We are happy to announce INET Framework version 4.2. Go ahead and  get it now!

This version introduces a new, efficient and powerful multidimensional representation of radio signals, which makes it possible to accurately simulate phenomena such as cross-talk and coexistence. Associated visualization components can display power density heat map, spectrum, spectrogram, etc. (see demo).

INET 4.2 also replaces existing queueing components with a new queueing framework and library that puts an end to the duality of internal and external queues, and can be used at multiple layers, including the creation of traffic generators and other applications (see tutorial). The release also comes with a number of additional improvements and bug fixes.

This version requires OMNeT++ 5.5.1 or later.

Notable backward incompatible changes

1. Representation of radio signals

The multidimensional (in terms of space, time, and frequency) analog domain representation of radio signals in the physical layer has been substantially changed. The old multidimensional mathematical function implementation, which was originally inherited from MiXiM, has been replaced with a completely new implementation. The reason behind this change is that the old implementation had several non-trivial open bugs, it was often 10+ times slower than the equivalent scalar signal representation, and due to its iterator-based API and its eager computational nature, it was less composable and extensible.

The new implementation is capable of representing all kinds of radio signals such as OFDM, FHSS, UWB, etc. It also allows mixing these wireless technologies arbitrarily. The new API is more flexible in terms of composition, and it allows arbitrary extensions to be combined with existing representations.

The new implementation has better performance than the old one both in terms of memory usage and execution speed. Thanks to the usage of shared pointers, it scales well to large networks with a small memory footprint and is easy to maintain and use. It also has comparable execution speed to the equivalent scalar signal representation. Futhermore, it allows the visualization of the power spectral density of individual signals and the transmission medium in Qtenv.

Simulation models which use the old C++ API will not compile, and need to be updated.

The transmitter timeGains and frequencyGains NED parameters, which determine the signal power over time and frequency, have been changed in the various dimensional radio models. The new syntax is more expressive and more user friendly. The changed interpretation of these NED parameters will cause an error in existing simulations that use it.

See the presentation from the OMNeT++ Community Summit 2019: https://summit.omnetpp.org/2019/assets/pdf/math.pdf

2. Queueing model

A new top-level source folder containing a new queueing model package has been added. The new queueing model provides reusable modules for various application areas. These modules can be used to build application traffic generators, queueing models for MAC protocols, traffic conditioning models for quality of service implementations, and so on.

The queueing model contains several different kinds of elements: sources, sinks, queues, buffers, filters, servers, classifiers, schedulers, etc. Some of the queueing elements were already present in INET, but most of them are written from scratch. The most important change is that the queueing model became synchronous by default, primarily in order to avoid event race conditions in complex queueing models, and also to increase performance by eliminating simulation events. The User’s Guide has been extended with a relevant chapter.

This change results in compilation errors and NED errors in simulation models which use the old queueing model. You may look at changes to existing MAC protocols to see how to update your code.

3. MAC protocols and DiffServ

All MAC protocols have been updated to use the new queueing model for their transmission queues in a very similar way. All protocols have been extended with a replaceable queue submodule, even in the default case, so there’s no internal queue anymore. Different queue length parameters have been removed from MAC modules, because complex transmission queues may have all sorts of parameters rendering the MAC queue length parameters useless.

The DiffServ implementation has also been updated to use the new queueing model.

These changes may cause existing models to silently produce different simulation results, because some module parameters such as txQueueLimit and queueLength MAC protocol parameters no longer exist.

4. Packet API

The interpretation of the Chunk API length parameter for negative values has been changed in the peek() and has() functions. The old version interpreted the value -1 as any length. The new version interprets negative values as any length up to the absolute value of the parameter. The change was required to properly implement the Chunk serialization API for all edge cases.

This change may result in incorrect behavior silently if the -1 parameter value was used explicitly. Generally, that is not expected to cause a problem because these APIs are not normally used in models.

The non-template versions of peekAtBack(), popAtBack(), and removeAtBack() in the Packet class has been changed to require the length parameter. The reason being that deserialization is only supported forwards, so there’s no way of knowing the length when a raw packet is used.

This change may result in compilation errors in existing code.

5. IEEE 802.11 (WiFi)

The IEEE 802.11 model has been changed to have explicit modules for both the PendingQueue and the InProgressFrames. Futhermore, several submodules of the Hcf module have been moved to the Edcaf module to better reflect their usage.

Throughout the 802.11 model has also been extended with several new signals and statistics. The ACK handling mechanism in QoS mode has been fixed.

Several parts of the IEEE 802.11 frame have been renamed to be consistent with the naming scheme:

   Ieee80211DataFrame -> Ieee80211DataHeader
   Ieee80211DataOrMgmtFrame -> Ieee80211DataOrMgmtHeader
   Ieee80211ManagementHeader -> Ieee80211MgmtHeader
   Ieee80211ManagementFrame -> Ieee80211MgmtFrame
   Ieee80211Frame -> Ieee80211MacHeader
   Ieee80211OneAddressFrame -> Ieee80211OneAddressHeader
   Ieee80211TwoAddressFrame -> Ieee80211TwoAddressHeader
   Ieee80211ACKFrame -> Ieee80211AckFrame
   Ieee80211RTSFrame -> Ieee80211RtsFrame
   Ieee80211CTSFrame -> Ieee80211CtsFrame

Most simulations are not affected, because the external interface of the 802.11 MAC has not been changed. Nevertheless, simulations which go deeper in the direct parameterization of the 802.11 MAC submodules have to be updated.

6. Transmission medium

The storage mechanism of radios and transmissions has been moved from the radio medium module to the communication cache submodule. This allows the usage of different strategies for different kinds of networks. For example, a dynamic network where radios are created and destroyed dynamically can have better performance with a non-default mechanism.

This change results in compilation errors if the underlying C++ interfaces were implemented in user code.

7. Various renames

The carrierFrequency parameters have been renamed to centerFrequency in several modules where they were named incorrectly.

With the addition of the new Ospfv3 implementation, the old OSPF implementation has been renamed from Ospf to Ospfv2.

These changes may require updating the affected simulations.

Notable backward compatible changes

1. OSPF version 3

A new OSPF protocol implementation has been added which implements version 3 of the protocol. This feature is a contribution of Lukáš Galbička and Marcel Marek.

2. TCP/IP ECN

The TCP/IP model has been extended with partial support for Explicit Congestion Notification (ECN). This feature is a contribution of Marcel Marek and Mohammad HabibAllah.

3. TTL and ToS in sockets

The UDP and TCP socket options have been extended with time-to-live and type-of-service parameters. This feature is a contribution of Mani Amoozadeh.

4. Packet API

The Packet API has also been extended with a PF_ALLOW_EMPTY flag to support returning Empty chunks. This feature makes certain algorithms easier to write, because the user doesn’t have to check for nullptr all over the place.

The PacketDissector::ICallback interface has been extended with a new callback called shouldDissectProtocolDataUnit() for the possibility to stop dissection for performance reasons.

5. Physical layer components

The physical layer dimensional model has been extended with a new NoiseSource and a new DimensionalBackgroundNoise module. The former is capable of generating noise periodically as a point source with optional mobility. The latter can be used to describe a non-isotropic background noise which changes over time and frequency.

6. Visualization of radio signals

The MediumCanvasVisualizer has been extended with the visualization of signal power spectrums, signal power spectrograms, and signal power maps. Spectrum figures display signal power density over frequency at a given position and moment of time. Spectrogram figures display signal power density over time and frequency at a given position. Power map figures display signal power density over space at a given frequency and moment of time.

All three kinds of figures can be used to display a particular signal or the total power density of transmission medium. The new visualization is also capable of displaying the above for the currently transmitted or received signal automatically while simultaneously comparing it to the total interfering signals and noise using color coding. The visualization takes into account the directional selectivity of radio antennas.

A new “network node”, called the Probe, allows the visualization of the total transmission medium power spectral density at any given location. The latest Qtenv supports dragging network nodes with Shift + left mouse click. This feature effectively allows the user to explore power spectral density in space by simply dragging a probe node.

See the following example videos: https://www.youtube.com/watch?v=oyjX03MSi7s https://www.youtube.com/watch?v=Oi1sq23IPYs https://www.youtube.com/watch?v=TyYQ53hUrns

7. Visualization of street maps

The new OpenStreetMapSceneCanvasVisualizer allows displaying an arbitrary street map file created by OpenStreetMap as the background of a compound module. The configuration is simple: the visualizer takes the map filename parameter and the geographic coordinate system takes longitude/latitude parameters to specify the origin of the scene.

8. Applications parameterized with traffic generators

New generic TCP and UDP applications such as UdpApp, TcpClientApp, TcpServerApp have been added with composable traffic source and traffic sink components. One can implement new behavior by assembling queueing elements. For example, new applications can be easily set up to simulate request-response based client-server applications (see TcpRequestResponseApp), or a remote terminal (see TelnetClientApp/TelnetServerApp).

9. Module initialization

A new named initialization stage, called INITSTAGE_ROUTER_ID_ASSIGNMENT, has been added. The configuration of the router ID has been moved to this stage.

10. Packet serialization and emulation

New chunk serializers have been added for several protocols. Changed several protocol field types and names in MSG files to be more correct. Fixed and refactored CRC calculation, CRC mode parameters and handling, CRC insertion and verification. Of course, the exact CRC calculation and verification are still optional due to performance reasons.

These changes make the emulation support more feature complete. Most of the example simulations are expected to work with serialized packets too. This can be simply tested by running the fingerprint tests with the sendRawBytes parameters of network interfaces set to true.

11. Regression testing with fingerprint calculation

A special fingerprint calculator (NetworkCommunicationFingerprintCalculator) has been added, which is capable of computing a simulation fingerprint using the timing and binary contents of packets sent between network nodes. This feature allows easier regression testing for some simulation models if the exchanged packets are expected to stay the same. This kind of fingerprint ignores all internal details of how the network nodes operate.

12. Documentation

The User’s Guide has been extended with a new chapter on the newly added queueing package. It has also been updated with respect to the new generic applications.

A new queueing model tutorial has been added. This tutorial contains very minimal explanation, it is rather provided to give a quick glance.

The tutorial is available at: https://inet.omnetpp.org/docs/tutorials/queueing/doc

13. Other minor changes

  • Module shutdown operation has been refactored and extended in simulation time to allow for graceful closing of TCP connections.
  • PCAP recording has been enhanced with automatic network type detection and optional packet conversion.
  • New PRE and POST module initialization signals have been added for dynamic module creation.
  • A new WeightedHistogramRecorder has been added which records histograms using weighted double values.
  • The packet inspector has been enhanced to display the front, back, and data parts of packets separately in Qtenv. Furthermore, packet tags and data tags are also displayed in children mode.
  • All applications have been extended for CreationTimeTag to calculate end-to-end delay.
  • Several applications have been extended with ToS and DSCP parameters.
  • The ManetRouter has been extended with a parameterizable routingApp submodule.
  • The InterfaceEntry module base has been added to all interface modules.
  • The MAC protocol base classes have been merged into one.
  • Extended the <disconnect> and <set-channel-param> commands in ScenarioManager.
  • Added OpenMP support to allow parallel computation for physical signal visualization.
  • Added notifications about changing the InterfaceProtocolData set to InterfaceEntry.

  • Added TcpSocket::ReceiveQueueBasedCallback to make writing applications easier.

  • Fixed small packet and chunk length discrepancies in several protocols.
  • Fixed TCP SACK rexmit queue inconsistency by Luca Giacomoni.
  • Fixed several memory leaks.

Numerous other bug fixes and small improvements.

Download INET-4.2.0 now.