It depends on what you want to simulate there are many tools available for simulating a traditional campus network. Campus networks are not very complex. Here is a link to a vast range of tools. Packet tracer is not very useful for simulating a campus network, I would advise against using it:
The above URL provide some examples of opensource projects and software. If you have access to software like OPNET or ITGURU, these are even better and are quite user friendly, unlike NS-2.
Tandin Sir, I too recommend you to use the GNS3 (Graphical Network Simulator), but while simulating the nodes, if you use the full fledged operating system like Windows 7, 8 or 10, there will be considerable restriction from the system's resources such as RAM and CPU. We can easily run around 8 nodes on a normal desktop PC. If you use a more sophisticated system, it would support proportionately more nodes.