Inside Comcast’s massive IP VOD network

Comcast (s CMCSA) subscribers might have noticed that the company has been putting a lot of effort to grow its video-on-demand (VOD) library, adding huge amounts of new movies for rental and ad-supported TV shows for viewers to catch up on. What they probably didn’t realize is that the increase in content is just one part of a massive restructuring of its network architecture that is shifting delivery from more than 100 locally distributed VOD servers to a more centralized, IP-based delivery system.

Move to IP adds speed and flexibility

The Comcast CDN, which the company has been building out over the last several years, is being leveraged as a way to more efficiently and flexibly roll out new services and ramp up the amount of content that it can serve to subscribers. The buildout was started as part of Comcast’s Project Infinity, which was announced way back in 2008. Since then, Comcast has not only made good on promising to add a massive number of new titles to its VOD offering, but by creating a simplified, IP-based architecture for delivery.

Prior to moving to an IP-based delivery system, VOD titles had to be added in each of 130 locations throughout the country, a massive undertaking each time a new movie or TV episode was added. According to John Schanz, EVP of National Engineering and Technical Operations at Comcast, that meant dealing with dozens of VOD “islands” every time something needed to be upgraded. But now VOD titles are delivered from four massive data centers located throughout the country.

Since Comcast was moving to IP behind the scenes, while it continued to push VOD services on its more traditional architecture, Schanz said the project was kind of like “landing planes on an aircraft carrier while it’s still being built out at sea.” But customers saw very little actual disruption on the front end while Comcast made its changes on the back end.

By simplifying the network infrastructure needed in its local offices, Comcast become a lot more efficient in how VOD is served up. There’s no longer the need to add duplicate storage to each local distribution center to boost the number of titles each can serve, for instance. Rather than ingesting a piece of content in each of 130 locations, it ingests that content once and distributes it via IP to the four regional data centers located in Atlanta, Philadelphia, Chicago and Northern California.

The result is what Schanz calls a complete shift in the units of measure with which Comcast can add new content or features. In terms of ingesting new content, what used to take days can now be done in minutes. And rolling out new features or upgrading infrastructure, which used to take years, can now be done in weeks or months.

The proof is in the pudding

IP-based innovation is driving a huge increase in the amount of content available: When Comcast first announced Project Infinity in 2008, the goal was to increase the number of VOD titles from 1,300 movies to 6,000 the following year. But now Comcast has more than 30,000 choices available in its VOD library. And it’s not just movies; the service has an ever-growing number of TV shows that are being added.

One reason that TV networks are becoming more comfortable with making their shows available on VOD is that they now have better tools to monetize those episodes. It used to be that ads had to be “burned in” to VOD assets, which meant that advertisements weren’t easily changed. If an ad was time-sensitive — for instance, promoting the release of a new movie — it would often be stuck to the same video asset long after the ad was useful. But with IP delivery, Comcast can take advantage of dynamic ad insertion to provide more timely and relevant advertising when people watch its VOD titles. It also provides more flexibility for content owners to set parameters around whether consumers can fast forward through VOD commercials and other capabilities.

As a result, Comcast now has shows from all four major broadcasters on its VOD platform, as well as a wide range of content from cable networks. It has episodes from more than 600 TV series available, a number that continues to expand.

What the future has in store

Moving to IP isn’t just about more efficiently adding new content to the mix, however. Switching to an IP-based system also provides more flexibility for adding new services and reaching new devices. Take, for instance, Comcast’s effort to build an app for Samsung TVs, or the upcoming availability of its VOD service on Xbox Live (s MSFT) for subscribers who also have that game console.

An IP- and cloud-based infrastructure is also at the heart of a new set-top box and user interface it’stesting in limited markets and could soon start rolling out more broadly to subscribers. The set-top box, which was developed under the code name “Xcalibur,” will provide more personalized features, the ability to add IP-based applications and social networking hooks.

With the buildout of its Comcast CDN, there are other new services and features that the cable provider could potentially roll out with little hassle — like a network DVR, for instance. Doing so would move the storage and playback of pre-recorded shows out of the consumer’s home or set-top box and into the cloud. While Schanz wouldn’t comment on future plans for such a service, he did say that the goal of the initiative was to create broad new capabilities so that technology is not a barrier to rolling out new services.

Photos courtesy of Flickr user Kevin Burkett and Serendigity.