The birth of agile optical networks

By Craig Iwata

In the 1990s, consumers and businesses began to embrace the Internet for a variety of uses, and telecom providers built a network infrastructure to support that demand. At that time, network traffic was very predictable, and providers planned for and accommodated traffic patterns manually by sending out technicians to repair and upgrade the networks as necessary-which taxed both end users waiting for new services and the overall operating expenses for the service providers. The market was segmented, with providers offering separate, “fixed” point-to-point networks for voice, video, and data needs.

Today, an entirely different evolution is taking place. Use of the Internet is now an integral part of how many businesses and consumers function every day. New uses for the Internet are creating a disruptive and unpredictable environment for networks.

When we consider that in early 2007 Apple announced more than 2 billion songs, 50 million television episodes, and more than 1.3 million feature-length films had been purchased and downloaded from the iTunes store, it is clear that the demand for bandwidth-hungry applications has exploded, and the popularity of video-on-demand (VoD), voice over IP (VoIP), IPTV, and other emerging applications is driving an ever-increasing need for flexible, fast, and high-quality network services.

The challenges such services present call for optical communication innovation that replaces slow, manual operational processes with simplified, dynamic network configuration and automated service provisioning. Telecom companies are upgrading their architectures to support voice, video, and data within a single network. Telecom companies and cable operators are also converging into a single market, competing to offer voice, video, and data services to consumers on a single bill.

For the telecom service provider, the question is no longer “to be agile or not to be agile” when it comes to network implementation. To maintain relevance in an ever-changing market, deliver the level of programming and service that end users expect, and still be cost-effective, service providers are turning to agile optical networks (AONs).

The key element of the AON is “dynamic reconfigurability,” or the ability for service providers to optimize network activity via optical equipment within the network that can be monitored and adjusted remotely.

Key benefits of the AON, as cited by Infonetics Research Inc., include:

  • Wavelengths can be remotely configured dynamically in reconfigurable optical add/drop multiplexer (ROADM) nodes.
  • Time for wavelength provisioning is reduced, typically from weeks or months to a few hours or days.
  • Opex is reduced, as human labor is reduced and truck rolls are minimized.
  • Efficiencies required for triple play, especially IPTV services, are enabled.
  • Capabilities required for dynamic wavelength services are provided.
  • Time-to-service revenue decreases.
  • Automation and/or automatic functions are provided through “points of agility.”
  • Resilience to respond to spontaneous bandwidth demands is provided; errors in the planning process are compensated.

The global AON component market is expected to expand rapidly, growing 43% from less than $100 million in 2004 to nearly $700 million in 2010, according to research from Ovum-RHK. The research also indicates that in that same period the fixed market is expected to decrease from more than $300 million in 2004 to less than $300 million by 2010.

There are several aspects that go into creating an AON. However, three technologies provide the basic building blocks: ROADMs, erbium-doped fiber amplifiers (EDFAs), and tunable transponders.

ROADMs are truly the central building block of the AON. These platforms dynamically reconfigure wavelength connections. With ROADMs deployed throughout the network, service providers can simply point-and-click to plan and respond to bandwidth demands. ROADMs offer service providers a dramatic reduction in capital and operating expenditures.

Most importantly, ROADMs can increase the speed at which service providers respond to the demands of their customers, including offering new services. And they grant service providers the flexibility to quickly and cost-effectively adapt to the increasingly unpredictable changes in network demands.

For its part, the EDFA automatically responds to changes in input power or number of wavelengths, enabling service providers to respond quickly to unpredictable traffic patterns. Another key benefit of EDFAs is the fact that, again, service providers can eliminate time-consuming and costly truck rolls to upgrade and fine-tune the network in response to evolving traffic patterns. This benefit reduces operating expenses for service providers.

Tunable transponders are a key technology for the successful deployment of AONs. Tunable transponders represent a significant improvement for service providers when it comes to costly inventory management. Unlike the rigid inventory requirements of the fixed transponders-where service providers needed to have one transponder and a spare for each wavelength available-a single tunable transponder can help manage the selection and changing of wavelengths.

Tunable transponders therefore reduce the need for multiple spare transponders. Service providers save money by reducing the number of transponders needed in a network and benefit from more cost-effective network planning.

Across the globe, market demand for delivery of broadband and packet-based services is requiring agile, high-capacity optical networks. Here’s how providers around the world are responding.

United States.In response to the unpredictable traffic patterns we’ve previously mentioned, every major service provider is deploying some amount of AON technology in its networks. Analysts predict that several imminent mergers and consolidations in the U.S. market will propel the move toward simpler and fewer all-IP networks, with next-generation voice, IP/Ethernet, and various other services and technologies traveling over all-optical networks.

Europe. Several major PTTs are making significant strides in upgrading their networks and shifting to an IP infrastructure. BT is moving ahead with its 21st Century Network program to convert its network to an entirely packet-based infrastructure with VoIP as a key service offering.

Several key value-added services are gaining widespread adoption, with IP virtual private networks (VPNs) and VoIP leading the list. Additional headway is being made for optical Ethernet, virtual LANs, bandwidth-on-demand, storage, and managed security.

Increased adoption of broadband and increasing broadband traffic are driving spending in edge, core, and optical networks.

Asia Pacific. The Chinese government announced a goal of 75 million broadband users by 2008-a goal that will drive growth in VPN, security, VoIP, and other emerging segments.

The Japanese government began working on plans in 2006 to bring 30 million consumers online at 10 Mbits/sec and 10 million consumers online at 100 Mbits/sec.

Most Asian carriers have plans for data, voice, and video convergence within the next 2 to 5 years, with carriers in Japan and Korea taking a particularly aggressive approach to rolling out triple-play services.

The widespread availability of affordable broadband and the continued migration to IP networks have tremendously affected the way we communicate both personally and professionally.

As media-rich applications streaming to us all from our personal computers turn us into bandwidth-on-demand addicts, there will continue to be a healthy urgency for innovation on the optics level. Service providers will need to increase the automation of their networks in long-haul, metro, and access. There will continue to be both evolutionary and revolutionary developments around the key building blocks of the AON.

Each component of the AON will evolve through technology breakthroughs and continue to provide the flexibility networks require. As more flexibility is built in, service providers can consider their “fear of the next YouTube” a thing of the past. Like that old dial-up noise our children will wonder about.

Craig Iwata is director of marketing for optical communications at JDSU (www.jdsu.com).


  • Broadband users will grow from 32 million lines in 2004 to nearly 57 million lines in 2008.1
  • VoIP lines in the United States will grow from 6.5 million in 2004 to 26 million in 2008.2
  • VoD streams worldwide will explode from 1.67 million in 2005 to 163 million in 2011.3
  • About 66% of online consumers in the United States log on daily, and an additional 16% log on several times a week for entertainment.4

  1. Telecommunications Industry Association (TIA) study, February 2005.
  2. Telecommunications Industry Association (TIA) study, February 2005.
  3. ABI Research, 2005.
  4. “Scream Test,” Philadelphia Enquirer, October 26, 2006.
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