Re: Simple Multicast - building a case for a BOF or WG

[Ken Carlberg <carlberg@time.saic.com>]

Dave,

caveat: my original comments where really beyond the scope being 
discussed for a new working group, so i guess the list should 
just consider this a side thread.

>  I wonder how much of an issue the QoS/R will ever be in practice because
> we seem to have evolved to a pretty hierarchical structure to internetworks,
> so the best QoS will typically come from following the hierarchy, i.e.
> from source thru tail circuit to local ISP to wide-area ISP, and then out
> and down to receivers.  Do you have a network topology of concern where
> this does not work out?

yes, several, but none that i can discuss openly.

from a generic perspective, one of the examples i like to use is the 
connectivity between Europe and the US.  right now there are several 
transatlantic links connecting the two regions -- involving several
ISPs.  if one simply focused on the shortest path from europe to a 
source in the U.S., there would be state/data along several of these 
links.  however, if we could use a different criteria, we could 
conceivably collapse this to just a single path between US and Europe 
and have the fan-out originate from one ISP in Europe.

besides the reduction there would also be a potential savings of 
monetary cost.  this assumes that transatlantic fiber costs more 
to use then transcontinental fiber.

>  Also, I dont believe that single-source has to be constrained to just
> use shortest path, although I agree that would require coordination with
> the RPF check.  It might be interesting to explore support for asymmetric
> routing as part of this issue, if we believed that satellites had a future.

i believe satelites, together with land mobile radio and other 'last mile'
wireless systems do have a place.  some being unidirectional, some,
bi-directional.

-ken