Subject: [Mipshop] FMIPv6: Hi message

From: Nicolas DICHTEL <[email-masked]>
Date: Thu, 01 Jun 2006 21:23:22 +0200

Hi everybody,

I've questions about HI message.
Let suppose that we are in predictive mode. MN sends a FBU to PAR. Then
PAR sends a HI to NAR. Following the draft, HI can contain only two
options (LLA of MN and PCOA) and set the flag S.
When NAR receives this HI message, how can it formulate a NCOA ? NAR cannot
find the "future" link where MN will be attached.

And if the HI message contains a NCOA, why set the flag S rather than use
the proposed NCOA ? FBU MUST contain a NCOA when it is sent from PAR's link.
So, why not automatically add this NCOA in HI message ?

Last question: in reactive mode, must PAR sends a HI message to NAR ? HI and
Hack messages don't appear on Figure 3, but in section 3.1:
  "For all these operations,
   the protocol provides ``Handover Initiate (HI)'' and ``Handover
   Acknowledge (HAck)'' messages. Both of these messages MUST be
   supported and SHOULD be used."
and in section 6.3.2:
  "The Fast Binding Acknowledgment message SHOULD NOT be
   sent to the MN before the PAR receives a HAck message from the NAR."
If there isn't any "network-resident contexts" on PAR, why don't sent
directly a FBack ? In reactive mode, NAR had already checked NCOA when it
got the FNA containing the FBU.

Regards,
Nicolas

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---

From: Michael Ye <[email-masked]>
Date: Fri, 02 Jun 2006 14:27:15 +0800

Hi Nicolas,

-----Original Message-----
From: Nicolas DICHTEL [mailto:[email-masked]] 
Sent: Friday, June 02, 2006 3:23 AM
To: [email-masked]
Subject: [Mipshop] FMIPv6: Hi message

Hi everybody,

I've questions about HI message.
Let suppose that we are in predictive mode. MN sends a FBU to PAR. Then
PAR sends a HI to NAR. Following the draft, HI can contain only two
options (LLA of MN and PCOA) and set the flag S. When NAR receives this
HI message, how can it formulate a NCOA ? NAR cannot find the "future"
link where MN will be attached.

Two applications used FMIP in mipshop WG was presented.

And if the HI message contains a NCOA, why set the flag S rather than
use the proposed NCOA ? FBU MUST contain a NCOA when it is sent from
PAR's link. So, why not automatically add this NCOA in HI message ?

I don't understand you ask this question.

      Before sending an FBack to an MN, PAR can determine whether the
      NCoA is acceptable to the NAR through the exchange of HI and HAck
      messages.  When assigned addressing (i.e., addresses are assigned
      by the router) is used, the proposed NCoA in the FBU is carried in
      HI, and the NAR MAY assign the proposed NCoA.  Such an assigned
      NCoA MUST be returned in HAck, and the PAR MUST in turn provide
      the assigned NCoA in the FBack.  If there is an assigned NCoA
      returned in the FBack, the MN MUST use the assigned address (and
      not the proposed address in the FBU) upon attaching to NAR.

read the above sentences , I don't know whether it can help you!

Last question: in reactive mode, must PAR sends a HI message to NAR ? HI
and Hack messages don't appear on Figure 3, but in section 3.1:
  "For all these operations,
   the protocol provides ``Handover Initiate (HI)'' and ``Handover
   Acknowledge (HAck)'' messages. Both of these messages MUST be
   supported and SHOULD be used."
and in section 6.3.2:
  "The Fast Binding Acknowledgment message SHOULD NOT be
   sent to the MN before the PAR receives a HAck message from the NAR."
If there isn't any "network-resident contexts" on PAR, why don't sent
directly a FBack ? In reactive mode, NAR had already checked NCOA when
it got the FNA containing the FBU.

Regards,
Nicolas

BR,
Michael Ye

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From: Rajeev Koodli <[email-masked]>
Date: Wed, 07 Jun 2006 12:43:40 -0700

> find the "future" link where MN will be attached.
I see your point. But, HI contains the NCoA as well. So, NAR can compute its
own prefix from NCoA, formulate a different NCoA to use (if it so wishes).

> So, why not automatically add this NCOA in HI message ?
Both Section 4 and 6.2.1 state that HI contains NCoA.

"The HI message contains the PCoA, Link-Layer Address, and the NCoA of 
the MN."

" Valid Options:

New Care of Address
..
"

Are you saying that we need to clarify better? If so, where would you 
like it to be
clarified?

> got the FNA containing the FBU.
Yes, in reactive mode you can send FBack directly when it knows that NAR has
checked NCoA in FNA. We can add "PAR MAY send FBack immediately in the
reactive mode".

-Rajeev

---

From: Nicolas DICHTEL <[email-masked]>
Date: Thu, 08 Jun 2006 09:55:23 +0200

> own prefix from NCoA, formulate a different NCoA to use (if it so 
Ok.
>> use
Maybe in section 6.2.1, in description of the option "New Care of 
Address", add:
"This option MUST/SHOULD be included." ?
> checked NCoA in FNA. We can add "PAR MAY send FBack immediately in the
Yes, this will clarify the "reactive" scenario.

Regards,
Nicolas