This is ns-3-allinone.
If you have downloaded this in tarball release format, this directory
contains some released ns-3 version, along with 3rd party components
necessary to support Python bindings and the Network Animator (netanim).
In this case, and if prerequisites are satisfied, one may run the
script build.py, and netanim and ns-3 will then be built.
This directory also contains the bake build tool, which allows
access to several additional modules including the Network Simulation
Cradle, Direct Code Execution environment, and click and openflow
extensions for ns-3.
To get started with ns-3, please consult the project tutorial available