Cisco Systems Inc. (Nasdaq: CSCO) says it's gone to great lengths to settle the technical challenges unique to a remote-storage DVR (RS-DVR), addressing the point that cable engineers and executives are calling the technology's Achilles' heel.

The viability of an RS-DVR is a hot topic, considering Cablevision Systems Corp. (NYSE: CVC) says it's ready to deploy the technology this summer. And Cisco has a role to play there thanks to the acquisition of Arroyo Video Systems three years ago. (See Cablevision Girds for Remote DVRs and Cisco Snatches VOD Vendor Arroyo.)

Ingest capacity is the weakest link of any RS-DVR, many say. Because of fair use rules, the system must write a copy of every recording requested, as opposed to traditional video-on-demand (VoD) systems that are built to deliver thousands of streams from one copy. (See Cablevision Girds for Remote DVRs, and Summer Debut for Cablevision Network DVR, and DoJ: Butt Out of Cablevision RS-DVR Case .)

"When you go from a mode where popular content has to be recorded multiple times, it brings the ingest capabilities of the box to another degree," says Carmelo Iaria, product line manager for Cisco's CDS-TV unit.

Cisco isn't saying whether it's involved in Cablevision's upcoming RS-DVR deployment. But Arroyo, before being acquired, had acknowledged a role in the MSO's original trial work. More recently, court documents noted that Cablevision was using Arroyo for the primary server in a network DVR. (See Inside Cablevision's 'RS-DVR' .)

Regardless of any Cablevision connection, Cisco is outfitting its gear to address the special challenges of RS-DVRs.

In Cisco's view, a VoD system might require less than 1 Gbit/s of simultaneous ingest, while an RS-DVR could need at least four times that. On the storage side, the ballpark for a VoD system would be 12 terabytes to serve 10,000-plus subscribers, while an RS-DVR would need 1,200 terabytes.

Planning ahead
Cisco's video product people say they identified the ingest challenge long ago and have been adjusting their servers accordingly.

The original Arroyo Vault (circa 2006) supported about 100 terabytes per rack, roughly 100 channels of ingest, and one Gigabit Ethernet feed. Cisco claims the newer CDE 420-4A model offers 240 terabytes per rack, eight Gigabit Ethernet ports, and the ability to ingest up to 1,000 channels simultaneously.

A "Next-Gen Content Library," which likely won't be announced until the second half of the year, is shooting for 700 terabytes per rack, two 10-Gbit/s Ethernet ports, and the capability to ingest more than 2,000 channels concurrently.

But until an MSO like Cablevision tries to scale an RS-DVR service, it won't be known whether even those specs are enough to handle the demand. "Some of these new applications are really changing the game," Iaria says.

Cisco has been tight-lipped about deployments involving servers spawned from the Arroyo acquisition. It claims to have server deals with four of the top five North American cable MSOs, but Time Warner Cable Inc. (NYSE: TWC), a pioneer of the Start Over service, is the only one made public so far.

That job has been a learning experience, says John Wheeler, a Cisco director of product marketing and business development. Start Over is a heavy duty processing task that calls for ingesting live channels and sending them to the edge of the network within 300 milliseconds.

Cisco expects RS-DVR interest to grow once Cablevision gets rolling. Several major MSOs, and even several telcos, have been "waiting… and watching Cablevision," Wheeler says.

That goes for operators in Europe and Asia, too. "The rights management issues are sticky in those markets, as well," he adds.

RS-DVRs and Arroyo's servers fit into Cisco's broader Content Delivery System (CDS), which aims to help MSOs and other service operators pipe all forms of on-demand video (Web TV stuff, too) to all forms of end devices -- TVs, mobile handsets, game consoles, to name but three.

That's not just Cisco's idea. Competitors such as Arris Group Inc. (Nasdaq: ARRS), Concurrent Computer Corp. (Nasdaq: CCUR), Motorola Inc. (NYSE: MOT), SeaChange International Inc. (Nasdaq: SEAC), Edgeware AB , and relative newcomer Verivue Inc. , have similar aspirations. (See Arris Pumps Up Video With Dolce's Verivue , Verivue Flips New Media Switch , Concurrent Sets Multi-Screen Strategy, Moto Unveils Mini VoD Server , and Edgeware Flashes the US.)

Numericable-SFR of France is using Cisco's CDS for VoD and some nDVR apps, and a "major" MSO in China is also using Cisco's system for a "Rewind TV" service that vaults up all of the live channels over a three-day period.

— Jeff Baumgartner, Site Editor, Cable Digital News

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