Figure 7-37 shows an Inter-AS network topology in which SP1 and SP2 are providing MPLS VPN services to geographically dispersed Customer A and Customer B sites.
Figure 7-37. Inter-AS Providers Implementing RR and BGP Confederation
Provider 1 uses the RR method to reduce iBGP mesh while Provider 2 uses BGP confederation to minimize the number of BGP sessions. ASBR2-AS1 in the provider network uses the Inter-AS redistribute connected option to distribute the next-hop to devices in Provider Network 1, while ASBR2-AS2 uses the Inter-AS next-hop-self method to distribute next-hop information to devices in Provider Network 2. Example 7-28 shows the ASBR, PE router, and RR configurations. Refer to Example 7-3 and Example 7-4 for CE configurations.
Example 7-28. ASBR and RR Configurations
hostname ASBR2-AS1 ! ip cef ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.10.10.102 255.255.255.255 ! interface Ethernet0/0 ip address 10.10.10.5 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.10.10.10 255.255.255.252 mpls ip ! interface Serial2/0 ip address 10.40.40.1 255.255.255.252 mpls bgp forwarding ! router ospf 1 redistribute connected subnets route-map adv-conn network 10.10.10.0 0.0.0.255 area 0 ! router bgp 1 no bgp default ipv4-unicast no bgp default route-target filter neighbor 10.10.10.100 remote-as 1 neighbor 10.10.10.100 update-source Loopback0 neighbor 10.40.40.2 remote-as 2 ! address-family vpnv4 neighbor 10.10.10.100 activate neighbor 10.10.10.100 send-community extended neighbor 10.40.40.2 activate neighbor 10.40.40.2 send-community extended exit-address-family ! access-list 10 permit 10.40.40.2 ! route-map adv-conn permit 10 match ip address 10 __________________________________________________________________________ hostname ASBR2-AS2 ! ip cef ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.20.20.102 255.255.255.255 ! interface Ethernet0/0 ip address 10.20.20.5 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.20.20.10 255.255.255.252 mpls ip ! interface Serial2/0 ip address 10.40.40.2 255.255.255.252 mpls bgp forwarding ! router ospf 2 network 10.20.20.0 0.0.0.255 area 0 ! router bgp 102 no bgp default ipv4-unicast no bgp default route-target filter bgp confederation identifier 2 bgp confederation peers 100 101 neighbor 10.20.20.100 remote-as 100 neighbor 10.20.20.100 ebgp-multihop 2 neighbor 10.20.20.100 update-source Loopback0 neighbor 10.20.20.101 remote-as 101 neighbor 10.20.20.101 ebgp-multihop 2 neighbor 10.20.20.101 update-source Loopback0 neighbor 10.40.40.1 remote-as 1 ! address-family vpnv4 neighbor 10.20.20.100 activate neighbor 10.20.20.100 send-community extended neighbor 10.20.20.100 next-hop-self neighbor 10.20.20.101 activate neighbor 10.20.20.101 send-community extended neighbor 10.20.20.101 next-hop-self neighbor 10.40.40.1 activate neighbor 10.40.40.1 send-community extended exit-address-family __________________________________________________________________________ hostname PE1-AS1 ! ip cef ! ip vrf Cust_A rd 1:100 route-target export 1:100 route-target import 2:100 ! ip vrf Cust_B rd 1:101 route-target export 1:101 route-target import 2:101 ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.10.10.101 255.255.255.255 ! interface Ethernet0/0 ip address 10.10.10.1 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.10.10.9 255.255.255.252 mpls ip ! interface Serial2/0 description connected to Cust_A CE1-A ip vrf forwarding Cust_A ip address 172.16.1.1 255.255.255.252 ! interface Serial3/0 description connected to Cust_B CE1-B ip vrf forwarding Cust_B ip address 192.168.1.1 255.255.255.252 ! router ospf 1 network 10.10.10.0 0.0.0.255 area 0 ! router bgp 1 no bgp default ipv4-unicast neighbor 10.10.10.100 remote-as 1 neighbor 10.10.10.100 update-source Loopback0 ! address-family vpnv4 neighbor 10.10.10.100 activate neighbor 10.10.10.100 send-community extended exit-address-family ! address-family ipv4 vrf Cust_B neighbor 192.168.1.2 remote-as 65001 neighbor 192.168.1.2 activate neighbor 192.168.1.2 as-override no auto-summary no synchronization exit-address-family ! address-family ipv4 vrf Cust_A neighbor 172.16.1.2 remote-as 65001 neighbor 172.16.1.2 activate no auto-summary no synchronization exit-address-family __________________________________________________________________________ hostname PE1-AS2 ! ip cef ! ip vrf Cust_A rd 2:100 route-target export 2:100 route-target import 1:100 ! ip vrf Cust_B rd 2:101 route-target export 2:101 route-target import 1:101 ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.20.20.101 255.255.255.255 ! interface Ethernet0/0 ip address 10.20.20.1 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.20.20.9 255.255.255.252 mpls ip ! interface Serial2/0 description connected to Cust_A CE2-A ip vrf forwarding Cust_A ip address 172.16.2.1 255.255.255.252 ! interface Serial3/0 description connected to Cust_B CE2-B ip vrf forwarding Cust_B ip address 192.168.2.1 255.255.255.252 ! router ospf 2 network 10.20.20.0 0.0.0.255 area 0 ! router bgp 101 no bgp default ipv4-unicast bgp confederation identifier 2 bgp confederation peers 100 102 neighbor 10.20.20.100 remote-as 100 neighbor 10.20.20.100 ebgp-multihop 2 neighbor 10.20.20.100 update-source Loopback0 neighbor 10.20.20.102 remote-as 102 neighbor 10.20.20.102 ebgp-multihop 2 neighbor 10.20.20.102 update-source Loopback0 ! address-family vpnv4 neighbor 10.20.20.100 activate neighbor 10.20.20.100 send-community extended neighbor 10.20.20.100 next-hop-self neighbor 10.20.20.102 activate neighbor 10.20.20.102 send-community extended neighbor 10.20.20.102 next-hop-self exit-address-family ! address-family ipv4 vrf Cust_B neighbor 192.168.2.2 remote-as 65001 neighbor 192.168.2.2 activate neighbor 192.168.2.2 as-override no auto-summary no synchronization exit-address-family ! address-family ipv4 vrf Cust_A neighbor 172.16.2.2 remote-as 65002 neighbor 172.16.2.2 activate no auto-summary no synchronization exit-address-family _________________________________________________________________________ hostname P1-AS1-RR ! ip cef ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.10.10.100 255.255.255.255 ! interface Ethernet0/0 ip address 10.10.10.2 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.10.10.6 255.255.255.252 mpls ip ! router ospf 1 network 10.10.10.0 0.0.0.255 area 0 ! router bgp 1 no bgp default ipv4-unicast neighbor 10.10.10.101 remote-as 1 neighbor 10.10.10.101 update-source Loopback0 neighbor 10.10.10.102 remote-as 1 ! address-family vpnv4 neighbor 10.10.10.101 activate neighbor 10.10.10.101 send-community extended neighbor 10.10.10.101 route-reflector-client neighbor 10.10.10.101 next-hop-self neighbor 10.10.10.102 activate neighbor 10.10.10.102 send-community extended neighbor 10.10.10.102 route-reflector-client neighbor 10.10.10.102 next-hop-self exit-address-family __________________________________________________________________________ hostname P1-AS2 ! ip cef ! mpls ldp router-id Loopback0 ! interface Loopback0 ip address 10.20.20.100 255.255.255.255 ! interface Ethernet0/0 ip address 10.20.20.2 255.255.255.252 mpls ip ! interface Ethernet1/0 ip address 10.20.20.6 255.255.255.252 mpls ip ! router ospf 2 network 10.20.20.0 0.0.0.255 area 0 ! router bgp 100 no bgp default ipv4-unicast bgp confederation identifier 2 bgp confederation peers 101 102 neighbor 10.20.20.101 remote-as 101 neighbor 10.20.20.101 ebgp-multihop 2 neighbor 10.20.20.101 update-source Loopback0 neighbor 10.20.20.102 remote-as 102 neighbor 10.20.20.102 ebgp-multihop 2 neighbor 10.20.20.102 update-source Loopback0 ! address-family vpnv4 neighbor 10.20.20.101 activate neighbor 10.20.20.101 send-community extended neighbor 10.20.20.101 next-hop-self neighbor 10.20.20.102 activate neighbor 10.20.20.102 send-community extended neighbor 10.20.20.102 next-hop-self exit-address-family
Example 7-29 shows that CE1-A and CE1-B see local and remote routes for VPN-A and VPN-B networks.
Example 7-29. Verifying End-to-End Connectivity
CE1-A#show ip bgp Network Next Hop Metric LocPrf Weight Path *> 172.16.10.0/24 0.0.0.0 0 32768 i *> 172.16.20.0/24 172.16.1.1 0 1 2 65002 i __________________________________________________________________________ CE1-B#show ip bgp Network Next Hop Metric LocPrf Weight Path *> 192.168.10.0 0.0.0.0 0 32768 i *> 192.168.20.0 192.168.1.1 0 1 2 1 i
Example 7-30 shows the result of the ping operation.
Example 7-30. Verify End-to-End Connectivity
CE1-A#ping 172.16.20.1 source 172.16.10.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.20.1, timeout is 2 seconds: Packet sent with a source address of 172.16.10.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 60/61/68 ms __________________________________________________________________________ CE1-B#ping 192.168.20.1 source 192.168.10.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.20.1, timeout is 2 seconds: Packet sent with a source address of 192.168.10.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 60/60/64 ms
MPLS Overview
Basic MPLS Configuration
Basic MPLS VPN Overview and Configuration
PE-CE Routing Protocol-Static and RIP
PE-CE Routing Protocol-OSPF and EIGRP
Implementing BGP in MPLS VPNs
Inter-Provider VPNs
Carrier Supporting Carriers
MPLS Traffic Engineering
Implementing VPNs with Layer 2 Tunneling Protocol Version 3
Any Transport over MPLS (AToM)
Virtual Private LAN Service (VPLS)
Implementing Quality of Service in MPLS Networks
MPLS Features and Case Studies