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In order to go for the CCNP R&S, you need a valid CCNA R&S certification.
So in your case, you need to take the ICND1 exam + ICND2 exam in order to be able to have the prerequiste needed to go for the CCNP R&S certification.
You can confirm this information in the following link:
What gustavoleon has replied above is so. I wonder, why would you go straight to CCNP R&S and bypass ICND2 exam? CCNP R&S enhances CCNA knowledge as it goes into deep. It basically covers the same concepts- while adding a few more topics.
Here are my 2 cents.
I don't know where are you at regarding your networking studies, however I would strongly recommend sitting for the ICND2 exam. Why? Well, hence you get deeper into different technologies, you'll need a solid foundation in order to get a good understanding.
Let's put it this way. Focus on the word "understand".
The word understand has differnt meanings. One of them is derived from an architectural reference which stands for, "standing under the foundations". So..Let's say you have a house, and you want to upgrade it by adding a new floor on top of it; you'll need to call an architect or engineer. This person will "stand under" the foundations in order to check if the weight you want to put on top of the house will actually support it.
I guess you can see where I'm going with this example above.
If your knowledge foundations are weak, most likely- hence you start adding more topics and knowledge- it'll crumble and fall apart. Focus on strenghtening your foundations- the basics. It's understandable that it may become tedious as you'll want to move on, however, trust me when I say that your foundations are everything. If you have good foundations, whatever you build on top, it'll stay there.
This, of course, can be applied in any aspect of your life as well
Well.. I'm off. Hope this helps you out.