Terayon's Flexible Traffic Cop for Broadband Data Networks


Terayon Communication Systems Inc. is introducing a new FlexCMTS it said will help operators to optimize their broadband data networks. Instead of engineering high-speed data services at the port level, the new Flex software will allow MSOs to manage those services at the traffic level. Terayon estimates MSOs could save between 35% and 65% a year on capital expenditures, or perhaps $2.5 million for every 100,000 homes passed by high-speed data.

"The service mix is changing," said Terayon senior director of product marketing Kanaiya Vasani. "Operators need something that is a lot more flexible."

The vendor's effort got a thumbs-up from Adelphia Communications Corp.

"Terayon's Flex CMTS architecture is exactly the kind of innovation we're looking for from our equipment vendors, namely innovation that promises to improve the quality and performance of the services we offer while simultaneously helping us manage our capital and operating expenses," MSO vice president of data engineering and operations Tom Buttermore said in a statement.

Vasani said the new software has major two components: "flexible coexistence" and "flexible association."

Current CMTS line cards have a fixed association and ratio of downstream and upstream ports. Operators are increasing downstream data speeds to 3 Megabits per second, which will require the installation of additional line cards, according to Terayon.

But the upstream bandwidth on those additional line cards goes unused.

Those fixed ratios also can cause delays in responding to changing customer bandwidth demands, leading to additional capital costs for handling those adjustments.

Terayon's FlexCMTS software associates the downstream and upstream ports across multiple line cards in a CMTS chassis.

Unused upstream and downstream bandwidth is used, when necessary, reducing the need for further line cards.

Terayon will activate the new features through a software upgrade to its BW 3500 CMTS platform, which Cable Television Laboratories Inc. has qualified for Data Over Cable Service Interface Specification 2.0.

The new software will help address a cable operator's "lowest common denominator" issues with DOCSIS modems, the "flexible association" piece of the new software.

A typical network today may contain DOCSIS 1.0, 1.1 and 2.0 modems, each of which have different maximum upstream bandwidth potential. DOCSIS 1.0 modems operate at quadrature phase shift key strengths, topping out at 5 Mbps.

DOCSIS 1.1 and 2.0 modems use 16 QAM, meaning they can run at 10 Mbps, but if they are in the same neighborhood as a DOCSIS 1.0 modem, their effective speed is limited to the DOCSIS 1.0 output of five megabytes, Vasani said.

FlexCMTS basically provides a "fast lane" out of the line card, allowing DOCSIS 1.1 and 2.0 modems to operate at full capacity, while DOCSIS 1.0 modems operate in their own "slower lane." "You create two modem pools," Vasani said, "and you manage the allocation of bandwidth to these two pools independently. And you can do that with the existing infrastructure."

Also, under that scenario, operators wouldn't even to have to go to the expense of swapping out older 1.0 modems to get the efficiency of newer ones.

The flexible association carries over to line-card speed configuration. The FlexCMTS software basically allows operators to "borrow" upstream or downstream capacity where needed. An area of town heavy with voice-over-Internet protocol subscribers may need more upstream capacity than a section of town where college students live, and where downstream capacity is at a premium.

"You can play with the ratios with the individual line cards," Vasani said.

Terayon said it has tested the software in its labs and in several MSO labs, and plans to release the FlexCMTS sometime in 2004.