Let's assume that there is a FooBar server in SiteA. If another
node in SiteA (NodeA) is communicating via a multi-party application
to a node in SiteB (NodeB), and wants to refer NodeB to the FooBar
server in SiteA, what does it do?
I thought we agreed, completely outside of IPv6 concerns, that
shipping addresses in application data was bad. So NodeA refers
NodeB to foobar-server.sitea.org. Q.E.F.