Replay Engine in LoadRunner

Loadrunner have support for Socket and Winlnet replay engines for replaying the script. We can control this setting from Replay>Run Time Settings.

In above screenshot we can see there is an option to change replay choice between Sockets and WinInet. By default Loadrunner use the socket options and we should also use Socket only unless we WinInet is the only choice.

Socket is a scalable approach which used Loadrunner proprietary interface to communicate with the network whereas WinInet uses WinInet API which is used by Internet Explorer to communicate with the network. WinInet helps in resolving issues with the playback but it is not recommended for running the load test as it comes with the limitation of scalability.

Switching to winInet option is a good step to troubleshoot the replay errors.