Number Portability Impacts on IP & Telecoms Interworking James Yu NeuStar, Inc.

1. Number Portability Impacts on IP & Telecoms Interworking James Yu NeuStar, Inc.

2. Number Portability • Number portability (NP) allows the telephone subscribers to keep their phone numbers when they change the • Service provider [Service Provider Portability] • Location [Location Portability] • Subscribed services [Service Portability]

3. Service Provider Portability • Supported in many countries • Adopted schemes vary • All Call Query • Query on Release • Dropback • Onward Routing Some involve centralized databases, others do not.

4. DB DB DB DB Service Provider Portability Schemes Centralized Centralized Number Porting Number Porting New SP New SP 1 3 4 2 Old SP Old SP Orig. Orig. 2 release w/o # Donor SP 1 All Call Query Query on Release Number Porting Number Porting New SP New SP 4 Old SP Old SP 3 Orig. Orig. 3 release w/t # Donor SP Donor SP 1 1 2 2 External or integrated External or integrated Dropback Onward Routing

5. Network Routing • North America • Location Routing Number (LRN) in the ISUP Called Party Number (CdPN) Parameter for routing • Called directory number (DN) carried in Generic Address Parameter • Translated Called Number Indicator (TCNI) in the ISUP Forward Call Indicator (FCI) Parameter set to indicate that database dip has been performed • Europe • Routing prefix added to the called DN in the ISUP CdPN Parameter • Proposed ISUP enhancements for NP (Q.769.1) • Adding routing prefix to the Called DN and use Nature of Address (NOA) field to indicate that or two separate parameters (one is new): one carries the routing number and the other carries the called DN. NOA used if the routing number is carried in the ISUP CdPN parameter • Number Portability Forward Information (network option) to indicate whether NP query is done or not and whether the DN is ported nor not

6. Database Query • North America • AIN (ANSI SS7 MTP/SCCP/TACP) • IN (ANSI SS7 MTP/SCCP/TACP) • ANSI IS-41 (ANSI SS7 MTP/SCCP/TACP) • GSM (PCS 1900) MAP (ANSI SS7 MTP/SCCP, ITU-TS TCAP) • Europe • INAP CS1 (ITU-TS SS7 MTP/SCCP/TACP) • INAP CS2 (ITU-TS SS7 MTP/SCCP/TACP)

7. NP Info. PictureTel PictureTel IP & Telecoms Interworking GWd1 New SW Internet GWo Number Porting Call orig. from SCN GWd2 Old SW SIPd1 /GKd1 SIPo /GKo SIPd2 /GKd2 Re-Association GK - Gatekeeper GW - Gateway NP - Number Portability SCN - Switched Circuit Network SIP - Session Initiation Protocol SW - Switch o - Origination d - Destination

8. Issues • Where to query for NP information At Originating GW/SIP Server/GK • Too many national variations to deal with -> need a common approach At Destination GW/SIP Server/GK • Too late, may be the wrong GW/SIP server/GK; not all the GWs/SIP servers/GKs can reach all the destination E.164 numbers Another entity within Internet • Additional delay • Inefficiency if it also handles user data (e.g., voice/data packets) The entity that retrieves the NP information may need to wait and collect all the address information before retrieving the NP information if overlap signaling is encountered.

9. Issues (Continued) • How to query for NP information • SS7/TCAP over IP (many national variations) • A new and common scheme • Need to standardize the scheme • Need to retrieve the routing information (e.g., LRN or routing prefix) if an existing scheme (e.g., DNS) is enhanced • NP information, if retrieved, needs to be carried over internet in a common format that can be converted to national ISUP at the destination GW • ISUP/SS7 over IP (e.g., between two GWs) • Encapsulated ISUP in SIP • SIP protocol • H.225.0

10. Conclusions • Number portability can occur in the SCNs and within Internet • Many issues are related to number portability and need to be addressed altogether • Develop efficient schemes • Use standardize ITU-TS and IETF protocols • Address all aspects of number portability (e.g., not just service provider portability)