hierarchy planning under /48

[Simon Oosthoek <simon@margo.student.utwente.nl>]

Hi all

another problem that I'm not sure how to solve correctly is hierarchy
planning and addressing of hierarchical routers...

I have a /48 and I want to subdivide this into multiple subnets using a
hierarchy, so

          R
     +--+--+--+ (/50)
     |  |  |  |
     R  R  R  R
     |  |  |  |
64R--+  (/56)
|
256 (/64)

(48 + 2 + 6 + 8 hierarchy)

A) Is it desirable to have the intermediate routers globally addressable?
B) what subnet would be most appropriate? 
C) subnets are always /64, so advertising a prefix higher up in the
hierarchy could be confusing for the routing?
D) I plan to use link local addresses for the static routing information, is
that normal?

TIA

/Simon