications Office
[email protected]
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Overview
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• How ENUM will be used – user
applications
• How ENUM will be used – operator
applications
• How ENUM will be administered
• Possible issues
• ENUM trials
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How ENUM will be used…
…for user applications
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Communications originating on IP-enabled
terminal
• Terminating on IP-enabled terminal
• Terminating on standard telephone terminal
Calls originating on telephony network
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How ENUM will be used…
…for user applications
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Communication originating on IP-enabled
terminal:
– ENUM may be used for determining:
• availability of Internet-based communications
service for B-party
AND / OR
• destination communications service preferred
by B-party
– A-party will need client software to query ENUM
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How ENUM will be used…
…for user applications
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For voice communications originating on IPenabled terminal…
– A-party will need VoIP client software
– If B-party termination is on standard telephone
terminal, A-party will need subscription to VoIP
service provider with gateway to telephony
network
– If B-party termination is on IP-enabled terminal, Bparty will need VoIP service
– ENUM may support alternate line service
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How ENUM will be used…
…for user applications
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Call originating on telephony network
– ENUM may be used when at least one of possible
destination communications services is Internetbased
– A-party will need proxy in telephony network
capable of querying ENUM
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How ENUM will be used…
…for user applications
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In what circumstances should call originating on
telephony network be routed via proxy?
–
SCENARIO A:
Supplementary service in originating network to check all
calls for ENUM entry for dialled number
–
SCENARIO B:
Access number dialled to select proxy service of particular
provider, which checks for ENUM entry for dialled number
– If ENUM entry exists under either scenario, call is
completed in accordance with information returned by
ENUM
…How ENUM will be used
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Typical SIP call flow from standard telephone
terminal to IP-enabled terminal
Telephone
(+1 908 555 1234)
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1 Dials +44 113 496 0000
Gateway routes
call to SIP server
Switched
circuit
network
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Gateway formats
domain name
SIP server routes
call to user
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SIP server
IP network
User
(+44 113 496 0000)
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Routes call
to gateway
Gateway
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6
4
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Query of Internet domain name system returns naming
address pointer record containing sip:[email protected]
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Gatekeeper queries Internet domain name system
using 0.0.0.0.6.9.4.3.1.1.4.4.e164.TLD
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Internet domain name system returns SIP
servers’ IP address
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Gateway looks up host for [email protected]
Public Internet
domain name
system
* Based on ITU-T Supplement, “Operational & Administrative Issues Associated with National Implementations of the ENUM functions”
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…How ENUM will be used
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Typical SIP call flow from IP-enabled terminal to
standard telephone terminal
SIP client formats
+1 908 555 1234 as
domain name
User
(+44 113 496 0000)
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SIP server
SIP client initiates
INVITE to server
using “tel” format URI
SIP server looks up gateway
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address from location server
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Telephone
(+1 908 555 1234)
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Client queries Internet domain name
system using domain name
4.3.2.1.5.5.5.8.0.9.1.e164.TLD
IP
network
Internet domain name system returns
URI (tel: +19085551234)
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Public Internet
domain name
system
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Call routed
to gateway
IP address
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Gateway
Switched
circuit
network
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Gateway
completes call to switched
circuit network
6 Location server returns
IP address of gateway
Location
server
* Based on ITU-T Supplement, “Operational & Administrative Issues Associated with National Implementations of the ENUM functions”
How ENUM will be used…
…for operator applications
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QUESTION:
– Why would network operators use ENUM?
ASSUMPTION:
– IP-based infrastructure is used in providing
telephone services
PROBLEMS:
– How can real-time operational functions that rely
on access to IN databases be performed?
– When should call be routed to IP-based POI?
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How ENUM will be used…
…for operator applications
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PROBLEM 1:
How can real-time operational functions that
rely on access to IN databases be performed?
– Examples of real-time operational functions
requiring access to IN databases:
– number portability
– number translation services
– Solution may be to establish ENUM-like database
to provide equivalent infrastructure, using
telephone number as key
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How ENUM will be used…
…for operator applications
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PROBLEM 2:
When should call be routed to IP-based POI?
– Certain numbers may only be reached via IPbased infrastructure
– Terminating network may offer both TDM-based
and IP-based POIs
– Solution may be to establish ENUM-like database
to identify availability of IP-based POI, using
dialled telephone number as key
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How ENUM will be used…
…for operator applications
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ENUM-like database required, which may be:
• internal to operator
OR
• established as extranet available to consortium
of operators
OR
• in Internet domain separated from domain used
for ENUM user applications
How ENUM will be
administered…
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Proposed that administration for ENUM is
divided into tiers
Each higher tier delegates authority for portion
of its domain name space to entities
responsible for lower tiers
Each higher tier provides pointers to data
contained in name servers for lower tiers
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…How ENUM will be
administered
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Tier 0
• Global name server contains records
•
Tier 1
• National name server contains records
•
Tier 2
corresponding to telephone country codes
Contains pointers to national-level name
servers
corresponding to individual telephone numbers
Contains pointers to name servers containing
data for individual telephone numbers
• Individual telephone number name server
contains naming address pointer records
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…How ENUM will be
administered
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What entities will be involved in ENUM
administration?
– Internet domain name system:
– name server providers
– registries
– registrars
– Service providers
– telephony service providers
– Internet-based application service providers
– End users
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…How ENUM will be
administered
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ITU
Policy, accreditation, ...
Potential transactions
Tier 0 Registry
National Policy
Framework
VALIDATION
FUNCTION
Tier 1 Registry
delegation
ENUM Registrar
ENUM Tier 2
Name Server
Provider
End User
Internet-based
applications
* Based on draft ETSI TS 102 051, “ENUM Administration in Europe”
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Potential issues…
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Some issues directly related to ENUM:
– Domain name system infrastructure
– who is competent to run registries?
– who selects and accredits registries?
– to whom are registries accountable?
– Control of ENUM resources
– who will control or have influence over insertion of
–
telephone numbers in ENUM? — “opt-in” by end users?
who will control or have influence over content of naming
address pointer records?
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…Potential issues
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Some issues directly related to ENUM:
– Integrity of ENUM resources
– how will authority to insert, maintain and remove ENUM
–
resources be authenticated?
how will ENUM data be protected from attack?
– Protection of data in ENUM resources
– how will privacy of personal information be protected?
– how will unwanted exploitation of personal data be
minimised?
– Special meaning of numbers
– will special tariffs associated non-geographic numbers be
preserved by Internet-based applications?
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…Potential issues
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Some issues related to applications that will use
ENUM:
– How will providers of applications that use ENUM
be subject to national jurisdiction?
– Will applications that use ENUM effectively bypass existing telephony services?
– How will Internet-based voice applications that use
ENUM determine terminating network for ported
numbers?
ENUM trials…
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Planned trials:
– United Kingdom
– major focus is on administrative issues
– Austria
– major focus is on technical issues
– Sweden
– currently in pre-trial study
– Netherlands
– currently in pre-trial study
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…ENUM trials
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Objectives of United Kingdom trial:
– Evaluate pros and cons of options for
implementing ENUM administration
– Evaluate processes, interfaces and protocols for
interactions between entities involved in ENUM
administration
– Determine technical and operational requirements
for provisioning ENUM records
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…ENUM trials
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Objectives of United Kingdom trial:
– Assess requirements of and implications for
Internet domain name system in providing ENUM
services
– Determine security and verification requirements
for provisioning and operation of ENUM
capabilities
– Test applications based on use of ENUM
capabilities
– Evaluate and refine economic benefits and costs
of supporting ENUM
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…ENUM trials
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Objectives of Austrian trial:
– Understand ENUM technology and its potential in
providing new applications and services to end
users
– Evaluate and refine economic benefits and costs
of supporting ENUM
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…ENUM trials
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Timetable for United Kingdom trial:
– planning — March 2002
– preparation  April - July 2002
– trial operational  August - December 2002
– evaluation — January - February 2003
Timetable for Austrian trial:
– planning — Apr - Jun 2002
– preparation — Jun - Oct 2002
– trial operational — Nov 2002 - Jan 2003
– evaluation — Feb - Mar 2003
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Selected references
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IETF RFC2915, “The Naming Authority Pointer (NAPTR) DNS Resource
Record”, September 2000, M. Mealling
IETF RFC2916, “E.164 number and DNS”, September 2000, P. Fältström
ITU-T Supplement, “Operational & Administrative Issues Associated with
National Implementations of the ENUM functions”, May 2002
Draft ETSI TS 102 051, “ENUM Administration in Europe”, June 2002
IETF ENUM Working Group:
http://www.ietf.org/html.charters/enum-charter.html
ITU ENUM web page:
http://www.itu.int/osg/spu/enum/
National ENUM activities in Europe:
http://www.eto.dk/numbering/enum.htm
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