30 July 2003—John Smith is taking it easy on a Saturday afternoon in Little Rock, watching the All-Scottish Sports Web Channel via cable modem. He’s watching the channel with about 50 000 other people—far fewer than the six million it typically takes to support a commercial broadcast TV channel. While John is watching the caber toss—an event in which young men throw around young tree trunks as a test of strength—the company that sold him his six-month-old freezer calls him on his cable phone. The company’s been monitoring the appliance via John’s cable system, and it’s calling to tell him that the freezer, packed with expensive eats for a party tomorrow, is on the fritz. Would John like a technician to come out to repair it? At the same time, his son Mike is playing an interactive, real-time, high-speed video combat game involving a dozen other players across the country, using the in-house network set up and maintained by the cable operator.
John and his family are fictional, but the cable modem capabilities they are enjoying should arrive in the next couple of years, thanks to the roll out of new software and equipment for transmitting data over cable. Major cable providers are in the midst of a massive deployment of services dependent on standards known as data over cable service interface specification—Docsis. The two newest are1.1 and 2.0.
John’s fictional niche Web channel and the freezer monitoring will both be enabled by Docsis 1.1; his son’s real-time interactive video gaming will be possible with Docsis 2.0. Cable operators are rolling out Docsis 1.1 right now; Docsis 2.0 is likely to arrive in 2004.
1.0 came first, of course. It was developed in 1996 by CableLabs (Louisville, Colo.), the cable industry’s research, standards, and testing organization. CableLabs not only develops standards, but also tests all vendor equipment for compliance with the standards and for interoperability.
The first Docsis standard did two things. It specified basic Internet connectivity, with a focus on high-speed downloading, relieving customers of hated dial-up modem delays. And by standardizing interfaces for cable modems and other devices, it opened the cable Internet equipment field to competition. ”The first high-speed cable modem was around $1500,” says Doug Semon, vice president of technology development and standards at Time Warner Cable Inc. (Stamford, CT). ”Now, a fully-featured DOCSIS 1.1 modem is less than $50.”
Basic Internet was not enough, either for the customers or the cable companies. So CableLabs released Docsis 1.1 in 1999, which was the same year CableLabs certified the first 1.0 equipment. It wasn’t until 2001 that the first Docsis 1.1 equipment was certified, and that’s what the cable companies are rolling out right now. The equipment involved includes both the cable modems and the head-end devices, where the head-end is the cable industry equivalent of a telephone company’s central office. To provide all the services available with a particular version of Docsis, both the head-end device and the cable modems must include the version-specific hardware and software.
Docsis 1.1 improves on 1.0 with better security, reduced signal distortion, less lag-time between data bits, and—for the first time—quality of service, telephone industry jargon for guaranteed bandwidth on demand. With quality of service, ”You can give a small-office/home-office customer a specified amount of bandwidth, a committed information rate,” says Jay Rolls, vice president of telephone and data engineering at Cox Communications Inc. (Atlanta, Ga.). Less lag-time between bits, also known as reduced latency, helps enable real-time Internet cable services where bit sequence and speed are important, like gaming, video-conferencing, and voice communications. Reduced signal distortion and better security enhance all services.
Schedule for Docsis 1.1 upgrade
At Time Warner, Semon says it will take all of 2003 to upgrade customers’ existing cable modems with Docsis 1.1 software. These modems were 1.1- or even 2.0-capable when purchased, but were deployed with 1.0 software since 1.1 wasn’t available at the time. The upgrade is performed through a software download to the modems, and it’s entirely transparent to customers. Semon expects that Time Warner’s installation of 1.1-compliant equipment in the head-ends will be completed by summer’s end.
Cox Communication’s year-end ”stretch” goal is to have 1.4 to 1.5 million cable modems running 1.1. As at Time Warner, these modems were 1.1-capable when purchased, but have been operating under 1.0. The company can perform software upgrades of thousands of modems in a day, so the stretch goal is quite reasonable. Rolls says that by year’s end, the company expects to have all of its head-end equipment running 1.1.
At Comcast Corp. (Philadelphia), Steve Craddock, senior vice president for new media development, says his company is deploying only Docsis 2.0 cable modems, although they are running in 1.0 or 1.1 mode. Again, software upgrades are all that’s required to convert them to 2.0 modems. As for head-end equipment, Craddock says, ”All new head-end devices being deployed by Comcast are full next-generation 1.1 equipment.” The company is considering upgrading existing 1.0 head-end devices so they can support basic quality of service for data transmission. Craddock says, ”We are deploying 1.1 devices, but still have 1.0s for regular serving purposes. 2.0 is still on the horizon.”
And on to 2.0
By 2004, however, CableLab’s latest standard, Docsis 2.0, will be available in both cable modem and head-end equipment, and that will have a dramatic impact on the amount of bandwidth customers can access. 1.0 and 1.1 equipment is capable of a maximum upstream rate of 10 Mb/s (and in practice, usually 5 Mb/s), compared to 30 Mb/s downstream. Docsis 2.0 equipment will enable 30 Mb/s rates in both directions, though for entire neighborhoods not individual customers. The improvement stems from better signal modulation and error correction.
While Docsis 1.1 helps enable real-time services, Docsis 2.0’s greater upstream bandwidth will make those services available to more customers, because there will be more bandwidth to share. 2.0’s new symmetric bandwidth—the same bandwidth in both directions—will let cable companies offer high-speed two-way services to businesses, which usually need to uplink as much or more information as they need to download.
Docsis 2.0-improved equipment will not only provide greater absolute upstream bandwidth, but it will also pack more information into signals in both directions. According to Rouzbeh Yassini, senior executive consultant at CableLabs and founder and CEO of YAS Broadband Ventures LLC (Andover, Mass.), Docsis 1.0 and 1.1 can transmit a maximum of 10 Mbps over a signal that spans six MHz. Thus, the 30-Mb/s downstream capacity of Docsis 1.1 systems requires a total of 18 MHz bandwidth (obviously, the bandwidth is not necessarily adjacent on the radio-frequency spectrum). With Docsis 2.0, one six MHz band can transmit 30 Mb/s—a tripling of capacity. That opens up huge opportunities for new Internet cable services, such as niche entertainment Web ”channels” that cater to small audiences (like our fictional All-Scottish Sports Channel).
Cable companies expect to start deploying Docsis 2.0 equipment and services sometime in 2004. ”Going from Docsis 1.0 to 1.1 is a big change, but 2.0 is extraordinarily important,” says Craddock. ”I can’t wait for it.”