Subject: [nemo] question about multihoming

From: "weiwei" <[email-masked]>
Date: Thu, 24 Feb 2005 12:51:08 +0100

Dear all,
 could anyone tell me the benefits of (n,1,n) over (n,1,1) when considering multihoming?

thanks,

weiwei

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From: Chan-Wah Ng <[email-masked]>
Date: Thu, 24 Feb 2005 21:48:59 +0800

Hello, weiwei,

I guess it is not a question of benefits.  It is a question of
deployment.  A possible scenario for (n,1,n) would be the joining of two
separate mobile networks into one.

/rgds
/cwng

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From: xuw <[email-masked]>
Date: Thu, 24 Feb 2005 14:48:20 +0100 (MET)

hi, cwng
so do you mean that there are no more benefits of using multiple MNP than
one ,from the perspective of load sharing or redundancy ? you know, i am
trying to compare these 8 cases from the perspective of benefits. for
instance, using multiple mobile router at least has the benefits of
handling the case that one mobile router is broken, comparing with the
case in which only one mobile router is used.
Or do you mean it is kind of non sense of comparing them ?? :)

thanks,
weiwei

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From: Chan-Wah Ng <[email-masked]>
Date: Thu, 24 Feb 2005 22:28:15 +0800

Hello, weiwei,

No, no.  That's not what I mean.  What I means is that there is no
obvious benefits for NEMO per se to have (n,1,n) over (n,1,1).  In fact,
I think any administrator who purposely configure an (n,1,n) is asking
for trouble.  However, as I have mentioned, there is a deployment
scenario where an (n,1,n) network might occur, so we have to consider
it.

/rgds
/cwng

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From: Thierry Ernst <[email-masked]>
Date: Fri, 25 Feb 2005 12:52:50 +0900

Dear all,

I'm not sure we can conclude right now that one case has a benefit over
another one:

- first, this hasn't been discussed much

- second, the document has been written to emphasize the issues (and not
to emphasize the benefits)

We would indeed appreciate feedback on the ML so that we know what cases
need to be supported for what purposes. That would help the NEMO WG to
decide which issues are worth to be solved, or which should be solved in
priority. If we don't receive such kind of explicit feedback, I'm afraid
that the WG cannot update its charter with new multihoming items.

So, instead of ChanWah, me or anyone else of answering what are the
benefits, may we have people posting which case they consider important
to be supported with an example scenario ?

About the multiple MR case itself, there are much more motivations than
redundancy. It could be increased bandwidth, ability to bring a new
egress iface in the NEMO in case the existing MR cannot be upgraded (no
slot available or embedder MR), etc.

Thierry

> obvious benefits for NEMO per se to have (n,1,n) over (n,1,1).  In
> fact, I think any administrator who purposely configure an (n,1,n) is
> asking for trouble.  However, as I have mentioned, there is a
> deployment scenario where an (n,1,n) network might occur, so we have
> to consider it.
> 
> /rgds
> /cwng
> 
> 
> > so do you mean that there are no more benefits of using multiple MNP
> > than one ,from the perspective of load sharing or redundancy ? you
> > know, i am trying to compare these 8 cases from the perspective of
> > benefits. for instance, using multiple mobile router at least has
> > the benefits of handling the case that one mobile router is broken,
> > comparing with the case in which only one mobile router is used.
> > >deployment.  A possible scenario for (n,1,n) would be the joining
> > >of two separate mobile networks into one.
> > >
> > >/rgds
> > >/cwng
> > >

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From: marcelo bagnulo braun <[email-masked]>
Date: Fri, 25 Feb 2005 10:50:51 +0100

Hi Thierry,

imho, both configurations are reasonable.
In particular, (n,1,1) seems a very natural case
OTOH, imho (n,1,n) is also natural, but perhaps not so intuitive. 
Imagine the case where home netwrok is multihomed so that the home 
network has several prefixes form different ISPs, This will imply that 
the nemo has multiple prefixes in order to benefit from the multihoming 
capabilities of the home network. Note that in this case, the multiple 
prefixes are not related to the nemo multihoming, but to the home 
network multihoming. imho this is a valid usage case.

Now, there is also the possibility to artificially turn a (n,1,1) into 
a (n,1,n) as a mechanisms to provide some nemo multihoming 
capabilities. This means that the home network has a single prefix, but 
the nemo has n prefixes, and for example each one is artificially 
associated with a MR (in order to enable for instance that the 
selection of the prefix determines the selection of the MR (you need 
additional stuff for this)). Now, in this scenario, i am not sure this 
is a good approach.

More details about this you can find them in
> http://www.ietf.org/internet-drafts/draft-bagnulo-nemo-multi6-00.txt

In particular check sections 3.1. and 3.2.

Regards, marcelo