On Thu, May 3, 2012 at 3:32 PM, Nick Hilliard <nick@foobar.org> wrote:
On 03/05/2012 21:00, Greg Shepherd wrote:
Sure, but GLOP predated SSM, and was really only an interim fix for the presumed need of mcast address assignments. GLOP only gives you a /24 for each ASN where SSM gives you a /8 for every unique unicast address you have along with vastly superior security and network simplicity.
SSM is indeed a lot simpler and better than GLOP in every conceivable way - except vendor support. It needs igmpv3 on all intermediate devices and SSM support on the client device. All major desktop operating systems now have SSM support (OS/X since 10.7/Lion), but there is still lots of older hardware which either doesn't support igmpv3 or else only supports it in a very primitive fashion. This can lead to Unexpected Behaviour in naive roll-outs.
I haven't seen a piece of network gear without SSM support in a very long time. The weak link is the applications. It was the OS stacks but that's finally caught up - it only took it 10 years... The weakest link is simply multicast deployment - if it's not everywhere it has little use. That's what AMT is promising to fix. And with AMT comes the opportunity to bring SSM to non-SSM-capable apps if it is implemented correctly. Greg
Nick