Subject: Re: [mobile-ip] Sending Binding Acknowledgement with routing header.

From: [email-masked]
Date: Wed, 15 May 2002 09:52:39 +0530

Hi,

From: [email-masked]

> In "Mobile IP Draft-17", in section 6.1.8 Binding Acknowledgement (BA)
> Message:  it is
> mentioned that No routing header are added to the message, and in
> section 9.4.4 Sending Binding Acknowledgements: it is mentioned that the
> packet, in which the binding acknowledgement is returned, is to be sent
to
> the mobile node at any address other than the mobile nodes home address,
it
> must be sent using a routing header (even if the binding was rejected ).
>
> this creates little confusion ........isn't it ?

I don't understand the reason why the above change (not inserting a
routing header to a BA).  Could anybody explain it?

Since all the packet should be sent with a routing header if the
sending node has a valid bindinc cache, a binding ack should have a
routing header also.  The MN thinks that the sending node doesn't have
a binging cache when it receives a packet without a routing header.
As a result, the MN will send a binding update..  If the MN receives a
binding ack without routing header, it sends a bu again even if the
binding ack indicates that the binding update has succeeded.
Otherwise, we must write a special code to treat a binding ack when
checking the route optimization status when receiving packets.

Regards,

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

Hi
I think in draft nowhere it is mentioned that MN will send BU when it
receives packet without routing header. MN will send BU when it receives
tunneled packet, right ?
And as BA is send to the source address of the BU message and source
address of the BU message is the COA, so for COA there will be no any
binding exist in the Binding Cache as key for searching Binding Cache is
the Home address, so CN will not add routing header.....
but the question is in section 9.4.4 Sending Binding Acknowledgements : it
says routing header must be added.....

Arvind

---

From: Keiichi SHIMA / 島慶一 <[email-masked]>
Date: Wed, 15 May 2002 13:35:03 +0900 (JST)

> says routing header must be added.....

I may have missed something.
I will check the draft and my code.

Regards,

---
Keiichi SHIMA

---

From: Keiichi SHIMA / 島慶一 <[email-masked]>
Date: Wed, 15 May 2002 18:20:11 +0900 (JST)

> receives packet without routing header. MN will send BU when it receives

Yes.  I think the following two are same.

- check if the packet is tunneled like below or not.
  [src:HA][dst:MNCoA]([src:HA][dst:MNHoA](payload))

- check if the packet doesn't have a mip6 routing header like below or not.
  [src:HA][dst:MNHoA](payload)

If the MN receives a packet sent from some address to its home address
without routing header, we can conclude that the peer doesn't have a
binding.  The original idea of this algorithm is presented by Hesham
Soliman on the mobile-ip mailing-list
<[email-masked]>

> the Home address, so CN will not add routing header.....

A BU is sent with a HAO.  It looks that the packet is logically sent
from the home address of the MN.  Since the source address of the BU
is the home address of the MN, the HA will send a BA to the home
address of the MN.  At this point, the HA has a valid binding cache
entry for the MN.  As a result, a routing header will be inserted as a
normal outgoing packet processing.

Am I missing something?

---
Keiichi SHIMA