This is about "what I know thing", and I can be wrong about what I'll show you specially in this article. If you find out that I'm wrong please let me know so we can discuss it further.

This is my second article, and it about how to monitor URB (USB Request Block) which is used by USB device driver. Honestly, I do not know exactly how USB protocol work, well, in fact I got this idea when I try to understand how to write USB driver. If you want to know exactly how this protocol work, please take a look at official USB "specification maintainer". The basic idea is the same as my previous article but this time with little bit variation.