US Patent 11336556 Route exchange between logical routers in different datacenters

Some embodiments provide a method for a first edge device in a first datacenter that implements a centralized routing component of a logical router that spans multiple datacenters and handles data traffic between a logical network implemented across the multiple datacenters and external networks. From a second edge device in a second datacenter, the method receives via routing protocol a route having a particular routing protocol tag. When the first datacenter is a primary datacenter for the logical router such that all data traffic between the logical network and the external networks is handled by one or more centralized routing components implemented at the first datacenter, the method uses the routing protocol tag to determine whether to advertise the received route to the external networks.