拓扑：
配置：
R1：
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!
ip multicast-routing
!开启组播路由
interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.1.254 255.255.255.0
ip pim sparse-mode
!开启pim-sm模式
interface Ethernet0/1
ip address 192.168.12.1 255.255.255.0
ip pim sparse-mode
!
interface Ethernet0/2
ip address 192.168.13.1 255.255.255.0
ip pim sparse-mode
!
!
router ospf 1
router-id 1.1.1.1
network 1.1.1.1 0.0.0.0 area 0
network 192.168.1.254 0.0.0.0 area 0
network 192.168.12.1 0.0.0.0 area 0
network 192.168.13.1 0.0.0.0 area 0
!配置底层igp路由
ip pim rp-address 2.2.2.2 override
!静态指定RP
R2：
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!
ip multicast-routing
!
interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.12.2 255.255.255.0
ip pim sparse-mode
!
interface Ethernet0/1
ip address 192.168.235.2 255.255.255.0
ip pim sparse-mode
!
!
router ospf 1
router-id 2.2.2.2
network 2.2.2.2 0.0.0.0 area 0
network 192.168.12.2 0.0.0.0 area 0
network 192.168.235.2 0.0.0.0 area 0
!
ip pim rp-address 2.2.2.2 override
!
R3:
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!
ip multicast-routing
!
interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.13.3 255.255.255.0
ip pim sparse-mode
!
interface Ethernet0/1
ip address 192.168.235.3 255.255.255.0
ip pim sparse-mode
!
!
router ospf 1
router-id 3.3.3.3
network 3.3.3.3 0.0.0.0 area 0
network 192.168.13.3 0.0.0.0 area 0
network 192.168.235.3 0.0.0.0 area 0
!
ip pim rp-address 2.2.2.2 override
R5:
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!
ip multicast-routing
!
interface Loopback0
ip address 5.5.5.5 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.235.5 255.255.255.0
ip pim sparse-mode
!
interface Ethernet0/1
ip address 192.168.2.5 255.255.255.0
ip pim sparse-mode
!
!
router ospf 1
router-id 5.5.5.5
network 5.5.5.5 0.0.0.0 area 0
network 192.168.2.5 0.0.0.0 area 0
network 192.168.235.5 0.0.0.0 area 0
!
ip pim rp-address 2.2.2.2 override
PC6:
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!
interface Ethernet0/0
ip address 192.168.2.6 255.255.255.0
ip igmp join-group 239.1.1.6
!路由器模拟PC，加入组播组
!
router ospf 1
network 192.168.2.6 0.0.0.0 area 0
!
PC7:
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!
interface Ethernet0/0
ip address 192.168.2.7 255.255.255.0
ip igmp join-group 239.1.1.7
ip igmp join-group 239.1.1.6
!
!
router ospf 1
network 192.168.2.7 0.0.0.0 area 0
!
PC8:
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!
interface Ethernet0/0
ip address 192.168.2.8 255.255.255.0
ip igmp join-group 239.1.1.8
ip igmp join-group 239.1.1.7
ip igmp join-group 239.1.1.6
!
!
router ospf 1
network 192.168.2.8 0.0.0.0 area 0
!
验证：
SERVER ping 239.1.1.6，如图：
注意，因为此实验环境存在MA网络的等价路径，所以第一次ping时会出现双倍数量的包，请多ping几次，待R2和R3声明（assert）谁为该网络的组播转发者后，再查看R1的组播路由表，如图：
发现R1会选择E0/2作为oif，组播包会走右边的R3（R2、R3路径等价，会选择IP地址较大的R3作为转发者），再到R5。
再查看R2、R3的组播路由表，会发现R2上去往239.1.1.6的oif是NULL，R3上去往239.1.1.6的oif是E0/1，与预期相符，如图：
