Rich's Media: The Power of Multicast
How Multicast is Changing the Face of Streaming
Conventional TV is ideally suited for the delivery of live programs where immediacy matters. But since the advent of videotape, live TV programs have been all too rare. A local network affiliate might broadcast only 1 hour per day of live content, and even these programs contain a lot of recorded material. So live video makes up only 4% of the typical broadcast day; the remaining 96% is dedicated to stored content.
Of course, cable news channels are an exception, but even they broadcast a lot of recorded content. And maybe the percentage is slightly higher during the rare nonrepeat Saturday Night Live episode or during an American Idol live voting show. Still, the point is that the vast majority of broadcast television consists of content that could easily be delivered by other means.
Today, if you set out to build a system that delivers stored content to consumers, you might not gravitate to the conventional TV model. You might build a system that allows viewers to select the content they want and then download it or stream it via the public internet. But there is a rub—internet bandwidth is not free and unlimited. While there is no increase in expense for a broadcaster for each additional conventional television viewer, there is a cost for every additional viewer via the public internet. Once a conventional television broadcaster obtains a television transmitter, it costs the same amount to deliver content to one or 1 million viewers. For internet delivery, it costs incrementally more to deliver content to each viewer. But if you own your network, then streaming is truly free. Enterprises have figured this out.
During a recent Streaming Media East session, we explored enterprise streaming with a defense contractor, an insurance company, a mortgage company, and an accounting firm. These were all large organizations with thousands of employees, some with branches in far-flung corners of the world. For live video, they all use the IP equivalent of television broadcasting: IP multicast.
Multicast, which is older than the World Wide Web, provides unlimited streaming distribution. Like television, it costs the same amount regardless of whether there is one viewer or there are 1 million viewers. While television broadcasters employ radio frequency (RF) engineers, enterprise multicast broadcasters employ IP staff members that specialize in their craft, and they have gotten really good at it. Today, it requires almost no effort to send a live broadcast to 50,000 employees.
The somewhat surprising news is how pervasive multicast has become. Just a few years ago, the suggestion that multicast should be enabled throughout an enterprise would have provoked groans about how hard the enterprise IT staff would push back. Now the IT staff has become a full partner, and the growth continues.
Interestingly, for many companies the adoption of enterprise multicast did not come about because of a serendipitous network upgrade. Rather, it was because enterprise streaming came to be recognized as a vital business service. In other words, the ROI for enterprise streaming justified a network upgrade.
But multicast is not universal. The connection from enterprise headquarters to branch offices commonly traverses the public internet, where multicast is verboten. Thankfully, low-cost "reflectors" and "stream splitters" are easily installed. These devices can receive a unicast and then deliver it as a multicast to the branch office, so thousands of remote viewers can tune in. The result is a global enterprise webcast with thousands of viewers but the cost of only a handful.
However, receiving a multicast at a corporate desktop can present a player problem. Because Windows Media Player supports multicast natively, it is currently the dominant technology. Silverlight, Microsoft’s next-generation multimedia technology, does not support multicast, although a new open source multicast plug-in is now available. Adobe Flash does not support multicast, while QuickTime supports live MPEG-4/H.264 multicast and is a standards-based solution, meaning it supports nonproprietary transport. At the same time, there is widespread deployment of MPEG-2 multicast, especially in the educational community, where VLC and other players prevail.
Coupled with intelligent content distribution systems that replicate stored content at branch offices, enterprises are becoming globally equipped to deliver live and stored content to all employees for many purposes. Giving employees access to key executives via regular live briefings, providing just-in-time training, and cultivating a corporate culture are just a few of the reasons both large and small organizations are deploying streaming media.