Choosing the right option to increase metro capacity



With several of the new metro/access providers faltering, RBOCs, interexchange carriers, and the surviving competitive local-exchange carriers (CLECs) have an opportunity to step in and fill the last mile gap in both tier one markets and many tier two and tier three cities that are refusing to be sidelined during the optical technology game. However, not every carrier has the infrastructure to take advantage of this opportunity. Thus, several metro players must sift through a variety of options for route expansion. Although today's criteria for making the best choice are based on individual circumstances, it quickly boils down to cost.

"One option available to the metro carriers is to buy fiber at 10 cents on the dollar from all of those CLECs that were laying fiber in the metro areas-and then went belly up," says Bill Kleinebecker, senior consultant at Technology Futures Inc., a communications consulting and analyst company based in Austin, TX. "The current carriers can buy the fiber of the defunct ones for a song to prepare for the wider bandwidths needed for Internet applications."

Kleinebecker views the leasing of dark fiber as a conservative route to take, while the economics and operational characteristics of the all-optical network become more evident. Having fewer carriers competing will also better assure a price floor as these new services come online.

Level 3 Communications Inc. (Broomfield, CO) is a dark fiber supplier with thousands of miles of optical networking that includes local loops in 36 cities in the United States, Europe, and Asia. The company believes leasing or buying dark fiber provides faster time-to-market and lower cost.

"In our view, the metro dark fiber option is many times overlooked, even though it makes the best economic sense under most circumstances," says Kevin Dundon, senior vice president for global infrastructure services at Level 3. "You can buy and deploy metro dark fiber much faster than building new infrastructure from scratch. Cost is minimal compared to tearing up streets or hiring a support organization to construct a new network."

But how does dark fiber actually stack up to purchasing the latest DWDM gear in terms of cost and time constraints? The cost, says Dundon, is the most significant concern-it is usually easier and cheaper to add new fibers than to install new DWDM equipment into an existing network.

However, Dundon concedes there are times when it may make sense to opt for DWDM over the acquisition of more fiber. For example, if the need for capacity is very high and the carrier is supporting multiprotocol applications, then metro DWDM may be the right option. Network bottlenecks such as along bridges, tunnels, or bored routes sometimes make it cost-prohibitive to add more fiber infrastructure. Long suburban routes in excess of 80 km may also be candidates for DWDM.

Normally, however, the decision is a matter of getting to the final cost equation through intensive evaluation of a provider's particular circumstances. The quality of existing fiber in older networks may make DWDM too costly. The more drop points on a metro ring, the more DWDM gear must be purchased-driving up the cost of that option. At short node-to-node distances of a few blocks to a few miles, acquiring dark fiber makes better economic sense, says Dundon-and in most metro areas today, there's plenty of fiber available.

"The abundance of fiber in metro markets means that serious dark fiber customers are usually able to strike a very attractive deal to lease or buy additional fiber strands," says Dundon. "The cost to splice, test, and light the additional fiber is significantly less than the cost of adding DWDM gear in most cases."

DWDM equipment manufacturers such as Lucent Technologies (Murray Hill, NJ) and Ciena (Linthicum, MD) are marketing their systems based on the metro area's need for longer distances, multiple protocols, and various speed differentials from DS-1 (1.544 Mbits/sec) to OC-192 (10 Gbits/sec).

"DWDM can help carriers squeeze more capacity out of their existing fiber plant and enable new revenue-generating services," says Brian Dunlap, vice president of metro networks at Lucent. "DWDM, particularly multiservice metro DWDM, provides fiber exhaust relief, scales as needed, is protocol-transparent, provides high-value managed wavelength services, and enables a wide range of protection options."

Ciena's director of product line management for its core transport division, Jim Westdorp, agrees that where distance and variety are requirements, DWDM is the best option. While dark fiber can support very low bandwidth and short-distance applications, DWDM has distinct advantages for diversity and efficient use of bandwidth.

"A network that supports a variety of services can also be managed under a single management platform, putting a dent in operational costs," says Westdorp. "Scalability and capacity are important features in the metro market; however, the need of the hour is flexibility. A network that is not flexible is one that requires a lot of preplanning and makes it difficult for the carrier-as the needs of the metro market are very dynamic."

As the economy begins to rebound to some semblance of normalcy, data traffic continues to spur network growth. The need for capacity build-out is already becoming an issue for metro carriers seeking an edge on the competition. Whether opting for dark fiber or DWDM gear, carriers seeking market share in the competitive metro space may only have one shot to get it right.

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