Re: about draft-ohira-assign-select-e2e-multihome-00.txt

["Kenji Ohira" <torus@yakitori.no-ip.com>]

Cedric,

> > My proposal can be summarized as follows.
> > 1. Assign IP addresses hierarchically.
> > 2. Use source address based routing.
> AFAIK the 2 points above were also suggested in Huitema's draft.
> >From my point of view your suggestion is :
> 1. Use Huitema's Host-Centric Multihoming with source-base routing
> 2. Let the end-hosts' applications decide which source address to use,
>    i.e. change end-hosts' API and applications (this is not clear in
>    your draft)
> Is that correct ?
Yes. You are faultlessly correct.

> If yes, how do you perform the source address selection ?
First of all, I think that multihoming can not nor should not be conclude 
within IP layer and that the source address selection is not issue in IP layer similarly.
So, this issue is out of scope of my draft.
Still more, this is why the title of my draft is not 'host-centric' but 'end-to-end' multihoming.

Of course, I know that this issue is still difficult in transport or application layer.
In my draft, I introduce a naive but workable method that examining each path 
determined by a pair of source address and destination address one by one in 
order of  match length between the source address and destination address.
Here, I would like to introduce more intelligent mechanism of selection such as
your NAROS system.

> Does that mean that all applications on the end hosts need to be
> modified in order to benefit from multihoming ?
No. I think that we can assume a certain 'typical model' of application and that
extended TCP or SCTP will be able to treat with multihoming for this model.
In this case, applications do not need to be modified.
However, someone/some applications may require to control the parameter for 
multihoming by itself.
For those, we have one solution by end-to-end path selection with extended 
socket APIs of TCP for end-to-end multihoming.
A. Matsumoto, co-author of my draft, is now working on this issue.
So please read draft-arifumi-lin6-multihome-api-00.txt.

July 11, 2003 (JST +0900)
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Kenji Ohira
Graduate School of Informatics, Kyoto University, JAPAN
mailto: torus@tori.cc / ohira@net.ist.i.kyoto-u.ac.jp