networkZONE Products for the week of December 2, 2002
Conexant says…
Home Run - Conexant & Jungo Team to Deliver DOCSIS
2.0 Single-Chip Cable Modem Reference Design With All The Trimmings
Supports CableHome Spec, Plus Seamless Interface To 802.11,
HomePlug, And HomePNA Devices
Conexant Systems introduced a single-chip cable modem that includes
technology specified in CableLabs DOCSIS 2.0, the latest version of the
cable modem standard. Conexant's new CX24951 device is backward and pin-compatible
with the company's earlier CX24943 DOCSIS 1.1/1.0 solution. In addition,
it builds on the proven dual-processor architecture of the company's earlier
solutions to provide the highest-performance and lowest-power consumption
of any cable modem on the market today.
"We are proud to be one of the first to support this exciting next-generation cable modem specification for improved data, voice, and video services while providing MSOs with the ability to offer their subscribers more efficient and value-added services," said Al Servati, director of Conexant's Broadband Communications Segment's cable modem business. "The CX24951 offers enhanced software programmability and performance along with extensive hardware and software support, allowing cable operators to expand subscribers and pursue new markets. With the introduction of our CX24951, we continue to show our commitment to providing the industry with innovative products."
Conexant's CX24951 supports the new upstream physical-layer modulation technologies, advanced time division multiple access (A-TDMA) and synchronous code division multiple access (S-CDMA) as specified in the DOCSIS 2.0 standard. The CX24951 has been enhanced to offer 500 millions of instructions per second (MIPS) of processing power that allows it to be used to support the CableLabs-led CableHome initiative, without the cost or complexity of adding an external network processor for firewall, virtual private networking (VPN) and routing operations. The CableHome project extends high-quality, cable-based services to network devices within the home, and addresses issues such as device interoperability, quality of service and network management. The solution also supports the CableLabs-led PacketCable initiative. PacketCable uses Internet protocol (IP) technology to enable IP telephony, multimedia conference, interactive gaming and other multimedia applications and services.
The CX24951 cable modem chip features the industry's widest variety of interconnect options. It includes an embedded interface that provides direct access to Conexant's HomePlug 1.0-certified powerline and HomePNA phoneline semiconductor solutions and other home-networking devices. An embedded universal serial bus (USB) transceiver ensures plug-and-play installations. In addition, the device's host interface supports the Personal Computer Memory Card International Association (PCMCIA) standard and can accommodate IP telephony products and IEEE 802.11a/b wireless networking transceivers. The programmability of the design also gives customers the flexibility to accommodate application-specific requirements, worldwide standards and unique value-added features.
The CX24951 joins Conexant's family of Internet access solutions built
upon a strong heritage of industry-standard products. This next-generation
cable modem is supported by a reference design that includes both hardware
and software, and speeds time-to-market for complete DOCSIS/EuroDOCSIS 2.0/1.1/1.0-capable
cable modem solutions used in Ethernet/USB or peripheral component interconnect
(PCI) applications. The reference design also features Conexant's advanced
CN2811 radio frequency silicon tuner and includes the full range of DOCSIS/EuroDOCSIS
2.0/1.1/1.0-capable software.
analogZONE Says . . .
While I am not a big fan of cable modem technology (mostly for non-technical reasons I won't bore you with here) Conexant's CX24951, makes fullest use with the DOCSIS 2.0 spec to deliver a very useful and easy-to-implement platform for all kinds of cable-based services that might change my mind. The CableLabs' DOCSIS 2.0 spec adds more security, a much-improved upstream channel capability, and support for everything from smart home management to cable telephony, the Conexant chip provides a high-powered, low-cost platform to support all kinds of applications. Complementing the specification and the hardware is a complete reference design supplied by Jungo, a software development house that has made much of its living implementing highly efficient protocol stacks and applications.
The CX24951 chip itself is a nice marriage of Conexant's cable modem PHY core, a programmable MAC processor, and a hefty ARM 9 RISC engine, coupled with enough on-chip memory and I/O to suit nearly any application (see Fig. 1.) The chip's MII interface allows it to easily interface with either a 10/100Ethernet, HomePlug (data over powerline), or HomePNA (data over phone line) PHY chip, also available from Conexant. The CX24951's flexible architecture also allows you to use the host interface to connect either an 802.11 wireless LAN chip set for home networking, or a CODEC/DSP chip for cable telephony applications (see Fig. 2.).
As I mentioned before, Conexant's modem/router chip interfaces directly with a variety of PHYs, including the CX11656 homePlug PHY, introduced by Conexant on Oct 14. The chip meets HomePlug standards, with a base rate that matches the HomePlug 1.1 specification at 14 Mbit/s, producing around 8 Mbit/s of usable throughput. It requires an external AFE today which will eventually be integrated within a year or so to further drive down the BOM which is currently about that of an 802.11 solution ($25-30.) Conexant is very aware that HomePlug could have very interesting applications for home automation and "smart" appliances, as well as in energy conservation and security. While some of their capabilities overlap, HomePlug can compliment 802.11 by extending its reach into areas where a single base station could not get to. Home Plug also does things that 802.11 does not, like reach deep into industrial buildings with thick walls, or other areas where RF does not propagate well. The PHY and associated MAC protocols are efficient and QoS-capable, perhaps even more so than the emerging 802.11e wireless QoS standard will be.
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About The Software Platform
Of course, tying all these chips together takes lots of software, and Conexant has taken a very sensible approach to this. In binging this versatile multi-PHY router reference design on the market, Conexant joins the short list of savvy chip vendors who have realized that in many applications, silicon is simply a software delivery vehicle. They have wisely teamed up with Jungo, an Israeli software vendor, to provide software and co-develop reference designs for their home gateway products that enable home control as well as data/router services. Together, they seem to have put together a platform to support the CX24951 and a variety of home networking technologies that will go head-to-head with the sophisticated DOCSIS offerings from arch-rival Broadcom, and perhaps even go one better.
The gateway reference design is based on Jungo's OpenRG software that can be quickly tailored to meet vendor's specifications. This latest version includes support for HomePlug and CableHome home networking specifications that allow cable modems to support traditional routing functions, plus extra services including firewall, NAT, and home networking, plus home control functions for HomePlug-enabled appliances and consumer products. The next version will probably support VPNs and other services as well. The PacketCable services module should also enable easy development of cable-based data and IP telephony applications.
I have no reason to dispute Jungo's claim that once they become familiar with the development environment, most designers can bring a CableHome-based product to finished production-ready design in as little as 6-8 weeks. CableLabs certification is streamlined. While I won't go into the specifics of Jungo's side of the reference platform in great detail here, it's an essential part of delivering the advanced functions and quick time to market that a home gateway will need to succeed. For Jungo's half of the story, you can go their website.
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ADSL Version Also Available
Finally, if ADSL is of more interest to you, there is the the CX82340, a somewhat comparable ADSL-oriented part introduced a couple of weeks ago at COMDEX. It features an integrated ADSL modem, router, and an 802.11b MAC/PHY. This ADSL modem/ router chip builds on the earlier CX8210 which had integrated network processor (ARM), Ethernet, USB, AFE and ADSL modem. This chip builds on a relationship with Intersil to integrate the 802.11 baseband and MAC functions and hook up directly to Intersil's Prism III radio front end chip set. The first spin has neglected the advanced 802.11a/g standards in the interest of quick time to market and reducing technical risk. Conexant's choice of a "firm" MAC architecture means that adding "g" and "a" capability will require a second spin of the silicon but this current product should address the bulk of today's market, I'd expect follow-on chips to cover these faster specifications well before the close of 2003.
Development should be relatively straightforward
since Intersil-provided software stacks are available to implement all drivers
and security software. QoS issues are neglected for the moment, but future
802.11g and 802.11e solutions will have the appropriate software available.
For a bit more information, you can click here to look at the full press
release for the CX82340.
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