Subject: [nemo] Comments on draft-clausen-nemo-ro-problem-statement-00.txt

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Mon, 08 Nov 2004 10:34:50 +0100

Hi Ryuji,

First of all, thanks for submitting the draft.

Your draft seems to address the problem of the Internet-to-NEMO
communication and the NEMO-to-NEMO communication when nesting is
involved, using a MANET approach. I agree with you that in the
NEMO-to-NEMO approach, having the MRs in a nested-NEMO running an Ad-Hoc
routing protocol would help to avoid traversing the Internet and also
avoid the encapsulation. On the other hand, I don't see that clear how
this would help the Internet-to-NEMO, at least as it is now described in
the current version of your draft.

The draft says:

   "Additionally, this would also ease the Internet-to-NEMO scenario. In
   order to deliver an IP datagram to a node in the nested NEMO network,
   only a path to the access router between the nested NEMO network and
   the Internet would be required: once an IP datagram arrives in the
   nested NEMO network, the routing tables in the mobile routers, as
   provided by OLSR, would allow direct routing to the destination.
   Thus, there would no longer be a requirement to do nested encapsula-
   tion on each logical hop (i.e. each transversal of a Home Agent) in
   order to be able to decapsulate and correctly forward IP datagrams in
   the nested NEMO network.

   Thus even if no route optimizations are performed in the Internet-to-
   NEMO scenario, an overhead reduction can still be achieved through
   much lower encapsulation requirements."

How this improvements are achieved? If a CN in the Internet sends a
packet to a MNN that is connected to a nested-NEMO, the packet would
traverse the HAs of every MR in the nested-NEMO until the MNN is finally
reached. Therefore, I don't see how this encapsulation would be avoided,
without making any additional change to the MR and/or HA and/or CN. Am I
missing something?

Thanks in advance.

Kind Regards,

Carlos J.

-- 
Carlos Jesús Bernardos Cano - http://www.it.uc3m.es/cjbc/
GPG FP: 58C3 4227 AF8D 01D4 5A09  A617 E6F2 B23E DAD6 AA40

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From: Ryuji Wakikawa <[email-masked]>
Date: Thu, 18 Nov 2004 16:19:52 +0900

Hello Carlos

Sorry for late reply.

You are right. 

We can not achieve an optimal route for Internet-toNEMO only with
MANET. In the Internet-to-"Nested"NEMO case, MANET can help optmized
routing for a few hops (that are inside nested NEMO).

For example, if nested MR sends BU with root-MR's CoA, packets are
directly reached to root-MR and root-MR can route packets to the
nested MR by MANET. You may be interested in ORC draft.
http://www1.ietf.org/internet-drafts/draft-wakikawa-nemo-orc-00.txt

thanks
ryuji

At Mon, 08 Nov 2004 10:34:50 +0100,
Carlos Jesús Bernardos Cano wrote:
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> Hi Ryuji,
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