Available with Network Analyst license.
The network dataset is referenced with a catalog path instead of a network dataset layer. A network dataset layer caches connection properties, which makes opening it faster.
Solutions
- Add the network dataset as a layer to ArcMap. Execute your geoprocessing tool using the network dataset layer as input. Share it as a package or service.
Do nothing. You can choose to accept the drawbacks and ignore the warning.
More Information
Whenever a network dataset is used for analysis, it has to be opened. Opening network datasets is expensive because they contain several advanced data structures and tables that must be read and cached. A network dataset layer references a network dataset on disk and caches properties about the dataset.
If the network dataset is referenced by a catalog path, it is opened each time the geoprocessing tool executes. By using a network dataset layer instead of referencing it by a catalog path, there is a performance advantage because after the dataset is shared as a service, the dataset is opened once when the service starts, and its connection properties are cached. When the geoprocessing tool executes, the dataset doesn't have to be reopened, which is a performance boost.