Examine the missing link in the all-optical network - Technology Information

Communications News, May, 2001

The optical last mile brings affordable custom service.

Until now, service providers have struggled to effectively serve business customers with affordable high-bandwidth services. Without a solution to eliminate the bandwidth bottlenecks that exist in today's copper first mile--the most congested piece of the network--delivering these services will be impossible.

The key to accessing these bandwidth-intensive applications lies within the network infrastructure that connects businesses to the information superhighway. The penetration of fiber optics into the core of the public network has enabled large amounts of bandwidth to be thrust through the transport infrastructure at breakneck speed.

While the migration of optical technologies into the metropolitan network--and the promise of infinite bandwidth that accompanies them--is a step in the right direction, direct fiber links are appropriate for only the largest business customers. The optical revolution that has taken place in backbone and metro networks continues to elude most businesses, still hampered by the excessive lead times and high cost of requesting anything beyond T-1 services.

The local access loop has served as the last bastion of refuge for the century-old copper infrastructure, and creates a bottleneck between the high-speed backbone and the LAN. Until this copper last mile is replaced with fiber optics, business users will not be able to economically tap into the high-bandwidth applications running across the WAN.

The last-mile bottleneck is further plagued with slow and costly truck rolls associated with upgrading the copper infrastructure. Business users need a solution that enables them to have bandwidth at their fingertips--flexible and scalable services that can be provisioned on the fly to meet their needs.

Until recently, fiber-optic SONET rings were the only effective means for deploying optics as a last-mile solution for only the largest business customers. DSL and cable modems represent technologies best suited for the residential market. The bandwidth demands of almost any next-generation service offering will quickly surpass the capacities of these technologies.

While only 3% of businesses today are actually connected to fiber, according to Vertical Systems Group, 76% of these small and midsize businesses reside within one mile of an existing fiber network. Why not eliminate the copper first mile and fan out the existing fiber to the individual businesses? The service provider who is first to touch the business customer with fiber will become the low-cost provider to that business.

Optical access networking (OAN) has emerged as a solution to mend the bandwidth bottlenecks that lie between the ever-expanding capacities in both the LAN and the WAN. A subset of OAN is passive optical networking (PON), which does not require the deployment of expensive electrical components between the central office and the customer premises. Instead, the only outside plant requirements (aside from fiber) are low-cost passive optical splitters and couplers.

By simply branching fiber off the ring to opportunity clusters of numerous businesses located within a given geographical area, service providers can go from optically passing to optically serving these end-users. Further, OAN technology is capable of providing not only dedicated wavelength services, but also fractional wavelength services, to a wide range of diverse customers with variable bandwidth requirements over a shared optical access infrastructure.

OAN eliminates the price gap between traditional T-1 and T-3 services by providing small and midsize business customers with the high-speed access solution that is right for them--from both a service rate and monthly pricing perspective. Since not all customers have the same needs, OAN allows customers to choose virtually any access speed to suit their service mix.

The addition of an advanced network management system allows high-speed bandwidth provisioning with a mouse click at the network operations center. For example, OAN allows retailers to upgrade their connections during the holiday season to accommodate heavy online shopping, without incurring the year-round cost of this additional bandwidth. Through this scalable allocation of bandwidth, utilizing IP and/or ATM, each business customer on the OAN needs to pay for only the services that he intends to use, avoiding the difficult choice between too little or too much bandwidth.

Optical access networking represents a technology with the flexibility and capacity to offer customized and affordable fiber-based services to businesses of all sizes.

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