The time has come to execute the migration according to the agreed design and plan.

The work carried out in the previous phases is intended to reduce errors, uncertainties and unexpected events before the change reaches the production environment.

Migration is where the architecture and the plan become reality.

The objective is not simply to complete the change, but to do so in a controlled manner, with the expected behaviour, and with identified risks understood and managed

But migration is not necessarily the end of the process. Once the new environment is in place, new traffic patterns may emerge. Business requirements may evolve, new dependencies may appear, and operational needs may become visible — sometimes precisely because the migration has changed the way the network is used.

This is where the cycle starts again.

The network continues to evolve, and what was once the right design may eventually need to be optimised or redesigned.