All things related to multicast

[Bill Owens <>]

On Mon, Feb 28, 2011 at 02:23:07PM -0800, Stig Venaas wrote:
> Hi Bill
> 
> On 2/28/2011 2:12 PM, Bill Owens wrote:
> >I think that the level of interdomain multicast is low, and not likely to 
> >increase. So I would like to talk about v6 multicast, since I've grown 
> >jaded and find ordinary v4 multicast to be quite boring ;)
> >
> >Actually, it's because I have been worrying for some time about how the 
> >transition to v6 multicast will affect the current users, though they may 
> >be few in number. Specifically because we will lose interdomain any-source 
> >multicast, which means that the original vic/vat model of sources being 
> >able to come and go as they please simply doesn't exist any more.
> 
> I believe you can still have this, using embedded-RP.
> 
> >This means no more "TV guide" function with SAP/SDP, which won't be much 
> >missed since the list has long been clogged with advertisements from 
> >admin-scoped groups coming from misconfigured sources. Unfortunately it 
> >also affects the folks at the Access Grid, based on what I can find out 
> >about how their software is set up.
> 
> But SAP/SDP cannot be done as now, at least you can't expect everyone
> in the world to use the same RP for a single common group. There is
> nothing stopping say Access Grid from using say an embedded-RP group
> for SAP/SDP though...

I agree, and in fact it might be possible for a future AG software kit to 
include a sort of 'portable RP' that could handle the embedded-RP function 
for a specific group. But I'm not sure how much that will change their model 
of operation; for example, whether a given AG conference happens on just one 
group address or uses multiples, whether they're preconfigured or grabbed on 
the fly as the conference is set up, etc. Embedded-RP will also require that 
the site hosting the RP remain active and participating (at least their RP) 
for the entire time. I had the impression that there isn't that sort of 
'host' role in the current model.

I suppose that I'm mostly worried about the AG community, one of the few 
regular users of interdomain multicast, not being aware of the changes that 
are coming down the pike and being unprepared to deal with v6 multicast. 
Google finds some discussion of adding v6 support to the tools themselves, 
but nothing about the switch away from ASM. Anyone know if that's being 
worked on already, and I'm just worrying for nothing? ;)

Bill.