AR4总部CE和isp的R1用一条物理链路，做成两条线连接，一条用子接口，2条一个是进入的流量，一个是出去的流量
主要是靠RT和RD来实现，有两种方法：
第一种：
原理是AR5和AR6发出的RT export报文全部对应R1上面的RT import，也就是说R1上面RT import设个队列（本身RT就可以设置多个），一个对应R5的出RT，一个对应R6的出RT，AR1上面的出RT export思路刚好相反，同样配置。
第二种：
如果R5和R6都设置相同的出和入RT，那R1就只设备一个出和入RT就可以了，同时可以接收和发送给两台设备，本案例配置就是这样，这样最简单。
分部R6的as号和总部重复了，用sub替换AS号解决，isp区域R1和总部R4用双线in和out也有as重复的问题，一个口子用sub替换as号做，一个口子用allow-so-loop来允许重复次数来做，思路是所有的as冲突问题都在isp部分来做，ce客户端不做配置。
ospf在发布loopback口子网络时，只支持32位，不支持24位，要支持就得打一条命令：
ospf network-type broadcast
实现效果：AR5和AR6的bgp路由来回都走总部AR4绕行
R1配置：
router id 1.1.1.1
wlan ac-global carrier id other ac id 0
set cpu-usage threshold 80 restore 75
ip vpn-instance in
ipv4-family
route-distinguisher 100:1
vpn-target 100:101 import-extcommunity
ip vpn-instance out
ipv4-family
route-distinguisher 100:11
vpn-target 100:100 export-extcommunity
mpls lsr-id 1.1.1.1
mpls
mpls ldp
isis 1
is-level level-2
cost-style wide
network-entity 49.0001.0000.0000.0001.00
is-name r1
firewall zone Local
priority 15
interface GigabitEthernet0/0/0
ip binding vpn-instance out
ip address 172.16.1.1 255.255.255.0
interface GigabitEthernet0/0/0.10
dot1q termination vid 10
ip binding vpn-instance in
ip address 172.16.10.1 255.255.255.0
arp broadcast enable
interface GigabitEthernet0/0/1
ip address 10.0.12.1 255.255.255.0
isis enable 1
isis circuit-type p2p
isis ppp-negotiation 3-way only
mpls
mpls ldp
interface GigabitEthernet0/0/2
ip address 10.0.13.1 255.255.255.0
isis enable 1
isis circuit-type p2p
isis ppp-negotiation 3-way only
mpls
mpls ldp
interface NULL0
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
isis enable 1
bgp 100
peer 2.2.2.2 as-number 100
peer 2.2.2.2 connect-interface LoopBack0
peer 3.3.3.3 as-number 100
peer 3.3.3.3 connect-interface LoopBack0
ipv4-family unicast
undo synchronization
peer 2.2.2.2 enable
peer 3.3.3.3 enable
ipv4-family vpnv4
policy vpn-target
peer 2.2.2.2 enable
peer 3.3.3.3 enable
ipv4-family vpn-instance in
peer 172.16.10.2 as-number 65000
peer 172.16.10.2 substitute-as
ipv4-family vpn-instance out
peer 172.16.1.2 as-number 65000
peer 172.16.1.2 allow-as-loop 2
R2
router id 2.2.2.2
wlan ac-global carrier id other ac id 0
set cpu-usage threshold 80 restore 75
ip vpn-instance vpn
ipv4-family
route-distinguisher 100:2
vpn-target 100:101 export-extcommunity
vpn-target 100:100 import-extcommunity
mpls lsr-id 2.2.2.2
mpls
mpls ldp
isis 1
is-level level-2
cost-style wide
network-entity 49.0001.0000.0000.0002.00
is-name r2
firewall zone Local
priority 15
interface GigabitEthernet0/0/0
ip address 10.0.12.2 255.255.255.0
isis enable 1
isis circuit-type p2p
isis ppp-negotiation 3-way only
mpls
mpls ldp
interface GigabitEthernet0/0/1
ip binding vpn-instance vpn
ip address 172.16.2.1 255.255.255.0
interface GigabitEthernet0/0/2
interface NULL0
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
isis enable 1
bgp 100
peer 1.1.1.1 as-number 100
peer 1.1.1.1 connect-interface LoopBack0
peer 3.3.3.3 as-number 100
peer 3.3.3.3 connect-interface LoopBack0
ipv4-family unicast
undo synchronization
peer 1.1.1.1 enable
peer 3.3.3.3 enable
ipv4-family vpnv4
policy vpn-target
peer 1.1.1.1 enable
peer 3.3.3.3 enable
ipv4-family vpn-instance vpn
import-route ospf 1 route-policy test
ospf 1 vpn-instance vpn
import-route bgp
area 0.0.0.0
network 172.16.2.1 0.0.0.0
route-policy test permit node 10
if-match ip-prefix test
ip ip-prefix test index 10 permit 5.5.5.0 24
R3：
router id 3.3.3.3
wlan ac-global carrier id other ac id 0
set cpu-usage threshold 80 restore 75
ip vpn-instance vpn
ipv4-family
route-distinguisher 100:3
vpn-target 100:101 export-extcommunity
vpn-target 100:100 import-extcommunity
mpls lsr-id 3.3.3.3
mpls
mpls ldp
isis 1
is-level level-2
cost-style wide
network-entity 49.0001.0000.0000.0003.00
is-name r3
firewall zone Local
priority 15
interface GigabitEthernet0/0/0
ip address 10.0.13.3 255.255.255.0
isis enable 1
isis circuit-type p2p
isis ppp-negotiation 3-way only
mpls
mpls ldp
interface GigabitEthernet0/0/1
ip binding vpn-instance vpn
ip address 172.16.3.1 255.255.255.0
interface GigabitEthernet0/0/2
interface NULL0
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
isis enable 1
bgp 100
peer 1.1.1.1 as-number 100
peer 1.1.1.1 connect-interface LoopBack0
peer 2.2.2.2 as-number 100
peer 2.2.2.2 connect-interface LoopBack0
ipv4-family unicast
undo synchronization
peer 1.1.1.1 enable
peer 2.2.2.2 enable
ipv4-family vpnv4
policy vpn-target
peer 1.1.1.1 enable
peer 2.2.2.2 enable
ipv4-family vpn-instance vpn
peer 172.16.3.2 as-number 65000
peer 172.16.3.2 substitute-as
R4
router id 4.4.4.4
wlan ac-global carrier id other ac id 0
set cpu-usage threshold 80 restore 75
firewall zone Local
priority 15
interface GigabitEthernet0/0/0
ip address 172.16.1.2 255.255.255.0
interface GigabitEthernet0/0/0.10
dot1q termination vid 10
ip address 172.16.10.2 255.255.255.0
arp broadcast enable
interface GigabitEthernet0/0/1
interface GigabitEthernet0/0/2
interface NULL0
interface LoopBack0
ip address 10.0.4.4 255.255.255.0
bgp 65000
peer 172.16.1.1 as-number 100
peer 172.16.10.1 as-number 100
ipv4-family unicast
undo synchronization
network 10.0.4.0 255.255.255.0
peer 172.16.1.1 enable
peer 172.16.10.1 enable
R5：
interface GigabitEthernet0/0/0
ip address 172.16.2.2 255.255.255.0
interface GigabitEthernet0/0/1
interface GigabitEthernet0/0/2
interface NULL0
interface LoopBack0
ip address 5.5.5.5 255.255.255.0
ospf network-type broadcast
ospf enable 1 area 0.0.0.0
ospf 1
area 0.0.0.0
network 172.16.2.2 0.0.0.0
R6
router id 6.6.6.6
interface GigabitEthernet0/0/0
ip address 172.16.3.2 255.255.255.0
interface GigabitEthernet0/0/1
interface GigabitEthernet0/0/2
interface NULL0
interface LoopBack0
ip address 6.6.6.6 255.255.255.255
bgp 65000
peer 172.16.3.1 as-number 100
ipv4-family unicast
undo synchronization
network 6.6.6.6 255.255.255.255
peer 172.16.3.1 enable
