Max Instances
This says....how many instances of the same version of the browser can run over the Remote System.
Let’s explain with an example
-browser browserName=firefox,version=12,maxInstances=5,platform=LINUX
-browser browserName=InternetExplorer,version=9.0,maxInstances=5,platform=LINUX
The above example will allow you to run 5 instances of Firefox 12 and as well as 5 instances of IE9 at the same time in a remote machine.
Max Session
This says, how many browsers (Any Browser and any version) can run in parallel at a time in the remote system.
Let’s go with an example
when maxSession=1 forces that you never have more than 1 browser running.
With maxSession=2 you can have 2 Firefox tests at the same time, or 1 Internet Explorer and 1 Firefox test).
Irrespective of what MaxInstances you have defined.
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