Subject: [MOBILE-IP] Multiple IP addresses per NAI

From: Pete McCann <[email-masked]>
Date: Mon, 3 Jan 2000 11:08:45 -0600

Hi, Gopal,

Maybe the Identification field can play this role, so we don't need to
do any new protocol specification.  Things could work this way: a
Registration Request that already has an IP home address does not get
allocated a new one.  Any Registration Request that is missing a home
address and has a unique Identification field does get allocated a new
address.  Retransmissions of the same Request with the same Identification
get the same address.

There could be some limit placed by the home agent on the number of IP
addresses that can be acquired by any given NAI; we may need to define
a new rejection code (number of IP addresses exceeded) if they are all
used up.

Maybe there are some pathological conditions involving lost Replies
that would cause addresses to be used up unnecessarily - for instance,
if a Reply is lost, the MN might retransmit a request with a new
Identification value and accidentally get a second address without
ever knowing about the first.  But the old address would time out
after the Lifetime expired anyway, so maybe it's not such a problem.

Thoughts?

-Pete

Gopal Dommety <[email-masked]> (GD) writes:

GD> Hello:

GD> There has been some discussion (several operators are also
GD> requesting for this) to be able to allocate multiple IP addresses
GD> based on one NAI (For example, connect a laptop, PDA, and cell
GD> phone with the same NAI simultaneously). One way of acheive this
GD> request is to have a field in the NAI extension to distinguish
GD> these requests. Authentication can be performend based on NAI and
GD> address allocation and session management functions can use this
GD> new field.

GD> Any thoughts??? let me know if you need further explaination of
GD> the problem.

GD> Thanks
GD> Gopal

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From: "Kent K. Leung" <[email-masked]>
Date: Mon, 3 Jan 2000 10:26:42 -0800

> address.  Retransmissions of the same Request with the same Identification

But this doesn't work for re-registration by the same MN.  How can
a HA differentiate between an MN that's doing re-registration vs.
MN registering another device?

> after the Lifetime expired anyway, so maybe it's not such a problem.

This scenario also exhaust addresses unnecessarily.  The expiration
of the leased address depends on the registration lifetime, which
may be long.

IMHO, I don't think using the Identification field is sufficient.

-- Kent --

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From: Pete McCann <[email-masked]>
Date: Mon, 3 Jan 2000 13:26:18 -0600

Hi, Kent,

>> address.  Retransmissions of the same Request with the same Identification

KKL> But this doesn't work for re-registration by the same MN.  How can
KKL> a HA differentiate between an MN that's doing re-registration vs.
KKL> MN registering another device?

Re-registrations will presumably have valid Home Address fields in the
registration request.  New registrations will have 0.0.0.0.

>> after the Lifetime expired anyway, so maybe it's not such a problem.

KKL> This scenario also exhaust addresses unnecessarily.  The expiration
KKL> of the leased address depends on the registration lifetime, which
KKL> may be long.

You may be right.

KKL> IMHO, I don't think using the Identification field is sufficient.

Maybe so, but I don't think we should necessarily augment the NAI
extension itself - that would slow down too many other efforts.  Maybe
a new Session ID extension should be created.

-Pete