MPLS_×××

實驗拓撲：

第一步：創建VRF

R2/R4:

ip vrf ***                         命名vrf爲「***」
rd 100:1                           設置RD
route-target export 100:1設置出口路由標記
route-target import 100:1設置入口路由標記     注：一端的出口標記和對端的入口標記需一致！

第二步：將CE接口設置成vrf轉發

R2：
interface FastEthernet0/1
ip vrf forwarding ***
ip address 12.1.1.2 255.255.255.0

R4：
interface FastEthernet0/0
ip vrf forwarding ***
ip address 45.1.1.4 255.255.255.0

注意：在配置完 「 ip vrf forwarding ***」後，接口上原先配置的ip地址會消失，需從新配置。

第三步：配置mpls域的igp

R2：

router eigrp 10
network 2.2.2.2 0.0.0.0
network 23.1.1.2 0.0.0.0
no auto-summary
eigrp router-id 2.2.2.2

R3：

router eigrp 10
network 3.3.3.3 0.0.0.0
network 23.1.1.3 0.0.0.0
network 34.1.1.3 0.0.0.0
no auto-summary
eigrp router-id 3.3.3.3
!

R4：

router eigrp 10
network 4.4.4.4 0.0.0.0
network 34.1.1.4 0.0.0.0
no auto-summary
eigrp router-id 4.4.4.4

配置IGP的目的是爲了是mpls域內路由互通，爲配置MP-BGP作準備

第四步：配置mpbgp：

R2：

router bgp 100
bgp router-id 2.2.2.2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 3.3.3.3 remote-as 100
neighbor 3.3.3.3 update-source Loopback0
!
address-family ***v4  配置***v4地址簇，與p路由器創建***v4鄰居
neighbor 3.3.3.3 activate
neighbor 3.3.3.3 send-community both 配置擴展團體屬性的發送包括了route-tag，***標籤等信息
exit-address-family
!
address-family ipv4 vrf ***   配置vrf地址簇，將CE點的路由協議重分發進mpbgp
redistribute eigrp 100
no synchronization
exit-address-family

R3：

router bgp 100
bgp router-id 3.3.3.3
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 2.2.2.2 remote-as 100
neighbor 2.2.2.2 update-source Loopback0
neighbor 4.4.4.4 remote-as 100
neighbor 4.4.4.4 update-source Loopback0
!
address-family ***v4                                 配置***v4鄰居的反射，解決iGP水平分割問題，也能夠不配反射，以R2-4創建全互聯鄰居關係代替 
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community both
neighbor 2.2.2.2 route-reflector-client
neighbor 4.4.4.4 activate
neighbor 4.4.4.4 send-community both
neighbor 4.4.4.4 route-reflector-client
exit-address-family

R4：

router bgp 100
bgp router-id 4.4.4.4
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 3.3.3.3 remote-as 100
neighbor 3.3.3.3 update-source Loopback0
!
address-family ***v4
neighbor 3.3.3.3 activate
neighbor 3.3.3.3 send-community both
exit-address-family
!
address-family ipv4 vrf ***
redistribute ospf 1 vrf *** match internal external 1 external 2   重分發ospf時注意匹配範圍（inter or external）
no synchronization
exit-address-family

第五步：配置site端的路由

site1：

R2：

router eigrp 100
no auto-summary
!
address-family ipv4 vrf *** 指定vrf地址簇的配置
redistribute bgp 100 metric 10000 100 255 1 1500  將mpbgp路由重                                                                                             分發進CE端
network 12.1.1.2 0.0.0.0
no auto-summary
autonomous-system 100 通告自治系統號（必須配置！）
exit-address-family
!

R1：

router eigrp 100
network 1.1.1.1 0.0.0.0
network 12.1.1.1 0.0.0.0
no auto-summary
eigrp router-id 1.1.1.1
!

site2：

R4：

router ospf 1 vrf *** ospf不能在進程下配置ipv4vrf地址簇，需在起進程時配置！
router-id 4.4.4.4
log-adjacency-changes
redistribute bgp 100 metric-type 1 subnets 將mpbgp路由充分發進ce端
network 45.1.1.4 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 45.1.1.5 0.0.0.0 area 0
!

第六步：配置mpls轉發

R2/R3/R4

全局：

ip cef 開啓cef轉發，必定要配置！！

mpls label range x00 x99                    指定本地標籤的分配範圍，以便於管理，  也可由系統自動分配
mpls label protocol ldp                        cisco路由器默認標籤分配協議爲tdp，這裏改成ldp協議
mpls ip                                                使路由器支持mpls 轉發  默認已配置
mpls ldp router-id Loopback0 force     設置標籤分配的源端口

接口下（PE和p端的接口）

mpls ip                                                 在接口上啓用mpls

現象：

1.查看R1的路由表：

Gateway of last resort is not set
     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
D EX    5.5.5.5 [170/307200] via 12.1.1.2, 01:09:39, FastEthernet0/1
     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, FastEthernet0/1
     45.0.0.0/24 is subnetted, 1 subnets
D EX    45.1.1.0 [170/307200] via 12.1.1.2, 01:09:39, FastEthernet0/1

查看R5的路由表：

Gateway of last resort is not set
     1.0.0.0/32 is subnetted, 1 subnets
O E1    1.1.1.1 [110/409610] via 45.1.1.4, 01:10:11, FastEthernet0/0
     5.0.0.0/32 is subnetted, 1 subnets
C       5.5.5.5 is directly connected, Loopback0
     12.0.0.0/24 is subnetted, 1 subnets
O E1    12.1.1.0 [110/11] via 45.1.1.4, 01:10:10, FastEthernet0/0
     45.0.0.0/24 is subnetted, 1 subnets
C       45.1.1.0 is directly connected, FastEthernet0/0

查看R2的vrf路由表：

show ip vrf *** route :

     1.0.0.0/32 is subnetted, 1 subnets
D       1.1.1.1 [90/409600] via 12.1.1.1, 01:14:33, FastEthernet0/1
     5.0.0.0/32 is subnetted, 1 subnets
B       5.5.5.5 [200/11] via 4.4.4.4, 01:13:04
     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, FastEthernet0/1
     45.0.0.0/24 is subnetted, 1 subnets
B       45.1.1.0 [200/0] via 4.4.4.4, 01:13:04

R2的bgp ***v4表：

R2#sh ip bgp ***v4 all
BGP table version is 9, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 100:1 (default for vrf ***)
*> 1.1.1.1/32       12.1.1.1            409600         32768 ?
*>i5.5.5.5/32       4.4.4.4                 11    100      0 ?
*> 12.1.1.0/24      0.0.0.0                  0         32768 ?
*>i45.1.1.0/24      4.4.4.4                  0    100      0 ?

R2的mpls轉發表

R2#sh mpls forwarding-table
Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
tag    tag or VC   or Tunnel Id      switched   interface
200    Pop tag     3.3.3.3/32        0          Fa0/0      23.1.1.3
201    Pop tag     34.1.1.0/24       0          Fa0/0      23.1.1.3
203    Untagged    1.1.1.1/32[V]     0          Fa0/1      12.1.1.1
204    Aggregate   12.1.1.0/24[V]    1164
205    302         4.4.4.4/32        0          Fa0/0      23.1.1.3

R3（p路由器）的***v4 bgp表：

R3#sh ip bgp ***v4 all

BGP table version is 5, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 100:1
*>i1.1.1.1/32       2.2.2.2             409600    100      0 ?
*>i5.5.5.5/32       4.4.4.4                 11    100      0 ?
*>i12.1.1.0/24      2.2.2.2                  0    100      0 ?
*>i45.1.1.0/24      4.4.4.4                  0    100      0 ?

R4的各表略

R4前往R1：

R4#traceroute vrf *** 1.1.1.1
Type escape sequence to abort.
Tracing the route to 1.1.1.1
  1 34.1.1.3 [MPLS: Labels 300/203 Exp 0] 132 msec 180 msec 188 msec
  2 12.1.1.2 [MPLS: Label 203 Exp 0] 100 msec 112 msec 84 msec
  3 12.1.1.1 128 msec *  124 msec

能夠看到，從R2發出的包帶有雙層標籤 內層爲203 外層爲300；其中203爲R2爲1.1.1.1的路由分配的***v4標籤，300爲R3分配的普通mpls標籤 而當報文到達R3時，由於「次末跳彈出機制（PHP）」報文將彈出上層標籤（普通mpls標籤300），到達R2後就剩下了***v4標籤（203），此時再根據***v4標籤查找標籤轉發表 發現出口無標籤，因而直接以ip報文形式傳給了R1。