Subject: RE: Solving the right problems ...

From: "vinton g. cerf" <[email-masked]>
Date: Wed, 27 Aug 2003 23:09:30 -0400

If you look at the instant messaging systems, they map a private identifier space (IM name or "handle") into IP addresses and apparently run background heartbeat to re-assign the mapping if the identifier in the heartbeat arrives in a packet with a different IP address than before - not sure whether or how hijack is avoided. Could one use the NAPTR concept to create a new identifier space with specific dynamics? It would take two lookups: one to DNS to get the NAPTR and one to resolve the NAPTR identifier into an IP address. The latter resolution need not necessarily be done via DNS.

vint

Vint Cerf
SVP Technology Strategy
MCI
22001 Loudoun County Parkway, F2-4115
Ashburn, VA 20147
703 886 1690 (v806 1690)
703 886 0047 fax
[email-masked]
www.mci.com/cerfsup

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From: Dave Crocker <[email-masked]>
Date: Tue, 2 Sep 2003 08:41:43 -0700

Vint,

vgc> If you look at the instant messaging systems, they map a private
vgc> identifier space (IM name or "handle") into IP addresses and
vgc> apparently run background heartbeat to re-assign the mapping if the
vgc> identifier in the heartbeat arrives in a packet with a different IP
vgc> address than before -

I was under the impression that they did not handle mobility nearly so
dynamically or automatically. Rather, I seem to need to log in whenever
I move. So they seem to do a login-time mapping. (On the other hand, the
login for IM is usually automatic.)

In any event, I suspect that your domain name-based suggestion is the
right one to pursue. That is, use DNS for the public, persistent name,
and have a record that points to a dynamic address-mapping registry.
(One might even think of mapping to a "presence" service...)

Somehow, dynamic DNS does not seem like such a good idea, for anything
that might change this much or this rapidly and serious host mobility.

d/
--
 Dave Crocker <mailto:[email-masked]>
 Brandenburg InternetWorking <http://www.brandenburg.com>
 Sunnyvale, CA  USA <tel:+1.408.246.8253>, <fax:+1.866.358.5301>

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From: Henry Sinnreich <[email-masked]>
Date: Tue, 02 Sep 2003 12:45:32 -0500

> Could one use the NAPTR concept to create a new identifier space with 
> specific dynamics? It would take two lookups: one to DNS to get the NAPTR 
> and one to resolve the NAPTR identifier into an IP address.

We will be soon able to test the speed of such a mechanism with the NAPTR
client built into SIP phones that are just emerging. I have copied here its
developer, Christian Stredicke and the ENUM co-chair Richard Shockey to
answer questions on this.

Thanks, Henry

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of vinton
g. cerf
Sent: Wednesday, August 27, 2003 10:09 PM
To: [email-masked]
Subject: RE: Solving the right problems ...

If you look at the instant messaging systems, they map a private identifier
space (IM name or "handle") into IP addresses and apparently run background
heartbeat to re-assign the mapping if the identifier in the heartbeat
arrives in a packet with a different IP address than before - not sure
whether or how hijack is avoided. Could one use the NAPTR concept to create
a new identifier space with specific dynamics? It would take two lookups:
one to DNS to get the NAPTR and one to resolve the NAPTR identifier into an
IP address. The latter resolution need not necessarily be done via DNS.

vint

Vint Cerf
SVP Technology Strategy
MCI

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From: "vinton g. cerf" <[email-masked]>
Date: Tue, 02 Sep 2003 13:51:34 -0400

>login for IM is usually automatic.)

no at least AIM tracks in real time

>that might change this much or this rapidly and serious host mobility.

agree

Vint Cerf
SVP Technology Strategy
MCI