Configuration of MP-iBGP on TransitNet PE-routers
Each PE-router within the network will need to be configured to run an MP-iBGP and standard BGP-4 session to the pair of route reflectors within the core of the TransitNet backbone. The configuration for the MP-iBGP sessions is the same address-family configuration under the BGP process as was performed on the route reflectors, except that the neighbor addresses used are the loopback addresses of the route reflectors.
When this configuration has been entered, the MP-iBGP sessions should become active. However, no updates will be received except for the default route from the Snet_Internet VRF because no VRFs will have been created and no customer interfaces have been associated with any VRFs. The default route update from the Snet_Internet VRF will not be used at this point as it has not been imported into any VRFs within any of the PE-routers.
When the MP-iBGP sessions become active, the following configuration steps will be necessary on each of the PE-routers to provide the relevant VRFs and BGP configuration for successful migration of VPN sites to the MPLS/VPN solution:
Creation of the relevant VRFs? Each PE-router within the TransitNet network should now be configured with all of the relevant VRFs that will be used on that PE-router. This can be achieved using a similar configuration to the one shown in Example 15-5.
Configuration of the static default route within the Internet_Customer VPN? Each customer that belongs to the Internet_Customer VPN will need to be capable of reaching the Internet gateway router for Internet connectivity.
Creation of address families within the BGP configuration? An address family must be created for each of the VRFs under the BGP configuration. This is necessary so that the routes contained within the VRF are advertised across the MP-iBGP sessions between PE-routers. Example 15-6 provides the necessary configuration to allow the M P-iBGP sessions to carry routes from the Snet_Customer and Internet_Customer VPNs.
Example 15-5 TransitNet PE-router VRF Configuration
ip vrf Snet_Customer rd 1234:100 route-target export 1234:16 route-target import 1234:16 route-target import 1234:17 route-target import 1234:18 ! ip vrf Internet_Customer rd 1234:102 route-target export 1234:18 route-target import 1234:18 route-target import 1234:16
Example 15-6 TransitNet PE-router BGP VRF Address Family Configuration
router bgp 1234 ! address-family ipv4 vrf Snet_Customer no auto-summary no synchronization redistribute static exit-address-family ! address-family ipv4 vrf Internet_Customer no auto-summary no synchronization redistribute static exit-address-family
