R1：
interface Tunnel12
ip address 192.168.12.1 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.1
tunnel destination 123.123.123.2
!
interface Tunnel13
ip address 192.168.13.1 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.1
tunnel destination 123.123.123.3
!
interface Ethernet0/0
ip address 123.123.123.1 255.255.255.0
half-duplex
no shutdown
!
interface Ethernet0/1
ip address 14.14.14.1 255.255.255.0
half-duplex
no shutdown
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 14.14.14.1 0.0.0.0 area 0
!
R2：
interface Tunnel12
ip address 192.168.12.2 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.2
tunnel destination 123.123.123.1
!
interface Tunnel23
ip address 192.168.23.2 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.2
tunnel destination 123.123.123.3
!
interface Ethernet0/0
ip address 123.123.123.2 255.255.255.0
half-duplex
no shutdown
!
interface Ethernet0/1
ip address 25.25.25.2 255.255.255.0
half-duplex
no shutdown
!
router ospf 1
router-id 2.2.2.2
log-adjacency-changes
network 25.25.25.2 0.0.0.0 area 0
!
R3：
interface Tunnel13
ip address 192.168.13.3 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.3
tunnel destination 123.123.123.1
!
interface Tunnel23
ip address 192.168.23.3 255.255.255.0
ip ospf 1 area 0
tunnel source 123.123.123.3
tunnel destination 123.123.123.2
!
interface Ethernet0/0
ip address 123.123.123.3 255.255.255.0
half-duplex
no shutdown
!
interface Ethernet0/1
ip address 36.36.36.3 255.255.255.0
half-duplex
no shutdown
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 36.36.36.3 0.0.0.0 area 0
!
R4:
interface Loopback0
ip address 4.4.4.4 255.255.255.0
!
interface Ethernet0/1
ip address 14.14.14.4 255.255.255.0
half-duplex
no shutdown
router ospf 1
router-id 4.4.4.4
log-adjacency-changes
network 4.4.4.4 0.0.0.0 area 0
network 14.14.14.4 0.0.0.0 area 0
!
R5:
interface Loopback0
ip address 5.5.5.5 255.255.255.0
!
interface Ethernet0/1
ip address 25.25.25.5 255.255.255.0
half-duplex
no shutdown
router ospf 1
router-id 5.5.5.5
log-adjacency-changes
network 5.5.5.5 0.0.0.0 area 0
network 25.25.25.5 0.0.0.0 area 0
!
R6:
interface Loopback0
ip address 6.6.6.6 255.255.255.0
!
interface Ethernet0/1
ip address 36.36.36.6 255.255.255.0
half-duplex
no shutdown
router ospf 1
router-id 6.6.6.6
log-adjacency-changes
network 6.6.6.6 0.0.0.0 area 0
network 36.36.36.6 0.0.0.0 area 0
!