It is possible to set various options via URL parameters in the Topology App.

For example, the following URL will always select vertex with id "10" and Provider "Enhanced Linkd"

/opennms/toppology?provider=Enhanced+Linkd&focus-vertices=10&szl=5

However, if multiple graphs are provided (e.g. via GraphML) it is not possible to specify a layer and therefore defining the focus may not work, as the vertices may not be in the default layer selected.

Therefore an url parameter should be provided to specifically select a layer by its namespace.