Sensor network simulator

Hi,

I want to conduct simulation and experiments for a sensor network environment. It would be good to have the following features in the simulator

1. The simulator will provide receiving timestamp of each packet

2. It has some kind of aggregation protocol implemented

3. DSR protocol is implemented

Mainly I need a good and heavily used Simulator for sensor network. It would be good to have the above mentioned properties but they are not mandatory.

Thanks,
Sultana