/**

 * @anchor modules_anchor

 *

 * @defgroup simulator Simulator

 * The "simulator" module contains: 

 *    - a time management class to hold a time and convert between various time units: ns3::Time 

 *    - a scheduler base class used to implement new simulation event schedulers:       

 *      ns3::Scheduler and ns3::SchedulerFactory 

 *    - a simulator class used to create, schedule and cancel events: ns3::Simulator

 *

 * @defgroup core Core

 * \brief The "core" module contains:

 *    - a Functor class: ns3::Callback  

 *    - an os-independent interface to get access to the elapsed wall clock time: ns3::SystemWallClockMs 

 *    - a class to register regression tests with the test manager: ns3::Test and ns3::TestManager

 *    - debugging facilities: \ref logging, \ref assert, \ref error

 *    - \ref randomvariable

 *    - a base class for objects which need to support reference counting

 *      and QueryInterface: ns3::Object and ns3::InterfaceId 

 *    - a set of low-level trace facilities integrated in the ns3::Object system: \ref tracing

 *    - a ns3::ComponentManager which can be used to manage the creation

 *      of any object which derives from ns3::Object through an ns3::ClassId 

 *    - a smart-pointer class ns3::Ptr designed to work together with ns3::Object

 *

 * @defgroup common Common

 * The "core" module contains: 

 *    - a packet class to create and manipulate simulation packets: 

 *      ns3::Packet, ns3::Header,  and ns3::Trailer. This packet class 

 *      also supports per-packet ns3::Tag which are  globs of data 

 *      which can be attached to any packet.

 *

 * @defgroup node Node

 * The "node" module contains:

 *    - a ns3::Node base class which should be subclassed by any new type of

 *      network Node.

 *    - models which abstract the MAC-layer from the IP layer protocols:

 *      ns3::NetDevice and ns3::Channel. 

 *    - models which abstract the application-layer API: ns3::Application,

 *      ns3::Socket, ns3::SocketFactory, and, ns3::Udp

 * 

 *

 * @defgroup devices Devices

 *

 * @defgroup internetNode InternetNode

 * 

 * The "internet-node" module contains a set of classes which implement the

 * APIs defined in the "node" module:

 *    - an Ipv4/Udp stack with socket support 

 *    - an ARP module

 *    - an InternetNode class which is a Node subclass.

 *    

 * @defgroup helper Helpers

 * 

 * @defgroup applications Applications

 *

 * @defgroup mobility Mobility

 *

 * @defgroup routing Routing

 *

 * @defgroup constants Constants

 * @brief Constants you can change

 *

 * @defgroup contrib Contrib

 */