Subject: RE: [Monami6] Simultaneous location in home and foreign

From: "Soliman, Hesham" <[email-masked]>
Date: Thu, 1 Dec 2005 11:27:33 -0500

> I am concerned about the issue which is described in 6.2.3
 > (Simultaneous location in home and foreign networks) of
 > draft-montavont-mobileip-multihoming-pb-statement-05.txt.
 > In order to achieve the goals of Monami6. even if when a MN is
 > connected to both Home and Foreign networks, I think that a 
 > HA should be 
 > able to be aware of the existence of multiple paths to the 
 > MN including 
 > the path to the MN's interface connected to the home network because
 > this is necessity for allowing the HA to initiate a change of 
 > forwarding destination.
 > 
 > With regard to this issue, one available method is that a MN creates 
 > CoA(home CoA) at a home network and assigns it to the interface
 > connected to the home network so that it can register it as new 
 > forwarding destination in addition to other forwarding destinations 
 > for the interfaces connected to a foreign network and also a HA can
 > maintain multiple paths to the MN. 
 > Any thoughts on this?

=> I think it's an important issue and will definitely address it
in the final solution. However, I don't think we can/need to create a 
"home CoA". We might be able to get away with specifying in the signalling
that only the flows explicitly specified should be forwarded to the 
CoA, otherwise, they should be forwarded using normal routing. 

Hesham

 > 
 > Regards,
 > Keigo
 > 
 > 
 > 
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 > Monami6 mailing list
 > [email-masked]
 > https://www1.ietf.org/mailman/listinfo/monami6
 > 

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---

From: Benjamin Koh <[email-masked]>
Date: Fri, 02 Dec 2005 09:38:57 +0800

Hi!

Replies inline.

> CoA, otherwise, they should be forwarded using normal routing. 

[BK]
>From what I understand in the MCoA draft, when the primary interface
returns home, all bindings are deleted. In that case how does the HA
know to forward the traffic to a CoA rather than simply assume that the
MN is at home (or can the HA even receive the incoming traffic assuming
that it is
not the default home router)?

Regards,
Ben

---

From: Benjamin Koh <[email-masked]>
Date: Fri, 02 Dec 2005 09:03:22 +0800

Hi!

[BK]
returns home, all bindings are deleted. In that case how does the HA
know to forward the traffic to a CoA rather than simply assume that the
MN is at home (or even receive the incoming traffic assuming the HA is
not the default home router)?

Regards,
Ben

---

From: Vidya Narayanan <[email-masked]>
Date: Fri, 2 Dec 2005 18:17:39 -0600

> not the default home router)?

I think this topic came up in discussion once prior to the last IETF.
I don't think that the other CoAs should be deleted when one of the
interfaces is "home". It would be much better to either allow the MN
to choose to "suspend" the CoAs or still keep using them as needed.

Vidya

---

From: Keigo Aso <[email-masked]>
Date: Mon, 05 Dec 2005 10:39:19 +0900

Hello,

On Fri, 02 Dec 2005 18:17:39 -0600

> to choose to "suspend" the CoAs or still keep using them as needed.
I think the method to maintain multiple paths to the MN ,like
"suspend" method, is effective for the MN because 
this will allow the MN to not have to register all the CoAs again.
However, when changing the path from the interface conntected to
home network to the interface conntected to foreign network,
I think HA-initiate change is difficult because the MN has to stop 
using the HoA at home link in order to allow the HA to start to 
intercept the packets destined to the HoA at home link.

Regards,
Keigo

---

From: Vidya Narayanan <[email-masked]>
Date: Mon, 5 Dec 2005 21:13:36 -0600

> this will allow the MN to not have to register all the CoAs again.

Yes, this is the intention.

> intercept the packets destined to the HoA at home link.

I think this is very topology dependent. In some topologies, this is
feasible, while in others, it is not. But, I don't think it matters -
if the HA has some policies set for each CoA, it can act according to
the set policies.

Vidya

---

From: Keigo Aso <[email-masked]>
Date: Wed, 07 Dec 2005 10:16:02 +0900

Hello,

Thank you for your comments.
Please find my comments inline.

On Mon, 05 Dec 2005 21:13:36 -0600

> if the HA has some policies set for each CoA, it can act according to
IMHO, I think this is relevant to the behavior of MN and HA at
home network.
When the MN uses the interface connected to the home network,
it can assign the HoA to the interface by requesting the HA 
to stop proxy Neighbor Discovery. In this situation, the MN-initiate
change from home to foreign is workable, however, 
I think the HA-initiate change from home to foreign is difficult 
because it has to interrupt the MN's Neighbor Discovery 
on the home network.

Regards,
Keigo

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 09 Dec 2005 03:17:04 +0900

At Fri, 02 Dec 2005 09:38:57 +0800,
> not the default home router)?

There are two options in the current draft. See Appendix-B.
One is when MN returns home with primary interface. MN deletes all
bindings.  Second is when MN returns with non-primary IF. MN will
delete binding for the non-primary IF (if it's active on HA) and keeps
other binding.

Note that, if RO is used, MN can utilize multiple paths even if it is
at home.

regards,
ryuji

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 09 Dec 2005 03:25:18 +0900

At Wed, 07 Dec 2005 10:16:02 +0900,
> because it has to interrupt the MN's Neighbor Discovery 

While HA needs proxy NDP for intercepting packets, MN needs to assign
its HoA to the interface attached to the home.  I'm not sure it's
really necessary to change this two during MN being in home. 
If MN really want to get flow at a particular IF at home, it can do RO
and request CN to send packets to the IF. 

You can use BU/BA for MN initiate change. 

regards,
ryuji

---

From: Benjamin Koh <[email-masked]>
Date: Fri, 09 Dec 2005 16:29:22 +0800

Hi!

> delete binding for the non-primary IF (if it's active on HA) and keeps
So the choice is between only using home link (home with primary
interface) and only using foreign link (returns with non-primary IF). In
both cases I'm still not utilising my multiple links to their fullest
potential.

> Note that, if RO is used, MN can utilize multiple paths even if it is
I believe that's only if CN is mobility-aware, if CN is a normal IPv6
node I don't think RO can be used.

Regards,
Ben

---

From: Chan-Wah NG <[email-masked]>
Date: Mon, 12 Dec 2005 13:01:10 +0800

> and request CN to send packets to the IF. 

That is assuming CN is RO-capable.  Plus, you cannot have different
flows from the CN going to different interfaces.  An extension to
multiple CoA registrations that allows simultaneous at home and foreign
would be far more desirable.

/rgds
/cwng

---

From: Benjamin Koh <[email-masked]>
Date: Mon, 12 Dec 2005 17:29:24 +0800

Hi!

> if the HA has some policies set for each CoA, it can act according to

[BK]
While it's true that the importance of HA-initiated changes varies
according to the topology in which it is deployed, I think it's
technically advisable to have a method that will work independently of
topology and orthogonal to the presence or absence of CoA policies.

Regards,
Ben