Usage Scenario
Route-filters are used to filter routes based on sets or a single element and modify route attributes of the routes that meet matching rules. To set a route attribute for the routes that meet matching rules, run the apply command.
The parameters in action clauses can be specific values or global variables referenced using $+global variable name. The parameters in a route-filter with pre-defined variables can be those defined in this route-filter.
Global variables cannot be referenced by the route attribute sets in the format of {element A, element B...}.