fan.standard recommended prefix mappings

[Andy Whitcroft]

At a recent sprint some side discussions were held on Fan Networking,
one of the outcomes from those discussions was that the existing Fan
Network configuration was effectively conflating two concepts; actual
underlay and overlay prefix pairings with recommended overlay prefixes
for specific underlay address ranges.

As part of sorting this out we have been separating out the recommended
mappings into a new configuration “fan.standard”.  This provides
underlay and overlay prefix pairs which are used when defining new
Fan Networks.  Essentially where local addresses fall into a specific
underlay prefix the recommended overlay prefix is then inferred.

The document below contains some background and the current plans for
these changes. Please add any input or feedback to the document so it
can be fed back into the implementation:

  https://docs.google.com/document/d/1gJDnLiR3cgt3pNvjLeV_431gVlvZFOwUHrcmkPzSX-A/

-apw