All things related to multicast

[Hitoshi Asaeda <>]

Greg,

> one-to-many content, even if not using the SSM group range,
> couldn't/shouldn't the SDP file still contain the source address? If

I agree.
But RFC4570 (SDP extension for source filter) allows to specify source
address. Hence it is not SDP's problem but the problem at the
application side or operational side.

> so, any application with IGMPv3 support (or AMT) could join the SPT
> without depending on MSDP. I'm guessing the SDP file was created
> automatically by the streaming device/software and is strictly
> following the ASM service model (even if it does support SSM). Until

For the applications working with SDP, it's not difficult to specify
source address as well as multicast address, if the applications
allows to insert source address unlike the old vic or rat.
However, there are other streaming applications using metafile,
e.g. windows media player. For these applications, data senders should
mention source addresses inside the metafiles or should notify
source addresses as their operations. SDP does not help for them.

> the streaming vendors begin offering this as a feature, the sdp file
> could still be hacked manually to add src.

Most recent applications such as vlc support to insert a single source
address, I think. (No use case for EXCLUDE mode operations though.)

> Time for a thread on mmusic.

I don't think so, because it's not sdp or any signaling protocol's
problem.
Defining "how multicast sessions should be notified to potential
receivers" is the most important thing for this matter. This is the
operational consideration.

Regards,
--
Hitoshi Asaeda