This migration strategy has been arrived for the phased migration from PSTN COPPER network to NGN based FTTH network. (refer the high level diagram in this blog)

REQUIREMENT / ASSUMPTION

• The same telephone number is used even after the migration from PSTN to NGN-FTTH network.
• The migration is planned in phased manner like when there is FTTH ready for one number; we have to do the migration.
• The NGN soft-switch and the core back bone is commissioned and ready for service. 

PREPARATION

• All the working telephone number levels in the migration area to be created in the NGN soft-switch and the Migration Master (MM) (Refer the diagram).
• Call routing to all the numbers in that level has to be done towards the NGN in the PSTN network.
• In the Migration Master, every number will be marked as NON-MIGRATED initially.
• In NON-MIGRATED state the call will be routed back to PSTN for termination.

MIGRATION

• The technician in the site after installing the new CPE at the customer place has to test the CPE for connectivity.
• Once the test is over, the technician will send SMS or update in the web portal of MM about the individual number to be migrated.
• The Migration Master will authenticate the request and check all the features of the telephone number for migration and change the parameters to make that telephone number to MIGRATED state.
• In the MIGRATED state the calls will not go back to the PSTN network and will start ringining in the NGN-FTTH network.
• For this telephone the migration is completed.
• The customer can enjoy the new NGN services in the FTTH network.
• Once all the migration is completed in this telephone number level, this level will be removed from Migration Master.

NGN MIGRATION STRATEGY