Subject: Re: [MOBILE-IP] Fast Handovers/offs

From: James Kempf <[email-masked]>
Date: Tue, 20 Jun 2000 13:19:17 -0700

Hi Charlie,

>
>BTW, it is interesting to note that proactive schemes typically
>rely on special features for signal measurement that _could_ be
>retooled to do layer-3 registrations anyway.  That is, if we
>could ever get appropriate changes made to the air interface
>and protocol control structures.
>

I'm not quite sure what you mean by this, but I think the changes in the
air interface would have to be quite substantial. Unlike radio
LAN protocols, the 3G schemes don't share radio channels, so
a mobile can only listen on one (bearer) channel at a time. Suppose that
a mobile on one RAN needs to switch to another, but there is
a mobile in the other RAN on the same channel. The mobile effectively
can't "see" the other base station, so it has no choice but to
perform the handoff through the network.

Actually, I feel (as the draft's co-author) that the proactive draft and the
regional registration draft have a natural synergy and that any solution to the
fast handoff problem will require some combination, including perhaps folding in
anchor handoff as well. Perhaps now is not the time to perform the
combination, however, since we are still working out the details of
the proactive draft.

                jak

---

From: "Karim El-Malki (ERA)" <[email-masked]>
Date: Wed, 21 Jun 2000 13:50:44 +0200

Hello Charlie

>  and protocol control structures.

I don't think such schemes always have to rely on (L1) signal
measurements. You may want to leave that intelligence to L1/L2
and just require some event notification (e.g. handoff), QoS info
etc. from L2 to L3. So I don't believe it is always appropriate
to make changes to air interface and protocols. At least that's
not the assumption we took in our Fast Handoffs:
draft-elmalki-soliman-hmipv4v6-00

Cheers,
Karim