Cisco Pushes Cable VOD
The company revealed the uMG9850, a VOD line card for the Catalyst 4500, and a chassis system called the uMG9820. Both products stem from a strategy Cisco revealed at the Cable-Tec Expo last May. (See Cisco Tackles Cable VOD and Cisco Intros Digital Video Solution.)
Cisco already supplies gear for cable operators' data networks, but the video network is a separate beast. Until recently, VOD feeds used the Asynchronous Serial Interface (ASI), a protocol for delivering MPEG-2 streams. Companies including Harmonic Inc. (Nasdaq: HLIT), Motorola Inc. (NYSE: MOT), and Scientific-Atlanta Inc. (NYSE: SFA) provided the equipment for ASI transport.
About two years ago, cable operators started using Gigabit Ethernet instead of ASI, taking advantage of Ethernet's low costs. "The rate at which they moved has surprised even us," says Paul Sanchirico, director of marketing for Cisco's video networking business unit.
The result is that the cost of hardware for one video stream is less than $20. "Analog technology, if we go back even three years ago, was around $250 per stream," says Paul Connolly, vice president of emerging businesses for Scientific-Atlanta. The shift to Ethernet has attracted new equipment competitors including Cisco and Internet Photonics Inc.
Cisco's new products are gateways that sit near the user's side of a VOD connection. They receive MPEG-2 streams via Ethernet and prepare them for transport over the hybrid fiber-coaxial network to the set-top box. Because this final transport step uses a scheme known as quadrature amplitude modulation (QAM), these gateways are commonly called QAMs (pronounced like "qualms," but try not to read anything into that.)
Cisco is claiming two advances with its QAMs. First, they've got a higher density than the competition. The standalone uMG9820 [ed. note: and how is that pronounced?] provides 24 QAM channels in one rack-unit box, which is enough to carry 240 video streams. Competitors offer only eight or 12 channels in the same space.
The density is important, because 24 QAM channels fills a Gigabit Ethernet pipe. Competitors can't take advantage of a full 1-Gbit/s feed except by daisy-chaining QAMs, an inefficient method that creates extra points of potential failure, Sanchirico says.
Competitors contend density doesn't mean as much without reliability. Scientific-Atlanta's QAMs carry only 12 channels per rack unit, but they're added in groups of two. A hardware failure in the unit takes out only two QAMs rather than all 12, Connolly says.
Cisco is also touting the ability to merge Ethernet switching capabilities with its QAM gateways, particularly in the case of the uMG9850 line card for the Catalyst 4500. But the need for that feature might be dwindling, says Gary Southwell, vice president of marketing for Internet Photonics.
Ethernet switching would be useful in a distributed network, where video servers are placed closer to the consumer, right next to the QAMs. This is the model Time Warner Inc. (NYSE: TWX) made famous, and it involves keeping content in multiple places, replicating it on multiple video servers around the network.
Southwell contends operators such as Cablevision Systems Corp. (NYSE: CVC) are favoring a centralized approach, where all the content originates from one location and is transported to the remote QAM gateways. This model is gaining favor because Gigabit Ethernet has wiped out most of the costs of transport. "That really allowed the centralized model to take off," Southwell says.
Cisco's uMG9820 and uMG9850 are due to ship next month.
— Craig Matsumoto, Senior Editor, Light Reading