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TCP Restart

In the summer of 2018, we’ve introduced the option to automatically restart a broken TCP session. This feature provided continuous TCP traffic, even when the network itself encountered hiccups.
At that time, this feature was only available on the ByteBlower server ports. In this first major release of 2019, we are bringing this feature to ByteBlower Wireless Endpoints.
A big aid to test mobile devices even in difficult Wi-Fi environments.

Watch it in action in this short demonstration short demonstration video

Need a flexible NBASE-T test solution?

2019 will be the year of WiFi 6! With throughput rates rising beyond the magical 1 Gbit/s barrier, NBASE-T network connectivity will become much more common.
The NBASE-T add-on to ByteBlower gives you 2.5 and 5G test-capabilities in addition to your current system. This upgrade keeps you up to date with future developments to Ethernet connectivity without the expense of a whole new system.
Four different network technologies from just a single system!

What's coming next?

Meanwhile the next version is already being worked on, which is expected in the summer months. Some of the new features you can expect:

  • Interactive charts
  • Wi-Fi details ( RSSI/BSSID/...) in API where available
  • JSON reports preview


You can download this version of the GUI here:

Information on how to use the CLT version of the GUI: Introduction to ByteBlower CLT

Changelog 2.10.2 (27th of June 2019)

  • The ByteBLower-CLT prints out its version number on startup. This makes it easier to know which version you're using.
  • A cleaner handling of the command line arguments. Removed the stack-trace when the arguments are incomplete.
  • Fixed including the images in this changelog.

Changelog 2.10.0 (24th of April 2019)


  • Default TCP window scale is now 7. This is closer the most common value on the internet today. New TCP templates will use this value.
  • Easier solution text for Wireless Endpoints without IPv6 configuration.
  • We're now also generating a latency distribution chart is for broadcast flows.
  • The support-portal and tutorial site are now accessible through the help-menu ( Help->Support Portal | Help->Tutorials ) .
  • You can now create scenario's immediately from the Flow view. Select a couple flows and pick the last option in the right click menu.
  • Show the total burst duration in the middle info panel of the FrameBlasting View. This makes it easier to configure burst.
  • To make it easier working with many frames, the Frame view now shows you size and type of the frames.
  • The archive view additionally shows the size of the testresult database. This makes it easier to clean up the largest items.
  • The CLT creates the output and store directories if they woulnd't exist yet. That makes the CLT easier to use in scripts.
  • The Windows CLT now uses the console where it is started from, rather than opening a new window. This makes working with the Byteblower CLT much more easy. It has thus now the same behaviour as the eclispec.exe.
  • The GUI backups the project also when started with a batch.
  • Instead of 5 packets, discovery traffic is sent for the whole NATDiscovery period. The rate remains 10 pck/s. In total at most 200 packets will thus be sent out.
  • A Wireless Endpoint test will stop when the WE returns to reserved, even when the TCP flow fails to connect completely.
  • The duration column of a TCP flow will be colored red in the ByteBlower report when a TCP flow doesn't reach its configured duration.

Bug fixes

  • Filenames of the reports are now unique filenames. This fixes an edgecase where multiple tests finish within the same second.
  • More robust Archive view. Fixed nullpointer exception when no format was found.
  • The edit button in the Frame Blasting view is disabled when no project is open.
  • The 'open HTML' button will always open the HTML report and not the one currently selected.
  • Made the UI more robust. Fixed null-pointer exceptions found in the GUI logs.
  • The save-as view tried to update itself after canceling. This generated hidden exceptions in the log.
  • Fixed a couple exceptions that occur when closing of the ByteBlower GUI. These were found in the Eclipse log.
  • Fixed hidden Exception when clearing the initial receive window size value in the TCP view.
  • Restarted TCP sessions using the same TOS values, slow start threshold, maximum receive window as the original session"
  • Result gathering works subtly different between MeetingPoint and ByteBlower server. As a result the same values were stored multiple times in the result-database. This was corrected in the backend. This tends to happend when stopping the test early.
  • The First HTTP and TCP snapshots are now always retrieved. In the past they were occasionally lost.
  • Changes in how the results are stored has solved the duplicated results in the CSV report.
  • A run-title (top, action bar) with ending spaces caused issues during report generation. These spaces are now trimmed away.
  • The table at the right-bottom corner of the Multicast view is now cleared on startup. It was initialized with the wrong data.
  • Changing the ethertype of a frame in the Frame View didn't also clear all state. Checksums for instance were still calculated.
  • Fixed null-pointer exception that happened when selecting multiple reports in the archive view and pressing enter"
  • Cleanup statusbar-text of the hexeditor in the frame view.
  • Our test-database was the cause of a number of bugs. We've updated the library to the latest stable version. This new release is unaffected.
  • Deleting many scenarios in a single batch triggered concurrency issue. This bug has been solved.

Version 2.8 of our popular ByteBlower® tool is ready to make IP testing faster and simpler than it already was! We’re on a constant quest to make ByteBlower more intuitive to deploy. So, we’ve added a range of new, practical features to the latest ByteBlower version. Your benefits? Faster, simpler and more efficient testing:

    • Save precious time by grouping multiple ByteBlower Ports together as a default destination for data flows.

      More info: Using ByteBlower Port groups.

    • Use the Frame View to directly import frames from a PCAP file.
    • Smarter TCP handling makes testing your mobile devices much simpler.
    • Testing TCP over IPv6 with a firewall will also be easier thanks to the new handy ‘Auto’ option.
    • To make testing more efficient – or more fun – we included a feature that provides detailed information on the estimated time remaining when you’re running a test scenario.


You can download this version of the GUI from these locations:

  • [[SecureDownload:ByteBlower/GUI/2.8.2/ByteBlower-GUI-v2-windows-x86-installer.exe:GUI Windows installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ Linux 32-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ Linux 64-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ByteBlower-GUI-v2-osx-installer.dmg:GUI Mac OS X installer]]

With the ByteBlower CLI, you can start test scenarios created with the GUI, by executing one single command.
You can download the CLI Command Line Tool here :

  • [[SecureDownload:ByteBlower/GUI/2.8.2/ByteBlower-CLT-v2-windows-x86-installer.exe:CLI Windows installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ Linux 32-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ Linux 64-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.8.2/ByteBlower-CLT-v2-osx-installer.dmg:CLI Mac OS X installer]]

Changelog 2.8.2 (2018-05-18)

  • Test runtime

    • In some occasions, the auto-discovery of the HTTP method switched the source and destination of the flow. This issue has been resolved.
  • CLT

    • The CLT wasn't able to run batches. Trying to use them gave the error that the name wasn't found. Running batches with the CTL is now fully supported again.

Changelog 2.8.0 (2018-01-20)

  • New Features

    • In the Port View, you can now create Port Groups, using the context menu. Port Groups can be used as destination for a Flow.
  • GUI

    • Simplified column width handling.

2.8.2 (2018-05-03)



  • Adding hardware support for the new chassis of the ByteBlower 2100 and 4100 series.

2.8.0 (2018-01-25)



  • Finegraded the status of a TCP flow. The status of the HTTP-request can now be requested.

This API release includes the beta release of the Python code. You find an introduction to the Python API in this howto.

The full change-log is found at the bottom of this article.


You can download this version of the TCL API from these locations:

  • [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ByteBlower-API-Tcl-windows-x86-installer.exe:Windows TCL installer]]
  • [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ 32bit TCL installer]]
  • [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ 64bit TCL installer]]
  • [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ByteBlower-API-Tcl-osx-installer.dmg:Mac OS X TCL installer]]
  • [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ including packages for all platforms for Tcl.]]

You can download this version of the Python API for python 2.7 from these locations:

  • [[SecureDownload:ByteBlower/API/Python/2.8.0/ByteBlower-API-Python-windows-x86-installer.exe:Windows Python installer]]
  • [[SecureDownload:ByteBlower/API/Python/2.8.0/ 32bit Python installer]]
  • [[SecureDownload:ByteBlower/API/Python/2.8.0/ 64bit Python installer]]
  • [[SecureDownload:ByteBlower/API/Python/2.8.0/ByteBlower-API-Python-osx-installer.dmg:Mac OS X Python installer]]


The HTML reference documentation for both the Python and Tcl API

  • Online:
  • Offline: [[SecureDownload:ByteBlower/API/Tcl/2.8.0/ documentation]]

Changelog 2.8.0 (2018-01-25)


  • The "Http.SessionInfo" class now also has methods to get the request status ("Request.Status.Get") and error message ("ErrorMessage.Get"). These methods were previously only available for the "Http.Client" class. With these changes it's now possible to monitor both server-side and client-side sessions.

2.7.10 (2017-12-20)



  • Improved bidirectional TCP performance.

Server Environment and Update

  • Due to a new iteration of certain hardware items, the new 3100 chassis was not detected as such.  So we updated the detection code to recognize this hardware.

2.7.8 (2017-12-11)



  • While reverting back from TCP "half-closed" in version 2.7.6, wireless Endpoints failed to perform TCP. The old TCP behaviour was not reverted completely.This is now fixed

Server Environment and Update

  • ByteBlower Update and byteblower-configurator: Some ByteBlower 3100 where not recognized as a 3100 and thus failed to update.

2.7.6 (2017-11-29)



  • HTTP flows no longer make use of the TCP "half-closed" state because it appears to cause problems in combination with NAT. This fixes the problem where sessions become inactive after a few minutes.
  • Fixed crash that occured when receiving invalid RPC messages.

Server Environment and Update

  • byteblower-configurator: Fixing a crash when unknown network interfaces are found.
  • ByteBlower Update and byteblower-configurator: Fix for update failure due to incorrect parsing of the HTTP proxy configuration.

2.7.4 (2017-10-30)



  • Greatly improved TCP stability when running many flows at the same time.
  • Configuring a high window-scale factor no longer results in very high round-trip times.
  • Fixed a rare crash that sometimes happened when running HTTP scenarios from the GUI.

Server Environment and Update

  • Adding support for new ByteBlower management NICs.

2.7.2 (2017-10-03)



  • Fix crash that occurred when trying to bind two HTTP servers to the same port.
  • Improve bidirectional TCP performance by reducing the number of TCP ACKs.

2.7.0 (2017-08-31)



  • The server can now retrieve the line speed of a ByteBlower interface
  • Improved performance on ByteBlower 1100, 1200 and 1300 series servers.

Server environment

  • byteblower-configurator
    • support for Time Synchronisation configuration.  Supporting NTP and PTP (depending the server type)
    • support for Timezone configuration
  • message of the day
    • Redesigned the output of the message of the day, so it shouldn't confuse the user
  • byteblower-update: provide more detailed progress information.



  • Parsing IANA correct

Server environment

  • byteblower-update
    • fixed a crash when the repository and the local environment were out of sync
    • apply the new proxy configuration immediately instead of require a logout and login
This version brings you two new features: the RFC2544 Wizard and a new view, the Solution View. Also, a number of bugs were fixed, and some minor features have been added. Have a look below for a complete overview.


You can download this version of the GUI from these locations:

  • [[SecureDownload:ByteBlower/GUI/2.7.6/ByteBlower-GUI-v2-windows-x86-installer.exe:GUI Windows installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ Linux 32-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ Linux 64-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ByteBlower-GUI-v2-osx-installer.dmg:GUI Mac OS X installer]]

With the ByteBlower CLI, you can start test scenarios created with the GUI, by executing one single command.
You can download the CLI Command Line Tool here :

  • [[SecureDownload:ByteBlower/GUI/2.7.6/ByteBlower-CLT-v2-windows-x86-installer.exe:CLI Windows installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ Linux 32-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ Linux 64-bit installer]]
  • [[SecureDownload:ByteBlower/GUI/2.7.6/ByteBlower-CLT-v2-osx-installer.dmg:CLI Mac OS X installer]]

WARNING: A 2.7.x GUI only works with a 2.1.x server or higher. To be able to use all new features, we advice to update the server to the latest 2.7.x version. See the server download page for information how to install this server version. GUI 2.x can be installed side by side with an 1.x GUI.

WARNING: On Mac OS X, the 2.7.x GUI needs to be installed on version 10.10 (Yosemite) or later.

Changelog 2.7.6

  • GUI

    • Enhanced the 'Settings Overview' in the Flow View. Added detailed information about the used Flow Template.
    • When opening a project, all item names are now checked for disallowed characters. If such characters are found, they are replaced with underscores.

Changelog 2.7.2

  • New Features

    • Scouting frames are now identical to the configured frames. This simplifies the behavior for users with specially configured frames or mixed frame-blasting flows.
    • Scouting frames are sent for RFC 2544 benchmarks.
    • Removed the heuristic when TCP flows on Wireless Endpoints are finished. This fixes HTTP PUT flows from the Wireless Endpoints with the 2.7.0 ByteBlower Server. This is solely visible in the real-time view, no reported results are changed.
      Increased robustness for scenarios with multiple Wireless Endpoints. If one of the Endpoints isn't reachable anymore, the results of the other Endpoints are still retrieved.
  • GUI

    • Fine-tuning of the internal object update algorithm. Not all project changes were immediately visible.
  • Reporting

    • The report warns if the Wireless Endpoint was unreachable after the test.
    • The type of the MeetingPoint was listed as unknown. It now shows the correct type.

Changelog 2.7.0

  • New Features

    • We have a new wizard, the RFC-2544 Wizard. Using this wizard, you can now create RFC-2544 benchmark tests to measure the throughput between ByteBlower ports. You can specify the allowed loss percentage and the number of iterations for each frame size. It supports IPV4, Automatic NAT Discovery, IPv6, VLANs and our Wireless Endpoints.
    • The Solution View. Here you get a nice overview of all errors and warnings in your project, and their solution.
  • GUI

    • Wizards can now immediately be used when creating a new project.
    • The 'Time Last Frame Sent' column has been removed from the Scenario View because it was confusing.
    • A valid MAC-address is now filled in automatically for new ByteBlower Ports.
    • From the Port View, you can now jump to the docked location in the Server View.
    • Some characters like slashes can now no longer be used for object names, because they caused problems in HTML reports.
    • Fixed bug in the Scenario View, when editing the start time of actions when the Flow is not yet specified.
    • Added Physical Load indication to the Frame Blasting View.
    • Don't allow editing read-only fields in the Frame View.
    • TCP Flow Templates are time based now by default.
    • Software updates are now retrieved from
    • Fixed bug in the Frame View. On Layer 3, when selecting a TOS preset, the first the first bit was not set.
  • Reporting

    • Reduced processing time for Latency snapshots.
    • Modified report filenames, to make them easier to read.
  • Runtime

    • The progress view has more feedback on active flows during a test-run.
    • A more lenient stop-condition for flows from and to Wireless Endpoints. This fixes some issues with retrieving test-results.

The focus of this release is to bring support for Wireless Endpoints to the Tcl API.

Wireless Endpoints support

The wireless Endpoint API is now enabled in the Tcl lower-layer API. All new features of the Wireless Endpoint / Meeting Point version 1.1.0 are supported:

  • IPv4
  • IPv6
  • Frame blasting: streams and triggers
  • Statefull TCP
  • Latency measurements

For more information, please check our documentation of the WirelessEndpoint.

These features require ByteBlower Meeting Point >= 1.1.0 and Wireless Endpoint >= 1.1.0

Known issues

  • Unimplemented protocols
    • Port Control Protocol (PCP)
  • Unavailable features
    • USB interfaces


A newer release version is available. The 2.6 API installers are not available any more on the support portal. Contact us at for this version of the API.


The HTML reference documentation for the API

  • [[SecureDownload:ByteBlower/API/Tcl/2.6.2/ documentation]]

Changelog 2.6.2 (2017-04-21)


  • Fixed captured returning frames of first capture in Rx.Capture.ResultSnapshot when starting a second capture on the same Rx.Capture.RawPacket object.
  • Fixed setting IPv4 address + netmask via Layer3.IPv4::Ip.Set <address>/<netmask>.
  • Tcl-HL: Calling Result.Get and Result.Clear on WirelessEndpoint related objects only in locked state.

Changelog 2.6.0 (2017-04-06)


  • Enabled Wireless Endpoint API:
    • Enabled in Tcl lower-layer API.
    • Tcl-HL: Added support for Wireless Endpoint streams, triggers and TCP.
    • Tcl-HL: Added example scripts.
  • You can now provide a timeout when connecting to servers and/or meeting point.
  • Updated documentation.
  • ByteBlowerServer and MeetingPoint have a ServiceInfo object which provides useful information about that service:
    • type
    • version
    • license
    • service UUID
    • Connection details (remote host / IP address / TCP port)
    • Management IP addresses
  • API version can now be obtained via ByteBlower::API.Version.Get.
  • HTTP Client now also shows the configured type-of-service in its description
  • Add support for the new capabilities architecture
    • Capabilities can be obtained for ByteBlowerPort and WirelessEndpoint.
    • Backward-compatibility is available for older servermeeting point and/or wireless endpoints.


  • Added missing exception class ByteBlower.Exception.NullPointer.
  • Fixed incorrect value when getting (configured) HTTP Client receive window scale.
  • Tcl-HL: Fixed script error in ::excentis::ByteBlower::FlowLossRate when transmission was out-of-resources.

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