Coax network processor refines MoCA apps

Now that using coaxial cable to distribute voice, video and data in the home is catching on with cable operators, Entropic Communications Inc. is releasing its next-generation coaxial network processor. The device addresses customers' cost concerns and offers some refinements over an earlier chip that preceded the Multimedia over Coax Alliance (MoCA) specification.

The release of the EN2210 coaxial network processor will help Entropic extend its lead in the small but growing market for MoCA v1.0-compliant chips. MoCA backers are betting the spec will pop up in numerous applications, ranging from media servers and home entertainment gateways to multiroom digital video recorders and network-capable STBs.

Entropic has shipped more than a million chips based on its c.Link protocol. Building on its first-mover status will be important for the relatively small company as the competitive landscape shifts.

Last month, leading STB chipmakers Conexant Systems Inc. and STMicroelectronics said they planned to develop MoCA-compliant chips. Broadcom Corp. is also quietly developing silicon. There are now seven chip suppliers in the MoCA consortium—a far cry from late 2005, when Entropic was the sole chip provider.

Entropic implemented quite a few changes in the EN2210, which follows the EN2010. The earlier chip "ran out in front of the specification," said John Graham, VP of marketing. "At that time, we were taking spectrum analyzers to people's homes, crawling around in attics, looking at a variety of switches and cable plants, hundreds of video appliances, such as TVs and VCRs, to see what sort of effect they had on the coax. A lot of that work went into the first chip, and the MoCA spec was built around it."

Turbo mode adds speed
The follow-on is a more-flexible platform that benefits from the design team's better understanding of the external BOM, such as the filter requirements. The developers also added more interfaces, such as GMII and MII ports, allowing the EN2210 to work as an equivalent Ethernet PHY. The MII includes a turbo mode that boosts throughput to 200Mbps. Also on board are FlexBus and PCI host interfaces.

Although the PHY is rated at 270Mbps, real throughput is just north of 100Mbps. That's enough to handle a few compressed high-definition streams, plus voice, data and the associated overhead.

Graham said the c.LINK platform also supports a 50 percent increase in data rate through packet aggregation to allow continued evolution of the standard.

To improve QoS, Entropic has added features such as parameterized constant-bit-rate, parameterized variable-bit-rate and prioritized traffic. These could be critical in preventing data from hogging bandwidth in a video-centric environment, especially if operators decide to open up their home networks to data-centric networked devices.

Some new twists include using the chip as a standalone networking solution in the low-RF range or using it at baseband frequencies of less than 50MHz. Typically, MoCA streams use RF frequencies between 850 and 1,500MHz, but Graham said that some telco operators are interested in the lower frequency, despite its greater susceptibility to interference.

Entropic has added in support for the 1394 protocol, though Graham isn't seeing big demand for it. "Everything is going over Internet Protocol, so it doesn't really fit. When we asked who is deploying 1394, or who wants to deploy it, nobody put their hand up," he said.

The EN2210 has a 1.2V, 1.8V and 3.3V supply and improved power dissipation (1.5W max., vs. 2.5W for the EN2010). The part, which can be paired with the EN1010 coaxial network interface, will ship in volume in the third quarter. Pricing is based on volume.

- Mike Clendenin
EE Times