Subject: [Mipshop] home addr option doubt

From: Emil Ivov <[email-masked]>
Date: Wed, 06 Apr 2005 14:43:04 +0200

Hello,

We had a little trouble understanding the exact place where a Home
Address option is to be included.

All that Section 6.3.1 of draft-ietf-mipshop-fast-mipv6-03.txt says is:
The FBU MUST also include the Home Address Option and the Home
Address is PCoA.

One way to do it would be to include the Home Address Option as an
option of the FBU itself.
	If that is the case shouldn't this be clarified a bit more? It could
probably also be included in the  "Mobility Options" part of the message
format together with:

       MUST contain alternate CoA option set to NCoA IP
       address when FBU is sent from PAR's link.

Another way to send the HAO would be to include it in a destination
options header as with BUs?
	If this is the case how should it be transported when an FBU is
encapsulated in an FNA? As a destination option of the FNA, or should
the AR addit when resending the FBU?

Any comments would be appericated

Thanks
Emil

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From: Vijay Devarapalli <[email-masked]>
Date: Wed, 06 Apr 2005 18:35:45 -0700

> options header as with BUs?

section 6.3.1 is talking about the Home Address Option in a destination
options header. not as a mobility option.

> the AR addit when resending the FBU?

the FBU will be an IP packet inside the FNA. the payload proto field
in FNA will be set to IPv6. here is the packet format

   IPv6 hdr (src=nCoA, dst=NAR)
   Mobility Hdr
       FNA
   IPv6 hdr (src=nCoA, dst=PAR)
   Dst Opts hdr
       Home Address option (pCoA)
   Mobility Hdr
       FBU

the NAR first processes the FNA part of the packet. if nCoA is valid,
it forwards the inner IP packet to the PAR.

   IPv6 hdr (src=nCoA, dst=PAR)
   Dst Opts hdr
       Home Address option (pCoA)
   Mobility Hdr
       FBU

Vijay

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From: Emil Ivov <[email-masked]>
Date: Thu, 07 Apr 2005 12:38:06 +0200

Thanks for the reply Vijay,

Don't you guys think that it might be handy to have a few words on that 
in the draft? It might be just me, but it didn't  seem that obvious when 
I read it.

Emil

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From: Rajeev Koodli <[email-masked]>
Date: Thu, 07 Apr 2005 14:43:16 -0700

Hello Emil,

the "Home Address Option" is borrowed from MIPv6, and hence
is always included with the FBU.

What would you like to see clarified?
"Home Address Option" => "Home Address Destination Option" in 6.3.1?
This might be possible in the final proof-reading, if not we can address it
in the next avatar.

Thanks,

-Rajeev

Emil Ivov wrote:

> Don't you guys think that it might be handy to have a few words on 
> that in the draft? It might be just me, but it didn't  seem that 
> obvious when I read it.
>
> Emil
>
> Vijay Devarapalli wrote:
>
>> Emil Ivov wrote:
>>
>>> Hello,
>>>

---

From: Emil Ivov <[email-masked]>
Date: Fri, 08 Apr 2005 13:28:53 +0200

Hello Rajeev,

> "Home Address Option" => "Home Address Destination Option" in 6.3.1?

That would most probably make it clearer yes.

Another thing that I'd personally find useful would be adding a few 
words on the fact that encapsulating an FBU means encapsulating it 
together with its IPv6 header (an HAddr option thereof). Again it might 
be just me but the words (6.3.3):

    A MN sends a Fast Neighbor Advertisement to announce itself to the
    NAR. When the Mobility Header Type is FNA, the Payload Proto field
    may be set to IPv6 in order to assist FBU encapsulation.

kind of left me in a doubt. (especially the "may be set to IPv6" part) .
Would it be possible to have sth like:

    A MN sends a Fast Neighbor Advertisement to announce itself to the
    NAR. When the Mobility Header Type is FNA and the message
    encapsulates a Fast Binding Update, the Payload Proto field
    MUST be set to IPv6 indicitaing the following IPv6 header of the
    encapsulated FBU.

... Something more explicit (like the comments in Vijay's letter) would 
probably be even better but I imagine it's a bit late for substantial 
changes in the text.

Cheers
Emil