What are the functions of Remote command Launcher, PortMapper and agent. Exactly what do they do and what knowledge is needed about these components as testers(I am specifically interested in HTTP and web applications).
What is port mapping and how is it done in LoadRunner.
Port Mapping is generally used where a custom application is using a non-standard port for HTTP requests.
This is a recoding option in the combined Web/Winsock protocol.
Basically say your application is using port 999 for HTTP requests, you would add this port to the port mapping recording option and LoadRunner would automatically record and translate requests on this port into HTTP requests.
The remote command launcher and the agent are useful items for the controller in it's communication with a Load Generator/Injector. These are not items that you would have direct interface with, only indirect through the installation of the generator/injector software and the communication with the same from the controller. I believe this information is convered in both training and the controller users guide.