How do you put a TV station on the Mbone?

david raistrick drais at
Fri Apr 29 22:34:26 UTC 2011

On Fri, 29 Apr 2011, George Bonser wrote:

> Exactly.  If more people/networks took advantage of multicast, it would 
> greatly reduce the bandwidth requirements, particularly for live events. 
> If there were 50 people listening to a popular radio show or watching a

1) As a consumer network (enterprise, home) - that case is VERY rare.  50 
people consuming it at your house?  Or at the office consuming the same 
feed?  (even at a 10k employee company, the rate of that is fairly low, 
particularly on the same leg of the network - I'd love to see some 
statistics that prove me wrong).   The amount of work that goes into 
supporting and maintaining this is much higher than the return I'd get 
from it.  Even assuming the upstreams supported it.

2) as a content provider, there's a lot of extra work involved to maintain 
this with my upstreams, and every mid-stream between me at the consumer 
networks.  I require specialists in multicast (comparatively speaking 
unicast specialists are a dime a dozen) and I have to fight a lot of 
politics with the upstreams, and I -still- have to support the unicast 
models so the folks who can't consume multicast can see my content.

3) as an a midstream network provider I have almost no motivation to 
support this.  Sure, my network usage would be reduced - but I (more or 
less simplified here, but) make my living on each bit of traffic I carry - 
if I offered a way for providers and consumers to reduce their traffic, 
that would reduce the amount they pay me.  Win for them, lose for me.

the fact of the matter is that until multicast or it's like -doesn't- 
require massive end-to-end support (and frequently configuration to 
support each stream), there won't be heavy use of it.    When I can turn 
up a multicast stream as easily as I can turn up a unicast stream, there 
is -still- a absolute lack of client-side software to recieve and playback 
the streams, and very limited support for broadcasting the streams.

...david (one time multicast specialist supporting a 200,000 seat 4 
channel multicast infrastructure, so I'm fully aware of what magic is 
really involved in maintaining it across divergent networks that -WE- 
owned (or could exercise control of).  before that streaming 40Gb/s (~200 
channels of unicast video for general consumers + on demand streams)

david raistrick
drais at   

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