Re: v6-in-v4 configured tunneling over v4 multicast (vs 6over4)

[Erik Nordmark <Erik.Nordmark@sun.com>]

> Good question.  I suppose the idea is to transition the network to 
> IPv6, and being able to do the same with v6.  I think the argument in 
> the original scenario was that if there is no mechanism for v6, people 
> could not transition their apps etc. to v6, or might delay the v6 
> deployment for the lack of support.
> 
> If truth be told, and considering dual-stack deployments, this is not 
> really convincing, because as it works with v4, and the only thing 
> missing from v6 is the support in their equipment, a correct 
> response could be continue using it w/ v4 and request implementing v6 
> multicast support, or buy only products which support that.

It would seem odd to have an organization which uses IP(v4) multicast
try to transition to IPv6 while forgetting that they need IPv6 multicast
support to allow their multicast applications to transition.

Since this is an operational WG, have we received requests from folks operating
IPv6 that they are running into this particular problem? 

> But delaying v6 deployment due to this might not be a good idea 
> either, which is why I thought a separate multicast tunnel could be an 
> easy solution to this problem.

Easy to specify in a short RFC, but do we know anything about the 
operational complexity (trouble-shooting etc) of the resulting
network? For all I know it might be a lot more complex than
just operating dual-stack (with multicast support for both v4 and v6).

  Erik