Consecutive Start Of Frames are grouped to prevent an overload of the display
This example shows the end of the enumeration of an HID peripheral and the start of an interrupt flow on endpoint 1 at an interval of 10 milliseconds (rounded down to 8 milliseconds by the operating system)
Like SOFs, consecutive NAK transactions of the same type are grouped
This illustration shows the writing of a file to a mass storage peripheral. We can see how each completed transaction is preceded by one or more NAKs wasting the bandwidth.