Ip 地址如上图，Loopback 0 分别为 x.x.x.x/32 R1/R5是CE。R2/R3/R4是ISP：R2/R4是PE，R3是P。
步骤一、ISP内部 运行IGP（ISIS）协议
R2：
router isis
net 24.0234.0000.0000.0002.00
interface Serial1/1
ip router isis
interface Loopback0
ip router isis
R3：
router isis
net 24.0234.0000.0000.0003.00
interface Serial1/1
ip router isis
nterface Serial1/0
ip router isis
interface Loopback0
ip router isis
R4：
router isis
net 24.0234.0000.0000.0004.00
interface Serial1/0
ip router isis
interface Loopback0
ip router isis
配置完检查邻居关系的建立：
R3# sh clns neighbors
System Id Interface SNPA State Holdtime Type Protocol
R4 Se1/1 *HDLC* Up 29 L1L2 IS-IS
R2 Se1/0 *HDLC* Up 27 L1L2 IS-IS
R2/R4上show ip route 查看路由是否学到
R2#sh ip route
34.0.0.0/24 is subnetted, 1 subnets
i L1 34.0.0.0 [115/20] via 23.0.0.3, Serial1/1
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
i L1 3.3.3.3 [115/20] via 23.0.0.3, Serial1/1
4.0.0.0/32 is subnetted, 1 subnets
i L1 4.4.4.4 [115/30] via 23.0.0.3, Serial1/1
23.0.0.0/24 is subnetted, 1 subnets
C 23.0.0.0 is directly connected, Serial1/1
步骤二、ISP内部实现MPLS
R2：
mpls label range 200 300
mpls ldp route-id lo 0
int s 1/1
mpls ip
R3:
mpls label range 300 400
mpls ldp route-id lo 0
int s 1/1
mpls ip
int s 1/0
mpls ip
R4:
mpls label range 400 500
mpls ldp route-id lo 0
int s 1/0
mpls ip
然后在R3上查看LDP 邻居的建立：
R3#sh mpls ldp neighbor
Peer LDP Ident: 2.2.2.2:0; Local LDP Ident 3.3.3.3:0
TCP connection: 2.2.2.2.646 - 3.3.3.3.33300
State: Oper; Msgs sent/rcvd: 34/37; Downstream
Up time: 00:23:03
LDP discovery sources:
Serial1/0, Src IP addr: 23.0.0.2
Addresses bound to peer LDP Ident:
23.0.0.2 2.2.2.2
Peer LDP Ident: 4.4.4.4:0; Local LDP Ident 3.3.3.3:0
TCP connection: 4.4.4.4.32962 - 3.3.3.3.646
State: Oper; Msgs sent/rcvd: 25/28; Downstream
Up time: 00:14:27
LDP discovery sources:
Serial1/1, Src IP addr: 34.0.0.4
Addresses bound to peer LDP Ident:
34.0.0.4 4.4.4.4
LDP邻居建立完成即可。
步骤三、ISP 中R2与R4（PE之间）建立MBPG-VPN关系
R2：
router bgp 1
no au 默认关闭的
no syn 默认关闭的
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 4.4.4.4 remote-as 1
neighbor 4.4.4.4 update-source Loopback0
!
address-family vpnv4
neighbor 4.4.4.4 activate
neighbor 4.4.4.4 send-community extended
exit-address-family
R4：
router bgp 1
no au
no syn
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 2.2.2.2 remote-as 1
neighbor 2.2.2.2 update-source Loopback0
!
address-family vpnv4
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community extended
exit-address-family
检查邻居是否建立成功：
R4# sh ip bg vpn all summary
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
2.2.2.2 4 1 35 33 9 0 0 00:25:47 2
R2# sh ip bg vpn all su
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 1 34 36 9 0 0 00:26:14 2
步骤四、VRF的导入导出
R2/R4
创建VRF
ip vrf OSPF
rd 1:100
route-target export 1:100
route-target import 1:100
接口下启用VRF
R2 interface Serial1/0
I p vrf forwarding OSPF
R4 interface Serial1/1
ip vrf forwarding OSPF
PE-CE间使用ospf路由协议
R1：
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 1.1.1.1 0.0.0.0 area 0
network 12.0.0.1 0.0.0.0 area 0
R2：
router ospf 1 vrf OSPF
log-adjacency-changes
network 12.0.0.2 0.0.0.0 area 0
R5：
router ospf 1
router-id 5.5.5.5
log-adjacency-changes
network 5.5.5.5 0.0.0.0 area 0
network 45.0.0.5 0.0.0.0 area 0
R4
router ospf 1 vrf OSPF
log-adjacency-changes
network 45.0.0.4 0.0.0.0 area 0
R2/R4 VRF 和BGP路由相互重分布
R2/R4
router ospf 1 vrf OSPF
redistribute bgp 1 subnets
router bgp 1
address-family ipv4 vrf OSPF
redistribute ospf 1 vrf OSPF match internal external 1 external 2
no synchronization
exit-address-family
R2/R4 上检查VRF路由是否学到
R2#sh ip bg vpn all
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf RIP)
*> 1.1.1.1/32 12.0.0.1 1 32768 ?
*>i5.5.5.5/32 4.4.4.4 1 100 0 ?
*> 12.0.0.0/24 0.0.0.0 0 32768 ?
*>i45.0.0.0/24 4.4.4.4 0 100 0 ?
查看R1/R5路由是否学到：
R1# sh ip route
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
5.0.0.0/32 is subnetted, 1 subnets
O IA 5.5.5.5 [110/129] via 12.0.0.2, 00:11:14, Serial1/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.0.0.0 is directly connected, Serial1/1
45.0.0.0/24 is subnetted, 1 subnets
O IA 45.0.0.0 [110/65] via 12.0.0.2, 00:11:14, Serial1/1
步骤五、测试MPLS ，查看转发过程标签转换情况
单方向从R1-R5观察：
R1#traceroute 5.5.5.5
Type escape sequence to abort.
Tracing the route to 5.5.5.5
1 12.0.0.2 48 msec 48 msec 32 msec
2 23.0.0.3 [MPLS: Labels 301/403 Exp 0] 112 msec 120 msec 160 msec
3 45.0.0.4 [MPLS: Label 403 Exp 0] 108 msec 120 msec 108 msec
4 45.0.0.5 128 msec * 104 msec
R2#sh ip cef vrf OSPF detail
5.5.5.5/32, version 9, epoch 0, cached adjacency to Serial1/1
0 packets, 0 bytes
tag information set
local tag: VPN-route-head
fast tag rewrite with Se1/1, point2point, tags imposed: {301 403}
via 4.4.4.4, 0 dependencies, recursive
next hop 23.0.0.3, Serial1/1 via 4.4.4.4/32
valid cached adjacency
tag rewrite with Se1/1, point2point, tags imposed: {301 403}
R3#sh mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
301 Pop tag 4.4.4.4/32 4760 Se1/1 point2point
R4#sh ip cef vrf OSPF detail
5.5.5.5/32, version 10, epoch 0, cached adjacency to Serial1/1
0 packets, 0 bytes
tag information set
local tag: 403
via 45.0.0.5, Serial1/1, 0 dependencies
next hop 45.0.0.5, Serial1/1
valid cached adjacency
tag rewrite with Se1/1, point2point, tags imposed: {}
本文出自 “海阔天空” 博客，请务必保留此出处http://haikuotiankong.blog.51cto.com/633188/1695312
原文地址：http://haikuotiankong.blog.51cto.com/633188/1695312
