/**
* @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 randomvariable
* - a base class for objects which need to support per-instance "attributes" and
* trace sources: ns3::ObjectBase
* - a base class for objects which need to support reference counting
* and dynamic object aggregation: ns3::Object
* - a smart-pointer class ns3::Ptr designed to work together with ns3::Object
* - a configuration class used to set and control all attributes and trace sources
* in a simulation: ns3::Config.
*
* @defgroup common Common
* The "common" 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 internetStack InternetStack
*
* The "internet-stack" module contains:
* - an Ipv4 stack
* - an ARP module
* - a UDP and a TCP implementation
*
* @defgroup routing Routing
*
* @defgroup helper Helpers
*
* @defgroup applications Applications
*
* @defgroup mobility Mobility
*
* @defgroup constants Constants
* @brief Constants you can change
*
* @defgroup utils Utils
* @brief The utils directory is for various programs and scripts related
* to code coverage, test suites, style checking, and benchmarking.
*
* @defgroup contrib Contrib
*/