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When a carrier says it wants to save you some money, often what it means is it wants to save itself some money. Just being a telecom carrier is so expensive that carriers almost always try to line up their capital outlays with some reasonably assured payback, no matter what build-out timetable they claim publicly. But that's easier said than done.
Take a carrier that's selling DSL or T-1 service interleaving voice and Internet access. The carrier figures it'll put a broadband voice and data aggregation box at the "edge" of its network, wherever that is. But suppose the carrier overestimates demand and places 24 or 48 T-1 lines worth of access aggregation in an office building's wiring closet - or a remote terminal feeding a suburban subdivision - and nobody buys the service. On the other side of that access box is probably a T-3 trunk going to waste. Enough of those at $7,000 a month and the carrier is out of business.
Now suppose the carrier underestimates demand and doesn't buy or build enough pipe from the edge to its point of presence. As a result, bandwidth is throttled back or sessions time out as if the users were 1980s bank tellers on an SNA network instead of "always on" broadband Internauts. Faces drop, threats fly and class-action lawsuits are filed, as happened to SBC Communications this year.
Giving carriers the flexibility to move the access edge to wherever it aggregates the right amount of traffic as markets change is the insight behind the family of broadband access aggregators from Advanced Switching Communications (ASC). Product names are as prosaic as the company name: A-1000, A-1240, A-2000, A-3010 and A-4000. But when ASC introduced these products in January - actually a renaming from boxes introduced last year but with a key new software feature - some of the nation's quickest-growing carriers promptly signed on.
The $15,000 A-1240 is a stackable 24-port broadband access concentrator that can feed T-1 lines to 24 office suites in a big-city office building. Or it can sit in a central office of an independent telephone company getting its feet wet on broadband service for a small town's businesses.
But maybe demand takes off beyond the carrier's wildest dreams. No problem. The carrier can take the card out of the A-1240, turn it on its side, and slide it into one of 18 slots of the 392-port
A-4000. All without breaking the bank, because the A-4000 chassis just provides a backplane, fans and other mechanical components. The switching is on the card, with the ability to map virtual LANs to wide-area virtual circuits for each tenant, residence or business location.
Other ASC products, housed in the same "pizza box" as the A-1240, are sized for different amounts of overall traffic at wherever the carrier defines the edge. One in particular, the A-2000, is especially designed for so-called second-stage DSL aggregation, a key need of local carriers to pull together DSL streams arriving from many buildings and neighborhoods before hauling them off to core networks.
The key software feature that gave ASC impetus this year is called MultiStream, which supports inverse multiplexing over ATM (IMA) and Multi-Link Frame Relay (MFR). Both specs are methods of choosing intermediate speeds between T-1 and T-3 to match traffic needs. Carriers may be slow to roll out IMA and MFR services to users, but they're quick to implement them on the trunk side if it'll save them money. The boxes are software-configurable to provide any service to any port.
ASC customers include BroadBand Office, a commercial real estate-funded carrier that's installing the A-1240 in every building it can find. Intermedia and Urban Media, also carriers that emphasize multitenant services, have recently signed on. ASC hopes to announce some big incumbent carriers as aficionados too. After all, even Bell companies want to save themselves - er, you and your remote-access users - some money.
Rohde is managing editor of The Edge, Network World's special print
and online coverage devoted to what's happening at the junction between
enterprise and carrier networks. He also authors Network World's "Eye
on the carriers" column.
Related linksAdvanced Switching Communications Web site
Intermedia offers bandwidth options
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