Slashdot Mirror

The translation list is here.

I never said anything about nuclear war, I specified fault tolerence. There's a big difference. Several tens of megatonnes of difference. Providers offering virtual circuits for extranets sometimes use MPLS, but not all. Service guarantees are over time and can be provided by packet marking and QoS. Isolation likewise. When providing full mesh services, which is what many corporate ISPs are moving towards, something like MPLS is a disadvantage. Containment and QoS is only safe at endpoints, and running anything heavier than you need on a full mesh (which itself is insanely hard on routers) is asking for trouble.

The MBONE, if it had ever been adopted

not every institution looking at the data will be interested in the same data at the same time

True and not true.

Multicast has developed to the point where there is little doubt that one service model, Single Source Multicast (SSM, explained further at the Multicast FAQ file) could serve unlimited numbers of receivers with a stream, even in the commodity Internet. And Multicast is powering most new IPTV deployments - see the U Wisconsin DATN for a cool example. BUT, content providers do not want to supply their content with global SSM multicast, and there is no strong demand yet for sourcing niche video channels. (Existing deployments use multicast to get from a local POP to the user, but do not allow multicasts in from outside.)

BTW, 3GPP MBMS and 3GPP2 BCMCS now allow for true multicast to wireless phones, but there is as yet little use of it.

The BBC is trying to change this with their Multicast trials, and I think it almost inevitable that multicast channels will be allowed into the "walled gardens," but end users are only likely to get this ability if there is strong customer demand for it.

Note, BTW, that multicast in practice won't help an ISP that has severely underprovisioned their edge circuits, at least if there is a typical distribution of channels being watched.

I'm a 'member' of a studio in Pennsylvania. For twenty dollars a year, you can buy a membership and download MP3s or OGGs from a long list of local music.

With outfits like
Steam Powered Studios , who needs Sony?

The internet is not meant to be a broadcast medium, nor is it very good as one. Ask online radio stations that not only must now pay high license fees, but also must buy lost of servers and bandwidth to stream audio to a few listeners, nothing like traditional broacast mediums (radio, tv, even broadcast cable and satelite) which scale much better.

That's absolutely true, if you look at unicast streaming methods. But there's definately technologies out there to get around that. Multicast is an excellent way to get over that nasty bottleneck that expensive bandwidth creates. The main problem with multicast? Not everyone has it. Its one requirement is that every device in the path be multicast enabled.

Check out this FAQ for a starter on multicast. Read up on PIM-SM, the dominant multicast protocol, and the future of multicast which is SSM. These are protocols that are designed specifically for one-to-many applications, which is ideal for things like audio and video streaming. Unfortunately, the only major OS with built-in SSM support is Windows XP. There's patches out there for specific Linux and FreeBSD kernels to add the necessary IGMP v3 support, but you won't see it in the main builds. Why? I wish I knew.

If your cable modem is DOCSIS 1.1 compliant, then it's capable of multicast. But most ISPs don't want to enable multicast. A lot of the time, they've never even heard of it, even though it's been around since the mid-80s. It's a requirement for IPv6, but Juniper and Cisco routers don't support it yet. I definately haven't seen any IPv6 multicast enabled applications.

Multicast is out there, and it's exactly the type of communication model that we need in order to scale audio and video streaming applications on the Internet. On 9/11, an audience of 2000 was watching CNN Headline News over a multicast feed from the University of Chicago. It was a single 300 kbps video stream that never ran into the issue of a bandwidth bottleneck that CNN's own website had. And quite frankly, that audience could have grown to over a million, and the University of Chicago's server never would have known it. It still would have been sending out a single 300 kbps stream, and still reached all those people.

Multicast keeps going. There are now many multicast connected IPV4 networks exchanging MBGP routes, but yes, very few networks multicast down to the end-user.

I've asked a few Internet2 people about multicast, and while the backbone certainly is, the "last mile" to users often is not.

I was recently working for a company that was delivering multicast webcasts from major streaming providers over satellite to ISPs. But most of us were laid off, I don't know what is going on now.

There are a few companies to help you get going with multicast such as Multicast Technologies. Also the GEANT network in Europe is multicast capable. And here is a list of active SDR listings, kind of a "tv guide" for multicast.

The original MBONE's routing architecture wasn't scalable. More sophisticated routing schemes have been devised fairly recently but to my knowledge there are next to no ISPs that offer multicast connectivity to consumers.

Marshal Eubanks of Multicast Tech did an interview on cnet radio (go here and search for multicast) he was pretty optimistic about multicast being deployed. He gave the startling figure that 20% of broadband users had access to the multicast internet. I was shocked by this because I have scoured the 'net looking for a consumer isp that would offer it to consumers and haven't found anything. Anyone have any info?

AC wrote:

Just curious, but what incentive is there for DSL providers to enable multicast anyway? I'm not trolling, or faming or anything, just asking a question; you seem to know about it. What are the benefits/costs for the company, benefits/costs for the consumer? What good is it for anyway? Thanks!

Multicast reduces bandwidth usage because if multiple users are receiving the same live stream on a network only one copy of the stream has to traverse that network.

The downside of multicast is that it requires every piece of equipment in between the source and receiver to be multicast enabled, there a costs to upgrading network infrastructure to support multicast. Operating a multicast enabled network can be complex because many of the protocols are immature, there are costs to training staff.

MBONE FAQ
Multicast FAQ from multicasttech

AC wrote:

Just curious, but what incentive is there for DSL providers to enable multicast anyway? I'm not trolling, or faming or anything, just asking a question; you seem to know about it. What are the benefits/costs for the company, benefits/costs for the consumer? What good is it for anyway? Thanks!

Multicast reduces bandwidth usage because if multiple users are receiving the same live stream on a network only one copy of the stream has to traverse that network.

The downside of multicast is that it requires every piece of equipment in between the source and receiver to be multicast enabled, there a costs to upgrading network infrastructure to support multicast. Operating a multicast enabled network can be complex because many of the protocols are immature, there are costs to training staff.

MBONE FAQ
Multicast FAQ from multicasttech

I think this is a very important question, thanks to Slashdot for finally posting it. Users should demand multicast connectivity. A multicast enabled internet would dramatically lower the cost of delivering multimedia content, thus making a wider variety of content available. Currently, delivering multimedia to large numbers of users is quite expensive, preventing many from having access to large audiences.

MSN used to offer multicast connectivity, I'm not sure when they stopped. Anyone know the story on this?

A few things consumers can do:

-if you are shopping for an ISP of any kind ask about multicast and try to get the question to get as high up the chain as possible.

-Sprint offers free multicast connectivity to its ISP customers, if yours peers with them let them know this. (does Sprint offer multicast connectivity to its consumer grade customers?)

-check to see if you've got multicast connectivity through this applet from multicasttech. If you are let other people know about your ISP, on forums like dslreports

I think this is a very important question, thanks to Slashdot for finally posting it. Users should demand multicast connectivity. A multicast enabled internet would dramatically lower the cost of delivering multimedia content, thus making a wider variety of content available. Currently, delivering multimedia to large numbers of users is quite expensive, preventing many from having access to large audiences.

MSN used to offer multicast connectivity, I'm not sure when they stopped. Anyone know the story on this?

A few things consumers can do:

-if you are shopping for an ISP of any kind ask about multicast and try to get the question to get as high up the chain as possible.

-Sprint offers free multicast connectivity to its ISP customers, if yours peers with them let them know this. (does Sprint offer multicast connectivity to its consumer grade customers?)

-check to see if you've got multicast connectivity through this applet from multicasttech. If you are let other people know about your ISP, on forums like dslreports

You can test whether your network is multicast enabled using the multicast tester applet. If you are, information about the content available can be found at the Internet 2 Multicast Calendar web site.

Cisco offers their IPTV, which is commercially available.

There are several H.323 streaming server commercially available as well. This standard is used by many Internet2 video applications.

There are also open source alternatives. The vic vac and rat tools long in use on the old mbone are certainly available in open source : for netbsd and for Linux.(You might want to read this before you get into these.)

If you want to multicast your streaming video, you should contact Multicast Tech.