Subject: RE: [mobile-ip] Draft Agenda for MIP WG @ IETF54

From: [email-masked]
Date: Thu, 20 Jun 2002 13:04:38 -0500

Hi Masataka,

>Basavaraj;
>
>> IETF Working group meetings are NOT the place for making
>> presentations. WG meetings are focused on discussing issues
>> pertinent to the ongoing work and also other relevant topics
>> that are within the scope of the charter. However with respect
>> to the *relevant topics*, there needs to be a considerable
>> amount of interest shown by the WG members in order to have
>> an agenda item for discussion. We normally view the discussions
>> on the mailing list to determine the level of interest in a
>> topic.
>
>Your misunderstanding is that "discussion" includes to recognize
>some existing topics irrlevant.

I am not categorizing your proposal as *irrelevant* to this WG. But if
you read what I said above 
    "with respect to the *relevant topics*, there needs to be a
    considerable amount of interest shown by the WG members in order to
    have an agenda item for discussion"

From the current discussion on the mailing list w.r.t this topic, I do
not see a strong interest yet. 

>
>> I
>> agree that the solution is quite valid for the WLAN environment
>
>Even if my draft were valid on WLAN environment only, it follows
>the current work iten of:
>
>	- Documenting any requirements specific to cellular/wireless networks.
>
>that there is no requirement of smooth handover by the network.
>

I think the requirement which you are deriving as  "smooth HO is not
required" simply because you recommend terminals to have two
transceivers is not sufficient. For terminals that do have two
transceivers, they may choose not to implement MIP based smooth
HO. But that is only one class of terminals and does not cover the
entire spectrum.

>Moreover, you obvviously ignoreing my draft stating:
>
>: 4. Applications of the Technique
>: 
>:    The technique described in sections 2 and 3 was deployed in recent
>:    PHS (personal handy phone, 32Kbps mobile telephone system available
>:    in Japan and other countries) service, only after which, PHS can
>:    support stable and smooth handover.
>: 
>:    In general, the technique requires two sets of transceivers, which
>:    increases the cost of terminals, which is welcome to wireless LAN
>:    chip vendors, it also reduce the cost of network by eliminating
>:    intelligent intermediate entities for half-hearted smooth mobility.
>: 
>:    Note that a CDMA based wireless transceiver can simultaneously use
>:    two access points with different code without additional RF modules.
>
>that the solution is proven to valid for the PHS environment and is
>more easily depolyable for CDMA environment.

I am not sure if you have taken into consideration that in CDMA
environments the MN is incapable of listening to the paging channel
information when in an active call. So even though you are taking into
consideration the soft HO capability of CDMA, the model that you
describe in your draft would not be applicable in certain conditions
(such as when you have to perform a hard HO, i.e to an access point
served by a different FA/AR).

>
>> but fail to understand what the MIP WG would have to do with it.
>
>Stop attempting to work on smooth handover in any environment.

I disagree. Smooth HO is required in certain environments. Your
"one-model" (dual transceiver approach) fits all solution is not
globally applicable. 

The point is, Smooth HO (in the MIP WG) is a network layer approach to
performing HOs. What you are suggesting in your draft is essentially a
lower layer method. HOs are a common aspect of wireless/cellular
networks, the difference here is the layer at which the HO is being
done.  

>
>> Of course if there is WG interest in the approach proposed by
>> you and issues relevant to this WG, we can always add it to the
>> agenda. If we see more discussion in terms of impacts/changes
>> required to MIP on the MN or FA/AR or HA, with the availability
>> of dual WLAN interfaces, that would be a more relevant topic for
>> discussion.
>
>Another relevant protocol topic is in the security section:

Its up to you to convince the WG about the relevance of the security
method. Access control is more of a AAA WG topic. 

>
>: 5. Security Considerations
>: 
>:    To prevent anonymous and/or unpaid access to the Internet, access
>:    points of MIS have packet-wise cryptographical authentication
>:    mechanism to disallow unauthorized access to the Internet.
>: 
>:    To prevent subscribers share a single subscriber ID with single
>:    payment, the mechanism disallows multiple terminals with a single
>:    subscriber ID simultaneously use access points.
>: 
>:    As a side effect, the mechanism, basically, disallows a terminal
>:    simultaneously use multiple access points.
>: 
>:    However, to allow for the smooth handover, a terminal is allowed to
>:    simultaneously use access points with overlapping service area.
>
>						Masataka Ohta

-Basavaraj

---

From: Masataka Ohta <[email-masked]>
Date: Fri, 21 Jun 2002 10:26:30 +0859 ()

Basavaraj;

>     have an agenda item for discussion"

I or you can see no difficulty that the topic of smooth handover
already get considerable amount of interest shown by the WG members.

For the topic of smooth handover, I have a proposal for presentation.

> >> presentations.

Presentation (and counter presentation) is essential to initiate (or
terminate) a pointed discussion.

You may remember that, Steve Deering made a presentation in last
SEAMOBY meeting, to deny the WG.

> transceivers is not sufficient.

I never said "smooth HO is not required".

My point is that, if smooth HO is required, it is offerred by
end systems by themselves.

Smooth HO by the network is not required.

> HO. But that is only one class of terminals and does not cover the

That is not an issue of terminals but networks.

As a commecial operater of mobile IP, MIS do not want to
complicate its network with intermediate intelligent entities
for not-so-smooth handover and let end systems solve the issue,
which is the end to end principle.

That's a feedback from the real world.

If there are other operators of mobile IP, I'm interested in their
opinion.

That MIP based smooth HO may be used by someone is not a valid
argument to develop useful protocols.

> information when in an active call.

You are assuming a network, a terminal of which, when in an active
call, can not receive packets unrelated to the call.

That is an extremely poor network to connect terminals with various
processes are working.

I, for example, want to have an active voice call with someone and,
simultaneously, have text-based chat with someone else.

> served by a different FA/AR).

Even in such poor networks, my proposal works with two transceivers
(and attenna, if you so wish).

> "one-model" (dual transceiver approach) fits all solution is not

You have failed to show it.

> performing HOs.

Mine is a network layer approach. It relies on network layer mobile
registration. It even works for transition between wired ethernet
and WLAN that it can not be a lower layer method.

> method. Access control is more of a AAA WG topic. 

Interaction between smooth HO and the access control do have the
relevance to MIP WG.

						Masataka Ohta

---

From: "James Kempf" <[email-masked]>
Date: Fri, 21 Jun 2002 09:53:41 -0700

> If there are other operators of mobile IP, I'm interested in their

Welll, Docomo is certainly interested in the ongoing work to standardize
fast and smooth handover for Mobile IP that is being pursued in the MIP
WG. Depending on particular Layer 2 solutions for particular link layers
such as WLAN, like using dual channels, is not acceptable. Currently, as
far as I know, there is only one 802.11 card that supports dual channel
handover and that is only available in Japan. I can't see that as being
an acceptable solution for an Internet (== worldwide) standard.

            jak

---

From: Masataka Ohta <[email-masked]>
Date: Sat, 22 Jun 2002 08:43:25 +0859 ()

jak;

> such as WLAN, like using dual channels, is not acceptable.

Just FYI, Docomo, in Japan, is operating PHS with smooth handover
capability with two receivers (two receivers are enough, if
transmitting frequency can be changed quickly).

Thank you for demonstrating that you lack experience on mobile
operations.

If there are operators of mobile IP, I'm interested in their
opinion.

It is not link specific. It is not even mobile protocol specific.
It just works with the existing Internet.

On the other hand, solutions requiring intermediate intelligent
entities depends on particular mobility protocol and link
layers that it is not acceptable on the global Internet.

> Currently, as
> handover and that is only available in Japan.

Huh? A terminal with two 802.11 cards works just fine.

Though we experimentally produced a PCMCIA card with dual 802.11
transceivers, to be used with PCs with a single PCMCIA slot,
PCs are not interesting devices for mobile use.

> I can't see that as being

What is not acceptable to the Internet is proposals requiring
intermediate intelligent entities, such as micro mobility agents.

You may use them in your private IP network, though.

						Masataka Ohta

---

From: "James Kempf" <[email-masked]>
Date: Fri, 21 Jun 2002 18:41:48 -0700

> transmitting frequency can be changed quickly).

The fact that Docomo operates a network having a particular Layer 2 does
not mean that this solution should apply to all Layer 2s. The FOMA
network doesn't use two receivers, it uses a single receiver and soft
handover. Packet PDC uses hard handover. It is not acceptable for IETF
to specify a particular Layer 2 technology for Mobile IP. IETF can state
what requirements would be optimal from the Layer 3 standpoint, or it
could specify standards for carrying Layer 2 information, but it can't
specify standards that only run on a particular Layer 2. Check RFC 1958.

> Thank you for demonstrating that you lack experience on mobile

I never claimed to be an expert in the operation of mobile networks. I'm
certainly always open to learning more, thanx for the info on PHS.

But you asked for an opinion from an operator, and so I gave one.

> Huh? A terminal with two 802.11 cards works just fine.

See Chip Maquire's email on interference effects.

> intermediate intelligent entities, such as micro mobility agents.

Exactly which drafts are you referring to here? Neither
draft-ietf-mobileip-fast-mipv6-xx.txt nor
draft-ietf-mobileip-lowlatency-handoffs-v4-xx.txt depend on intermediate
agents. They just require that the access routers support extensions to
mobile IP and routing protocols.

            jak

---

From: Masataka Ohta <[email-masked]>
Date: Sat, 22 Jun 2002 19:08:07 +0859 ()

jak;

> not mean that this solution should apply to all Layer 2s. The FOMA

The fact is that Docomo operates a PHS network NOT having a
particular L2 functionality and still support smooth handover.

PHS, in early days, has poor handover capability, because of its
L2.

Then, one day, with terminals with two receivers, without
modifying the problematic L2, smooth handover became
possible. 

Smooth handover of PHS is NOT offered by L2, which still
poorly support handover.

Smooth handover with two transceivers (receivers) works with PHS,
simple plain WLAN or simple plain wired ethernet.

> It is not acceptable for IETF
> to specify a particular Layer 2 technology for Mobile IP.

Welcome to IETF.

> IETF can state

Just as an evidence that I thoroughly checked RFC 1958, you can check
the RFC stating:

: Acknowledgements
: 
:    This document is a collective work of the Internet community,
:    published by the Internet Architecture Board. Special thanks to Fred
:    Baker, Noel Chiappa, Donald Eastlake, Frank Kastenholz, Neal
:    McBurnett, Masataka Ohta, Jeff Schiller and Lansing Sloan.

the RFC, in addition, states:

:   The Internet level protocol must be independent of the hardware
:   medium and hardware addressing.  This approach allows the Internet to
:   exploit any new digital transmission technology of any kind, and to
:   decouple its addressing mechanisms from the hardware. It allows the
:   Internet to be the easy way to interconect fundamentally different
:   transmission media,

My proposal works independent of the hardware medium and hardware
addressing.

Which particular layer 2 technology, are you saying, is necessary
to support smooth handover with two receivers?

There is none and it works with any layer 2 technologies.

> But you asked for an opinion from an operator, and so I gave one.

What I asked is an opinion from mobile IP operators,

: If there are other operators of mobile IP, I'm interested in their
: opinion.

though opinions from anyone could have been useful.

> See Chip Maquire's email on interference effects.

And the interference is no problem.

You need information not only on PHS but also on WLAN.

> mobile IP and routing protocols.

Unnecessarily complex routing protocol is intelligence in the
network. You can check RFC 1958 to understand that routing should
not do much job.

The access router supporting the unnecessarily complex routing is
an intermediate intelligent entity.

In general, functionality in a network substitutable by functionality
on end systems, are not allowed by the end to end principle.

A foreign agent in a network, which MIS decided not to have (
FA is collocated on MN), is an intermediate intelligent entity.

That you do it at higher layers does not make it unintelligent.
E.g. NAT or an application layer gateway operating at layers
of IP and above is an intermediate intelligent entity.

							Masataka Ohta

---

From: "James Kempf" <[email-masked]>
Date: Mon, 24 Jun 2002 08:26:00 -0700

> There is none and it works with any layer 2 technologies.

I'm sorry, Ohta-san, but it does not. It does not work with cdma2000 and
it does not work with wCDMA. If you think this is so, then please point
to the paragraphs in the spec that say it will. These protocols are
designed to use soft handover with a single Rake receiver on the mobile
station. They are not designed to use two receivers.

            jak

---

From: Masataka Ohta <[email-masked]>
Date: Tue, 25 Jun 2002 01:07:01 +0859 ()

jak;

> station. They are not designed to use two receivers.

Huh?

W.r.t CDMA, I stated in my draft that:

What are you trying to deny?

Can you please point to the paragraphs in the spec that say it will
need multiple RF modules?

> These protocols are
> designed to use soft handover

As is stated in RFC 1958,

:   2.3 It is also generally felt that end-to-end functions can best be
:   realised by end-to-end protocols.

:   To quote from [Saltzer], "The function in question can completely and
:   correctly be implemented only with the knowledge and help of the
:   application standing at the endpoints of the communication system.
:   Therefore, providing that questioned function as a feature of the
:   communication system itself is not possible. (Sometimes an incomplete
:   version of the function provided by the communication system may be
:   useful as a performance enhancement.")

that some link layer has link specific functionality (such as link
soft handover of some CDMA link layer) may be useful as a incomplete
performance enchancement (though, in general, performance rather
degrades), it is merely allowed as an exception.

IP layer solutions can ignore that some link protocol is designed
to use soft handover.

That CDMA has an imcomplete L2 function does not mean we should
not have a complete version at L3.

						Masataka Ohta