Subject: RE: [nemo] Questions on multiple mobile network prefixes in a BU

From: "Tan, Tat Kin" <[email-masked]>
Date: Mon, 26 Apr 2004 11:47:16 +0800

Hello Pascal and Alex,

Thanks for both your explainations. I still have further questions if
you do not mind.

With what Alex had explained, that if there is 10 or 20 different nested
networks then each of the MR of these 10 or 20 networks will send its
own BU for updates and not all consolidated into 1 single BU by the
upper most (in this text, the term "aggregated" is used). 

First, how will the 10 or 20 networks know there needs an update and
hence trigger the sending of BUs? If the 10 or 20 networks were told to
update by some mechanism such as the upper most MR sending out
information telling all its lower link to update, then would this be too
much overhead interms of BU traffics? If this is true, this also mean
the moving of the entire NEMO is not transparent to the networks within?
The objective of the NEMO isnt it true that is to make the move of the
network transparent to other nested network within?

Second, based on the assumption of first question, will more security
concerns be arise if the upper most MR is moving constantly (from
Network A to B and then to C ....and so on), and the inner networks that
updating the BU is being confused? (inner network may still be updating
Network A while upper MR is already in C maybe....) ? Maybe this
question is not valid since the NEMO objective is to make the network
movement not a concern to inner networks...?

I agree with Pascal's suggestion that to make a clean trees and then
later worry abt the idea of proxying BU. Somehow, thoughts just came and
it might just be too confusing :)

Thanks.

rgds,
tatkin

-----Original Message-----
From: Pascal Thubert (pthubert) [mailto:[email-masked]] 
Sent: Monday, April 19, 2004 4:21 PM
To: Tan, Tat Kin; [email-masked]
Subject: RE: [nemo] Questions on multiple mobile network prefixes in a
BU

>> My question is, how can this be achieved? I mean if there is 10 or 20
different nested networks are within that moving networks and could a
single BU be able to cater all information? 

Hi Tatkin, 

I will not paraphrase Alex since I had a chance to read his mail and
agree with his answer concerning the coverage of the nemo basic support.

But I must admit that like you, I toyed with the idea of proxying BU
prefix information, in the context of nested RO. Note that there's a
number of issues to fix first like loop avoidance. I suggest we start
looking at making clean trees of mobile routers and then we know that we
can start proxying/bridging is a loopless fashion.

Pascal

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 26 Apr 2004 11:38:07 +0200

Tan, Tat Kin wrote:
> With what Alex had explained, that if there is 10 or 20 different 
> nested networks then each of the MR of these 10 or 20 networks will 
> send its own BU for updates and not all consolidated into 1 single BU
>  by the upper most (in this text, the term "aggregated" is used).
> 
> hence trigger the sending of BUs?

Each MR "detects" it is in a foreign network when it receives an RA with
a prefix different than its preconfigured home prefix (just like MH
detects its is in a foreign network, by Mobile IPv6 mechanisms).  After
detecting it moved, it keeps sending BU's when a binding lifetime expires.

> If the 10 or 20 networks were told to update by some mechanism such 
> as the upper most MR sending out information telling all its lower 
> link to update, then would this be too much overhead interms of BU 
> traffics?

The fact that the "uppermost" or "top-level" or "root" MR sends a BU
following a change in its Care-of Address does not mean that each MR
below it must send a BU; each such MR sends BU only when that respective
MR changes its CoA (no relation to the moments when upper MR's change
their CoA).

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 26 Apr 2004 11:38:07 +0200

Alex