Subject: Re: [MOBILE-IP] Handoff framework [Was Re: [MOBILE-IP] Another novicequestions!]

From: James Kempf <[email-masked]>
Date: Mon, 7 Aug 2000 13:09:13 -0700

>> I disagree that the outcome of the current effort will be specific
>> solutions for different types of link layers. Based on the scope and
>> the parameters that we are working on we will limit getting into link
>> layer details.
>
>From the last handoff only meeting that I attended, the conclusion
>seemed to be that different proposals had different link
>characteristics in mind (for example, one proposal assumed
>coverage was overlapping so that registrations to new FA can go
>through old base station; one assumed link layer authentication etc.)
>and so different solutions made sense in different settings.
>

Fundamentally, I don't think there is any way to escape using link
layer support for fast handoff. If the link layer doesn't provide
any support, you are left with RFC 2002. Conversely, if the link
layer provides support but L3 doesn't use it, then the potential
for optimizing handoff is lost.

I think it should be possible to characterize the link layer support
at an abstract level as a collection of events available to L3 from
L2 at a particular time and place, and with particular parameters.
This avoids getting into specifics of a particular link layer and
instead allows L3 mechanisms to be matched to their (abstract) L2
support.

It may even provide designers of new radio link layers with some guidance
about what they need to do to enable fast handoff at L3.

                jak

---

From: Sebastian Thalanany <[email-masked]>
Date: Sun, 13 Aug 2000 13:09:09 -0500

The use of  an abstraction of link layer characteristics(ie. optional
triggers etc.) to assist L3 is fundamental to the realization
of efficient wireless mobile handoffs. I agree with Jim.

Regards,
  Sebastian Thalanany

---

From: Arthur Ross <[email-masked]>
Date: Sun, 13 Aug 2000 11:52:05 -0700

>of efficient wireless mobile handoffs. I agree with Jim.
I support this as well. The trick, of course, is going to be coming up with
that OOP- or WIN-like abstraction. And, like Jim said, in the attempt may
lie a VERY USEFUL large-scale gedanken experiment in helping to clarify
what the physical layer designers' problem(s) is(are), and how the legacy
stuff either a) fits in, or b) can be patched up. This is, IMHO, precisely
the sort of enlightened collective discussion of this problem that has been
needed for a long time.

   -- Arthur

   Dr. Arthur H. M. Ross
   2325 East Orangewood Avenue
   Phoenix, AZ 85020-4730