In this topic, provider will use OSPF as a PE-CE protocol. R5 Lo 0 is in area 0, Lo 1 is in area 1, Lo 2 is redistributed into OSPF.
In this section, provider will run OSPF super-backbone for the OSPF process used for adjacent with customer. On R5, I add another loopback network which is Lo 10 and put into area 1.
Configuration
R1
ip vrf one
rd 1:1
route-target export 1:1
route-target import 1:1
!
interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Loopback1
ip vrf forwarding one
ip address 1.1.1.1 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.12.1 255.255.255.0
ip router isis
duplex auto
speed auto
mpls ip
!
interface FastEthernet0/1
ip vrf forwarding one
ip address 192.168.14.1 255.255.255.0
duplex auto
speed auto
!
router ospf 1 vrf one
log-adjacency-changes
area 0 sham-link 1.1.1.1 2.2.2.2
redistribute bgp 1 subnets route-map BLK_SHAM
network 192.168.14.1 0.0.0.0 area 0
!
router isis
net 49.0000.0000.0001.00
metric-style wide transition
passive-interface Loopback0
!
router bgp 1
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 ipv4
neighbor 2.2.2.2 activate
no auto-summary
no synchronization
exit-address-family
!
address-family vpnv4
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community extended
exit-address-family
!
address-family ipv4 vrf one
redistribute ospf 1 vrf one match internal external 1 external 2
no synchronization
network 1.1.1.1 mask 255.255.255.255
exit-address-family
!
ip prefix-list SHAM seq 5 permit 1.1.1.1/32
ip prefix-list SHAM seq 10 permit 2.2.2.2/32
ip prefix-list SHAM seq 15 permit 3.3.3.3/32
!
route-map BLK_SHAM deny 10
match ip address prefix-list SHAM
!
route-map BLK_SHAM permit 100
!
mpls ldp router-id Loopback0 force
R2
ip vrf one
rd 1:2
route-target export 1:1
route-target import 1:1
!
interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface Loopback1
ip vrf forwarding one
ip address 2.2.2.2 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.12.2 255.255.255.0
ip router isis
duplex auto
speed auto
mpls ip
!
interface FastEthernet1/0
ip vrf forwarding one
ip address 192.168.25.2 255.255.255.0
duplex auto
speed auto
!
router ospf 1 vrf one
log-adjacency-changes
area 0 sham-link 2.2.2.2 1.1.1.1
redistribute bgp 1 subnets route-map BLK_SHAM
network 192.168.25.2 0.0.0.0 area 0
!
router isis
net 49.0000.0000.0002.00
metric-style wide transition
passive-interface Loopback0
!
router bgp 1
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor IBGP peer-group
neighbor IBGP remote-as 1
neighbor IBGP update-source Loopback0
neighbor 1.1.1.1 peer-group IBGP
!
address-family vpnv4
neighbor IBGP send-community extended
neighbor IBGP route-reflector-client
neighbor 1.1.1.1 activate
exit-address-family
!
address-family ipv4 vrf one
redistribute ospf 1 vrf one match internal external 1 external 2
no synchronization
network 2.2.2.2 mask 255.255.255.255
exit-address-family
!
ip prefix-list SHAM seq 5 permit 1.1.1.1/32
ip prefix-list SHAM seq 10 permit 2.2.2.2/32
ip prefix-list SHAM seq 15 permit 3.3.3.3/32
!
route-map BLK_SHAM deny 10
match ip address prefix-list SHAM
!
route-map BLK_SHAM permit 100
!
mpls ldp router-id Loopback0 force
R4
interface FastEthernet0/0
ip address 192.168.14.4 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router ospf 1
log-adjacency-changes
network 192.168.14.4 0.0.0.0 area 0
R5
interface Loopback0
ip address 5.5.5.5 255.255.255.255
!
interface Loopback1
ip address 5.5.5.1 255.255.255.255
!
interface Loopback2
ip address 5.5.5.2 255.255.255.255
!
interface Loopback10
ip address 5.5.5.10 255.255.255.255
ip ospf 1 area 1
!
interface FastEthernet0/0
ip address 192.168.25.5 255.255.255.0
speed 100
full-duplex
!
router ospf 1
log-adjacency-changes
redistribute connected subnets route-map CONN
network 5.5.5.1 0.0.0.0 area 1
network 5.5.5.5 0.0.0.0 area 0
network 192.168.25.5 0.0.0.0 area 0
!
ip prefix-list LO2 seq 5 permit 5.5.5.2/32
!
route-map CONN permit 10
match ip address prefix-list LO2
Verification
Due to running super backbone area on Provider routers, provider networks is considered virtual area 0 from the customer routers point of view. So R5 Lo 0 is appeared as intra area routes, Lo1 and Lo10 appeared as inter area routes. In other words, other side of the customer router can see the correct OSPF route type.
R4#show ip route ospf
O 192.168.25.0/24 [110/12] via 192.168.14.1, 00:17:19, FastEthernet0/0
5.0.0.0/32 is subnetted, 4 subnets
O 5.5.5.5 [110/13] via 192.168.14.1, 00:17:19, FastEthernet0/0
O IA 5.5.5.1 [110/13] via 192.168.14.1, 00:17:19, FastEthernet0/0
O E2 5.5.5.2 [110/20] via 192.168.14.1, 00:13:15, FastEthernet0/0
O IA 5.5.5.10 [110/13] via 192.168.14.1, 00:13:20, FastEthernet0/0
Note
Due to super backbone emulated, from R1 perspective, prefixes from R5 are learnt through OSPF, not via MP BGP anymore.
R1#show ip route vrf one
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback1
2.0.0.0/32 is subnetted, 1 subnets
B 2.2.2.2 [200/0] via 2.2.2.2, 00:27:32
C 192.168.14.0/24 is directly connected, FastEthernet0/1
O 192.168.25.0/24 [110/2] via 2.2.2.2, 00:27:17
5.0.0.0/32 is subnetted, 4 subnets
O 5.5.5.5 [110/3] via 2.2.2.2, 00:27:17
O IA 5.5.5.1 [110/3] via 2.2.2.2, 00:27:17
O E2 5.5.5.2 [110/20] via 2.2.2.2, 00:23:02
O IA 5.5.5.10 [110/3] via 2.2.2.2, 00:23:08
R1#show bgp vpnv4 unicast vrf one
Route Distinguisher: 1:1 (default for vrf one)
*> 1.1.1.1/32 0.0.0.0 0 32768 i
*>i2.2.2.2/32 2.2.2.2 0 100 0 i
r>i5.5.5.1/32 2.2.2.2 2 100 0 ?
r>i5.5.5.2/32 2.2.2.2 20 100 0 ?
r>i5.5.5.5/32 2.2.2.2 2 100 0 ?
r>i5.5.5.10/32 2.2.2.2 2 100 0 ?
*> 192.168.14.0 0.0.0.0 0 32768 ?
r>i192.168.25.0 2.2.2.2 0 100 0 ?
So consequently, if R1 wants to filter out some prefixes when advertising to R4, it cannot be filtered at the BGP > OSPF level. For testing this, I will add 5.5.5.10/32 under "SHAM" prefix, which prefix is denied when redistributing from BGP to OSPF. But it doesn't work.
R1(config)#ip prefix-list SHAM seq 20 permit 5.5.5.10/32
R4#show ip route ospf
O 192.168.25.0/24 [110/12] via 192.168.14.1, 00:32:38, FastEthernet0/0
5.0.0.0/32 is subnetted, 4 subnets
O 5.5.5.5 [110/13] via 192.168.14.1, 00:32:38, FastEthernet0/0
O IA 5.5.5.1 [110/13] via 192.168.14.1, 00:32:38, FastEthernet0/0
O E2 5.5.5.2 [110/20] via 192.168.14.1, 00:28:33, FastEthernet0/0
O IA 5.5.5.10 [110/13] via 192.168.14.1, 00:28:38, FastEthernet0/0
GNS File : http://www.4shared.com/rar/4ERKR8Oy/mpls_vpn_pe-ce_with_ospf__supr.html
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