Subject: [Monami6] draft-ietf-monami6-multiplecoa-00.txt

From: "Tero Kauppinen (JO/LMF)" <[email-masked]>
Date: Wed, 14 Jun 2006 08:29:27 +0300

"5.1.  Management of Care-of Addresses and Binding Unique Identifier

    There are two cases when a mobile node has several Care-of Addresses:

    1.  A mobile node uses several physical network interfaces and
        acquires a Care-of Address on each of its interfaces.

    2.  A mobile node uses a single physical network interface, but
        multiple prefixes are announced on the link the interface is
        attached to.  Several global addresses are configured on this
        interface for each of the announced prefixes."

I do not understand why the following case is not included:

    3.  A mobile node uses several physical network interfaces and each
        interface is configured with several global addresses.

-- 
Tero

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From: Gábor Fekete <[email-masked]>
Date: Wed, 14 Jun 2006 11:49:19 +0300

Hi Tero,

>         interface is configured with several global addresses.

Only if that "global address" is a CoA.
I think point 2 makes the confusion. So I'd instead suggest modifying
point 2 like this:

     2.  A mobile node uses a single physical network interface, but
         multiple prefixes are announced on the link the interface is
         attached to.  Several care-of addresses are configured on this
         interface for each of the announced prefixes.

Also
a. If every global address is a CoA then you don't need point 3 since point 1
   includes it.
b. Not every CoA is global. A CoA may be non-global unicast routable
   address (i.e. site-local), even though it is not advised (according 
   to RFC 3775).
c. If a global address is not a CoA then the mobile node does
   not have it as a CoA :)

So, your point 3 is not needed.

Regards,
Gabor

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From: Benjamin Koh Tien-Ming <[email-masked]>
Date: Wed, 14 Jun 2006 17:03:49 +0800

Hi!

I believe case (3) is accounting for the scenario where the mobile node
has several physical network interfaces and acquires multiple Care-of
Addresses on each interface. Or is this already an amalgation of cases
(1), (2) and hence not considered?

> a. If every global address is a CoA then you don't need point 3 since
> point 1 includes it.

Point 1 reads "and acquires a Care-of Address on each of its
interfaces." leading to the logical conclusion that each physical
network interface has only 1 Care-of Address. Is that the original
intention? Perhaps rephrasing it to "and acquires one or more Care-of
Address(es) on each of its interfaces." would resolve this issue.

Regards,
Ben

-- 
/<<<<<<<<<<<<<<<<<<<<++>>>>>>>>>>>>>>>>>>>>\
| Benjamin Koh Tien-Ming                   |
| R & D Engineer                           |
| Panasonic Singapore Laboratories Pte Ltd |
| Tel: (65)6550 5481  Fax: (65)6550 5459   |
| E-mail: [email-masked]  |
\>>>>>>>>>>>>>>>>>>>>--<<<<<<<<<<<<<<<<<<<</

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From: "Tero Kauppinen (JO/LMF)" <[email-masked]>
Date: Wed, 14 Jun 2006 12:25:07 +0300

> Address(es) on each of its interfaces." would resolve this issue.

Exactly, I think either 1) should be modified as you suggest or a new 
case is added. Rephrasing would probably be a better choice.

> Ben

/Tero

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From: Gábor Fekete <[email-masked]>
Date: Wed, 14 Jun 2006 12:29:39 +0300

Hi Benjamin,

Combining your clarification and my previous reasoning, I say that both
1 and 2 should be modified as follows:

     1.  A mobile node uses several physical network interfaces and
         acquires __one__ Care-of Address on each of its interfaces.

     2.  The mobile node is attached to a link on an interface where multiple
         prefixes are announced.  Several Care-of Addresses are configured
         on this interface for each of the announced prefixes.

So, point 1 covers the case when each interface has only one CoA
and point 2 covers the case when an interface have multiple
CoAs.
Note that point 2 covers the multiple interface case too due to the
"on __an__ interface" wording.

Regards,
Gabor

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From: "Tero Kauppinen (JO/LMF)" <[email-masked]>
Date: Wed, 14 Jun 2006 12:55:40 +0300

>          on this interface for each of the announced prefixes.

What about the case when the node configures several addresses from one 
prefix?

-- 
Tero

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From: marcelo bagnulo braun <[email-masked]>
Date: Wed, 14 Jun 2006 13:22:24 +0300

just one nit..

>          prefixes are announced.

s/announced/available

announced seems too Router Advertisement oriented and the dhcp case 
seems to be left out

regards, marcelo

>   Several Care-of Addresses are configured

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From: marcelo bagnulo braun <[email-masked]>
Date: Wed, 14 Jun 2006 13:24:12 +0300

El 14/06/2006, a las 12:55, Tero Kauppinen (JO/LMF) escribió:

> What about the case when the node configures several addresses from 
> one prefix?
>

i fail to see any application for such a case, do you have any specific 
case where that would be useful/reuqired in mind?

otoh, i don't see any reasons why not include/support it, (other than 
the difficulty in writing a text than can express all these cases in a 
simple way :-)

regards, marcelo

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From: Masafumi Watari <[email-masked]>
Date: Wed, 14 Jun 2006 19:37:08 +0900

> announced seems too Router Advertisement oriented and the dhcp case 

Also adding...

Is "several" more than two or does it include two?  Just curious...

s/several/multiple/ might be better.

regards,
watari

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From: Keiichi Shima <[email-masked]>
Date: Wed, 14 Jun 2006 19:42:07 +0900

On 2006/06/14, at 19:24, marcelo bagnulo braun wrote:

>> What about the case when the node configures several addresses  
>> from one prefix?
>>
>
> i fail to see any application for such a case, do you have any  
> specific case where that would be useful/reuqired in mind?

IPv6 nodes sometimes have more than one address generated from one  
single prefix.  For example, the temporary addresses.

(Although I'm not a fun of tempaddr :-)

---
Keiichi SHIMA
IIJ Research Laboratory <[email-masked]>
WIDE Project <[email-masked]>

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From: marcelo bagnulo braun <[email-masked]>
Date: Wed, 14 Jun 2006 13:48:50 +0300

> single prefix.  For example, the temporary addresses.

indeed, i always forget about this case...

yes this could be useful for anonymity support (but i guess that other 
stuff is needed as well to provide such feature...)

OTOH, this seems to be coneptually different than multiple addresses 
because of multihoming...

regards, marcelo