Tried to install S4B server 2015 in my lab. Tried this from a computer with no internet access, also I did not install any prerequisites.
“Error: Prerequisite installation failed: Prerequisite installation failed: SqlInstanceRtc For more information, check your SQL Server log files. Log files are in the folder C:\Program Files\Microsoft SQL Server\MSSQL*.Rtc\MSSQL\Log, where the * represents your SQL Server version number. For example, SQL Server 2012 uses this path: C:\Program Files\Microsoft SQL Server\MSSQL11.Rtc\MSSQL\Log.”