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

2. Number Portability u 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 u Supported in many countries u Adopted schemes vary – All Call Query – Query on Release – Dropback – Onward Routing Some involve centralized databases, others do not.

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

5. Network Routing u 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) u 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 u 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 u 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) u Europe – INAP CS1 ( ITU-TS SS7 MTP/SCCP/TACP ) – INAP CS2 ( ITU-TS SS7 MTP/SCCP/TACP )

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

8. Issues u 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 o verlap signaling is encountered.

9. Issues (Continued) u How to query for NP information – SS7/TCAP over IP (many national variations) – A new and common scheme u Need to standardize the scheme u Need to retrieve the routing information (e.g., LRN or routing prefix) if an existing scheme (e.g., DNS) is enhanced u 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 u ISUP/SS7 over IP (e.g., between two GWs) – Encapsulated ISUP in SIP – SIP protocol – H.225.0

10. Conclusions u Number portability can occur in the SCNs and within Internet u 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)