http://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/NetworkAnalysisUtilities/GPServer
http://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/GPServer
http://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/MapServer
http://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiego/NAServer
http://sampleserver6.arcgisonline.com/arcgis/rest/services/NetworkAnalysis/SanDiegoSync/GPServer