Subject: RE: [Mipshop] FMIPv6 - Encapsulating FBU into Mobility Header (FN A)

From: Narayanan Vidya-CVN065 <[email-masked]>
Date: Wed, 10 Aug 2005 16:01:27 -0500

> 
> The NAR doesn't really know about the FBU, only the PAR does. 
> So I don't see how it could retransmit the FBack. Besides, 
> loss rates on wired backbones are typically a couple orders 
> of magnitude less than on wireless links, even taking 
> congestion into account (yes, I know some backbones are 
> wireless too but they are typically point to point microwave 
> links that can be managed like wired links).
> 

True. I was thinking of a case where the PAR sends the FBack to the MN both directly and via the NAR - the NAR may optionally decide to cache and re-send it to the MN, once it attaches to it. If this is not done, what happens when the MN moves to the NAR and didn't receive the FBack? Does it now just fall back to regular mip6? 

Vidya

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From: "Ji Zhang" <[email-masked]>
Date: Wed, 10 Aug 2005 22:59:19 +0100

Hi Vidya,

Sorry to jump in.

> True. I was thinking of a case where the PAR sends the FBack to the MN

==>As far as I remember, this case is specified in rfc4068.

both directly and via the NAR - the NAR may optionally decide to cache and
re-send it to the MN, once it attaches to it.

==>I agree this can help in some case.

If this is not done, what happens when the MN moves to the NAR and didn't
receive the FBack? Does it now just fall back to regular mip6?

==>It will simply turn to the reative mode, no? Once the MN connects to the
NAR and confirms its nCoA, it can start the regular MIPv6 operation. This is
independent of the FMIPv6 operation, IMHO.

Ji

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From: "James Kempf" <[email-masked]>
Date: Wed, 10 Aug 2005 14:57:32 -0700

Sounds like you are talking about predictive handover, right? The PAR sends
the FBack to both the old and the new link, and if the MN has moved already,
the NAR buffers until the MN arrives, then the FBack is the very first
packet the MN gets when it comes up on the new link (the packet on the old
link is dropped after a time) .

If the FBack is dropped over the air on the new link, there is very little
point in having the MN redo the FBU, because by that time, the MIP handover
should be well underway.

            jak

----- Original Message -----
From: "Narayanan Vidya-CVN065" <[email-masked]>
To: "'James Kempf'" <[email-masked]>; "'Syam Madanapalli'"
<[email-masked]>
Cc: <[email-masked]>
Sent: Wednesday, August 10, 2005 2:01 PM
Subject: RE: [Mipshop] FMIPv6 - Encapsulating FBU into Mobility Header (FN
A)

both directly and via the NAR - the NAR may optionally decide to cache and
re-send it to the MN, once it attaches to it. If this is not done, what
happens when the MN moves to the NAR and didn't receive the FBack? Does it
now just fall back to regular mip6?