Subject: [nemo] Does NEMO have to be based on network layer?

From: Patrick Lam <[email-masked]>
Date: Tue, 19 Jul 2005 09:58:49 -0700 (PDT)

Dear all,

I think this may be a stupid question that has been
asked many times before (although I can't find any
answer on the net).  It was raised from a discussion 
among our group of research students trying to
understand more about NEMO.

Does NEMO have to be based on network layer?

What I mean is that -- can the functionalities of a
mobile router be replaced by an AP (e.g., 802.11 AP)? 
Therefore, the AP is connecting to a bunch of MNNs
through an ingress link, while connecting to a fixed
router wirelessly through an egress link.  That is,

MNNs<--link layer-->AP<--link layer-->fixed router

The "link layer" here can be anything from 802.11 to
satallite link.  Then the mobile network will mean
the, say, 802.11 network surrounding the AP.

I think having the IP as the "common ground" is very
advantageous.  However, we are just wondering whether
it has to be based on IP at all.

Regards,

Patrick

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From: "T.J. Kniveton" <[email-masked]>
Date: Tue, 19 Jul 2005 14:39:27 -0700

Well, NEMO stands for Network Mobility. So it wouldn't make too much 
sense to do it at a layer lower than the Network layer.

Of course, you can take an AP and stick it to an egress interface.. but 
as soon as the AP physically moves, and changes egress networks, its 
sessions will all die. This is the essence of what NEMO solves: taking 
a Network and making it Mobile. Here, by "mobile", we mean that its 
egress attachment point can traverse the fixed Internet hierarchy.

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From: Thierry Ernst <[email-masked]>
Date: Wed, 20 Jul 2005 12:52:32 +0900

Futher commenting on this, this solutions may be fine, but in restricted
scenarios, i.e the ones when there are no L3-layer mobility, i.e.
mostly at the scale of a campus. Of course, a satellite link spans a
larger area, but the sole satellite link won't alsways be used, so you
will need to perform a L3 handoff, right ?

If you read draft-ietf-nemo-multihoming-issues, you will notive there
are scenarios in which your solution at L2 wouldn't work. So, in the
end, a L3 solution is needed.

Thiery

On Tue, 19 Jul 2005 14:39:27 -0700
"T.J. Kniveton" <[email-masked]> wrote:

> Of course, you can take an AP and stick it to an egress interface..
> but as soon as the AP physically moves, and changes egress networks,
> its sessions will all die. This is the essence of what NEMO solves:
> taking a Network and making it Mobile. Here, by "mobile", we mean that
> its egress attachment point can traverse the fixed Internet hierarchy.
> 
> 

-- 
Thierry Ernst, PhD
WIDE, Jun Murai Lab., Keio University, Japan
Nautilus6 Chair: http://www.nautilus6.org
Web: http://www.sfc.wide.ad.jp/~ernst/
T:+81-44-580-1600 F:+81-44-580-1437
--

---

From: Alexandru Petrescu <[email-masked]>
Date: Thu, 21 Jul 2005 17:18:44 +0200

> MNNs<--link layer-->AP<--link layer-->fixed router

Along the lines of the above topology is a Mobile Router that is
actually a bridge, and I think there is some discussion about Home
Network models considering that, search "bridge" in
http://www.mobilenetworks.org/~pthubert/draft-ietf-nemo-home-network-models-03.txt

Alex