If you build it, they will come: With the potential capacity of fiber reaching new highs, carriers need solutions to help them manage these meganetworks

Since the demand-side model has been around as long as dial tone, it may be difficult for many in the telecommunications industry to accept the fact that the ideal on which they planned their networks soon will be as antiquated as the rotary phone.

Carriers can no longer afford to forecast demand first and then build just enough capacity into their networks to hit that projection.

History has demonstrated that these forecasts fall short of capacity needs-not to mention user expectations. As a result, carriers are moving toward a supply-side orientation in which tremendous amounts of capacity are ready to meet users' insatiable demand for advanced voice, data, video and Internet services.

The availability and pricing of network bandwidth have always been linked with the industry's origin as a regulated utility. But deregulation and the Internet's rise are breaking up old pricing regimes and organization structures.

An emerging combination of new technologies and suppliers will create a long-lasting abundance of bandwidth that will alter the supply-demand equation of the telecommunications industry permanently, Forrester Research Inc. of Cambridge, Mass., predicts.

As supply expands faster than demand, Forrester sees the emergence of a new math for calculating bandwidth based on a changing model of prices, capacity and interchangeable networks. Where carriers traditionally priced their service to recover sunken costs, new bandwidth providers will price based on aggressive forward-looking costs rather than today's rate-of-return calculations.

Further supporting this new model, according to Forrester, is the fact that while demand is expected to double annually over the next five years, supply will far eclipse this rate-achieving 100-fold growth.

That is why it is important that both incumbents and entrants find new ways to lower their costs to transport a bit over a kilometer. Telecommunications equipment vendors need to respond with flexible solutions that essentially eliminate carriers' need to perform capacity planning.

Achieving endless capacity Although the supply-side model is clearly the future of telecommunications, carriers still need to clear a couple of hurdles before it can be realized.

First, they need to find a cost-efficient way to achieve greater capacity on their existing fiber networks if they are to provide affordable-yet profitable-services to their customers. Once this capacity is realized, carriers must manage it. This second point is crucial. Without it, carriers will be left with half a solution.

Until recently, the options for increasing transport bandwidth capacity were to add new fiber and deploy overlay transport networks, or to increase the time division multiplexing transmission rate-usually four-fold-of a given transport system.

Although TDM-based capacity upgrades effectively increased the available bandwidth across a given fiber, this approach was one-dimensional in that the capacity was determined solely by the transport bit rate. The only way to expand the capacity was to change the lower bit rate system to a higher bit rate system.

Given the growth limitations of TDM-only solutions, dense wave division multiplexing systems have the advantage offering an orthogonal dimension in which to expand capacity over a fiber facility. Fiber capacity over a DWDM-based infrastructure is increased by simply adding wavelengths, which are independent of the TDM bit rate.

If a carrier combines the two, throughput can be increased modularly along two dimensions-TDM bit rate and DWDM channels. Leapfrogging current DWDM offerings, which offer a maximum of 80 Gb/s of capacity on a fiber, new ultra-dense wave division multiplexing (UDWDM) systems can be configured to handle up to eight fibers transmitting 400 Gb/s each-a staggering increase. This translates into a maximum system capacity of 3.2 Tb/s of voice, video and data traffic-the equivalent of transmitting more than 90,000 volumes of an encyclopedia in one second.

At this triple-terabit rate, carriers can realize equipment savings of up to 40% over lower capacity systems. UDWDM systems also can support a simultaneous mix of multigigabit speed rates of 2.5 Gb/s and 10 Gb/s over one fiber.

In addition, carriers can pay as they grow, adding capacity as needed while leveraging the existing infrastructure. With this much potential capacity at their disposal, carriers can clear the first hurdle to a supply-side telecom model, making increased fiber capacity cost-effective. Next, they need to find a way to manage a bandwidth-intensive network.

More capacity, fewer components For a bandwidth management solution to be successful it must integrate functions that existed previously in discrete network elements.

That's the idea behind a network bandwidth manager offered by Lucent Technologies-a new modular networking system capable of integrating access and interoffice transport facilities onto a single network element.

The system simplifies the way a carrier manages voice, data or video traffic in the central office because bandwidth can be routed automatically between any transport facility via the bandwidth manager (Figure 1).

Once the transmission signal enters such a setup, all interconnection is internal to the system. The integrated design reduces failures by more than a 60% and virtually eliminates the most common cause of CO-based service interruptions-human error in intra-office cabling and manual cross-connect frames.

Multiple equipment interconnections require software commands. The network element consolidation results in a 30% to 60% reduction in equipment costs. In addition, space requirements within the network node are reduced up to 85%.

The bandwidth management approach effectively replaces the need for stand-alone broadband, wideband and ATM digital cross-connect systems, as well as ATM and IP core switches and routers (Figure 2).

A scalable, multifabric architecture also provides carriers with a cost-effective multiservices platform that allows transport bandwidth management and services delivery within network/service nodes. For example, the solution could integrate multiple access and transport rings within a given network node. For this application, only STM fabric would be needed for connecting STS-1/Nc tributaries between the ring interfaces. If wideband grooming is needed between the access and transport rings, the ATM fabric could be added to perform this capability via VT1.5/DS-1 circuit emulation.

As the network evolves to ATM-based transport facilities and PVC/SVC services, the ATM fabric can grow to meet those needs. This also mitigates the need for a separate ATM core switch.

Carriers can realize the goal of the terabit office by applying an integrated solution to the capacity and bandwidth management needs across multiple routes emanating from an office. This is the next step in the evolution toward complete nodal bandwidth management across all layers within a CO.

While a bandwidth manager performs layered, nodal bandwidth management across STM, ATM and/or IP transport signals and services, carriers can add an optical cross-connect system to provide optical-layer bandwidth management among the UDWDM systems (Figure 3).

Network management, cross-connects, switching and other functions now can be performed primarily in the optical domain. By eliminating the expensive transitions between multiple hierarchies necessary today when performing traditional networking functions, carriers can cut the cost and complexity of transport networks even further.

The crystal ball In the not-too-distant future, carriers no longer will be in the business of providing transport products.

Transport will become a cost component of a greater service. Restaurants do not charge individually for milk, eggs, sugar and flour-they charge for dessert. Similarly, carriers will not charge for minutes of use or bandwidth but for information management services.

There is no denying that the fundamental economics of the telecommunications world are changing rapidly. New arrivals to the bandwidth party already are planning multiterabit networks, which is far more capacity than can be filled by demand trends.

The supply-side belief is that excess supply will spur rapid increases in demand by opening up the bandwidth needed to push through networked applications like multimedia, interactive games and Internet video-on-demand. With many carriers embracing this model, the debate whether OC-192 is enough capacity soon will become irrelevant. With a supply-side model, there can never be enough capacity.

Before carriers adopt a supply-side orientation and begin installing tremendous amounts of capacity, they need innovative solutions that not only will expand but also will manage the capacity of their existing fiber plants. An integrated high-capacity transport and bandwidth management platform, able to deliver unprecedented fiber capacity, along with a full range of bandwidth management capabilities, will meet those needs. The rest should take care of itself.

When carriers build a network with excess capacity, the customers will come.