A topology service may include a topology database and topology service interface used by clients to query the topology database. The topology database may describe a topology of resources of an infrastructure that may include racks of resources such as network, compute and storage resources. The topology database may be populated using discovery information returned as a result of issuing discovery requests to switches. The discovery information may identify connectivity between switches and other resources. The discovery information may be processed to determine assigned switch roles and additional derived information such as regarding instances of topological entities in the infrastructure. The derived information may identify instances of racks, rows and data centers in the infrastructure. The topology database may identify particular resources included in the different racks, rows, and data centers as well as connectivity between resources and communication capabilities of resource interfaces.