If you did all four modules part of the CCNA Exploration curriculum, you could aim for taking the composite exam directly. You are correct, the "Network Fundamentals" and "Routing Protocols and Concepts" are in line with the ICND1 exam, while "LAN Switching and Wireless" and "Accessing the WAN" will provide the foundation for the ICND2 exam. You might qualify for an exam discount if you meet the qualificatives at the end of th NetAcad CCNA Exploration course.
Nevertheless, I would advise to get the official cert guide book(s) too to prepare for the exam(s).
Im going to disagree just a little with my fine friend Christian...actually Exploration 1 & 2, are only "roughly" matched to ICND 1. They actually cover more. ICND 1 only covers Rip, for example, leaving eigrp and ospf for the second exam. Not a huge thing, and of course its better to be overprepared, than under.
Having said that, I encourage most of the students I work with to attempt the ICND 1 after completing academy 1 and 2.
And Christian is right on about the study guide books. The academy is meant for one purpose, and study books are meant for another...namely studying for the actual exam. They follow a one to one correlation with the blueprints.
I recommend the ICND 1 books (CCENT) by Odom, Lammle, or Cioara - any of those will be fine, and you will pass easily, if you have already plowed through the academy material. Use a study book and you will do much better on the exam.
Thanks for the advices.
One more question : how do I "practice" ?
These books don't contain any labs or so, right ?
Ofc I can use Packet Tracer and do all the labs which are in CCNA EXPLO 1 and 2.
But is there something else ?
For the real exam, which simulator is used ?
I assume there is a practice exam even for CCENT, so how can I prepare
for this ? Do I need to know every command (without notes) ?
Sorry for these questions, it's still not very clear to me.
PT is all you need to practice with...just do all the labs from the academy. If you buy the Lammle CCNA book he has a bunch of PT labs included.
As far as seeing what the actual exam is like, search the cisco website for the sample exam which give you a good feel for the real thing.
If you want regular practice exams you can either purchase those from cisco, or boson, etc. The books I recommended all come with practice exams.