检验
本节讲述了如何检查你的配置是否工作正常.
· show ip vrf - Verifies that the correct VRF exists.
· show ip vrf interfaces - Verifies the activated interfaces.
· show ip route vrf Customer_A - Verifies the routing information on the PE routers.
· traceroute vrf Customer_A 200.0.6.1 - Verifies the routing information on the PE routers.
· show ip bgp ***v4 tag - Verifies the BGP.
· show ip cef vrf Customer_A 200.0.6.1 detail - Verifies the routing information on the PE  routers.

更多的排错命令详见： MPLS ××× Solution Troubleshooting Guide.
下面的输出是命令 show ip vrf 的结果
     Pescara#show ip vrf 
     Name                         Default RD                             Interfaces 
     Customer_A                100:110                              Loopback101 
     Customer_B                100:120                              Loopback102

下面的输出是命令show ip vrf interfaces 的结果.
Pesaro#show ip vrf interfaces
   Interface                  IP-Address              VRF               Protocol
  Loopback101             200.0.6.1         Customer_A            up
  Loopback111             200.1.6.1         Customer_A            up
   Loopback102            200.0.6.1         Customer_B            up

下面的 show ip route vrf 命令的结果显示在2 个×××l 里面都有相同的网段 200.0.6.0/24. 这是因为两个×××客户 Customer_A 和Customer_B 使用了重叠的IP 地址.

Pescara#show ip route vrf Customer_A
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR

Gateway of last resort is not set
C 200.0.4.0/24 is directly connected, Loopback101
B 200.0.6.0/24 [200/0] via 10.10.10.6, 05:10:11
B 200.1.6.0/24 [200/0] via 10.10.10.6, 04:48:11

Pescara#show ip route vrf Customer_B
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route

Gateway of last resort is not set
C 200.0.4.0/24 is directly connected, Loopback102
B 200.0.6.0/24 [200/0] via 10.10.10.6, 00:03:24

在Customer_A 的2 个站点间使用Traceroute，可能可以看到MPLS 网络使用的label stack。
（如果配置mpls ip ttl .）
Pescara#traceroute vrf Customer_A 200.0.6.1
Type escape sequence to abort. Tracing the route to 200.0.6.1
1 10.1.1.13 [MPLS: Labels 20/26 Exp 0] 400 msec 276 msec 264 msec
2 10.1.1.6 [MPLS: Labels 18/26 Exp 0] 224 msec 460 msec 344 msec
3 200.0.6.1 108 msec * 100 msec
Note: Exp 0 是QoS 使用的一个字段