Transcript ENUM Administration Major Issues

ENUM Administration
Penn Pfautz
AT&T
732-420-4962
[email protected]
2/12/2001
ENUM Administration
• Mixes domain registration and telephone number
administration
– Rights to ENUM domain tied to corresponding number
assignment in the PSTN
– Rights to number in ENUM lost when service on
number is disconnected
– Generally, telephone service provider is only party that
knows about number assignments & disconnects
– Design issue for industry & regulators: How to balance
need for TSP involvement with burden on TSP and a
competitive environment?
2/12/2001
ENUM Hierarchy
Tier 0 - e164.arpa
(RIPE-NCC)
$ORIGIN e164.arpa.
1 IN NS nsnanp_enum.com
4.6 IN NS sweden_enum.com .
...
Tier 1 – Registry- defined by ITU
member state
nsnanp_enum.com
(1.e164.arpa)
4.6.e164.arpa
Sweden
Tier 2 – Service Registrar
$ORIGIN 3.7.9.1.e164.arpa.
7.8.7.6.6.3.2 IN NS e164.att.net.
8.8.7.6.6.3.2 IN NS joes-enum.com
$ORIGIN 7.8.7.6.6.3.2.3.7.9.1.e164.arpa.
IN NAPTR 10 10 "u" "sip+E2U"
"!^.*$!sip:[email protected]!"
IN NAPTR 102 10 "u" "mailto+E2U" "!^.*$!mailto:[email protected]!" .
IN NAPTR 102 10 "u" "tel+E2U"
"!^.*$!tel:+19732366787!"
.
e164.att.net
Tier 3 – Application Service Provider
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sip.att.com
.
e164.arpa
• .arpa TLD since infrastructure
• RIPE NCC will host
• Essentially populated with identities of
name servers for country codes
• ITU indicates to RIPE authority for each
country code
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Tier 1 (Registry)
• Entries point to Service Registrar for a number
• Provider(s) determined by national authorities
– NANP-wide or per NANP nation?
• Because of number portability, Tier 1 name server
must point to Service Registrar on an individual
number basis; numbers can’t simply be delegated
to the carrier to which their Central Office code or
thousands block was initially assigned
2/12/2001
Tier 2 (Service Registrar)
• Hosts NAPTR (service) records for a
telephone number
• All records for a given number must be in
one name server
• Major issue is who can be Service Registrar
– Two “strawman” models presented to IETF
• Any properly accredited domain name registrar
(model I)
• Telephone service provider (model II)
2/12/2001
Reference Model I (General)
T1E
Legend
ASP Application Service Provider
TIE Tier 1 Entity (Registry)
T2E Tier 2 Entity (Registrar)
TSP Telephony Service Provider
New T2E
A
H
B
C
T2E
End User
F
G
D
TSP
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E
ASP
** End User can be the end user itself or
an agent authorized to represent
the end user.
** TSP can offer application services
also. The “TSP” entity performs
functions specific to the TSP.
Reference Model I – Pros &
Cons
Pros:
• EU determines T2E, EU has more control
• EU can be T2E (e.g., universities and enterprises)
for his/her own TN(s)
• Enable competitive T2E service offering
Cons:
• More complicated interactions among involved
entities
• More efforts at T2E to manage the NAPTR RRs
2/12/2001
Reference Model II (T2E=TSP)
T1E
Legend
ASP Application Service Provider
TIE Tier 1 Entity (Registry)
T2E Tier 2 Entity (Registrar)
TSP Telephony Service Provider
A’
B’
T2E/TSP
End User
E’
C’
D’
New T2E/TSP
2/12/2001
ASP
** End User can be the end user itself or
an agent authorized to represent
the end user.
** TSP can offer application services
also. The “TSP” entity performs
functions specific to the TSP.
Reference Model II – Pros & Cons
Pros:
• Fewer interfaces to deal with
• Easier to verify EU’s identity and ownership of the TN
• More incentives for TSPs to get involved in enum process
(e.g., verify EU’s ownership of a TN and inform T1E about
TN service disconnect)
Cons:
• Only TSPs can be T2E, non-competitive if there is only one
TSP in a serving market
• Non-TSPs cannot be T2E
– (except through delegation from TSP)
• EUs cannot be T2E for their own TNs
• EUs cannot get enum service if none of TSPs in the serving
market offers enum service
2/12/2001
Telephony Service Specific
Records
• Are there services for which the TSP should have
right to put records in ENUM?
• How can TSP control records in Tier 2 of end user
choice?
• How might these records be distinguished?
• Alternative is to treat TSP like any other
application service provider
• Ability of TSP to populate ENUM for customer
will facilitate penetration
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Major Issues
• Will the US populate its numbering resources in
e164.arpa?
• Will the countries of the NANP take an integrated
or independent approach to ENUM
implementation?
• What entity or entities will provide Tier 1
functionality?
• What entities may be Service Registrars?
• How will authentication of rights to numbers be
assured
• How will disconnect notification be handled?
• Will there be special telephony service specific
records?
2/12/2001