Re: noid and applications (generic requirements from applications)

[Brian E Carpenter <brc@zurich.ibm.com>]

Tony,

Doesn't this objection also apply to passing an FQDN around,
since FQDNs can also be unreachable, due to 2-faced DNS
and the like?

In other words, referral is a very deep problem in the
non-transparent network that we sometimes still describe as
"the Internet." I suspect this is a problem that multi6 is
unable to solve; we should simply not make it worse.

   Brian

Tony Li wrote:
> 
> Patrik,
> 
> That is going to be exceedingly difficult.  As long as we
> are using IP addresses in applications and we are hiding
> the actual reachability of the address from the application,
> we are guaranteed to be allowing an application to pass along
> an unreachable address.
> 
> Note that this is a result of the layering violation of
> passing around an IP address in the application.  Asking us
> to warp the world to support architectural mistakes strikes
> me as suboptimal.
> 
> Regards,
> Tony
> 
> |  -----Original Message-----
> |  From: Patrik Fältström [mailto:paf@cisco.com]
> |  Sent: Thursday, November 13, 2003 8:08 AM
> |  To: Erik Nordmark
> |  Cc: Tony Li; multi6@ops.ietf.org
> |  Subject: Re: noid and applications (generic requirements
> |  from applications)
> |
> |
> |  On 2003-11-13, at 08.49, Erik Nordmark wrote:
> |
> |  >> Of course, if we're going to open an implementation, we might want
> |  >> to make the point of referral the FQDN, not the locator(s).
> |  >
> |  > Yes. Especially with noid, where the multihomed node needs
> |  to have a
> |  > FQDN,
> |  > this makes a lot of sense.
> |
> |  This is ok for an application which of course should use the
> |  FQDN, but,
> |  even when using whatever "thing" the application uses to
> |  establish the
> |  connection (which it gets via the FQDN) that should be
> |  usable without
> |  knowledge of the network topology. I guess one can formulate
> |  it as it
> |  must have features like:
> |
> |    (A=B) and (B=C) gives (A=C) where '=' is "can communicate with"
> |
> |  and
> |
> |    (A->B) gives (B->A) where '->' is "can send data to"
> |
> |      paf