On the BGP/MPLS IP VPN network shown in the figure, an administrator wants to use...

In a hub-and-spoke VPN topology:

Spoke sites should be able to communicate only with the hub, not directly with each other.

This is achieved through RT (Route Target) control:

Spokes export routes with ERT = 200:1

Hub imports those routes with IRT = 200:1

Hub exports routes with ERT = 100:1

Spokes import those hub routes using IRT = 100:1

This results in:

Spokes receive hub routes, but

Spokes do not receive each other ' s routes, preventing direct spoke-to-spoke communication.

Official Huawei Extract:

" In a hub-spoke topology, spokes use one RT to export (e.g., 200:1), and the hub uses that as its import RT. The hub exports routes with a different RT (e.g., 100:1), and spokes import that RT. This enforces centralized traffic control through the hub. "

— [Huawei HCIA-Datacom Certification Guide – MPLS VPN and Route Target Control]