A Large Tier 1 Telco with 20 million subscribers needs to move all of their...

For tens of millions of subscribers, a staged migration should partition the estate into logical blocks and move them progressively. During the coexistence period, an on-demand path must handle customers whose data has not yet been migrated so that new Salesforce-originated orders are not blocked. This allows business operations to continue while the bulk migration proceeds over time. In a Communications Cloud implementation, this pattern provides the cleanest balance of reuse, governance, and runtime efficiency. Repeated outages for bulk migration are unsuitable for a Tier 1 provider, and an all-at-once cutover unnecessarily concentrates risk. Staged plus on-demand processing gives operational continuity and controlled reconciliation. The alternative designs either introduce unnecessary coupling, fail to preserve the required lifecycle state, or move standard platform behavior into bespoke code. Keeping the solution within the documented product, pricing, migration, or orchestration framework also gives operations teams clearer monitoring and recovery paths. For production readiness, the configuration should be exercised with realistic data volumes and representative MACD scenarios so that the behavior remains correct after the initial sale and throughout subsequent service changes.

Study Guide Reference:Large-scale migration; staged migration; on-demand migration; coexistence; service continuity.