Turning the DLC frog into a prince

Depending on whose figures you go by, between one third and 40% of the nation's phone lines are served from digital loop carriers. DLCs are those remote-terminal boxes that concentrate and extend loop lengths into neighborhoods located some distance from the telco central office.

And predictions are easy to come by that DLCs will serve more than half the phone lines some time this decade, at least in residential arenas. That'll happen for two reasons - one a matter of choice and the other a matter of necessity.

Some carriers, such as SBC with its Project Pronto, have announced they're banking on remote loop-concentration terminals for their broadband buildouts. But beyond that, the incumbent telcos' universal-service obligation means they all have to deal with suburban sprawl and rural growth. That means even more DLCs to reach all those new homes, schools and businesses.

The irony is that DLCs have traditionally been viewed as the enemy of DSL, because they break up the copper path from central office to customer premise. So it might seem this is exactly the wrong time for a boom in DLC installations.

That's where a key edge infrastructure company like Advanced Fibre Communications (AFC) of Petaluma, Calif., comes in. All leading DLC vendors, such as Alcatel, Lucent, Nortel Networks and Marconi, have "next-generation" DLC products in the market or in development that act like remote-terminal Digital Subscriber Line Access Multiplexers or provide some other broadband path to the user.

But AFC built what it calls a multiservice DLC right from the start. Its flagship UMC1000 employs a hybrid architecture utilizing a 100M bit/sec TDM bus, an 800M bit/sec ATM cell bus and a 5.3G bit/sec serial bus. This unique three-bus architecture simultaneously supports copper, fiber and wireless feeder systems and loop interfaces for plain old telephone service, T-1, asymmetric DSL and high-bit-rate DSL.

AFC's DLC guru, senior product manager Mark Abrams, says putting in the right system the first time is important because DLC installations are notoriously difficult to upgrade. Even today, many telcos continue to install old DLC systems - especially Lucent's SLC-96 dating from the old AT&T/Bell Labs days - just to get phone service out to new neighborhoods.

But AFC has had more success selling its systems to competitive carriers than to big incumbents. To bulk up against the big vendor names, expect to see AFC emphasizing partnerships and interoperability announcements with key hardware and software providers. After allying with subscriber-management provider Redback, AFC last week announced integration with CoSine Communications' IP Service Delivery Platform. CoSine's product is one of the new generation of scalable systems that provide IP tunneling, managed firewalls, URL filtering and antivirus protection from the service-provider network instead of the customer premise.

CoSine, AFC pair loop concentration with service delivery, The Edge, 09/05/00

AFC had a rocky couple of years in 1998 to 1999, with a management shakeup, international sales problems and headaches ramping up customer service for big accounts. But its new management team just ratched revenue up 45% to $101 million for the second quarter. Now it's aiming to show old and new service providers that the choice of DLC system right at the classic local-loop bottleneck is one of the most important decisions they'll make.

There's a lot more about DLC systems in our research area.

Plus, there'll be a lot more of "View from The Edge" from now on. Starting this week, we're publishing twice weekly. Look for it in your e-mail or on the Web site, now generally updated on Tuesdays and Thursdays.

Gov't to review CLEC access to Project Pronto
The Edge, 08/14/00<./p>

Details of SBC's DSL plan spark concerns
Network World, 03/27/00.

Advanced Fibre Communications