hostname R4
!
ip multicast-routing
!
interface Loopback104
 ip pim sparse-dense-mode
 ip igmp join-group 239.255.1.1
!
interface Serial0/0/0
interface Serial0/0/0.43 point-to-point
 ip pim sparse-dense-mode
!
interface Serial0/0/0.124 point-to-point
 ip ospf network point-to-multipoint
!
interface Serial0/0/1
 ip pim state-refresh origination-interval 30
 ip pim sparse-dense-mode
!
router ospf 1
 router-id 4.4.4.4
 log-adjacency-changes
 network 172.16.0.0 0.0.255.255 area 0