If you find a shortest path from location A to B and now want to find another path, you can make the shortest path a little slower and solve again! To make the path slower, you can take the output of the route solve and load it as a line barrier into the same route analysis layer. You can set it to be a scaled cost barrier and set the scale to be 10 percent higher. So, you can set the scale as 1.1, that is all costs of lines under that line barrier will be multiplied by 1.1 or ten percent more. Solve. You should get a different path. Now take the route output and again add it as a scaled cost line barrier with scaled cost of 1.1 and solve. So roads that are common will now be scaled 20 percent. OR you could have taken the first line barrier and changed its scale to 1.2 and solve may give you another path.
This is a good way to generate some alternate paths. But not a good way to generate ALL paths.
Jay Sandhu