NTL to trial ultra-fast broadband using DOCSIS 3.0

The UK cable operator NTL is preparing to trial DOCSIS 3.0 to enable 100Mbps Internet connections to the home. The company is determined to exploit the advantage that it believes the new data-over-cable standard gives cable operators and is aiming for a 2008-09 commercial roll-out of ultra-fast broadband services.

Steve Upton, managing director of networks at NTL, says he wants to differentiate his service from DSL triple-play with speeds that cannot be matched over copper pairs. He is
convinced that telcos have no technical response to DOCSIS 3.0, which uses a concept called channel bonding to achieve its high speeds.

In effect, the traditional channel segments taken from the analogue world – 7/8MHz in Europe and 6MHz in the US – are physically broken, so that any IP data packet can be routed across any part of the frequency set aside for cable data services. If two channels are bonded in EuroDOCSIS, packets for a movie download can use up to 16MHz of bandwidth for the duration of the download, for example, instead of just 8MHz.

The packets are intelligently routed across the spectrum range and bought back together in the DOCSIS 3.0 modem at the customer premise. This channel bonding is also referred to as
wideband technology.

The more channels are bonded, the more spectrum there is at any given moment for a particular service demand (like a video download off the Internet). Thus the frequent references to the idea of a turbo-button for broadband connections.

Upton told the ECCA (European Cable Communications Association) conference in Vienna this February that the biggest challenge for ultra-fast broadband is not technical, but marketing based. “The question is what customers are willing to pay for,” he told the largely European cable audience. “Is there something of sufficient value to the customer that it allows us to invest in a technology platform that out-runs DSL?

“There is only one application today that drives huge amounts of bandwidth and that is video. So the question is whether customers want video enough to fund the network upgrade and maybe they are already giving us the answer.

“An increasing share of our network traffic today is peer-to-peer (P2P) and most of that is video, so one option is to use DOCSIS 3.0 to enable legitimate P2P video content and not just to the PC, but the set-top box. We could play a major role in legitimising this emerging market and if we don’t then maybe others will on our network.”

Upton believes NTL can make it easy for consumers to download legally, and would thus gain the support of content owners. “We could change the video download experience from something that takes all night to something that can be achieved over a cup of coffee.”

The current cost of DOCSIS 3.0 modems prohibits their use in every customer home and, until prices fall, NTL plans to deploy modems at the street cabinet level and then run Ethernet over coax to homes and straight into the PC. This architecture means the high bandwidth will be shared by small groups of customers to begin with.

Upton says NTL’s preliminary cost modelling suggests that DOCSIS 3.0 can be deployed cost-effectively, assuming the modems become cheaper or are sited at the network edge in this way.

“The cost of DOCSIS 3.0 modems is quite significant so if we are going to get this right, we need to break the chicken-and-egg situation. We won’t get low cost modems unless we have scale and we won’t achieve scale without low cost modems.”

One of the vendors involved in the NTL trial is ARRIS, whose Cadant C4 CMTS (Cable Modem Termination System) and Touchstone wideband modem will be used. These incorporate the company’s FlexPath channel bonded software – technology that is already being used by unnamed MSOs (Multiple System Operators), thought to be in Japan and Korea.

Due to physical differences, DOCSIS 3.0 modems are unlikely to ever reach the lower cost of DOCSIS 2.0 modems, ARRIS believes.

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