Charter Communications moves VOD to next level with gigabit Ethernet technology

Charter Communications is a Gigabit Ethernet technology approach to video-on-demand to squeeze flexible video services into the constrained hybrid fiber/coax networks’ bandwidth. Gig-E incorporates IP streaming along a major portion of the route from the cable headend to the home, thus cutting the cost and bandwidth consumption of delivering typically compressed cable over those network pieces.

Without Gig-E, cable operators used asynchronous serial interface (ASI) between video servers that store the video and provide services into remote or local motivators.

“You either had the service going ASI to QAM [quadrature amplitude modulation] or even QAM in the servers. Both these options forced you to go for a very limited flexibility in your architecture,” said Nimrod Ben-Natan, director of cable solutions for Harmonic, which, along with nCUBE, is providing the VOD technology.

Gig-E, said Ben-Natan, helps cable level a playing ground with direct-to-home networks like DSL or fiber to the home, which can transport video directly from the source to the receiver.

“The beauty of Gig-E is that you can now take your servers and put them into locations in your network and leverage gigabit Ethernet switching, gigabit Ethernet networking and gigabit Ethernet transport to actually carry the video-on-demand and MPEG-2 movies into your hub sites,” said Ben-Natan.

Hub sites are the middle point between the headend and the node, which, in turn, is the demarcation point between fiber and coaxial cable in a cable hybrid fiber/coax network. Harmonic builds an edge device for insertion at the hub site that takes the stream from gigabit Ethernet and translates it into cable’s QAM modulation.

“You actually take the cable network and make it more like an IP from the VOD perspective,” he said.

The network offers cost savings, in addition to simplification, said Greg Thompson, nCUBE’s chief technical officer.

“A year or so ago it probably cost on the order of $150 per video stream. That has dropped significantly with these new Gig-E over DWDM technologies to more on the order of $30 or $40 per stream [for transport alone] and that has directly fed into the cost-effectiveness of being able to deploy VOD,” he said.

Cable operators see VOD--and its sibling subscription video-on-demand--as a way to combat the encroachment of interactively constrained satellite services and match the one-on-one capabilities of direct-to-home services like DSL.