[MLB-WIRELESS] Nasa Tv over MW

Tyson Clugg tclugg at umd.com.au
Thu Sep 20 11:00:00 EST 2007


> >More importantly however what would happen if say 100 people all wanted
> >to watch NASA TV at the same time on the network eg due to a shuttle
> >launch? Would the streaming tv have to be carried 100 separate times
> >across the network thus overloading the system or is there some way to
> >distribute one signal across the network and people can just passively
> >receive the streamed packets?
> 
> You would need multicast, which means that all routers in the network 
> need to support IGMP and one or more multicast routing 
> protocols.  Otherwise it's one stream per user, which will kill the network.

Multicast is already enabled on the MW network - we use it with our core
routing protocol (OSPF).

However, dynamic multicast is better suited to this sort of stream - if
nobody is watching Nasa TV, then the multicast data would simply be
wasting what little bandwidth we have.  Unfortunately, dynamic multicast
protocols are still largely in the realm of academics.

If someone can demonstrate dynamic multicast working correctly (initial
testing with <5Kbps streams on the MW network, please!), and we can be
assured that the overheads are small then I'd be happy to see this
proceed.

Cheers,
Tyson Clugg.




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