The last 3 labs have been a similar problem with 3 different solutions. This one uses MP-eBGP to peer across different ASes for PEs (that are in different ASes). In order to accomplish this, the ipv4 bgp peering between R2 and R4 need to advertise the loopbacks of R3 and R6 (PE in AS1 and PE in AS2, respectively), they also need to advertise or redistribute into the IGP so the R3 and R6 can know of each other's loopback for MP-eBGP multihop peering. Don't forget to send-label for ipv4 peering. Finally, VPNv4 peer between R3 and R6.
Configs:
R2 - AS1 ipv4 peering point to AS2
R2#sh run | b router
router ospf 1
log-adjacency-changes
redistribute bgp 1 subnets route-map LOOP6
network 150.1.2.2 0.0.0.0 area 0
network 150.1.12.2 0.0.0.0 area 0
!
router bgp 1
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 150.1.24.4 remote-as 2
!
address-family ipv4
neighbor 150.1.24.4 activate
neighbor 150.1.24.4 send-label
no auto-summary
no synchronization
network 150.1.3.3 mask 255.255.255.255
exit-address-family
!
R4 - AS2 ipv4 peering point to R2
router isis
net 00.0000.0000.0004.00
is-type level-2-only
redistribute bgp 2 route-map LOOP3
!
router bgp 2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 150.1.24.2 remote-as 1
!
address-family ipv4
neighbor 150.1.24.2 activate
neighbor 150.1.24.2 send-label
no auto-summary
no synchronization
network 150.1.6.6 mask 255.255.255.255
exit-address-family
!
R3 - AS1 PE - ebgp vpnv4 multihop peering to R6
!
router bgp 1
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 150.1.6.6 remote-as 2
neighbor 150.1.6.6 ebgp-multihop 255
neighbor 150.1.6.6 update-source Loopback0
!
address-family vpnv4
neighbor 150.1.6.6 activate
neighbor 150.1.6.6 send-community extended
exit-address-family
R6 - AS2 PE - ebgp vpnv4 multihop peering to R3
router bgp 2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 150.1.3.3 remote-as 1
neighbor 150.1.3.3 ebgp-multihop 255
neighbor 150.1.3.3 update-source Loopback0
!
address-family vpnv4
neighbor 150.1.3.3 activate
neighbor 150.1.3.3 send-community extended
exit-address-family
!
