Yeah I know, at first glance it looks scary. I am used to the SI3D environment, where the material and texturing processes are very straightforward.
But in fact, when you get used to it, it's simple.
All bump information is "vector"-type (the yellow lines and dots), wich is a different kind of parameters than the color (the red lines/dots). So to be able to connect everything together you have to go through conversions. The only reason I used the Vector2color and Color2vector nodes are to be able to place an Intensity node between the bumpmap and the phong.
The Render Tree allow many many types of connections, so you have a great creative control over the object's shading.
Salutations - Cheers
Bernard Lebel