1. 1 Routing options Originating operator Recipient operator Block operator PortingChoice All Call Query Onward routing

2. DonorRecipient Time Authorisation Response (number + account number) Authorisation Request Instruction Preparation Phase Activation Phase (no checks) Deactivates Applies onward routing Checks Subscriber active on donor Ported number active on recipient Authorisation Phase Overlap Informs all operators Other operators update routing RunMyProcess ID and bill check either phase Time limit Requests Issues SIM Activates Instruction blocked by RMP if outside limit Finalisation 2

3. Call routing 3 Block network Switch Incoming call to B-number Home Location Register Where is B-number? Mobile Station Roaming Number (MSRN) Call to MSRN Visited network Visited Switch

4. Call routing 4 Serving network Switch Incoming call to B-number Where is B-number? Mobile Station Roaming Number (MSRN) Call to MSRN Visited network Visited Switch Switch SRF/FNR/ HLR Block network Where is B-number? Prefix + B-number Call to Prefix + B-number SRF/FNR/ HLR

5. Central database VPN or Internet Operator 1Operator 2 Operator 3Operator 4 Porting process Broadcasts results Served numbers 1Served numbers 2 Served numbers 3 Served numbers 4 Routing All numbers 1+2+3+4 Routing All numbers 1+2+3+4 Routing All numbers 1+2+3+4 Routing All numbers 1+2+3+4 Porting