[PDB Tech] allow empty IP field or not?

[Chris Caputo]

Sometimes folks have the IPv6 flag enabled, but they aren't yet doing IPv6 
at a particular IXP.  If they fill out the IPv6 address, we've seen 
participants with automated session configuration based on PeeringDB try 
to ND for a router that isn't yet configured to handle the ND.  This 
results in broadcasts/multicasts on the fabric which our janitor must then 
chase down to get quashed.  Members then tell the janitor that, hey we saw 
it in PeeringDB, and then the janitor has to explain that in the 
particular case they are not yet doing IPv6...

When this happens with IPv4 it is no big deal since the arpsponge handles 
it, but for IPv6 it is inconvenient.

Chris/SIX