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Re: [MEXT] About the flow binding charter item

Hi Hesham

Please see my inline response...

BR
Frank
----- Original Message ----- From: "Hesham Soliman" <hesham at elevatemobile.com> To: "Frank Xia" <xiayangsong at huawei.com>; "marcelo bagnulo braun" <marcelo at it.uc3m.es>; "mext" <mext at ietf.org> Cc: "Julien Laganier" <julien.laganier.ietf at googlemail.com>; "Jari Arkko" <jari.arkko at piuha.net> 
Sent: Wednesday, May 20, 2009 11:13 AM
Subject: Re: [MEXT] About the flow binding charter item






On 21/05/09 12:43 AM, "Frank Xia" <xiayangsong at huawei.com> wrote:


Hi Marcelo

Texts are copied here for simplification:

2- whether the information should be sent from the MN to the HA only
or it should also be sent from the HA to the MN and if the
information exchanged in each direction should affect the CoA and/or
the HA address.


IMHO, we should define operation from HA to MN.

A very simple analogy,  there is "Binding Revocation
for IPv6 Mobility", and I think there are the same reasons
to have ""Flow Binding Revocation for IPv6 Mobility"


=> There is nothing in common between a binding revocation message which
tells the MN that it needs to remove a binding maintained by the sender (the HA), and a message that tells the MN to use a particular address for one or more flows where the HA knows nothing about the conditions of the interface 
associated with such address. I don't understand how one can draw the
analogy above. In one case the HA knows everything there is to know, in the 
other the HA knows nothing.


Frank=>I am sorry because I am the one draw the analogy :-)
Just I said before, HA can run Flow Binding based on
previous  MN flow binding operation. HA initiated operation
is just complimentary to your draft which is  MN initiated.





We have some details in our draft
http://tools.ietf.org/id/draft-xia-mext-ha-init-flow-binding-00.txt.


=> It's not about creating messages, it's how they would be used. Creating
messages is easy.

Frank=>You are right.   However,  BU/BA solution is tied to
MN->HA way operation which seems to have some limitation
in some scenario I tried to explain.



Hesham




BR
Frank

----- Original Message -----
From: "marcelo bagnulo braun" <marcelo at it.uc3m.es>
To: "mext" <mext at ietf.org>
Cc: "Jari Arkko" <jari.arkko at piuha.net>; "Julien Laganier"
<julien.laganier.ietf at googlemail.com>
Sent: Wednesday, May 20, 2009 8:04 AM
Subject: [MEXT] About the flow binding charter item



Hi,

There seems to be some discrepancies about the MEXT charter item
regarding the work on flow bindings.
Since the charter is the guide for our work, it would be important to
clarify it, so we can have a unified interpretation of the charter.
Please note that what it is in the charter is not cast in stone, but
it seems to reflect previous consensus and we need good reasons to
change it.

So, the current charter item about flow bindings reads:

- A "Flow/binding policies exchange" solution for an exchange of
policies from the mobile host/router to the Home Agent and from the
Home Agent to the mobile host/router influencing the choice of the
Care-of Address and Home Agent address. The solution involves two
specifications, one for the policy format and another for its
transport [both Standard Track].

The first problem with this text is the use and interpretation of the
word policy. Since the policy word may have a broad interpretation.
it would be important to make the charter more explicit about the
expected work. We understand that it is the WG consensus that what
need to be exchanged is a solution for the exchange of flow binding
rules.

So, we understand that it would be more explicit to replace the usage
of the expression Flow/binding policies exchange by Flow Binding
rules exchange. Would that reflect with the WG interpretation?

Second, the current charter item explicitly mentions that the
proposed approach must support sending flow binding information from
the MN to the HA and also from the HA to the MN. Moreover, the
current charter talks about influencing not only the selection of the
CoA but also the selection of the HA address. However, our current WG
document does not supports sending information from the HA and it
does not cover the possibility of influencing the HA address. So, one
possible interpretation of the charter would be that the MN sends
flow binding information to influence the CoA selection and the HA
sends flow binding information to influence the HA address selection.
Other interpretation is that both the MN and the HA send information
regarding both the HA address and the CoA selection.

So, we would like that the WG express their opinion on both items
mentioned above:

1- whether we should replace Flow/binding policies exchange by Flow
Binding rules exchange in the charter

2- whether the information should be sent from the MN to the HA only
or it should also be sent from the HA to the MN and if the
information exchanged in each direction should affect the CoA and/or
the HA address.

Regards, Julien and marcelo


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