Hi Hussein,
I had to think about this for awhile and do another lab…something interesting happened With the DMVPN topology that I usually use (switch in the middle), multicast traffic went directly from spoke1 to spoke2. Take a look at this Wireshark capture:
The ICMP request from spoke1 isn’t encapsulated. The reply from spoke2 is.
So I labbed this up again, replaced the switch in the middle with a router. When you do this, all multicast traffic from spoke1 to spoke2 goes through the hub (because we have a static multicast map for the hub IP address). There is no direct spoke-to-spoke multicast traffic.
The only way to achieve that is by adding the ip nhrp map multicast command with the IP address of the remote spoke. Not a feasible solution as it doesn’t scale well. With two spoke routers it’s no problem but if you want multicast traffic between all spoke routers then you’ll need a full mesh of “ip nhrp map multicast” commands.
If you want to see it for yourself, here’s the physical topology I used:
And the configurations are here:
Spoke2-show-run-2018-03-23-14-53-06-clean.txt (1.1 KB)
Hub-show-run-2018-03-23-14-53-01-clean.txt (932 Bytes)
Spoke1-show-run-2018-03-23-14-53-03-clean.txt (1.1 KB)
ISP-show-run-2018-03-23-14-53-08-clean.txt (471 Bytes)
Rene