步骤
1、配置AS 100中的内部互联路由ISIS 100
2、配置MPLS LDP
R2\R3\R4
3、配置R2\R4的BGP
4、配置R2\R4的vrf
vrf：ABC
RD:11:22
RT:11:22 44:55 import-extcommunity
RT:11:22 export-extcommunity
vrf：CBA
RD:44:55
RT:11:22 44:55 import
RT:44:55 EXPORT
5、启用R2/R4的VPNV4
ipv4-family vpnv4
policy vpn-target
peer 4.4.4.4 enable
6、路由引入
ipv4-family vpn-instance ABC
import-route isis 1
isis 1 vpn-instance ABC
is-level level-2
cost-style wide
network-entity 49.0002.0040.0400.4004.00
import-route bgp
