配置思路：
1.首先配置ISP内部的IGP协议，一般使用OSPF、ISIS路由协议。
2.配置ISP内部的mpls、ldp协议。
3.为PE设备创建VRF，把连接CE的接口划分进VRF（vpn、RD、RT）。
4.配置PE和CE之间的路由协议（静态路由、默认路由、OSPF、RIP、ISIS等，OSPF用的较多）。
5.PE之间创建MP-BGP邻居
6.PE路由器上做路由双向引入（如ospf引入bgp、bgp引入ospf）
接口ip地址配置忽略。
1、配置AS100内ISIS为IGP协议
[R1]isis 1
[R1-isis-1]network-entity49.0001.1111.1111.1111.00
[R1-isis-1]int lo0
[R1-LoopBack0]isis enable 1
[R1-LoopBack0]int g0/0/2
[R1-GigabitEthernet0/0/2]isis enable 1
[R2]isis 1
[R2-isis-1]network-entity49.0001.2222.2222.2222.00
[R2-isis-1]int lo0
[R2-LoopBack0]isis enable 1
[R2-LoopBack0]int g0/0/2
[R2-GigabitEthernet0/0/2]isis enable 1
[R2-GigabitEthernet0/0/2]int g0/0/1
[R2-GigabitEthernet0/0/1]isis enable 1
[R3]isis 1
[R3-isis-1]network-entity49.0001.3333.3333.3333.00
[R3-isis-1]int lo0
[R3-LoopBack0]isis enable 1
[R3-LoopBack0]int g0/0/1
[R3-GigabitEthernet0/0/1]isis enable 1
[R1]ping -a 10.0.1.1 10.0.3.3
PING 10.0.3.3: 56data bytes,press CTRL_C to break
Reply from 10.0.3.3: bytes=56 Sequence=1 ttl=254 time=70 ms
2、配置运营商网络AS100的MPLS和LDP
[R1]mpls lsr-id 10.0.1.1
[R1]mpls
[R1-mpls]mpls ldp
[R1-mpls-ldp]int g0/0/2
[R1-GigabitEthernet0/0/2]mpls
[R1-GigabitEthernet0/0/2]mpls ldp
[R2]mpls lsr-id 10.0.2.2
[R2]mpls
[R2-mpls]mpls ldp
[R2-mpls-ldp]int g0/0/2
[R2-GigabitEthernet0/0/2]mpls
[R2-GigabitEthernet0/0/2]mpls ldp
[R2-GigabitEthernet0/0/2]int g0/0/1
[R2-GigabitEthernet0/0/1]mpls
[R2-GigabitEthernet0/0/1]mpls ldp
[R3]mpls lsr-id 10.0.3.3
[R3]mpls
[R3-mpls]mpls ldp
[R3-mpls-ldp]int g0/0/1
[R3-GigabitEthernet0/0/1]mpls
[R3-GigabitEthernet0/0/1]mpls ldp
3、配置PE设备之间的MP-BGP
[R1]bgp 100
[R1-bgp]peer 10.0.3.3 as-number 100
[R1-bgp]peer 10.0.3.3 connect-interface lo0
[R1-bgp]peer 10.0.3.3 next-hop-local
[R1-bgp]ipv4-family vpnv4 unicast
[R1-bgp-af-vpnv4]peer 10.0.3.3 enable
[R1-bgp-af-vpnv4]peer 10.0.3.3 advertise-community
[R3]bgp 100
[R3-bgp]router-id 10.0.3.3
[R3-bgp]peer 10.0.1.1 as-number 100
[R3-bgp]peer 10.0.1.1 connect-interface lo0
[R3-bgp]peer 10.0.1.1 next-hop-local
[R3-bgp]ipv4-family vpnv4
[R3-bgp-af-vpnv4]peer 10.0.1.1 enable
[R3-bgp-af-vpnv4]peer 10.0.1.1advertise-community
4、在PE上创建VPN实例并与接口进行绑定
[R1]ip vpn-instance vpna
[R1-vpn-instance-vpna]ipv4-family
[R1-vpn-instance-vpna-af-ipv4]route-distinguisher1:4
[R1-vpn-instance-vpna-af-ipv4]vpn-target4:6
[R1-vpn-instance-vpna-af-ipv4]int g0/0/0
[R1-GigabitEthernet0/0/0]ip bindingvpn-instance vpna
[R1-GigabitEthernet0/0/0]ip add 10.0.14.124
[R1]ip vpn-instance vpnb
[R1-vpn-instance-vpnb]ipv4-family
[R1-vpn-instance-vpnb-af-ipv4]route-distinguisher1:5
[R1-vpn-instance-vpnb-af-ipv4]vpn-target5:7
[R1-vpn-instance-vpnb-af-ipv4]int g0/0/1
[R1-GigabitEthernet0/0/1]ip bindingvpn-instance vpnb
[R1-GigabitEthernet0/0/1]ip add 10.0.15.124
[R3]ip vpn-instance vpna
[R3-vpn-instance-vpna]ipv4-family
[R3-vpn-instance-vpna-af-ipv4]route-distinguisher3:6
[R3-vpn-instance-vpna-af-ipv4]vpn-target4:6
[R3-vpn-instance-vpna-af-ipv4]int g0/0/0
[R3-GigabitEthernet0/0/0]ip bindingvpn-instance vpna
[R3-GigabitEthernet0/0/0]ip add 10.0.36.324
[R3]ip vpn-instance vpnb
[R3-vpn-instance-vpnb]ipv4-family
[R3-vpn-instance-vpnb-af-ipv4]route-distinguisher3:7
[R3-vpn-instance-vpnb-af-ipv4]vpn-target5:7
[R3-vpn-instance-vpnb-af-ipv4]int g0/0/2
[R3-GigabitEthernet0/0/2]ip bindingvpn-instance vpnb
[R3-GigabitEthernet0/0/2]ip add 10.0.37.324
5、为公司A配置基于BGP的PE-CE连通性
[R4]bgp 10
[R4-bgp]peer 10.0.14.1 as-number 100
[R4-bgp]network 10.0.4.4 32
[R1]bgp 100
[R1-bgp]ipv4-family vpn-instance vpna
[R1-bgp-vpna]peer 10.0.14.4 as-number 10
[R6]bgp 20
[R6-bgp]peer 10.0.36.3 as-number 100
[R6-bgp]network 10.0.6.6 32
[R3]bgp 100
[R3-bgp]ipv4-family vpn-instance vpna
[R3-bgp-vpna]peer 10.0.36.6 as-number 20
[R4]ping -c 1 -a 10.0.4.4 10.0.6.6
PING 10.0.6.6: 56data bytes,press CTRL_C to break
Reply from 10.0.6.6: bytes=56 Sequence=1 ttl=252 time=50 ms
R4\R6能够正常通信。
6、为公司B配置基于静态路由及OSPF协议的PE-CE连通性。
在R1上为VPN实例为vpnb创建静态路由
[R1]ip route-static vpn-instance vpnb10.0.5.5 32 10.0.15.5
在R5上创建缺省路由
[R5]ip route-static 0.0.0.0 0 10.0.15.1
在R1的BGP视图下使用ipv4-family vpn-instance vpnb命令进入VPN实例vpnb视图，然后将VPN实例vpnb的静态路由引入BGP
[R1]bgp 100
[R1-bgp]ipv4-family vpn-instance vpnb
[R1-bgp-vpnb]import-route static
至此，R5和R1之间的PE-CE连通性配置完成。
配置R3和R7之间的连通性，在R7上进行普通的OSPF配置
[R7]ospf 1 router-id 10.0.7.7
[R7-ospf-1]area 0
[R7-ospf-1-area-0.0.0.0]network 10.0.37.00.0.0.255
[R7-ospf-1-area-0.0.0.0]network 10.0.7.70.0.0.0
在R3上为VPN实例vpnb创建OSPF进程
[R3]ospf 1 vpn-instance vpnb
[R3-ospf-1]area 0
[R3-ospf-1-area-0.0.0.0]network 10.0.37.00.0.0.255
在R3的OSPF视图下使用import-route bgp命令将VPN实例vpnb的BGP路由引入OSPF
[R3]ospf 1
[R3-ospf-1]import-route bgp
在R3的BGP视图下使用ipv4-family vpn-instance vpnb命令进入VPN实例vpnb的视图，然后将VPN实例vpnb的OSPF路由引入BGP
[R3]bgp 100
[R3-bgp]ipv4-family vpn-instance vpnb
[R3-bgp-vpnb]import-route ospf 1
至此，R3和R7之间的连通性已经配置完成。
[R3]dis bgp vpnv4 vpn-instance vpnbrouting-table
*>i10.0.5.5/3210.0.1.101000?
*>10.0.7.7/320.0.0.020?
*>10.0.37.0/240.0.0.000?
可以看到此时还引入了10.0.37.0的路由，使用路由过滤可去掉此路由。
[R3]ip ip-prefix 1 deny 10.0.37.0 24
[R3]ip ip-prefix 1 permit 0.0.0.0 32
[R3]route-policy 10 permit node 10
[R3-route-policy]if-match ip-prefix 1
[R3-route-policy]bgp 100
[R3-bgp]ipv4-family vpn-instance vpnb
[R3-bgp-vpnb]import-route ospf 1route-policy 10
[R3]dis bgp vpnv4 vpn-instance vpnbrouting-table
*>i10.0.5.5/3210.0.1.101000?
*>10.0.7.7/320.0.0.020?
发现已经过滤了相应路由。
ping -c 1 -a 10.0.7.7 10.0.5.5
PING 10.0.5.5: 56data bytes,press CTRL_C to break
Reply from 10.0.5.5: bytes=56 Sequence=1 ttl=252 time=40 ms
发现仅有10.0.5.5能够ping通，实现了vpnb的互通！
