The sweet spot in the late 1990s was the DS3 aggregation of disparate traffic into an OC-48 bit rate, pumping information through an optical fiber at 2.5 gigabits per second. The hardware and software components came together, augmented by ASICs and/or FPGAs for density, and they were housed in one shelf. The resulting Cerent 454 product was no bigger than a microwave oven. The engineers responsible for these seeds of success include the following:
1. Processors and memory were part of every module, an idea adopted from the digital loop carrier market
2. High performance transport was carried over from the quality demands of the long haul transport market
3. Power was distributed across each module using the concept of point-of-use power supplies or PUPS
4. Steven Liu completed the bulk of the DS3 software coding before Harris replaced him in late 1998.
While Cerent’s product implementation, known as the Cerent 454, elegantly needed only these four modules to operate in the DS3 to OC-48 sweet spot, competing platforms from Nortel and Lucent required at least a baker’s dozen of modules to deliver like functionality. As Hui Lui, Cerent's former Director of Hardware Engineering says, “If we were conservative, we couldn't have created the Cerent 454. The system would've been too hot and too expensive, the board footprints would've been too small, and the chips would've been too big to fit...”
This is one application where taking a risk on innovation paid off handsomely.
Note the compactness of Cerent’s plug-in as compared to business cards (using late 1990s technology).
The 12-port DS3 module used ¼ of the bandwidth, the OC-12 module another ¼ of it, and the 4-port OC-3 a third ¼ portion of 2.5G (OC-48) bandwidth. There were sufficient low-speed slots to add a final fourth ¼ of the bandwidth as well as standby modules of like type to ensure redundant operation for all traffic types.