A Tuner Ducoment Window allows you to examine and modify internal network parameters and optionally save your parameter settings as a document for future use. By opening a previously saved Tuner Document, the corresponding parameter settings are restored.
The Tuner Presets under the Basic tab can be tried instantly to see if they improve the performance of your network. Just select a preset and press Apply. If you find a tuner preset that helps, you can save them (under the File menu) and restore them at a later time.
If you select "Quit after restore", the IPNetTunerX application will quit automatically when launched from the corresponding document. To prevent the application from quitting, launch the application first, and then open your settings document. To load your parameter settings automatically when you login, you can press "Save As Login Item". IPNetTunerX will save your settings to "~/Library/Preferences/com.sustworks.IPNetTunerX.loginItem.ipnt" and designate this as a login item for your account. You can also launch IPNetTuerX as Mac OS X startup item as described in the Location Helper section.
If none of the "Tuner Presets" result in a noticable performance improvement, there are several possibilities: (1) Your Internet link is already operating at close to maximum performance so no tuning is necessary; (2) There is a more subtle interraction between your Mac and networking environment not addressed by these examples. To understand the settings files and their contents, some knowledge of TCP/IP tuning is required.
To see all the parameters you can tune, click on the "Advanced" tab and use the Up/Down arrow keys to step through all of the parameters. To see only those parameters that are currently active, check the "Step to next non default setting" checkbox. The popup menus in the upper left can also be used to select a parameter. The upper menu selects a group of parameters, and the indented menu below it lists the corresponding parameters from that group. The large text view in the middle of the window provides a brief identifying description of each parameter.
To change a parameter value, enter a new value in the text field to the right of the parameter popup and press Apply. The Current value and Default value are shown for reference immediately below the input field. You can confirm your changes by examining the "Current" value along with the status information in the lower left corner of the window. You can restore all parameters to their default values by pressing "Load Defaults".
IPNetTunerX "settings documents" are text files formatted as an XML property list (or plist) so you can also examine them using a standard text editor.
The general approach to network tuning is to measure the actual performance using tools such as those included with IPNetTunerX or IPNetMonitorX and then compare this with the expected performance based on the type of network connection used. If you are getting above 80% of your theoretical maximum throughput, tuning is probably unnecessary. If not, it is worth doing some detective work to understand what if any tuning problems are slowing your network and how to address them.
A good place to start is with the Link Rate and TCP Rate tools provided by reading the corresponding help text. Don't be afraid to experiment with various parameters. If performance suffers, just press "Load Defaults" or restart your Mac and all parameters will be reset to their defaults. IPNetTunerX does not modify any network parameters except in RAM (temporary memory).
It is difficult for us to tell you which parameters to tune without measuring the actual characteristics of your network. There's more information about TCP/IP network tuning in the pages that follow.
You can edit the parameter descriptions or add new UNIX sysctl parameters by editing the ipnt_parameters.plist file in the applications resource bundle.