RE: [MBONED] APPSDIR review of draft-ietf-mboned-64-multicast-address-format-01

["Manfredi, Albert E" <[e-mail]>]

> From: [e-mail] [mailto:[e-mail]] On
> Behalf Of Brian Haberman

> On 5/9/12 10:52 PM, Lee, Yiu wrote:
> > Hi Carsten,
> >
> > Thanks very much for reviewing the document. I just want to add a
> point to
> > your question about how applications decide when to use this
> multicast
> > address format. In fact, they don't. Imagine a use case where a
> legacy
> > IPv4 IP-TV receiver (an app) wants to join a channel which is
> broadcasted
> > in IPv6. The app will continue to send the igmp-join (say 224.1.2.3).
> 
> How does the IPv4 IP-TV know to join 224.1.2.3?

My suggested answers would be:

The IP-TV server provider's EPG web site provides the IP-TV with the multicast group address.

> How is 224.1.2.3 advertised to the IPv4 IP-TV clients if the content is
> generated by an IPv6 source?  Does the source need to be configured to
> use one of these IPv4-in-IPv6 multicast addresses?

The EPG web server detects that the client IP-TV is using IPv4, so it provides the IPv4 address.

> > There will be a function in the network which is statically
> configured
> > that when it receives a igmp-join, it would covert to a corresponding
> > mld-join. The IPv6 address in the join message will follow what is
> > described in this draft. This Adaptive Function is transparent to the
> > application and managed by the network.
> 
> Are you limiting this approach to only mapping at the IGMP/MLD
> protocols?
> 
> How does your Adaptive Function know which IPv6 multicast prefix to use
> when mapping the IPv4 multicast address in the IGMP Report message to
> MLD?

This has to be table lookup. The IPv6 prefix for these IPv4 multicast groups is always the same, or the service provider has a table that specifies the IPv6 prefix for use with each IPv4 group.

Bert