配置思路：思路顺序无所谓，什么先后都可以。
配置：
AR1：
interface GigabitEthernet0/0/0
ip address 10.0.12.1 255.255.255.0
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
interface LoopBack1
ip address 11.11.11.11 255.255.255.255
bgp 200
peer 10.0.12.2 as-number 100
ipv4-family unicast
undo synchronization
network 1.1.1.1 255.255.255.255
network 11.11.11.11 255.255.255.255
peer 10.0.12.2 enable
AR2：
interface GigabitEthernet0/0/0
ip binding vpn-instance 1
ip address 10.0.12.2 255.255.255.0
interface GigabitEthernet0/0/1
ip address 10.0.23.2 255.255.255.0
mpls
mpls ldp
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
ip vpn-instance 1
ipv4-family
route-distinguisher 1:1
vpn-target 100:1 export-extcommunity
vpn-target 100:1 import-extcommunity
mpls lsr-id 2.2.2.2
mpls
mpls ldp
bgp 100
peer 4.4.4.4 as-number 100
peer 4.4.4.4 connect-interface LoopBack0
#
ipv4-family unicast
undo synchronization
peer 4.4.4.4 enable
#
ipv4-family vpnv4
policy vpn-target
peer 4.4.4.4 enable
#
ipv4-family vpn-instance 1
peer 10.0.12.1 as-number 200
#
ospf 1 router-id 2.2.2.2
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.0.23.0 0.0.0.255
AR3：
interface GigabitEthernet0/0/1
ip address 10.0.34.3 255.255.255.0
mpls
mpls ldp
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
interface GigabitEthernet0/0/0
ip address 10.0.23.3 255.255.255.0
mpls
mpls ldp
mpls lsr-id 3.3.3.3
mpls
mpls ldp
ospf 1 router-id 3.3.3.3
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.0.23.0 0.0.0.255
network 10.0.34.0 0.0.0.255
AR4:
ip vpn-instance 1
ipv4-family
route-distinguisher 1:1
vpn-target 100:1 export-extcommunity
vpn-target 100:1 import-extcommunity
mpls lsr-id 4.4.4.4
mpls
mpls ldp
interface GigabitEthernet0/0/0
ip address 10.0.34.4 255.255.255.0
mpls
mpls ldp
interface GigabitEthernet0/0/1
ip binding vpn-instance 1
ip address 10.0.45.4 255.255.255.0
interface LoopBack0
ip address 4.4.4.4 255.255.255.255
bgp 100
peer 2.2.2.2 as-number 100
peer 2.2.2.2 connect-interface LoopBack0
ipv4-family unicast
undo synchronization
peer 2.2.2.2 enable
ipv4-family vpnv4
policy vpn-target
peer 2.2.2.2 enable
ipv4-family vpn-instance 1
peer 10.0.45.5 as-number 300
ospf 1 router-id 4.4.4.4
area 0.0.0.0
network 4.4.4.4 0.0.0.0
network 10.0.34.0 0.0.0.255
AR5:
interface GigabitEthernet0/0/0
ip address 10.0.45.5 255.255.255.0
interface LoopBack0
ip address 5.5.5.5 255.255.255.255
interface LoopBack1
ip address 55.55.55.55 255.255.255.255
bgp 300
peer 10.0.45.4 as-number 100
ipv4-family unicast
undo synchronization
network 5.5.5.5 255.255.255.255
network 55.55.55.55 255.255.255.255
peer 10.0.45.4 enable