Current Development

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Main Page - Current Development - Developer FAQ - Tools - Related Projects - Project Ideas - Summer Projects

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On this page, we will try to summarize current ns-3 development work. If you are interested in collaborating on one of these projects, or reviewing work by others, please do not hesitate to contact the individuals identified, or the page maintainer.

There are a few other places to look for current activity on ns-3 development:

  • the current release page will list code under consideration for merging, and bugs being worked. The next release, ns-3.21 release, is scheduled for August 2014.
  • we should have entries for all of our known bugs in the Bugzilla bug tracker.
  • Related projects list some active and past projects that are associated with ns-3.
  • We maintain a suggested project ideas page for people interested in trying to start something new, or finish off some existing work.
  • We conduct code review discussions on the Google Group 'ns-3-reviews'


How to get involved

ns-3 always can use more time and assistance from contributors of all skill levels. One of the best ways to learn a tool is to try to get involved in its development processes, even if it is as simple as pointing out stale information or documentation on our web pages. Ideas on how to get started are on our project ideas page.

If you are new to ns-3 and want to contribute code, please read these guidelines: Contributing to ns-3 and review the information on this page below.

Note: ns-3 developers sometimes hang out on IRC at #ns-3 at IRC logs

Also, please check out the Current events page to learn of upcoming events for ns-3.

Code reviews

All new code (other than maintenance code committed directly by a module's maintainer) goes through a public code review. The process is described here. This page is devoted to listing code reviews that have been publicly announced.

Currently open code reviews:

* New power and rate control mechanisms

* new VANET routing example

* Minstrel modifications

Some older code reviews can be found here:



In 2013-14, the project is focusing on the following initiatives:

  • modular build system
    • Already done: bake is now a build system for DCE, and is included in ns-allinone-3.18
    • Remains to be done: use bake to make ns-3 libraries more modular (per the wiki page above)
  • starting and stopping of objects
    • Already done: Base class of ns3::Object has been patched, and Start/Stop has been deconflicted from object initialization
    • To be done: Make our core objects (Nodes and NetDevices) and protocol models do reasonable things when "Start" and Stop" methods are called on them.
  • merge of the Direct Code Execution framework
    • Already done: DCE is part of ns-3; the current release as of October 2013 is DCE 1.1
  • data collection and experiment control frameworks
    • Already done: Initial capabilities of this module were merged to the ns-3.18 release.
    • To be done: Add statistical processing, dump output to databases

Current development for main trunk of ns-3


ns-3.21 has RED and CoDel queue models, without support for ECN or other CoDel variants.

The following goals are being worked; more details at AQM enhancements:

  • an IP-aware priority queue sublayer, such as in Linux
  • pfifo_fast qdisc
  • SFQ_Codel and FQ_Codel
  • ECN support in all AQMs

GSoC and SOCIS summer projects

ns-3 participated with four projects in the 2014 Google Summer of Code.

ns-3 is participating with one project in the 2014 Summer of Code in Space. The main aim of this project is to contribute satellite-relevant TCP models, but to facilitate those models, some additional ground work on adding and testing TCP options is being done.

ns-3 core

This is a feature goal for ns-3.23 release.

CSMA model

This is a feature goal for ns-3.22 release.

There has been discussion in the June 2014 timeframe about improving this model:

These improvements have been recommended:

  1. Implement backoff counter decrement as a function of line state (see this initial code review)
  2. Divide CSMA implementation between CSMA/CD & CSMA/CA (which are totally different)
  3. Implement a distance system (not the same propagation delay for every nodes); see Vedran Miletić's work code review issue
  4. Audit the ns-3 examples to find instances where CSMA is being used with inappropriate link delay (where multiple access may perform very suboptimally)

Multipath TCP

Changes to IPv4 RouteOutput() and IPv4 global routing implementation

  1. Modification to TcpSocketBase and TcpL4Protocol in order to prevent multiple calls on RouteOutput() on each TCP socket.
  2. Split LookupGlobal() for RouteInput() and RouteOutput() usage.
  3. Change existing RandomECMP attribute from a boolean to an enum (mode).
  4. Implementation and test code for round-robin ECMP mode.
  5. Implementation of ECMP per-flow based on existing patch in bug 667 where applicable.

An MPTCP model

(this text added by Morteza Kheirkhah): We are currently implementing a new MPTCP model, which conforms with the RFC 6824 and closely follows the MPTCP Linux kernel design. The implementation is not complete yet; the first publicly available version will be released in the next few weeks. If you are interested to contribute to or test our source code please contact Morteza Kheirkhah ( This work is part of our research on multipath transport protocols in data centres.
More information about our group can be found at:
A brief description of the MPTCP model can be found in our recent short paper, Multipath-TCP in ns3, which was presented at the WNS3 2014.

Past development efforts

Most of these activities are now dormant or concluded and some of the information is stale.   
We are keeping here as a placeholder until this section can be cleaned up.

ns-3 core

Multi-threaded simulation implementation for multicore

Linux namespaces and ns-3

Device and channel models

Optical network: WDM, PON and RoF

See Optical network models.

Miscellaneous wifi enhancements

Patch to pause and resume an interface

802.11 model extensions

There are several efforts ongoing to extend the ns-3 Wifi model.

Harmonization with ns-2 802.11 Ext models

  • summary: ns-2.33 added a new 802.11 model with much more detailed channel modeling. An effort has been started to port over reusable components from that implementation to ns-3's wifi model, while reusing already implemented basic components. The goal is a harmonization of the 802.11 models of ns-2 and ns-3. Leading aim is to support research on vehicular networks. Planned near-term features:
    • Equalizing PHY models including capture effects, user-definable coding rates (e.g. 5.9 GHz from 802.11p)
    • EDCA QoS extensions of 802.11e
  • Already finished features:
    • Nakagami/Rayleigh propagation loss model
  • ns-developers post:
  • code location:
  • status: under current active development. Time frame till this is completed: 4-5 month.


  • summary: University of Florence (LART lab) has begun work on an 802.11n model for ns3. The main goal is to simulate the frame aggregation feature. In the future, they aim to implement the High Throughput terminal behaviour with MIMO technology. They plan to add, to ns-3's 802.11 model, the following 802.11n features:
    • Frame Aggregation
    • Block ACK
    • HCF (EDCA and support for HCCA)
    • TXOP
    • HT terminal (also with protection modes)
    • MIMO

Also interested to verify the 11n terminal throughput when are associated terminal of a/b/g standards.

  • Already finished features (in ns-3.5):
    • HCF, TXOP, Frame Aggregation
  • Merged for ns-3.8:
    • Block ACK
  • code location: Repository has been removed.
  • status: Frame aggregation and block ack merged already; Tommaso Pecorella announced his lab's next steps here. Current development is on hold.

Wireless Interference (Jamming) Model

Vehicular Ad Hoc Networks (VANET)

  • summary: Michele Weigle's group is working on VANET and has posted a patch for review in the past, but has taken it off the table for ns-3 merge consideration until more work is done.
  • code location: None publicly posted at this time.

Wireless Sensor Networks (i.e., 802.15.4 + 6LoWPAN + RPL)

Tommaso Pecorella announced his plans here

Current status is:

  • RPL implementation (storing, multicast): 5th refactoring going on. Moving responsibility to ParentSet and MeasureCollectors for metrics other than HC.
    • RPL is based on ROLL RFCs and drafts
    • Objective functions implemented are of0 and minrank-hysteresis-of
  • 6LoWPAN has been merged in ns-3-dev and will be included in ns-3.19.
  • 802.15.4 will rely on the lr-wpan module (currently being implemented by Boeing).
    • A patch to the lr-wpan code to enable its use with 6LoWPAN (and the full IPv6 stack) has been created. The patch adds a number of functionalities to the module and will be either included in lr-wpan or provided as a separate patch.

A wiki page will be created before 3.19 release to explain in detail the current implemented functionalities, the models limitations, the work status and provide a guide to setup a simple simulation.

Boeing is working on lr-wpan (IEEE 802.15.4-2006) support; details here.


In addition to the LENA project above, several developers expressed their interest in enhancing the LTE code initially developed within the GSoC 2010:

  • Leo Razoumov announced possible interest in the following contributions:
    • MIMO
    • PHY model abstractions
    • scheduling models
    • mobility and traffic models
  • Giuseppe Piro and his group (DEE, Politecnico di Bari) announced the intent to continue with the development of the LTE module, focusing mainly on the following MAC layer aspects:
    • RRM
    • scheduling
    • AMC
  • Marco Mezzavilla and his group (DEI, University of Padova) announced interest in working on the following, and have posted a repository in February 2011 details here:
    • MAC layer
    • mobility
    • traffic modelization
    • MIMO
  • Sandra Frei announced that a group is working on Evolved Packet System (EPS) support
    • GTPv1-U (for the user plane)
    • GTPv2-C (for the control plane)
    • Diameter: Supported use cases: default- and dedicated bearer establishment
    • NAS (ESM, EMM) A combined initial attach with a default bearer establishment. Dedicated bearer establishment
    • X2AP HO without SGW relocation. Endmarker messages are not supported

Link layer

802.21 media independent handover


Network layer

API and functionality for marking TOS bytes in packets

DSR routing

DSDV routing

Transport layer

TCP Vegas

Multipath TCP

NS-3 module for MPTCP (Multipath TCP). The current release is compatible with 3.8 version of NS-3. A check of the compatibility with the latest version is needed.

Codel, fq_codel in ns-3

Application layer

Chord/DHash DHT

Synchronous posix/sockets API

real-world application integration

ns-3-simu sockopt patches



Jeremy Norman and the iNSpect team have posted some plans for a visualization library for ns-3:

George Riley has made a prototype animator for PointToPoint links.

Joe Kopena is working on what he calls a "decorator"

Hagen Paul Pfeifer is working on a MANET visualizer

Graphical simulation builder

Pierre Weiss and Sebastien Vincent have written an ns-3 scenario generator in Qt.


| NetExplorer is Gnome/Gtk network animation tool for NS-3.


L2 Ethernet switch module

Parallel simulations (2008)

Delay Box for ns-3

Matt Crinklaw is working on a port of ns-2 DelayBox to ns-3.

Simulation Configuration and State Detection

In order to configure simulations across multiple, probably virtualized, machines a large amount of configuration must be performed in order to construct the component systems. The oppportunity for human error to creep in during this process renders it essentially manually unworkable for all but the simplest topologies. Craig Dowell is thinking about how to address this problem.

Simulation Configuration

Build system and project infrastructure

Modular build and package management

This issue is being tracked (requirements and wish list) on this page

State of Doxygen

Need to bring Doxygen into compliance (no errors, no warnings for missing documentation).


  • investigate hooking code coverage (lcov) into the report
  • investigate how the whole buildbot farm may be made available to a maintainer to test out a non-ns-3-dev repo.

Code contribution guidance

Tom took action item to simplify and clarify the project code contribution guidelines (for people wishing to contribute new code to ns-3).

Samples directory

Consider cleanup and move of samples/ directory to examples/?


Considering to refactor documentation to split the existing manual into a model library and a software core reference manual, to add a lighter-weight tutorial, and to add a "cookbook" of howtos for common ns-3 tasks.


Status: INRIA is organizing some updates to the website.