General Instrument Corp. and FORE Systems Inc. have forged an alliance that adds new force to arguments that delivering data in the ATM framework to the home is becoming a viable option.
The agreement is part of a new strategy at GI, which expects asynchronous transfer mode technology to become the backbone technology for the digital headend of the future, said Ed Zylka, director of marketing, network telecommunications systems, at GI Communications. "As a company, we're saying ATM is going to play a strong role," Zylka said.
While Zylka said the deal does not mean personal computers and set-tops will all use ATM, "It does say that the next step for GI, beyond the development we've done for digital TV and cable-delivered data, is to create a strong core network technology."
The move, announced two weeks ago, comes as Cable Television Laboratories Inc. and other groups are racing forward with attempts to define protocols for "next-generation" cable modems. These modems will enter the production line on the heels of initial commercial deployment of first-generation boxes, now under way in a handful of communities.
"We absolutely expect that ATM will be one of the standards adopted for high-speed data service to the home," said David Nelsen, director of the outbound technology group at FORE.
The GI strategy drew praise from Microsoft Corp., which has been working with GI and FORE for two years and has long espoused ATM as the best framework for all types of digital communications in the future, including MPEG video.
"We believe this announcement will help speed Microsoft's efforts to bring new services to PCs and televisions," said Microsoft senior vice president Craig Mundie in a prepared statement.
GI and FORE are working together to produce an ATM-based telecommunications network system that will include a cable modem that receives signals in the 53-byte ATM format and delivers data in that format to the PC.
It will operate at 25 megabits per second in the downstream, matching a newly standardized bit rate for ATM in the local area network (LAN) environment, with return signals traveling at lower speeds over the hybrid fiber-coax network.
Zylka said he could not disclose whether this version of next-generation product would have the option of converting signals at the modem from ATM to Ethernet for delivery over 10baseT to the PC. But he made clear that GI will offer next-generation, high-speed units, whether as a single dual-purpose modem or two separate models, that give operators the option of linking to the PC via Ethernet.
The ATM-to-the-PC option marks the market introduction of relatively low-cost 25-mbps ATM interface cards that can be inserted into Pentium and other high-end PCs equipped with PCI slots.
"The card will cost about twice what a good Ethernet card costs," Zylka said, pegging the price in the $200 range.
As envisioned by the manufacturers, consumers would purchase the cards while the cable operator would supply the modem, although built-in PC modems might eventually become part of the product line.
The companies have made considerable progress already in their run-up to production, and they will have gear available for limited field testing soon, with volume production coming in the second half of the year, Zylka said.
GI's new system will come fast on the heels of the March launch of its first-generation SURFboard modem system, which employs the Ethernet protocol to deliver data at 27 mbps in a 6-megahertz channel downstream while relying on user-supplied telephone modems for upstream connections.
While both systems operate at high speeds, ATM offers considerable advantages over Ethernet, Nelsen said.
He said ATM's peak rate of 25 mbps is more than twice as fast as Ethernet's 10 mbps rate."
And, with ATM, you can guarantee the level of service in terms of minimum bit rates," he added.
This means ATM is much more viable for audio and video because it can be set to assure the minimum throughput and continuous bit stream is maintained to support video, Nelsen asserted.
Officials also noted that ATM supports scalability to larger networks and higher-bandwidth allocations and offers the option of billing by usage rather than connect time.
The FORE technology under development for cable networks is a stripped-down version of the new ATM system for LANs, which, at 25 mbps, will allow broadband data to run over standard twisted pair cable in the office environment.
Whereas the ATM network interface cards for LANs, which should be available by the start of 1997, support a broad range of protocols common to the business environment, the cable version will focus on data packaged for transport in the IP (Internet Protocol) format, which includes all online as well as Internet services and online stored media, such as CD-ROMs.
The GI/FORE system will employ a backbone ATM switch capable of serving up to 1,000 users per port, with aggregate speeds of up to 10 gigabits per second divided across up to 64 ports. This type of switch will allow the cable system to connect through an ATM bypass of the long-distance network directly to the ATM backbone "cloud" of the Internet, Zylka noted.
Expanding the ATM base in the headend to employ the technology in switching all types of traffic coming in from outside networks over SONET (synchronous optical network) and other digital transport systems will require use of more advanced ATM switches. Zylka said GI is talking with FORE and other vendors about possible supply of such gear for its cable headend ATM backbone array.
"Positioning ATM in the headend really future proofs the network for investments in future services," Zylka said. "Operators won't be stranded with an IP-only service. In two to three to five years when other, more advanced data protocols come into play, operators won't have to rip out their headends to get into the new classes of service."
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