Case Study-Inter-AS Implementing Route-Reflector and BGP Confederation in Provider Networks

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 Configuration on Cisco IOS Software
MPLS Configuration on Cisco IOS Software
ISBN: 1587051990
EAN: 2147483647
Year: 2006
Pages: 130
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