For Tier 1 operators around the world, legacy TDM services are significant contributors to revenues and  the bottom line. However, legacy infrastructure and services are becoming increasingly expensive to run, manage, and support—impacting OPEX and negatively affecting margins. To address this challenge, Telefónica UK decided to migrate legacy TDM services in its core network on to a modern, more efficient networking platform. With Ciena’s power-efficient equipment, these costs have been reduced, helping the organization to lower its costs and carbon footprint.