Re: You asked about multicast scope

[Iljitsch van Beijnum <[e-mail]>]

On 28 Mar 2012, at 12:08 , Fred Baker wrote:

>> I haven't read the spec yet, but isn't PCP supposed to work in the service provider run NAT64/CGN case, too? In that case, the multicasts need to escape out of the site or even organization to reach the service provider at least in the SOHO case. So this would be a scope just shy of global, maybe a new "service provider" scope?

> I personally rarely use "zero configuration" and "service provider" in the same sentence...

Am I understanding you correctly when I take that to mean that the admin (value 4) scope is appropriate because then the people running the multicast routing can determine exactly how far these packets travel?

That makes sense, but there is one potential issue, that I think some people who are well-steeped in IPv6 multicast should look at: in this situation, the scope value 4 may need wider distribution than side-wide, which is scope 5. I can't find any documentation on whether that's ok or not between sessions right now, but I'm reluctant to assume that a lower scope value can have wider distribution than a higher one without having a spec that explicitly says so or hearing from some implementers.

Iljitsch