Industry Canada 1 Bob Leafloor Colman Ho Peter Chau Industry Canada January 2003 (ENUM) T E lephone NU mber M apping.

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Industry CanadaIndustry Canada

Bob LeafloorColman HoPeter Chau

Industry CanadaJanuary 2003

(ENUM)(ENUM)TTEElephone lephone NUNUmber mber MMappingapping

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DisclaimerDisclaimer

The views, thoughts and information contained in this presentation are solely intended assist in opening a dialogue on how best to proceed with ENUM in Canada

These views, thoughts and information do not necessarily represent views, policies, opinions or understandings of Industry Canada

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What is ENUM?What is ENUM?

ENUM is a protocol developed by the IETF (RFC 2916) that enables:

• End-user Subscriber Services• subscriber defined preferences for incoming

communications

• Network to Network Services• network elements to find services on other network

elements using only a telephone number

• Enhanced SPAM Services• ENUM could become the worlds largest database of active,

legitimate email addresses –SPAM gold mine?

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An end-user service that specifies alternative contacting methods for that

end-user

An important integrator of the PSTN, the Internet and other IP based networks

Facilitates terminating calls from other networks to IP based networks.

Why ENUM?Why ENUM?

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1. Transform the telephone number into an ENUM DNS name

2. Query the DNS to resolve that name and retrieve information (NAPTR RRs) that have been associated with the telephone number

3. Choose a service from the DNS NAPTR response on the various types of services (including order & preference) associated with the telephone number

ENUM 3 Step ProcessENUM 3 Step Process

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The result of an ENUM DNS query is the NAPTR records, which specify the alternative methods of contact with their

order of processing and preference

ENUMDatabase

Choose a service from the DNS responseChoose a service from the DNS response

The ultimate choice of contact rests with the

sender

QueryChoose

NAPTR

Choice

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• ENUM is specified in IETF RFC 2916

• RFC 2916 specifies a unique one-to-one bi-directional mapping algorithm between E.164 telephone numbers and DNS names

• RFC 2916 specifies e164.arpa to be the ENUM DNS Name Space Root

• Therefore NAPTR information rooted outside e164.arpa is not ENUM

Points of ConsiderationPoints of Consideration

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• The ITU-T as part of it’s E.164 responsibility is cooperating with the IETF on ENUM

• Some ITU Member States oppose the use of e164.arpa as the ENUM root

• A final decision has yet to be made on the root within ITU

• E164.arpa is being used for the ENUM trials, in accordance with the ITU interim procedures


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• Draft procedures at the ITU require that ITU Member States (countries) opt-in to ENUM before any DNS names corresponding to the E.164 telephone numbers under that countries jurisdiction can be added to the ENUM domain space

• Canada has yet to reach a decision as to whether or not to opt-in


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• Industry Canada is the Canadian ITU Administration and hence the opt-in/opt-out authority from an ITU perspective

• The US has essentially decided to opt-in

• Since CC 1 is a shared country code, a US opt-in has implications for Canada and for other CC 1 members


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• The ITU draft procedures will remain draft until the e164.arpa issue is resolved

• The application of ‘ENUM’ technology to networking problems, or to enable new network features can be dealt with through existing processes

• ENUM Services could potentially facilitate SPAM, so far this has not been discussed


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• The ENUM domain name space will be organized in tiers, likely three tiers 0, 1, and 2

• Tier-0, the ENUM domain name space root, would be administered by the ITU-T/Ripe NCC

• Countries would opt-in or opt-out at the Tier-0 level

• The Tier-0 name server would have ‘NS’ (Name Server) records for the Tier-1 name server(s) of the opted-in countries

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• The organization below Tier-0 for countries opting-in would be their responsibility

• This would include:• Administration• Operation• Competition• Privacy/Security, etc.

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• Industry has, at least, business interests in ENUM?

• Industry Canada interests include Telecom policy, privacy, security, etc., etc.

• CRTC interests include Telecom regulation, numbering, etc., etc.

• CIRA is responsible for the DNS name space under ‘.ca’, including the dispute resolution process for that domain name space

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• ENUM Hijacking occurs when the assignee of a complete ENUM domain name is not the assignee of the corresponding E.164 telephone number

• Administration of E.164 telephone numbers and ENUM domain names are likely to be done separately

• Should CIRA be responsible for the DNS name space under e164.arpa corresponding to Canadian E.164 telephone numbers?

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• Country Code 1 (CC 1) being integrated is a special case

• If the ‘NS’ delegation from Tier-0 for CC 1 is at the ‘1’ level then it needs to point to a single Tier-1 name server for all of CC 1

• If the ‘NS’ delegation from Tier-0 for CC 1 is at the ‘1+NPA’ level then it can potentially point to a separate Tier-1 name server for each NPA of CC 1, as per the following example

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Directs the DNS query to the countries

Tier-1 registries

An NS record is provided for

each Tier-1 1+NPA registry

Stores a list of service specific internet

addresses in the form of URI’s in a DNS resource record called NAPTR for

each subscriber Returns the full list of

Internet addresses associated with the E.164 number being

queried

Directs the DNS query to the customer’s

Tier-2 providersAn NS record is

provided for each

subscriber’s telephonenumber

Tier-2

9 . 7 . 3 . 1 . 6 . 4 . 9 . 3 .1 . 6 . 1 . e164 . arpa

Tier-1 Tier-0

Tiered Structure – An ExampleTiered Structure – An Example

National ITU/Ripe NCC

Registry RegistryProvider

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• The US ENUM Forum (www.enum-forum.org) is a US industry lead group developing a proposed US implementation strategy for ENUM

• The Forum has developed document 6000_1_0 a comprehensive proposed set of implementation specifications

• The Forum is currently working on proposals for the Tier 1 Contracting Entity and on Architectural Alternatives

US Forum PerspectiveUS Forum Perspective

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• For Tier 1 Contracting they are considering:

• Government Procurement• Industry Limited Liability

Company

• For Architectural Alternatives they are considering the five following alternatives:


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• Five Possible Solutions:• Single Tier 1 for all NANP countries• Single Tier 1 in US

• With delegation from Tier 0 by 1+NPA

• With delegation from Skinny Tier 1

• Multiple Tier 1 operators in US• With delegation from Tier 0 by 1+NPA

• With delegation from Skinny Tier 1

US Forum Perspective - Architecture US Forum Perspective - Architecture ProposalProposal

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Single Tier 1 for NANP Countries

• Assumes:

• All of country code 1 is delegated to a single Tier 1

• All participating NANP countries can/will form a single contracting entity

Tier 0

Tier 1

Tier 2


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Single Tier 1 for US• Requires either delegation from Tier 0 by

NPA or Skinny Tier 1

Tier 0

US Tier 1

Tier 2

Delegation by NPA

Tier 0

US Tier 1

Tier 2

Delegation of country code 1

Skinny Tier 1

Delegation by NPA


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Multiple Tier 1 Operators in the US• Assumes:

• US NPA’s are delegated to multiple tier 1 entities from Tier 0; or

• All of country code 1 is delegated to a single skinny Tier 1


Tier 0

US Tier 1s

Tier 2

Delegation by NPA

Tier 0

Delegation of country code 1

Skinny Tier 1

US Tier 1s

Tier 2

Delegation by NPA

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No consensus on architectural alternatives• Any solution which involves the delegation of

country code 1 from Tier 0 will require agreement from all 19 NANP countries

• Delegation of US NPAs from Tier 0 may require negotiation with Tier 0

• How many registries should operate for those NPAs in the US?

US Forum Perspective - SummaryUS Forum Perspective - Summary

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• Industry Canada has been following ENUM for some time now

• A working group was established under TSACC, a presentation was made to CSCN, etc.

• The US picture was initially unclear and Industry Canada, TSACC and industry were essentially at a wait and see

• But that was then and this is now…..

Canadian PerspectiveCanadian Perspective

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• Proposed ENUM service offerings in Canada should originate from industry!

• When the US goes forward on ENUM, we need to recognize that:

• Their selected architectural alternative will have implications for Canada as we share the same Country Code

• If the US service is a success, Canadian subscribers may ask why there is no Canadian service

CanadianCanadian PerspectivePerspective

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• Canadian ENUM interested parties include:• Industry• Industry Canada• TSACC• CRTC• CRTC/CISC Working Groups

• Committee on Numbering (CSCN)• Network Working Group

• CIRA• Customers


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• Some items for our consideration include:• The Tier-1/2 structure, administration, and operation

• Location requirements (if any) for Tier-1/2 operators

• Interfacing with other members of CC 1 on implementation

• How 1+800 etc., for Country Code 1 should be handled

• How to keep ENUM transparent to NANP/NANPA and vise versa

• DNS security requirements for ENUM

• Privacy, Confidentiality, Integrity, Availability, and Identification and Authentication requirements for ENUM

• What threats and vulnerabilities may ENUM be subject to


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Bob LeafloorColman HoPeter Chau

Industry CanadaJanuary 2003

(ENUM)(ENUM)TTEElephone lephone NUNUmber mber MMappingapping

Thank youThank you

Industry Canada 1 Bob Leafloor Colman Ho Peter Chau Industry Canada January 2003 (ENUM) T E lephone NU mber M apping.

Documents

enum dns query

enum dns namequery

enum trials

enum domain spacecanada

dns namesrfc

dns naptr response

enum roota final decision

telephone numbers