It may be a little easier if Siates A & B were the same AS, but I assume you are already peering with the MPLS provider with Site A being AS 65000 and Site B being 65001. Here's an example below. It probably needs some tweaking and may be not be 100%, but it should give you an idea on how to accomplish things.   SITE A ! router bgp 65000  neighbor 10.1.1.2 remote-as 65001  neighbor 10.1.1.2 description SITE_B  neighbor 1.1.1.1 remote-as 65555  neighbor 1.1.1.1 description MLPS_SITE_A !  address-family ipv4   neighbor 10.1.1.2 activate   neighbor 1.1.1.1 activate   neighbor 1.1.1.1 weight 100 (Prefer MPLS routes to remotes)   neighbor 1.1.1.1 route-map Prepend-Site-B out (Prepend Site B's routes)   neighbor 1.1.1.1 filter-list 5 out  (Advertise only Site A & Bs routes)   neighbor 1.1.1.1 filter-list 10 in   (Don't want to see Site B's AS)   neighbor 1.1.1.1 activate   network 10.10.10.0 mask 255.255.255.0 (Site A network) ! ! ! ip as-path access-list 1 permit ^65001$ ! ! route-map Prepend-Site-B permit 10  match as-path 1  set as-path prepend 65000 65000 65000 ! ! ip as-path access-list 5 permit ^$ ip as-path access-list 5 permit ^65001$ ! ! ip as-path access-list 10 deny _65001$ ip as-path access-list 10 permit any ! ! ====================================================== SITE B ! router bgp 65001  neighbor 10.1.1.1 remote-as 65000  neighbor 10.1.1.1 description SITE_B  neighbor 2.2.2.2 remote-as 65555  neighbor 2.2.2.2 description MLPS_SITE_B !  address-family ipv4   neighbor 10.1.1.1 activate   neighbor 2.2.2.2 weight 100  (Prefer MPLS routes to remotes)   neighbor 2.2.2.2 route-map Prepend-Site-A out  (Prepend Site A's routes)   neighbor 2.2.2.2 filter-list 6 out   (Advertise only Site A & Bs routes)   neighbor 2.2.2.2 filter-list 20 in  (Don't want to see Site A's AS)   neighbor 2.2.2.2 activate   network 20.20.20.0 mask 255.255.255.0 (Site B network) ! ! ip as-path access-list 2 permit ^65000$ ! ! route-map Prepend-Site-A permit 10  match as-path 2  set as-path prepend 65001 65001 65001 ! ! ! ip as-path access-list 6 permit ^$ ip as-path access-list 6 permit ^65000$ ! ! ! ip as-path access-list 20 deny _65000$ ip as-path access-list 20 permit any ! !   Hope this helps ... View more