Personally, I love the Sybex books for reference, but not so much for certification. I have always found it more useful togo straight to the horses mouth so to speak. The CCNA library from Cisco is great, and not overly expensive for what you get.

Strictly speaking, layer 3 is considered to be where routing happens. I think there is merit to the arguement that it requires services from the other layers, but then again, you have to look at it like an oger, you need all the layers to make the wh...