At this time, I think its much more interesting to talk about the
properties of the mapping system and protocol than to make a
decision on reuse vs. new protocol. Push vs. pull, dynamics,
security properties, trust model, scalability requirements,
aggregated vs. flat, etc. that you talked about in the rest of
this thread are the important questions now. Of course, its
useful to think about what the real-world implementation of
the concepts could be, e.g., a new BGP instance, but lets
not get hang up on the protocol selection just yet.