Im looking for alternative ways for analyse my network dataset. So, there is another way to analyse an GIS network? I mean if there are any useful plug-in capable to determine service areas, routes, or even VRPs like Arcmap does? Road Graph plugin can do all this stuff?
Use PgRouting. PgRouting works with PostGIS and so it falls into your category of "another OS GIS". Underdark has created a whole suite of tutorials (including installation instructions) here. A search on this site for pgrouting will generate a lot of other discussion, links and tips.