Spirent iTest v4.3.1
As per iTest design we have to use the option in the session profile "FIle to write response to" to write the whole session response to the file.
If we are executing multiple sessions in the common testcase below one is the solution to write each session response into a separate file.
In the session profile "FIle to write response to" option specify the path as below
eg: C:/Users/vijay/Desktop/ls_reports/[info step sessionID].txt
By using [info step sessionID] command in the URI, the file name will create based on the session name so that we can avoid conflicts for each session.