How do you put a TV station on the Mbone? (was: Royal Wedding...)

Antonio Querubin tony at
Sat Apr 30 19:35:32 UTC 2011

On Sat, 30 Apr 2011, Chris Adams wrote:

> I can also see how this affects the ISPs providing bandwidth to the
> content providers.  In our colo for example, we rate-limit customers to
> the paid-for bandwidth at the colo port.  With multicast however, they
> could use significantly more bandwidth, because every router in our
> network could potentially send the stream to many ports.

Only if you're using hubs or dumb switches.  If your switch is multicast 
aware, the multicast traffic only goes to ports with active listeners for 
a particular group.  Routers send multicast traffic only if there are 
active downstream listeners (where "downstream" doesn't mean the same for 
unicast as it does multicast).

Antonio Querubin
e-mail:  tony at
xmpp:  antonioquerubin at

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