stejoel wrote: » I was looking at a Sybex practice exam and there were several questions on csma/cd csma/ca,eee 802 standards,osi layers etc... I had been studying A+ 2006 In Depth by Jean Andrews, CBT Nuggets and watching Professor Messer's videos all of which really didn't go into much detail about these types of things. I do see that it is explained in the book by Docter, Dulaney and Skandier. My question is how do I know if this material will be on the exam and why do some study books go into it and others don't?