mulcast assignments

Fri May 4 23:45:14 UTC 2012

On Fri, May 4, 2012 at 2:53 AM, Jeff Tantsura
<jeff.tantsura at ericsson.com> wrote:
> Hi,
>
> All modern routers support mapping from IGMPv2 to PIM SSM, all static, some others thru DNS, etc

I am not sure what you mean here. To support SSM, you need IGMPv3. Most
routers do support IGMPv3, but there is still a fair amount of legacy
gear at various
edges which doesn't.

Regards
Marshall

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