SQL Server backup speed

I've been prompted by the ceo of my company to get some information on the speeds of every step in the backup of a SQL Server. So basically the points on back are
VDI >> Network >> Disk >> Tape
But what is needed to be known is how they move to the next process. Meaning each junction is a direct flow or a door where the process needs to reach a certain point, be it certain size or full completion, to begin. As well as actual performance specs i.e. a 100 mb connection is going to move data nearly as fast. And if anything needs to be written to memory first and whatnot. So basically I need to figure out the expected speeds for each step. If nobody knows themselves, if they know somewhere else that I could find the information that'd be really helpful.