And I've seen plenty of gear without SSM support: Some of the larger offenders: Juniper Clusters. Cisco ASA Some Linksys managed switches (no IGMP snooping support for it). I really wouldn't think it'd be that hard to implement SSM if the equipment had functional ASM support, but that's a story for another day I guess. Most development for mcast largely occurred between the last 90s and early 2000s it seems. Since ~2005 once the hopes of inter-domain multicast fizzled and IPTV failed to launch in any meaningfully way, multicast development has largely been neglected by the major equipment vendors and cast away as some funky thing used by certain enterprise and educational market segments. At least, IMHO... On Thu, May 3, 2012 at 6:44 PM, Greg Shepherd <gjshep@gmail.com> wrote:
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