December 2, 2009
Multicast Ready for Comeback
The multicast protocol for adding broadcast-like functionality to the Internet has been around for nearly two decades. Various technical limitations, however, have impeded its widespread adoption. Could it be making a comeback?
Yes, if for no other reason than the advent of IPv6, which activates IP multicast by default. It may also gain traction by way of secure multicast for advanced repeating of television (SMART), a technology developed by Ventura CA-based startup Worldcast.
An early investor in Worldcast was Ray Miller, a Cable Television Pioneer, past chairman of the NCTC, a director of the Outdoor Channel and current chairman of Country Cablevision. Miller said he believes that multicast has the possibility of turning the traditional cable television programming distribution model on its head.
How so? It will allow programmers to get their content out for a fraction of the cost of traditional satellite distribution. In the future, it could also enable a new type of lower-cost cable TV distribution architecture in which cable operators could provide thousands of virtual channels, while only having to pass along the channels that consumers want to watch.
CDNs vs. multicast
The broadcast TV linear programming model has not translated well to the Internet owing to a mismatch between the technologies.
Broadcast TV leverages the airwaves and satellite links to bring the same content to everyone, while the Internet requires more bandwidth for more viewers. Broadcasters pay nothing for additional user to receive their signal. In contrast, a content provider on the Internet must pay for more server and network capacity as their audience grows.
The most common approach for overcoming this challenge using traditional TCP/IP technology is to create multiple copies of the content that is cached close to the users. For example, Akamai, the largest content distribution network (CDN), worked very closely with Microsoft’s Silverlight technology to develop a novel architecture for scaling up live programming feeds. In this system, special content management servers store and retransmit video to the end users.
During last year's Olympics, NBC used Silverlight technology and Akamai to carry more Olympics coverage than could be carried on their traditional television broadcasts.
In the past, NBC would have had to configure and deploy more servers as the number of recipients grew. But Akamai’s new architecture allowed NBC to scale up on demand without having to go through the hassle of provisioning more servers. The downside was that NBC had to pay more money for Akamai’s content distribution servers as the traffic grew.
Multicast technology only provides an advantage when content is streamed live to a large audience. It does not work with content that is stored on a server and played back later, such as YouTube videos or Hulu programming.
Dawn of multicast
Multicast technology was first proposed by Internet pioneer Steve Deering in 1991 as a way to broadcast information to multiple sites on the Internet.
Multicast allows the routers to share the signals rather than requiring a server to do so. Although most IPv4 routers today support multicast it must be manually turned on by each network provider. In contrast, multicast is turned on by default in IPv6, which is likely to increase the use the of technology.
One of the main challenges with multicast technology is a chicken-or-egg kind of dilemma.
No one benefits until it becomes widely available. Network operators don’t benefit until they are faced with sending a lot of the same traffic to different users at the same time. Multicast will not reduce the number of servers that content providers need until it is widely available. Multicast is widely available in Japan, Korea, Europe, and on university campuses in the U.S., but is not widely used on commercial networks in the U.S.
Joe Breen, assistant director of networking at the University of Utah and Worldcast consultant, said there has been a lot of research on commercial multicast networks. But there have been some technical issues associated with the multicast implementations from different routing equipment vendors.
“There have been a lot of bugs in the carrier platforms, and that has scared people away,” Breen said. However, he believes that these problems will be ironed out with the roll out of IPv6.
Building a better multicast
Raw multicast technology is rather primitive, said Worldcast CTO Ian Stewart. “Because multicast got really beat up by the technical revolution, nobody came up with a tool to make it secure, reliable and bi-directional," he said.
Encryption protects a Worldcast SMART transmission from piracy and prevents others from taking over a broadcast, as Captain Midnight did with HBO in the last 1990s. An upstream channel built into SMART monitors the quality of the stream seen by the end user and tracks their viewing habits. Forward error correction sends along extra packets to keep the quality of video high even when packets are lost as basic multicast technology makes it difficult to retransmit lost packets.
The SMART platform also allows broadcaster to insert targeted advertising based on a user’s viewing history. The commercials can be stored on the client, and then played between live video feeds, which allow the commercials to be customized for each user.
SMART works on multicast-enabled networks, and also support existing TCP/IP networks that have not been multicast enabled. This gives broadcasters a way to get started immediately, and then gain additional benefits as more multicast links are turned on. Breen said that Verizon, AT&T, and SureWest are all looking at multicast as one way of providing live video programming over their broadband networks.
Stewart believes that the SMART platform will help content providers develop more viable business models for streaming live programming on the Web.
“A lot of the ISPs think that they more traffic they carry the more money they can make,” he said. “They have only just begun to realize that video streaming is killing them. SMART enables the business model, which has been missing from multicast.”
World’s largest cable operator?
Dynamic Media International is a new video programming startup founded by Alan Bailey, formerly a VP at Paramount Pictures. The company plans to use the Worldcast SMART technology to provide linear multicast programming over the Internet. Bailey jokes the 300 million households passed by multicast make them the largest cable operator from day one.
Dynamic Media plans to launch through U.S. colleges and universities. The company can send each university a single stream, which can then be picked up by all of the authorized students. The encryption capability built into SMART will allows them to control access and sell subscriptions to premium channels.
Bailey said that he would have had to pay $35,000 per month to launch a channel over traditional satellite technology, which would not have supported their highly targeted business model. With the Worldcast technology, Dynamic Media only has to pay for a modest Internet connection.
“We felt that the traditional model was too much of a shotgun approach,” Baily said. “A lot of the channels get very spotty viewership, and it is not precisely measured. We wanted to target it more so we could go to an advertiser and tell them exactly who is watching.”
Dynamic Media plans to give away the first three months for free and to charge $2.99 for all 14 channels. Bailey expects to initially offer the content as a standalone service, but as the technology matures, and more Internet connections become multicast enabled, he hopes to work with other partners.
“In the long run, we hope to be providing programming to cable operators, and they could set up the advertising on a revenue shared basis,” he said. “We have also offered to white label channel for advertisers or colleges and business, so instead of 14 channels we could be offering 50-60.”