Data and Maps for ArcGIS 2013 was the last version of that product to include a pre-made network dataset. You can get a very nice network dataset in the Street Map Premium for ArcGIS product (StreetMap Premium for ArcGIS | Street Dataset | Geocoding Addresses), though that is not free.
You can also access some network analysis services from ArcGIS Online in ArcMap ( What are the ArcGIS Online network analysis services?—Help | ArcGIS for Desktop ). These services utilize the network dataset stored in ArcGIS Online, so you do not need to have one of your own in order to take advantage of some network analyses. You just need an ArcGIS Online organization named user account with permissions to use the services and credits available, as the services do consume credits (ArcGIS Online | Service Credits).
I hope that answers your question!