Confirming source-routed multicast is dead on the public Internet

Miles Fidelman mfidelman at
Wed Aug 1 17:38:56 UTC 2018

On 8/1/18 12:24 PM, Saku Ytti wrote:

> Hey Mankamana,
>> other than billing problem, is there any other reasons why multicast would not be viable for public internet ?
> Imagine someone like youtube or netflix would like to use multicast,
> instead of caches. They'd need to start new multicast stream for every
> content with small delay (to get more viewers on given stream), how
> much delay would consumer tolerate before content starts? 1min? 5min?
> So every minute or every 5 minute new stream of movie would be sent,
> except it would need to be sent many times, for each bitrate
> supported.
> Each of these streams is wide (wider than unicast) HW state that needs
> to be stored on every device on path, for unicast we only store 1
> narrow HW state per destination, for multicast we store 1 wide HW
> state per flow/stream, we don't have the hardware to do that, if there
> would be any significant demand for multicast.
> It only works when there is no use-case for it, and even then, it's
> insecure DoS vector.
Personally, I think the use case is a lot stronger for multi-person 
video conferencing.

Miles Fidelman

In theory, there is no difference between theory and practice.
In practice, there is.  .... Yogi Berra

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