One of the errors made in nearly every technology market is to think of trends in terms of the technologies they affect rather than the causes that drive them. So it is with optical and electrical (opto-electrical) convergence in the telecom network.
Certainly, optics is hot and Carrier Ethernet is becoming critical to planners. But it's the why behind these trends that will help you prepare for the changes they represent and link them to coherent business and infrastructure policies.
As technology improves in the optical transport of digital data, it reduces the unit cost of provisioning capacity. Given a stable or predictable level of traffic growth, the reduction in cost shifts the planning focus from managing aggregation for optimum utilization to managing capacity to control operations costs.
Since capacity gains are created at the optical network layer, optical planning is impacted first. But the lowest electrical layer is the bridge between traffic and transport, so it is impacted, as well. Optical enhancements have created increased interest in converging the optical and lowest electrical layers -- usually Ethernet -- into a single transport layer and a single set of devices.
IP convergence at the higher layers of the network is also driving opto-electrical convergence. While networks are segregated into packets (Ethernet/IP) and circuits (SONET/TDM), the value of having these electrical layers on a common backbone promotes optical independence.
But as TDM use declines and packet use explodes, there is less to be gained by maintaining independent optical networks, so TDM and packet can be converged with optical. That's particularly true when incremental capacity investment is almost completely in the packet realm. Driven from both above and below, converging optical and electrical layers is inevitable.