Enable scaling for stretched VXLAN campus networks

To support large-scaled stretched VXLAN campus networks, we provide routing policy options, sample routing policies, and new statements to optimize how remote host routes are managed across the access, distribution, and core layers in large-scaled VXLAN campus networks stretched across sites using DCI.

With this feature, you can configure the network to install remote host routes in the core layer but not in the distribution and access layers. The distribution and access layer devices only install EVPN Type 5 subnet routes for remote host destinations. The configuration includes policies to ensure the EVPN Type 5 subnet routes are the preferred routes on the distribution and access layer devices. This design reduces the route table burden on access and distribution devices as the network scales.