Option A方案，要点是，PE与ASBR之间建立MP-BGP关系，PE-P-ASBR使用MPLS LDP传输公网标签，ASBR与ASBR之间建立vpn-instance的EBGP邻居来延续私网标签的传输，另外AR1与AR8同属一个AS，由于AS的EBGP防环策略，需要配置allow-as-loop命令来指定重复次数，不指定为1

由于AS200与AS100配置镜像，只放PE1与ASBR1配置

PE1：

#
 sysname AR2-PE1
#
ip vpn-instance PE1
 ipv4-family
  route-distinguisher 100:1
  vpn-target 100:200 export-extcommunity
  vpn-target 100:200 import-extcommunity
#
mpls lsr-id 2.2.2.2
mpls                                      
#
mpls ldp
#
interface GigabitEthernet0/0/0
 ip binding vpn-instance PE1
 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 
#
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 PE1 
  peer 10.0.12.1 as-number 64512 
#
ospf 1                                    
 area 0.0.0.0 
  network 2.2.2.2 0.0.0.0 
  network 10.0.23.2 0.0.0.0 
#
return

ASBR1：

#
 sysname AR4-ASBR1
#
ip vpn-instance ASBR1
 ipv4-family
  route-distinguisher 100:4
  vpn-target 100:200 export-extcommunity
  vpn-target 100:200 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 ASBR1
 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 ASBR1 
  peer 10.0.45.5 as-number 200 
#
ospf 1                                    
 area 0.0.0.0 
  network 4.4.4.4 0.0.0.0 
  network 10.0.34.4 0.0.0.0 
#
return