6.2. Multicast Testing
SG shows successful ping from R6 to Group. didnt work for me...and historically for others... one gentleman gives nice solution from below link at old forum "ip multicast multipath"
i would be nervous to use that solution...but great idea for real world.
my fix to get succesful pings was to make R3 to prefer path to vlan26 and loopback over the ospf (with distance command). wierd that R3's routing decision breaks R6 pinging ablility....