mulcast assignments

Jeff Tantsura jeff.tantsura at
Fri May 4 06:53:00 UTC 2012


All modern routers support mapping from IGMPv2 to PIM SSM, all static, some others thru DNS, etc


On May 3, 2012, at 12:34 PM, "Nick Hilliard" <nick at> 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.
> Nick

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