When installing SQL Server 2014 SSIS, what are the meaning of "authentication level"?
Here is a link on SQL Server 2014 for you to Grant Permissions to Integration Services Service 

https://msdn.microsoft.com/en-us/library/Hh213130(v=sql.120).aspx  

The first step is: Run Dcomcnfg.exe. Dcomcnfg.exe provides a user interface for modifying certain settings in the registry.

The following link for DCOM settings were last reviewed in 2006, but the options look unchanged. 

https://support.microsoft.com/en-us/kb/176799

This describes Default Authentication Level (Packet Level) which is the screenshot that you posted.

Other subheadings describe several other facets of the DCOM setup.