Broadcom Corp. has come out with a brand-new single-chip modem design it says will take a big bite out of the cost for operators to deploy Voice-over-Internet Protocol (VoIP)-capable cable modems.

In production now, the BCM3368 system-on-a-chip design scraps the concept of a separate digital signal processor in favor of a Reduced Instruction Set Computer (RISC) processing architecture, creating a single chip that controls all modem functions. RISC processors streamline the number of computing instructions used, thereby creating chips that can operate at higher speeds. The VIPER chip clocks in at 800 million instructions per second.

"As a part of that we have actually added some commands to our processor [which] allow it to do many of the things that a DSP is good at doing, but without having a separate DSP memory and a high-speed interface to the DSP," said Jay Kirchoff, Broadcom's director of marketing for cable modems. "Now, in this new solution, all of this is performed out of a single, or unified memory architecture. So we don't have latencies from one processor to talk to another processor over the interface or to go from memory-to-memory transfers. We've actually been able to speed up what can be done."

Using this design, the VIPER processor can support primary multi-line VoIP service and cable data functions, thereby cutting the number of modem components by as much as 20 percent. The resulting lower price for the modems will allow cable operators to buy and use them in their data deployments and assure a quick upgrade to voice service down the road.

The chip incorporates DOCSIS 2.0 and PacketCable 1.0 support, and Broadcom's cable modem partners have already developed modems using the design. The resulting modems have already gone through PacketCable 1.0 certification at CableLabs, Kirchoff said.

"You could potentially see products by the end of this quarter," he said.

The chip's incorporation of Session Initiation Protocol (SIP) as well as PacketCable 1.0 support also gives it a market for wireless voice gateways able to meld Wi-Fi and cable modem capabilities. Further, the chip includes a built-in firewall in anticipation of the fact that wireless and IP-based applications will need increasing protection against Internet hackers.

"Certainly denial of service attacks are one way that becomes a threat to the user, and you could imagine as people become knowledgeable about technology or more devious or whatnot - you could imagine what a denial of service attack could potentially do on a voice product," Kirchoff said. "So we've addressed that with a firewall included in our reference design that our customers are using, that before this really was limited to gateway applications."

Priced at $25 each in volumes of 100,000 units, the chip will probably become a mainstay in Broadcom's cable modem silicon product portfolio.

"We expect that this will become our primary voice-over-IP product, and that voice-over-cable could be as much as 60-plus percent by the end of next year of all modem products," Kirchoff said.