Subject: RE: [seamoby] IRTF mm problem statement

From: Vincent Park <[email-masked]>
Date: Tue, 1 May 2001 16:52:23 -0400

I think I agree with Phil R. There is a lot going on the wireless space and
any attempt to custom build IP protocols for wireless sounds to me like the
wrong path to take...

The idea here is to abstract a specific (hard) problem for the routing
experts in the IETF (host routing or fast subnet routing or whatever you
want to call it) and let the IRTF folks scratch their heads for a
while....If anything, Seamoby, has been very useful in allowing people to
explore the mobility space in general, realize the enormity of the
task/issues/interactions etc and hopefully identify *core* pieces of
technology that are missing....

I hope that the new IRTF group is going to be about **one of these core
missing pieces** i.e.: host routing. At this state wirless links maybe need
to be abstracted in the way wired-line links are (Up, Down, Relative merit).
Later on, when we have a better understand how things might work we may
consider exposing more of the characteristics of the "wireless world" to the
routing protocol....but lets first walk before we fly...

-Vince

Vincent D. Park
Flarion Technologies, Inc.
Bedminster One   
135 Route 202/206 South
Bedminster, NJ 07921

-----Original Message-----
From: Phil Neumiller [mailto:[email-masked]]
Sent: Tuesday, May 01, 2001 4:05 PM
To: Phil Roberts; 'Arthur Ross'; [email-masked]
Subject: Re: [seamoby] IRTF mm problem statement

Hi Phil R./Arthur,

> One might think that a good chunk of this problem can be abstracted
without
> any awareness of radio link characteristics.  The point of this particular
> piece of research has to do with updating reachability awareness and
> forwarding tables within the routers the mobile attaches to rather than
how
> to figure out which points the mobiles can reach and how well they can
reach
> it.

I see this is where the disconnect is Phil R.  We HAD gone much further in
SeaMoby of our discussions of micro-mobility than your current list of
drafts.
We entertained issues related to the mobile and its view of the network.
Also, most people were familiar with the OBAST paper which describes
a method for macro/micro/local mobility where the air interfaces properties
of CDMA are socketed as Arthur has described (mainly because I recited
enough times on the list) [even in the CRAPS BOF I had to make this
argument]{See thwap thread a while back on SeaMoby list}.

>
> It would be hard also to make too many assumptions about what that radio
> system could be.  You include that the architecture should have a
provision
> for a diversity combiner but surely there are networks over which
something
> like this would run on which there is no diversity combiner?

Also, Phil R., I had discussed many times on the SeaMoby list that diversity
combining is not just for CDMA.  When done over IP, other radios, even
TDMA radios can take advantage of it in the outer-loop sense.  I have
several
patents pending on how to do this with TDMA, and frequency hop radios,
not just DSSS.  Of course those are Motorola's and don't do us much good
here in the IETF unless some other folks can come up with some stuff
independently. :-)

> I wasn't privy
> to all the discussions in the fast handover design teams in MIP but there
> was at least some effort put in to thinking about what happens when this
is
> running over a fairly lossy medium.  Whether or not a ping-pong effect
> should be handled in these protocols was also discussed and highly
> controversial.

Again we discussed this in the SeaMoby list and CRAPS list and OBAST
list numerous times.  The TADD/TDROP timers as used in CDMA can
work for any RF interface to reduce ping-pong if done in a borrowed and
abstract way over IP.

> Both of those can be characteristics of wireless systems
> with multiple access points, and both may be quite independent of whether
it
> is a TDMA or CDMA or whatever system running at 800MHz, 1800MHz, or
> whatever.

In this sense I agree with you, but only so far as it can be done in a
common way.
Macro-diversity selection can be done with almost any radio type, and OBAST
it is an option.  OBAST allows optionalk make-before-break with any radio
type.
OBAST allows simultaneous and different link layers to be active if they
want to
use it.
>
> There has been reluctance so far to design within the IETF a radio
> technology specific subsystem.  I personally am not willing to push for
> that.  Perhaps you can get a discussion going on in the new wireless
> interest list Phil N set up to organize an effort to promote such.  It
seems
> that productive work along the path already specified in the document can
go
> on and the possibilities for exploring ratholes by adding in radio
> technology specific issues might be plentiful.

We don't need to explore a rathole here.  What we need to do is ask
ourselves
what things can be made common for all RF L2s and be put over IP? This
is the IMPORTANT question to ask yourself.  Really!  Of course I sound like
a broken record, but I think (I hope, Pat and James and Gary and many
others) are
starting to think about this and understand it.  Perhaps not in the same
with
the same zeal that I express. :-)  I am pretty confident that Arthur is on
the
right track.  His arguments about radio physics can be hidden with an OO
like abstraction of putting macro-diversity over IP.  That is the big first
step
to consider.

I will show deference to the draft author and chair.  If you want this
conversation
moved over to the new list that is fine I will try and summarize it and move
it over.

Thanks,

Phil N.

---

From: "Phil Neumiller" <[email-masked]>
Date: Tue, 1 May 2001 16:04:10 -0500

Hello Vincent,

----- Original Message -----
From: "Vincent Park" <[email-masked]>
To: "'Phil Neumiller'" <[email-masked]>; "Phil Roberts" <[email-masked]>; "'Arthur Ross'" <[email-masked]>;
<[email-masked]>
Sent: Tuesday, May 01, 2001 3:52 PM
Subject: RE: [seamoby] IRTF mm problem statement

> any attempt to custom build IP protocols for wireless sounds to me like the

Hmm.  I (and Arthur)  AM (is)/WAS/were suggesting abstraction not custom
protocols.   So I don't  understand your statment at all.

> technology that are missing....

There are some other real hard problems too.  Mobile nodes move and
the physics of this is will be completely ignored if we just focus on
host routing.  May as well NOT call it micro-mobility then.  I can't see
how this can be called micro-mobility at all in fact.  Can somebody please
explain this to me?  I feel like I just fell off a turnip truck or something???

Thanks,

Phil