September 29, 2004 4:00 AM PDT
Perspective: Broadband dreams and multicast 'beams'
See all Perspectives
If technology pundits are to be believed, the most cutting-edge way to do this would be to fire up your home PC, download a movie (from a vast, legal online library of movies) and watch it via your wireless home network on your big-screen TV. The reality, however, is vastly different.
What's the problem? Unfortunately, the Internet is not ready to be a true entertainment medium. It cannot provide the instant gratification and quality consumers have come to expect from DVDs--once you have the DVD, that is. As a result of its architecture, the Internet cannot cater to a vast number of people simultaneously asking for large files such as movies.
Broadband Internet service providers advertise their "fast Internet" speeds. They often claim to give you more than a megabit per second, but the reality is that at any given moment, they make available only an average of approximately 20 kilobits per second for each subscriber: one-fiftieth the bandwidth they advertise.
Yes, you may experience speeds of 1mbps or more--but most likely only when, one, you request a small piece of content like a Web page, not a movie, and two, most of your neighbors are not using their Internet connections. In other words, your ISP is counting on you spending only a tiny fraction of time using its network to look at your e-mail or check up on your eBay auction.
If you started using the network to download movies--and your neighbors did, too--your ISP would have one-fiftieth of the bandwidth required. This would make downloads slow and painful. Watching that Internet-delivered movie "on demand" becomes impossible. And forget about using the Internet to download the high-definition movies that Hollywood will be introducing in the near future: These high-def movie files require five times the data of current DVDs.
So, are you stuck with the trips to the video store to get the flicks you really want? The folks at MovieBeam don't think so.
How does it work? MovieBeam starts with one insight. Today's Internet fails when you are sending the same movie "file" to millions of movie watchers. A better way would be to "broadcast" the same movie to those millions. So instead of sending millions of files, MovieBeam only sends one. To do this, it built a proprietary data network that inserts the movie bits into unused television broadcast spectrum. Since the broadcast tower does all the really hard work, the investment in infrastructure is minimal. MovieBeam "beams" 10 movies a week over this network to the easy-to-install MovieBeam receiver that stores the movies in a high-capacity hard drive.
With this system, popular movies are "pre-positioned" in the MovieBeam receiver; the movie you want to watch is (hopefully) already in your home and available "on demand" when you want to watch it. There are no download issues, and the quality is not constrained by Internet bandwidth, so all movies are in DVD quality. And the system will work just as well for high-def movies.
Today's Internet simply cannot compete with MovieBeam's efficiencies. If MovieBeam wanted to use the Internet, it would be sending 10GB of data--roughly the size of 10 compressed DVDs--to every MovieBeam user. If there were a million MovieBeam users, that would translate into 10 petabytes (!) of data each week--the equivalent of 15 percent of total U.S. Internet traffic for this service alone. And, of course, should more people want the service, the network requirements would increase proportionately.
Current Internet technology simply cannot keep up. However, there is a solution to make the Internet more of a "broadcast" platform, and therefore a more effective entertainment medium.
"Multicast" is a technology that efficiently broadcasts data over the Internet. With multicast, only one copy of the movie file would cross the Internet--and that one copy would be replicated for each user who wants a copy. If the Internet were "multicast-enabled," MovieBeam would send out only 10 gigabytes per week over the Internet, no matter how many users it had.
Multicast was developed in the 1980s, and most routers that handle Internet traffic are already configured for it. So why hasn't it yet been enabled?
Unfortunately, ISPs are slow to embrace multicast, and there is no plan for them to work together to deliver multicast yet. But it is time for them to develop such a plan. One possibility: ISPs could broadcast popular content over satellite networks. Whatever the plan, it is my hope that multicast will be enabled soon, and when it is, the Internet will finally make good on its true broadband promise.
Biography
Vint Cerf is chairman of the Internet Corporation for Assigned Names and Numbers and senior vice president of technology strategy at MCI. Widely known as one of the "fathers of the Internet," Cerf is the co-designer of the TCP/IP protocols and the architecture of the Internet.
See more CNET content tagged:
movie,
Internet Service Provider,
movies,
broadband Internet,
broadband
On my 384Kb/s DSL, I consistently get over 300 kb/s throughput. On my nominally 1.5 MB ADSL, I consistently get over 1 megabit.
20 kb/s is less than half the speed of 56K modem.
I just don't believe it, 'cause if it was true, there'd be big class-action "bait-and-switch" litigation.
I agree w/ his opinion that multicast needs to be implemented across consumer internetworks. The current network topologies and business models prohibit content owners from providing higher quality content. The flipside to this argument however is that ISP "x" would potentially have to either perform a massive infrastructure upgrade to support multicast or even forklift existing infrastructure.
Mr. Cerf you would be surprised to know that there are upstream providers and content owners/distributors that are ready for downstream providers to support multicast.
If you were to get all of your neighbors to actively downloads or browse at the same time, the would have to split the bandwidth up depending on how much bandwidth is reaching your neighborhood. On an average, his claim is very true. Although you say you do reach the bandwidth that your promises you, there is no way you would reach that if you were in an area where many people were using the at one time. An example would be New York. The bandwidth in a city as active as this could very easily be somewhere around 20 - 40 kilobits per , because this is all your has dedicated to you. With all of this said, his claim is correct based on his discussion of movie . If the replaced the local movie rental store, then there would be millions of people downloading movies. If this were happening at this exact , the would be very slow. are not ready for this kind of change. Yes, you may your bandwidth and then some more, but if the load is intense, your has really only dedicated you 20 kilobits per second (download speed, not throughput or downstream).
Also, about the bottlenecking of the speed. "" can be split, but this would not help if the was not ready to split the . The speeds today are just not fast enough, and would by far surpass your opinion sir.
and there is no 'downloading' to a local hard
drive before the watching starts. This fact
completely rules out multicast as a solution,
because every video stream needs to be controlled
individually.
In Asian countries (like Japan) subscribers can
get symmetric 20 Mb link for a bit less than US
customers pay for their 'big' 3 Mb service. The
concept of broadband is very relative. Anyways,
with a 20 Mb link, there is no issue in getting
HD-TV service, in addition to phone and internet.
The technology for such does exist and we must
not think that the US has is the best example on
what can be done with it. At least, not yet.
If you were to get all of your neighbors to actively downloads or browse at the same time, the ISP would have to split the bandwidth up depending on how much bandwidth is reaching your neighborhood. On an average, his claim is very true. Although you say you do reach the bandwidth that your ISP promises you, there is no way you would reach that if you were in an area where many people were using the internet at one time. An example would be New York. The bandwidth in a city as active as this could very easily be somewhere around 20 - 40 kilobits per seccond, because this is all your ISP truely has dedicated to you. With all of this said, his claim is correct based on his discussion of movie transfering. If the internet replaced the local movie rental store, then there would be millions of people downloading movies. If this were happening at this exact momment, the internet would be very slow. ISPs are not ready for this kind of change. Yes, you may recieve your alloted bandwidth and then some more, but if the load is intense, your ISP has really only dedicated you 20 kilobits per second (download speed, not throughput or downstream).
Of course I think there is a roll for multicasting--today's broadcast and cable networks could migrate to the internet and multicast there...there will always be a certain amount of content people will want to watch at the same time e.g. live events, breaking news or stuff people will want to discuss over the veritable watercooler the next day. But I think you need both the on-demand option with a wide selection plus a limited feed of multicast programming.
Over any network that is IP Multicast-enabled, Wavexpress Multicast channels offer different genres of content. Users subscribe to whatever channels interests them. Programs for those channels are cached and later deleted according to rules set by the content publisher. Users also have complete discretion as to how much content is cached and, of course, greater granularity is possible such that a consumer could elect to only cache a portion of the content on a particular channel.
One of the great advantages to cached IP Multicast, besides the greatest bandwidth efficiency, is that you can surf the web with no degradation. For example if you are a cable modem user and your cable operator has provided you a 1.5 Mb/s connection, the Multicast packets do not count against the throttle. So these packets do not slow down your regular (unicast) web surfing and the Multicast content is cached transparently. Additionally, this service works great across wireless LANs because the content is packaged in files which employ forward error correction so you can have substantial packet loss with no loss in video quality.
1) The 20Kbit shared access is only from the ISP to the global
internet, and it requires all 50 to be online at the same time -
which they of course never are. With a 10% concurrency, the rate
is suddenly a respectable 200K.
2) But video and TV programs are likely to be streamed from
servers within an ISP network, and thus only depend on the line
to each household. DSL can in most cases do more than 2mbit
but even up to 8mibt, and the new ADSL2+ can do up to 20mbit
or more. Cable modems can do 40 mbit/channel and with 80
channels the capacity is 3.2 GB for each loop. And loops can be
made smaller by inserting new headends in the tree network.
3) Compression means less bandwidth is required to transmit
DVD-quality video and TV. With the new H.264, 1-1.2 mbit/s is
considered DVD quality.
4) Multicasting not useful for video as it requires local storage
with is impractical and not desired by content providers. But
multicasting is key for live TV transmissions, which can give
cable, satellite and terrestrial broadcasters a serious run for
their money.
5) There will be multiple broadband paths into the home. WiMax
ISPs will start operations next year and offer DSL-like
performance at perhaps even lower prices and different
coverage. Hence, each network will not be maxed out at all
times.
Is this something that could be done? tested? anytime soon at a
Public Access TV stations, which have limited distribution only to
a local area via cable? Could their programs be made available
to a wider audience this way?
Thanks,
Hal
1. It's not typically IP routed, but ATM based, so it doesn't understand IP-based (typical) mulitcast.
2. It is oversubscribed typically at 4:1 minimum, but often much higher than that, meaning that if you have a 1.5Mb/s link, then 4 or more neighbors will share an aggregation of 1.5Mb/s. Ratios of 50:1 or greater are not uncommon.
The idea has promise, but still has the typical "last-mile" problem.
Now with the broadband boom there *may* be enough demand to revisit this, but I expect any potential investors would be gun-shy at this point.