[c-nsp] SSM and multicast IP addresses

[Phil Mayers]

netman wrote:
> In order for Source Specific Multicast (SSM) to work properly, does the 
> source addresses need to be in the 232.x.x.x range?
> 
> Will SSM work with source addresses in the 224.1.x.x range?

SSM is PIM without an RP. The joins and prunes are just sent towards the 
source. It will work on any range you configure it on. However, when the 
PIM joins pass into other networks, they'll "change direction" towards 
the RP for that domain.

Basically - don't abuse network ranges like this. Use 232/8 or a 
locally-scoped block from 239/8 or you'll run into trouble.