Subject: RE: PANA and IP addresses

From: George Tsirtsis <[email-masked]>
Date: Tue, 25 Jun 2002 09:09:38 -0400

Hi all,

I have always hoped that we will not need to introduce such limitation. In
the case of PANA running between end node and access router I would prefer
to have a model were having an IP address in advance of PANA is not
required. Note that this is especially important in IPv4 were an IP address
is not so easy to auto-configure. In IPv6 a link local address could be
easily used to start things up. ...but even in this case I am not sure that
link-local addresses is all you imply below...

Another thing that has not been discussed enough here is the relation, if
any, of PANA with Mobile IP. It has been aired a few times, but never really
discussed, that PANA could provide the control functionality that is kind of
missing or was kind of introduced with MIPv4 FAs but removed in MIPv6. If
this combination is desirable then what address would you use prior to PANA
and prior to MIP registration? requiring assignment of a locally significant
address prior to PANA would introduce delays...certainly in the IPv4 case. 

thoughts?

George
P.S.: sorry for the long absence from this list...too busy with the day job.

-----Original Message-----
From: Thomas Narten [mailto:[email-masked]]
Sent: Thursday, June 20, 2002 12:25 PM
To: [email-masked]
Subject: PANA and IP addresses

We've had some discussion about when a PANA client obtains an IP
address. Specifically, does it have to have a proper unicast IP
address (e.g., link-local, or regular address) prior to invoking PANA,
or should a client be able to invoke PANA prior to obtaining any IP
address (e.g., using the all 0s address).

One model for how PANA can be used is that a client obtains an address
using normal means (e.g., using DHCP). That address has only limited
utility, because various enforcement points (e.g., an access router)
have filters limiting the useability of the address. The client then
invokes PANA, and once the PANA authentication is successful, the
address is given greater capabilities (e.g, the PAA/AAA infrastructure
interacts with the enforcement points to change the capabilities of
the address).

In this model, there is no requirment that PANA be used by clients
prior to their obtaining IP addresses.

Question: is this model sufficient and reasonable to deal with the
deployment scenarios people have in mind with PANA? If not, why not,
and what other models do folks have in mind and what advantages do
they have over the simple model described above?

Note also, that there are variations to the above too. One could
imagine that after the PANA exchange, the client invokes DHCP again,
but this time the DHCP exchange includes authentication info (learned
through PANA) that allows the client to obtain a different address
than it already has. 

Thomas