在MPLS ×××网络里的客户，如果使用动态路由OSPF，就会被MPLS网割断，形成的区不完整。
解决这个问题方法使用sham-link命令，可以使分割两面的区一体化。
R3和R5是PE，R1是P，R7和R8是CE，R3和R8的F0/0之间建立area 0区，R5和R7的F1/0之间也建立area 0区，如果用一般重分发的方法，得到对端的OSPF路由是O IA而不是O的，虽然双方都是用的area 0，使用sham-link来完整0区。在R7和R8的lookback接口启用area 1和2。
sham-link建立有些必要条件，要使用lookback接口作为起始和终端，要用/32地址
interface Loopback2
ip vrf forwarding ***-1
ip address 1.1.1.3 255.255.255.255
接口的IP路由要通过MP-BGP送达对端，
router bgp 100
address-family ipv4 vrf ***-1
redistribute ospf 2 vrf ***-1
network 1.1.1.3 mask 255.255.255.255
使用的OSPF进行号要相同，如没有什么必要，不需要配置domain-id
router ospf 2 vrf ***-1
area 0 sham-link 1.1.1.3 1.1.1.5
redistribute bgp 100 subnets
network 10.10.1.0 0.0.0.255 area 0
R3#sh ip ro vrf ***-1
Routing Table: ***-1
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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
1.0.0.0/32 is subnetted, 2 subnets
C 1.1.1.3 is directly connected, Loopback2
B 1.1.1.5 [200/0] via 5.5.5.5, 00:36:34
10.0.0.0/24 is subnetted, 4 subnets
C 10.10.1.0 is directly connected, FastEthernet1/0
O IA 10.10.2.0 [110/2] via 10.10.1.2, 00:06:30, FastEthernet1/0
O 10.10.3.0 [110/2] via 5.5.5.5, 00:06:30
O IA 10.10.4.0 [110/3] via 5.5.5.5, 00:06:30
R3#sh ip b v v ***-1 10.10.1.0
BGP routing table entry for 123:1:10.10.1.0/24, version 21
Paths: (1 available, best #1, table ***-1)
Advertised to update-groups:
1
Local
0.0.0.0 from 0.0.0.0 (3.3.3.3)
Origin incomplete, metric 0, localpref 100, weight 32768, valid, sourced, best
Extended Community: RT:123:1 OSPF DOMAIN ID:0x0005:0x000000020200
OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:10.10.1.1:0
mpls labels in/out 22/aggregate(***-1)
R3#
R3#
R3#
R3#sh ip b v v ***-1 10.10.2.0
BGP routing table entry for 123:1:10.10.2.0/24, version 43
Paths: (1 available, best #1, table ***-1)
Flag: 0x820
Advertised to update-groups:
1
Local
10.10.1.2 from 0.0.0.0 (3.3.3.3)
Origin incomplete, metric 2, localpref 100, weight 32768, valid, sourced, best
Extended Community: RT:123:1 OSPF DOMAIN ID:0x0005:0x000000020200
OSPF RT:0.0.0.0:3:0 OSPF ROUTER ID:10.10.1.1:0
mpls labels in/out 25/nolabel
R3#
R3#
R3#sh ip b v v ***-1 10.10.3.0
BGP routing table entry for 123:1:10.10.3.0/24, version 29
Paths: (1 available, best #1, table ***-1, RIB-failure(17))
Not advertised to any peer
Local
5.5.5.5 (metric 3) from 1.1.1.1 (1.1.1.1)
Origin incomplete, metric 0, localpref 100, valid, internal, best
Extended Community: RT:123:1 OSPF DOMAIN ID:0x0005:0x000000020200
OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:10.10.3.1:0
Originator: 5.5.5.5, Cluster list: 1.1.1.1
mpls labels in/out nolabel/21
R3#
R3#
R3#sh ip b v v ***-1 10.10.4.0
BGP routing table entry for 123:1:10.10.4.0/24, version 34
Paths: (1 available, best #1, table ***-1, RIB-failure(17))
Not advertised to any peer
Local
5.5.5.5 (metric 3) from 1.1.1.1 (1.1.1.1)
Origin incomplete, metric 2, localpref 100, valid, internal, best
Extended Community: RT:123:1 OSPF DOMAIN ID:0x0005:0x000000020200
OSPF RT:0.0.0.0:3:0 OSPF ROUTER ID:10.10.3.1:0
Originator: 5.5.5.5, Cluster list: 1.1.1.1
mpls labels in/out nolabel/22
R3#
R8#sh ip ro
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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
1.0.0.0/32 is subnetted, 2 subnets
O E2 1.1.1.3 [110/1] via 10.10.1.1, 01:13:49, FastEthernet0/0
O E2 1.1.1.5 [110/1] via 10.10.1.1, 01:13:49, FastEthernet0/0
10.0.0.0/24 is subnetted, 4 subnets
C 10.10.1.0 is directly connected, FastEthernet0/0
C 10.10.2.0 is directly connected, Loopback0
O 10.10.3.0 [110/3] via 10.10.1.1, 01:13:49, FastEthernet0/0
O IA 10.10.4.0 [110/4] via 10.10.1.1, 01:13:49, FastEthernet0/0
R8#sh ip os da
OSPF Router with ID (10.10.5.1) (Process ID 2)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
10.10.1.1 10.10.1.1 1385 0x8000002B 0x006C0D 2
10.10.3.1 10.10.3.1 2 (DNA) 0x80000007 0x00DABC 2
10.10.3.2 10.10.3.2 3 (DNA) 0x8000000A 0x00C6FE 1
10.10.5.1 10.10.5.1 549 0x80000009 0x008840 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.10.1.1 10.10.1.1 1385 0x80000003 0x00B328
10.10.3.1 10.10.3.1 1125 (DNA) 0x80000004 0x009342
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.10.2.0 10.10.5.1 549 0x80000003 0x00AA5F
10.10.4.0 10.10.3.2 3 (DNA) 0x80000001 0x00A06A
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
10.10.5.1 10.10.5.1 549 0x80000003 0x009252 1
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.10.1.0 10.10.5.1 552 0x80000003 0x00B555
10.10.3.0 10.10.5.1 552 0x80000003 0x00B353
10.10.4.0 10.10.5.1 552 0x80000003 0x00B252
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
10.10.1.1 10.10.5.1 552 0x80000003 0x009D6B
10.10.3.1 10.10.5.1 552 0x80000003 0x009174
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
1.1.1.3 10.10.1.1 361 0x80000004 0x0074EA 3489661028
1.1.1.3 10.10.3.1 42 (DNA) 0x80000001 0x006CF3 3489661028
1.1.1.5 10.10.1.1 361 0x80000004 0x0060FC 3489661028
1.1.1.5 10.10.3.1 16 (DNA) 0x80000001 0x005806 3489661028
R8#ping 10.10.4.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.4.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 112/128/160 ms
R8#
下面贴一下完整配置。
R8
hostname R8
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
interface Loopback0
ip address 10.10.2.1 255.255.255.0
ip ospf network point-to-point
!
interface FastEthernet0/0
ip address 10.10.1.2 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet1/0
no ip address
shutdown
duplex auto
speed auto
!
router ospf 2
log-adjacency-changes
network 10.10.1.0 0.0.0.255 area 0
network 10.10.2.0 0.0.0.255 area 1
!
no ip http server
R3
hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
ip vrf ***-1
rd 123:1
route-target export 123:1
route-target import 123:1
!
!
interface Loopback1
ip address 3.3.3.3 255.255.255.255
!
interface Loopback2
ip vrf forwarding ***-1
ip address 1.1.1.3 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.5.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet1/0
ip vrf forwarding ***-1
ip address 10.10.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet2/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
router ospf 2 vrf ***-1
log-adjacency-changes
area 0 sham-link 1.1.1.3 1.1.1.5
redistribute bgp 100 subnets
network 10.10.1.0 0.0.0.255 area 0
!
router ospf 1
log-adjacency-changes
network 3.3.3.3 0.0.0.0 area 0
network 192.168.1.0 0.0.0.255 area 0
network 192.168.5.0 0.0.0.255 area 0
!
router bgp 100
no synchronization
bgp log-neighbor-changes
network 1.1.1.3 mask 255.255.255.255
neighbor 1.1.1.1 remote-as 100
neighbor 1.1.1.1 update-source Loopback1
neighbor 2.2.2.2 remote-as 100
neighbor 2.2.2.2 update-source Loopback1
no auto-summary
!
address-family ***v4
neighbor 1.1.1.1 activate
neighbor 1.1.1.1 send-community both
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community both
exit-address-family
!
address-family ipv4 vrf ***-1
redistribute ospf 2 vrf ***-1
no synchronization
network 1.1.1.3 mask 255.255.255.255
exit-address-family
!
no ip http server
R1
hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
interface Loopback1
ip address 1.1.1.1 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.6.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet1/0
ip address 192.168.1.2 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet2/0
ip address 192.168.3.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
router ospf 1
log-adjacency-changes
network 1.1.1.1 0.0.0.0 area 0
network 192.168.1.0 0.0.0.255 area 0
network 192.168.3.0 0.0.0.255 area 0
network 192.168.6.0 0.0.0.255 area 0
!
router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor aaa peer-group
neighbor aaa remote-as 100
neighbor aaa update-source Loopback1
neighbor 2.2.2.2 peer-group aaa
neighbor 3.3.3.3 peer-group aaa
neighbor 4.4.4.4 peer-group aaa
neighbor 5.5.5.5 peer-group aaa
neighbor 6.6.6.6 peer-group aaa
no auto-summary
!
address-family ***v4
neighbor aaa send-community both
neighbor aaa route-reflector-client
neighbor 2.2.2.2 activate
neighbor 3.3.3.3 activate
neighbor 4.4.4.4 activate
neighbor 5.5.5.5 activate
neighbor 6.6.6.6 activate
exit-address-family
!
no ip http server
R5
hostname R5
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
ip vrf ***-1
rd 123:1
route-target export 123:1
route-target import 123:1
!
!
interface Loopback1
ip address 5.5.5.5 255.255.255.255
!
interface Loopback2
ip vrf forwarding ***-1
ip address 1.1.1.5 255.255.255.255
!
interface FastEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.3.2 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet2/0
ip vrf forwarding ***-1
ip address 10.10.3.1 255.255.255.0
duplex auto
speed auto
!
router ospf 2 vrf ***-1
log-adjacency-changes
area 0 sham-link 1.1.1.5 1.1.1.3
redistribute bgp 100 subnets
network 10.10.3.0 0.0.0.255 area 0
!
router ospf 1
log-adjacency-changes
network 5.5.5.5 0.0.0.0 area 0
network 192.168.3.0 0.0.0.255 area 0
network 192.168.7.0 0.0.0.255 area 0
!
router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor 1.1.1.1 remote-as 100
neighbor 1.1.1.1 update-source Loopback1
neighbor 2.2.2.2 remote-as 100
neighbor 2.2.2.2 update-source Loopback1
no auto-summary
!
address-family ***v4
neighbor 1.1.1.1 activate
neighbor 1.1.1.1 send-community both
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community both
exit-address-family
!
address-family ipv4 vrf ***-1
redistribute ospf 2 vrf ***-1
no synchronization
network 1.1.1.5 mask 255.255.255.255
exit-address-family
!
no ip http server
R7
hostname R7
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
interface Loopback0
ip address 10.10.4.1 255.255.255.0
ip ospf network point-to-point
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 10.10.3.2 255.255.255.0
duplex auto
speed auto
!
router ospf 2
log-adjacency-changes
network 10.10.3.0 0.0.0.255 area 0
network 10.10.4.0 0.0.0.255 area 2
!
no ip http server