This could well be the last year of significant sales of Sonet and SDH transport gear, according to industry analysts and vendors. Particularly as the volume of Internet Protocol-based video grows, the telecom industry is moving more quickly to replace its existing transport gear with more flexible, higher-bandwidth carrier Ethernet and wavelength division multiplexing technology.

“In data networking and optical networking, 2007 is the zenith year for Sonet/SDH--a growing part of the network is going to be these platforms that allow for migration to Ethernet over WDM as a transport vehicle,” said Michael Howard, president of the Infonetics consultancy. “Basically, we can measure now the start of this trend toward IP and Ethernet over WDM. It is really going to be IP over Ethernet WDM transport.”

Ericsson is expecting 2007 to be a major year for the shift to doing IP directly over optical, agreed Joe Baker, director of business development for North America. While the current base of Sonet/SDH products doesn’t go away any time soon, the investment dollars are shifting, he said.

Service providers that have invested billions of dollars in deploying Sonet gear since the early ‘90s have prolonged the life of that equipment by developing Ethernet over Sonet, but with the bandwidth consumption that video will require, complete elimination of the Sonet layer is more logical.

“Carrier Ethernet is the logical replacement for Sonet with much more video friendly and more scalable data networks,” said Peter Carbone, architect in the CTO’s office at Nortel. “We are going to have to rebuild the metro networks and it makes sense to do it with Ethernet.”

The driving force behind that change is the new dynamics of Internet usage, Carbone said.

“My son wants me to change our firewall at home so he can host video games,” he said. “Users are now rendering graphics and dealing with lots of input and output. Before, it was only video conferencing, and that was pretty sporadic. If they are downloading minutes of video, somebody is uploading them – that is driving more upstream bandwidth. Many of home networks are hosting peer to peer communications.”

Instead of browsing the Internet, which is what today’s networks were designed for, users are “continuously online doing gaming, music downloads, video or whatever--certainly not the kind of traffic of the access networks were designed for,” Carbone said.

Large cable operators have already made the transition, said Howard, because they have been transporting video on demand, which causes unpredictable spikes in traffic volume based on use. They are using reconfigurable optical add-drop multiplexers (ROADMs) to take the manual process out of provisioning bandwidth.

“If you look at what big MSOs have been doing over last 4-5 years – it’s Ethernet over WDM with ROADM for video on demand,” he said. “It’s the best solution and the only attractive solution for that application.”

Telecom service providers have been more reluctant to make the switch because of their investment in Sonet/SDH, but they, too, are seeing the need, and could discontinue their investment as soon as 2008, Howard said.

“Verizon has roadmap for their network, AT&T has RFPs our – the reason they haven’t moved forward quickly is that they have huge investments in Sonet,” he said. “Carriers have continued to buy Sonet, although they tell us they are slowing their investments in Sonet/SDH.”