OMNeT++ is built as an extensible, modular and component-based C++ simulation library and framework. It is primarily designed for building network simulators.
"Network" is meant in a broader sense that includes wired and wireless communication networks, on-chip networks, queueing networks, and so on.
Domain-specific functionality such as support for sensor networks, wireless ad-hoc networks, Internet protocols, performance modeling, photonic networks, etc., is provided by model frameworks, developed as independent projects.
OMNeT++ offers an Eclipse-based IDE, a graphical runtime environment, and a host of other tools. There are extensions for real-time simulation, network emulation, alternative programming languages (Java, C#), database integration, SystemC integration, and several other functions.
NOTE: OMNeT++ is free for academic and non-profit use. Commercial users must obtain a license from omnest.

What's New in This Release:
IDE:
· Analysis tool: added support for computed scalars. Read the updated the User Guide for further details.
· Analysis tool: added Logarithmic X axis option to scatter chart.
· Added NED editor support for named channels.
· Added support for opening files from the command line, i.e. use: $ omnetpp Aloha.ned
· Added full screen mode (Ctrl-Shift-F11).
· Usability improvements in the Analysis Tool.
· Better error reporting in the Sequence Chart and Event Log views.
· The CDT C++ code analyzer has been turned off as it was reporting too many false positives.
· The IDE has been switched over to use CDT’s DSF debugger instead of the older CDI.
· The IDE no longer runs the C/C++ Indexer before build (the code now collects the information for makefile dependency generation by other means)
· Added pretty printing of STL containers (std::map, etc), simtime_t and other objects to the debugger; see the updated User Guide for details.
· Updated the bundled MinGW (GCC, linker and GDB).
· Updated...