Multicast

Video on the web has not seen it’s peak yet. And I am not talking about more people watching youtube, but about having all major TV networks streaming their line up in real time in an efficient manner. For TV on the web to take over the traditional cable/sat/aerial, multicasting is needed.

IP multicast allows to share the bandwidth needed to stream video on the web between “nodes”. Right now, if 1 million people request a specific video on a server somewhere, that video will be served 1 million times from that server. This is very expensive bandwidth-wise, and obviously more clever solutions are needed. Multicast allows to share the load with ISPs. The ISP will receive the stream and then share it in real time to the customers who request it, instead of hitting the main server over and over again. It is like a cache, but a cache that updates all the time.

We are years away before multicasting becomes common. I’d say anywhere between 5 and 8 years. In fact, 2015 sounds like a good year… The problem is that it requires the ISPs to support multicasting. I don’t think Comcast does (or that it wants to support it). Operating systems will need to be updated too, Vista has support for it, Leopard doesn’t. And the most difficult change of all: it requires new features on people’s routers/firewalls. Only few router models support “IGMP” right now, and the ones that do, are usually ridden with problems. If you are in the UK and you have the right router/ISP, then you can try BBC’s multicasting.

But eventually, the situation will straighten out. And then video on the web will be really cheap, which means that most will jump on streaming HD video right off the bat. And then it will flourish for good and cable-TV companies will go the way of the dodo.

9 Comments »

Alex wrote on December 14th, 2007 at 2:23 AM PST:

The sad thing is that most ISPs don’t won’t to bother with multicast, they’re just happy enough with getting thousands of subscribers to surf the web and check email.

My ISP won’t even consider the BBC trial, so I doubt many people will get it for a long time.


Luis wrote on December 14th, 2007 at 4:54 AM PST:

If I understand correctly, this multicast system will only work when lots of people view something at the same time? Or at least more or less at the same time?

In Spain we have a digital TV that goes through the ADSL internet connection. I think that what they do can be called “broadcasting”, but the end users have some flexibility for watching programs at different times due to a Tivo-like device that records automatically things in a hard drive. I guess this is the only solution to the problem right now, and probably even better than multicasting.

For a true “a la carte” TV I guess the bandwidth problem will always remain. I mean a site like Youtube with thousands of videos (but full movies, full series, and all high quality) so you can watch what you want when you want. For this you need individual connections between the source and the end user, and with millions of users that’s overkill.


Phil wrote on December 14th, 2007 at 7:21 AM PST:

The BBC has been trialling multicast for ages. I used to watch News 24 with it (it’s now available 24/7 using standard streaming). However you never know when they are going to turn the streams on/off (for testing I presume) so you can’t really depend on them being available. I wonder whether they will _ever_ launch the multicast service officially ?


Brent Noorda wrote on December 14th, 2007 at 11:21 AM PST:

Are you unhappy with the on-demand streaming (which can never be much helped by standardized multicasting) from networks such as ABC, FOX, Discovery, or the other stream provide by Move Networks?


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Eugenia wrote on December 14th, 2007 at 1:10 PM PST:

Brent, what do you mean? I am not unhappy with anything, it’s just that the networks and other TV channels can’t fully move to the web to complement their other broadcasting ways.


Brent Noorda wrote on December 14th, 2007 at 9:10 PM PST:

I assumed you were recommending a solution, because why would you recommend a solution if there isn’t a problem. I misunderstood. Sorry.

I was interested in the topic because in the past few weeks I screwed up on tivo and missed on two shows I wanted to see. In one case I tried the bittorrent route, and in the other case the TV networks web page. The bittorrent case went terribly slow (perhaps comcase was throttling?) while the ABC show went amazingly well.

You suggest video on the web can be made really cheap. Is that assuming the Great Internet Brownout of 2010 does not happen?


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Eugenia wrote on December 14th, 2007 at 9:45 PM PST:

The solution is for the video providers, the user won’t see anything different than before. ABC can handle the demand right now because not many people are watching episodes online through their site. Yet. But if they want to do a full broadcasting via the web, then they will run out of bandwidth sooner than later.


popper wrote on December 17th, 2007 at 5:39 AM PST:

there seems to be lots of confusion abound 😉

IP Multicast has been around since the day DOT, as has IP Broadcast but we are not concerned about that here, as Multicast is the way forward with a twist.

“IGMP” isnt the problem today, its the worlds ISPs themselves that are infact the luddites here, they turned it off, and just wont turn it back on.

everything required for End User multicast in already installed and powered in the routers and related kit at your local ISP TODAY, they turned it off thats all as they didnt see a need for it (the poor blinkered beak counters).

to get an idea of how long multicasting has been around, do a simple search on the ‘MBONE’ network to see just how it was once user tested.

even today, the UK universitys janet network still has their routers and related kits multicast options turned on and usable by students, but alas, the average end users and the great bedroom developers of the worlds ISPs cant use this great option until the ISP turns it back on.

iv been advocating the ISPs turn on multicasting for years now and finally ordinary people are starting to realise just how it may improve their useage and save VAST amounts of bandwidth.

Eugenia, your not seeing the bigger picture yet, and the users are the people that will see the difference, ill explain.

its gets better though, take the old MBONE ideas as a base and update the old mindset for the future and todays P2p applications and the small groups of seeds at any given time.

currently everything p2p related is using by far the werst transport in that as you said ,if 10 or 100 users want that Eugenia-video.AVC.torrent they will use the IP unicast tcp/udp method.

that as you say means sending 10 or 100 copys one to each person, in the case of torrent the bandidth is shared but it can be so much better with multicast extension that already exist graffed into the AZ client for instance.

http://bamboo-dht.org/
http://bamboo-dht.org/tutorial.html

“Marcel has also written a report about his experiences building a multicast protocol on top of Bamboo. It may also be useful for tutorial purposes. ”

if we still cant get the ISPs to turn on multicasting at their routers and related kit we can still use sumthing like
http://www.cdt.luth.se/~peppar/progs/mTunnel/
“multicast Tunnel – mTunnel

The mTunnel is an application that tunnels multicast packets over an unicast UDP channel. Several multicast streams can be sent over the same tunnel while the tunnel will still only use one port. This is useful if tunneling through a firewall.
The applications primary goal is to allow for easy tunneling of multicast over for instance a modem and/or an ISDN connection.

The mTunnel has a built in Web-server allowing for easy access to information about current tunnels. This server listens by default on port 9000 on the machine where started.

The mTunnel also listens on session announcements for easier tunneling of known sessions.

If you download and install this package please send me an email! 🙂 (peppar@cdt.luth.se)

The latest public version is 0.3 released 980102.
README Changelog
Download: Windows UNIX

This version is NOT compatible with earlier versions of mTunnel!

I have also written two papers about this application: Paper1 – 1998 Paper2 – 1997 ”

theres always the DOCSIS (pre 2.0B-)3.0 that mandates multicast all the way to and from the end users kit if the the likes of the UKs Virgin Media see fit to follow the spec and activate the IPv6 multicasting but thats a while away yet before we can try and get the developers to start adding multicast capabilitys as per above as the java code base.

hell just havingthe abaility to VLC multicast video on 224.whatever UDP to your mates on the same internal ISP links would be a very good start to saving vast amounts of bandwidth on you uplink.

its pritty simple, you setup a webpage were you can register your interest in upcoming video streams and after a short time and/or more than 2 people what it, the server user sends out the auto invite to join such and such a multicast IP and send the video.

later if the devs add in the ability , we use the multicast DHT to automate this action and send as required to say upto 10 or 100 at a time, and in turn ,they will have their part of the multicast swarm take any parts they want/need if its a re-send or new request doesnt matter much.

its just as now but with updated multicast client server P2p style as its new core, MASSIVE BANDWIDTH SAVED long term.

thats the basic outline ,ill leave it to you to think about and improve if you see fit .code it up and test it on a Mtunnel even if you think your able or know someone that can….


Ygg wrote on December 17th, 2007 at 7:18 AM PST:

of course leopard supports multicast, i’m using it atm

and for luis, imagenio does use multicast for the ip channels you get on the imagenio homepage, they’re currently migrating from mpeg2 to mpeg4 and will add DRM beginning of 2008 if everything goes well

which it never does, it’s spain after all 😉


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