All things related to multicast

[Marshall Eubanks <>]

Debbie;

One note : IGMPv3 is a replacement of v2, not just a addition of SSM to 
v3.
It adds some nice features (for example, edge devices don't have to 
listen to the traffic
from every other edge device, which can solve some problems in "Star" 
NBMA LANs).

However, RFC 3376 mandates that

   In order to be compatible with older version routers, IGMPv3 hosts
   MUST operate in version 1 and version 2 compatibility modes.  IGMPv3
   hosts MUST keep state per local interface regarding the compatibility
   mode of each attached network

So, old boxes running ASM will cause new boxes running SSM to fail, at 
least on the
local LAN.

At present I do not know of any killer aps with SSM that are deployed, 
but of course that is partially a chicken and egg situation (and, if I 
am wrong, I am sure someone will correct me).

I do have an SSM video group up and running.

Regards
Marshall


On Mar 7, 2005, at 11:21 AM, debbie fligor wrote:

> So I've got a feature request in at Apple for IGMPv3 support, and 
> they'd like to know what Mac users wont be able to do if we don't have 
> that support.  I'm not that up on what's out there SSM-wise, can those 
> of you that know what's available now, and what's in the pipeline that 
> is SSM based help me out here?
>
> any other useful points I should make? does having an IGMPv2 speaker 
> using multicast on the same subnet as IGMPv3 speakers cause issues, 
> problems (I vaguely recall that the local switch might back out to v2, 
> but I'm not sure if that's only for the one host or for 
> everything...).
>
> thanks for any help you can provide!
>
>
> > The feature has been requested and I'd be happy to add impact 
> > information if you can give me some kind of idea about how this 
> > University will be impacted. I know that the number of machines will 
> > be difficult to determine, but what features or services will Mac OS 
> > X clients be unable to use should IGMPv3 not be added when the 
> > University starts using it? I read the part about wanting to use the 
> > Mac OS X machine for testing purposes, but more information on how it 
> > affects everyone else will help.
>
> --
>
> -debbie
> Debbie Fligor, n9dn       Network Engineer, CITES, Univ. of Il
> email: 
>
>           <http://www.uiuc.edu/ph/www/fligor>
> "Every keystroke can be monitored. And the computers never forget."