All things related to multicast

[Leonard Giuliano <>]

Can you encrypt the traffic and just distribute the keys to the people you 
want to be able to view it?  The semantics of addressing lends itself 
easily towards "internal" and "external"; going beyond that is probably 
not ideal with addressing.

Or put more simply, how would you solve this problem if it were unicast 
(WWUD)?  I don't see how mcast provides any special considerations for 
this situation.  However you would solve this for unicast, I'd do the same 
for mcast.

-Lenny

On Tue, 21 Oct 2008, Julian Y. Koh wrote:

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-) Short question:
-) 
-) We here at NU are working on a project where we're looking at the
-) possibility of sharing multicast video with another school, but with that
-) school only.  What's the brain trust's opinion on how we should think about
-) setting that up in terms of what group addresses to use?
-) 
-) Longer version w/ more detail:
-) 
-) We have a set of 37 video channels that we distribute to our campus and, in
-) the case of 2 of those (CSPAN and CSPAN2), to Internet2 and private
-) multicast-enabled peers.  The CSPAN channels obviously use our GLOP
-) addressing (233.0.103.0/24), and all the other channels are on
-) administratively scoped groups from the 239/8 block.
-) 
-) Another school in the area is thinking about using the same video solution,
-) and thus came up with the idea of sharing some of the costs with us and
-) getting some of their channels from our encoders.  We are planning on
-) setting up a private BGP peering session, probably via MREN.
-) 
-) This content would only be sent to this other school, so we don't want to
-) use our GLOP addressing.  OTOH, it seems like we don't really want to use
-) 239/8 space either, since that opens us up to possible group address
-) overlap.  Plus, we have filters on our border router that would block 239/8
-) traffic.  We could make exceptions, but exceptions in router configurations
-) are, as I'm sure we'd all agree, are not fun.
-) 
-) So, is there some middle ground between 239/8 and GLOP addressing that
-) exists for something like this?
-) 
-) Thanks in advance!
-) 
-) 
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-) -- 
-) Julian Y. Koh                         
<mailto:>
-) Network Engineer                                   <phone:847-467-5780>
-) Telecommunications and Network Services         Northwestern University
-) PGP Public Key:<http://bt.ittns.northwestern.edu/julian/pgppubkey.html>
-)