They didnt ask much about the OSI model or about the different protocols. But not to say they wont ask it in the suppl exams ..
The did cover most of the work, ask a lot of short questions, we got a picture of Sattelites and had to answer q's on GEO, MEO ect and some on power
they also didnt ask much about the steps for upgrading , did get a mcq about hardware upgrade if I remember correctly
Best is realy to study all the prescibed work, I know it is a lot!
The exam was all in all fair if you studied and most of the questions where straightforward. There were one or two that were a bit "tricky" - read what they ask