nanog mailing list archives

Re: mulcast assignments


From: Nick Hilliard <nick () foobar org>
Date: Thu, 03 May 2012 23:32:56 +0100

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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