CMTS Shakeout Trials Due

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Cable-modem-termination-system vendors will soon be able to say with confidence that their Data Over Cable Service Interface Specification 1.1 solutions are ready for deployment.

But first, they must pound their systems with high levels of traffic generated by a wide variety of DOCSIS 1.1 cable modems from different vendors, according to Paul Nikolich, vice president of technology and standards at Broadband Access Systems Inc.

There are several CMTS vendors, including Broadband Access, Arris Interactive LLC, Motorola Broadband Communications Sector, 3Com Corp., Terayon Communication Systems Inc. and Cisco Systems Inc.

"This is a classic chicken-and-egg situation," Nikolich said. "In theory, operators could roll out DOCSIS 1.1 and leave all of the existing DOCSIS 1.0 cable modems in their systems. The two can coexist. However, this type of network will not function as well as a pure DOCSIS 1.1 environment. Operators will have to undertake a DOCSIS 1.1 CMTS upgrade in order to ensure that their systems are configured for all of the throughput and latency guarantees."

He added that operators will have to meet signal-to-noise ratio requirements, both upstream and downstream, between the CMTS and the cable modems in order to accommodate the vast flood of synchronous streams after these DOCSIS 1.1 cable modems are deployed.

"We want to focus on a robust implementation," Nikolich said. "We estimate that it is going to take us approximately six to eight months to roll out a DOCSIS 1.1 CMTS-software upgrade to our CMTS platform."

Besides overall CMTS performance, CMTS port density is going to be a big issue for operators. For the DOCSIS 1.1-based high-availability-type services, operators will want higher-performing edge-router switching that is both carrier-class and scalable, he said.

In addition to looking forward to additional physical-layer improvements beyond DOCSIS 1.1, Nikolich is watching ongoing developments such as the deployment of AT & T Corp.'s "LightWire" architecture.

"LightWire reduces the number of homes in a node and, in turn, this has a big impact on the noise reduction upstream," he added.

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