12 January 2006

CDG Conference Call

Integrating Existing Number Portability Solutions in Carrier-ENUMDouglas Ranalli, NetNumber, Inc.

2

About NetNumber

• Provider of next generation addressing solutions to carriers and operators based on the NetNumber TITAN platform.– Transactional IP-Telephony Addressing & Numbering (TITAN)

• Common transaction platform in operator’s network for both SS7/C7 and IP Addressing:– Number-Portability, Flexible-Numbering (GTT), etc:

• Multiple protocols: – AIN 0.2, PCS-1900, GSM/MAP, IS-41, INAP, DNS, SIP and ENUM.

• Multiple interfaces:– T1/E1 low-speed link, SIGTRAN and IP.

– Carrier-ENUM: Flexible implementation options for the discovery of carrier-controlled IP-services.

• ENUM query:– Different address resolution models can be configured on a country-by-country

basis. – Up to 43,000 transactions/second on a single TITAN Edge server.

• SIP Invite with 302 redirect:– SIP Invite to a TEL URI results in a SIP 302 “temporarily moved” response with one

or more SIP URIs as contact addresses. – Up to 15,000 transactions/second on a single TITAN Edge server.

3

Customer/Partner Examples

4

Carrier-ENUM Background

• Private service discovery infrastructure.• Accessed by all types of carriers.• Common domain name: “e164enum.net”• Standard query/response protocol as defined

by RFC 3761.• Supports number-portability.

• Focus of this presentation:– Carrier-ENUM implementation models that leverage existing

number-portability solutions.

5

IMS ENUM Call-Flow Example

1. End-user dials E.164 to initiate service.

2. S-CSCF issues ENUM service discovery query to on-site or hosted ENUM server for a SIP-URI.

3. S-CSCF resolves host name within SIP URI using on-site or hosted private DNS infrastructure.

4. S-CSCF sends SIP Invite to destination I-CSCF.

5. I-CSCF queries HSS to get address of S-CSCF.

6. I-CSCF proxies Invite to destination S-CSCF.

7. Standard SIP/SDP session negotiation follows.

Orig.S/W

S-CSCF

OSS

InternalNAPTR

2

Originating Carrier

ENUMServer

DNSServer

Destination Carrier

S-CSCF

Dest.S/W

7

4

3

1

I-CS

CF

HSS

5

6

6

ENUM Implementation Options

• DNS Delegation– ENUM service discovery via DNS delegation through Tier-0,

Tier-1, Tier-2 infrastructure.

• Central Portability Database– Central portability database fulfills role of Tier-0 and Tier-1 for a

given country.• Solution utilized by GSM, CDMA and GRX/CRX interconnect

providers in North America today.

• Number-Block Assignment– Existing number-block assignment data fulfills the role of Tier-0

and Tier-1 for any non-ported network. • Simple extension of model being used in North America today.

• IMSI Query– MAP query for IMSI address fulfills the role of Tier-0 and Tier-1

for any carrier/operator that supports IMSI addressing.• Solution being used by GSM operators in Europe today to

interconnect MMS.

7

DNS Delegation

Orig.S/W

S-CSCF

OSS

InternalNAPTR

2

Originating Carrier

ENUMServer

DNSServer

Tier-0Tier-1

Destination Carrier

Tier-2ENUM

S-CSCF

Dest.S/W

2a

2b

7

4

3

1

I-CS

CF

HSS

5

6

2. S-CSCF issues ENUM service discovery query to on-site or hosted ENUM server for a SIP-URI.

a. ENUM Server queries Tier-0 to identify a country-specific Tier-1 then queries the Tier-1 to identify the destination operator (NS record of operator’s Tier-2 name server).

b. ENUM server queries the destination Tier-2 nameserver to get a NAPTR record identifying an appropriate network entry-point (I-CSCF address) in the form of a SIP URI.

8

Central Portability Database

Administrator

InterconnectNAPTR Portability

Data

Orig.S/W

S-CSCF

OSS

InternalNAPTR

2

8

Originating Carrier

ENUMServer

DNSServer

Destination Carrier

S-CSCF

Dest.S/W

7

4

3

1

I-CS

CF

HSS

5

6

2. S-CSCF issues ENUM service discovery query to on-site or hosted ENUM server for a SIP-URI.

• ENUM Server checks for locally provisioned portability data to identify the destination operator then checks for locally provisioned interconnect data to discover an appropriate I-CSCF address (or NS record) for the destination operator.

Key Benefits: • Resolution is extremely fast. No Tier-1 or Tier-2 wide area network queries required.• Originating operator can locally provision an appropriate interconnect address for a

destination partner.

9

Number-Block Assignment

Administrator

InterconnectNAPTR Number

BlockData

Orig.S/W

S-CSCF

OSS

InternalNAPTR

2

8

Originating Carrier

ENUMServer

DNSServer

Destination Carrier

S-CSCF

Dest.S/W

7

4

3

1

I-CS

CF

HSS

5

6

2. S-CSCF issues ENUM service discovery query to on-site or hosted ENUM server for a SIP-URI.

• ENUM Server checks for locally provisioned number-block assignment data to identify the destination operator then checks for locally provisioned interconnect data to discover an appropriate I-CSCF address (or NS record) for the destination operator.

Key Benefits: • Resolution is extremely fast. No Tier-1 or Tier-2 wide area network queries required.• Originating operator can locally provision an appropriate interconnect address for a

destination partner.

10

IMSI Query

Orig.S/W

S-CSCF

OSS

InternalNAPTR

2

Originating Carrier

ENUMServer

DNSServer

Destination Carrier

HLR

S-CSCF

Dest.S/W

2a

7

4

3

1

I-CS

CF

HSS

5

6

STP

MAP"SRI_for_SM"

Administrator

InterconnectNAPTR

2. S-CSCF issues ENUM service discovery query to on-site or hosted ENUM server for a SIP-URI.

• ENUM server issues MAP query for an IMSI address to identify the destination operator then checks for a locally provisioned I-CSCF address (or NS record) for the destination operator.

Key Benefits: • Leverages existing operator investment in IMSI addressing to fulfill Tier-0 and Tier-1 function. • Originating operator can locally provision an appropriate interconnect address for a

destination partner. • Solution already being used to interconnect MMS services today.

11

Recommendation

• Document multiple options for integrating existing number-portability solutions in Carrier-ENUM.– Operators and GRX/CRX/IPX providers will benefit from

flexibility.• Various Carrier-ENUM implementations work equally well in on-

site or hosted ENUM server deployments. • Different solutions can be applied to different country-codes.

– Solutions can be enhanced by use of third-party interconnect registries.

• Multiple interconnect registries available today or under development.

• Interconnect registries facilitate the exchange of appropriate interconnect data (points of interconnect) between carriers/operators.

– Eliminate requirement for manual entry of interconnect data.– More sophisticated than wide-area-network query to a Tier-2

nameserver.» Different interconnect addresses for different partners.