OSPF sham link configuration – Cisco

SHAM LINK created in VRF in same area as VRF
Loopback inteface for src/dest of SHAM LINK created in VRF
Looback advertised into BGP as VPNv4 route
*optional* ROUTE-MAP to keep Loopback from redistributed into CE routers

PE1

PE1(config-router)#router ospf 1000 vrf C11_12
PE1(config-router)#area 1000 sham-link 10.2.1.1 10.2.1.2 cost 40
!
int loop1
ip vrf forwarding C11_12
ip add 10.2.1.1 255.255.255.255
!
router bgp 65123
address-family ipv4 vrf C11_12
neighbor 129.53.20.20 remote-as 65123
neighbor 129.53.20.20 activate
network 10.2.1.1 mask 255.255.255.255
!
!
route-map SHAM_LINK deny 10
match ip address SHAM_LINK
route-map SHAM_LINK permit 20
!
ip access-list standard SHAM_LINK
permit 10.2.1.1
permit 10.2.1.2
!
router ospf 1000 vrf C11_12
redistribute bgp 65123 subnets route-map SHAM_LINK
network 10.10.111.1 0.0.0.0 area 1000

PE2

PE2(config-router)#router ospf 1000 vrf C11_12
PE2(config-router)#area 1000 sham-link 10.2.1.2 10.2.1.1 cost 40
!
int loop1
ip vrf forwarding C11_12
ip add 10.2.1.2 255.255.255.255
!
router bgp 65123
address-family ipv4 vrf C11_12
neighbor 129.53.10.10 remote-as 65123
neighbor 129.53.10.10 activate
network 10.2.1.2 mask 255.255.255.255
!
!
route-map SHAM_LINK deny 10
match ip address SHAM_LINK
route-map SHAM_LINK permit 20
!
ip access-list standard SHAM_LINK
permit 10.2.1.1
permit 10.2.1.2
!
router ospf 1000 vrf C11_12
redistribute bgp 65123 subnets route-map SHAM_LINK
network 10.10.112.2 0.0.0.0 area 1000

Screenshot 2014-03-20 08.18.07

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