Exam JN0-664 Topic 10 Question 31 Discussion

Explanation
BGP route target filtering is a technique that reduces the number of routers that receive VPN routes and route updates, helping to limit the amount of overhead associated with running a VPN. BGP route target filtering is based on the exchange of the route-target address family, which contains information about the VPN membership of each PE device. Based on this information, a PE device can decide whether to accept or reject VPN routes from another PE device.
BGP route target filtering can be configured on PE devices or on route reflectors (RRs). Configuring BGP route target filtering on RRs is more efficient and scalable, as it reduces the number of BGP sessions and updates between PE devices. To configure BGP route target filtering on RRs, the following steps are required:
* Configure the family route-target statement under the BGP group or neighbor configuration on the RRs.
This enables the exchange of the route-target address family between the RRs and their clients (PE devices).
* Configure the resolution rib bgp.l3vpn.0 resolution-ribs inet.0 statement under the routing-options configuration on the RRs. This enables the RRs to resolve next hops for VPN routes using the inet.0 routing table.
* Configure an export policy for BGP route target filtering under the routing-options configuration on the RRs. This policy controls which route targets are advertised to each PE device based on their VPN membership.