Overlay NGN migration approach to deliver multimedia services

The market is ready for next generation networks and the multimedia services that they offer. Start-up operators can easily capitalise on the demand for a wide spectrum of services offered by emergent NGN technologies. They only have to implement the services demanded by the market. The situation is different for "Brownfield" operators. Their legacy networks were specifically built for voice services and then adapted to support data. Incumbents are forced to consider how to migrate consumers to a multimedia NGN whilst keeping a positive cash flow. Profitability depends not only on the business case for future multimedia services but also on the containment of the legacy network operating costs. Incumbents have to maximise the revenue from new services whilst minimising the cannibalisation of existing revenues. This paper outlines the NGN "Overlay" approach as the migration strategy that will meet these challenges.