A researcher in my field* recently created an "Urban Network Toolbox", an ArcGIS extension built upon Network Analyst. It calculates a number of measures on urban networks, such as betweenness and reach.
He was criticized for relying on ArcGIS, a commercial tool not available to many researchers, especially outside the US. But ArcGIS was a convenient platform, since it contains the Network Analyst extension, simplifying the work required for the analysis.
Are there open source network analysis tools that do the work of the Network Analyst extension? Are there other methods for creating the network datasets required as input for the toolbox? My understanding of the toolbox is that it uses the network dataset to calculate a distance matrix for a given set of points on the network. The toolbox does not use any of the higher level problem solving tools in Network Analyst.
*Quantitative Urban Morphology, perhaps? No one seems settled on a name for the broader field. The particular brand of research I do is with Space Syntax.