Distributed and Centralized Routing

L3 routers can be configured in centralized mode or distributed mode.

In centralized mode, routing is configured only on the border leaf pairs. In contrast, for distributed mode, routing is configured on the corresponding leaf nodes where the endpoints reside.

During router creation, You can provide centralized mode or distributed mode as input:
openstack router create R1  --distributed
openstack router create R2  --centralized
The default option is centralized, so the following command creates centralized routing:
openstack router create R2

The L3 service plugin passes this information to EFA. Then, the EFA Tenant Service configures VRF or routing on border leafs or on leaf nodes, based on the configuration mode.