Xenon/Argon Mesh Primer?

Can anyone point me towards more detail on how the Mesh network functions. I’ve read a guide on how sensor nodes at the extremes of a network can use sleep modes to run on batteries and have this working, kind of, but the sleeping seems to upset the general networking. Is there:

a) Documentation on functioning of the mesh I can use for background reading.
b) Any way of getting data about the connectivity within the mesh to see which nodes can see each other or perhaps signal strengths. I have looked at online documentation but couldn’t see any useful functions.
c) Can I designate modules as end nodes?