John C Klensin wrote:
Similarly, various applications folks within the IETF have
pointed out repeatedly that any approach that assigns multiple
addresses, associated with different networks and different
policies and properties, either requires the applications to
understand those policies, properties, and associated routing
(and blows up all of the historical application-layer APIs in
the process) or requires request/response negotiation that TCP
doesn't allow for (and blows up most of the historical
application-layer APIs). One of the original promises about
That is a very old problem of IPv4, except that DNS takes care
of multiple addresses of name servers at IP level and SMTP
(and some TELNET implementation, though it is not very useful)
supports multiple addresses of mail servers at TCP level.
Thus, API of IPv4 must change.
IPv6 was no need for changes to TCP and consequent transparency
to most applications. Ha!
There is no need for IPv6 specific changes.
Masataka Ohta