Creating a network analysis layer using geoprocessing

Steps:

1. Start ArcMap by clicking Start > All Programs > ArcGIS > ArcMap 10.1.
2. Click Geoprocessing > Search For Tools.
3. Type make network analysis layer in the search box.
4. Click Search Tools.

   The geoprocessing tools that make network analysis layers are listed in the Search window.

5. Click the name of the tool that makes the network analysis layer you want.

   For example, if you want to create a route layer, click Make Route Layer.

   The tool's dialog box opens.

In geoprocessing, the network analysis layer properties are set in the tool dialog box before the layer is created. This is in contrast to ArcMap, in which properties are set after the analysis layer is created.
6. Fill in the parameters of the tool.
7. Click OK.

The network analysis layer is created as an in-memory workspace. It is added to the ArcMap table of contents and the Network Analyst window.