When the Topology Network Discovery type is selected for a site, only routers and subnets are discovered and stored in the SMS site database. This data is used by Network Trace to provide more information about the network links between SMS site systems.
The following diagram shows what this type of Network Discovery finds when it runs on Server 1 with 0 router hops specified: subnet D and Router 1.
Network Discovery Properties Dialog Box: General Tab
Network Discovery Overview