Subject: [netlmm] Closing the multihoming issue

From: Basavaraj Patil <[email-masked]>
Date: Thu, 11 Oct 2007 00:16:27 -0500

Hello,

After a week of discussion and many many emails, we seem to be
deadlocked on the way forward.

The authors have proposed a solution which addresses the issue of
unmodified hosts attaching via multiple interfaces to a PMIP6 domain.

The proposed solution (abridged version):
- Includes an option which indicates the access type via which the MN
  is attaching to the network and hence provides the LMA with
  additional information
- It is the policy of the LMA which decides the assignment of the
  prefix to an MN attaching via a second interface.
- The prefix assigned to a second interface of the MN can be a unique
  prefix depending on the access tech type indicated in the PBU or it
  can be the same prefix as assigned to a previous interface (policy
  decision) 
- In the scenario where the LMA decides to assign the same prefix to
  the second interface, the LMA waits for a dereg from the MAG serving
  the first interface (which ensures that IF1 of the MN is disabled
  via any of L1/2/3 means) prior to assigning the interface via MAG2
  to the MN.
- The solution does not break the link model that has been decided on
  for PMIP6 or the IPv6 addressing model (details of this have been
  discussed in earlier emails).

The issue as has been raised arises only when the MN attaches via
multiple interfaces to the same PMIP6 domain and is assigned the same
LMA (to which the above solution is proposed). In the case where the MN
attaches via another interface is a different PMIP6 domain from the domain
which serves the earlier interface, the MN is assigned a unique prefix.

We believe that this is a solution that addresses the multihoming
issue and allows unmodified IP hosts to operate with no disruption to
its connectivity. The WG may decide to work on a comprehensive
solution to multihomed hosts in a PMIP6 domain separately in the
future.

I think it is time the chairs made a decision on this issue.

-Basavaraj

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From: Alexandru Petrescu <[email-masked]>
Date: Thu, 11 Oct 2007 11:10:05 +0200

> unmodified hosts attaching via multiple interfaces to a PMIP6 domain.

I will read the Sri's solution separately.

>   prefix to an MN attaching via a second interface.

If LMA is to assign a prefix to MAG for use by MN then it should do so 
with DHCPv6.  Why do you propose something else than DHCPv6?

I don't see why I should read further, in this mail.

Alex

> I think it is time the chairs made a decision on this issue.

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From: "Ved Kafle" <[email-masked]>
Date: Thu, 11 Oct 2007 18:34:33 +0900

Hi Raj,

Find my comment inline.

> -----Original Message-----
> From: Basavaraj Patil [mailto:[email-masked]] 
> Sent: Thursday, October 11, 2007 2:16 PM
> To: [email-masked]
> Subject: [netlmm] Closing the multihoming issue
> 
> 
> 
> Hello,
> 
> After a week of discussion and many many emails, we seem to 
> be deadlocked on the way forward.
> 
> The authors have proposed a solution which addresses the 
> issue of unmodified hosts attaching via multiple interfaces 
> to a PMIP6 domain.
> 

This assumption that the MN disables its one interface for being
connected through another interface is not realistic. An unmodified
multihomed MN does not inform the MAG serving the first interface, hence
the MAG can not send a dereg to the LMA.

- Ved Kafle

> The issue as has been raised arises only when the MN attaches 
> via multiple interfaces to the same PMIP6 domain and is 
> assigned the same LMA (to which the above solution is 
> proposed). In the case where the MN attaches via another 
> interface is a different PMIP6 domain from the domain which 
> serves the earlier interface, the MN is assigned a unique prefix.
> 
> We believe that this is a solution that addresses the 
> multihoming issue and allows unmodified IP hosts to operate 
> with no disruption to its connectivity. The WG may decide to 
> work on a comprehensive solution to multihomed hosts in a 
> PMIP6 domain separately in the future.
>

---

From: "Ahmad Muhanna" <[email-masked]>
Date: Thu, 11 Oct 2007 17:10:39 -0500

Hi Raj,

I support your proposal and closing this issue and moving forward.
Although, I have some optimization comments inline.

Regards,
Ahmad

> Sent: Thursday, October 11, 2007 7:16 AM
> To: [email-masked]

[Ahmad]
Since the issue only surface during initial registration only (initial
P-BU), LMA can identify the MN BCE using the MN-ID + Access type. I do
not believe that we need to have Interface ID included at all.

>   prefix to an MN attaching via a second interface

[Ahmad]
Most access technologies is able to differentiate between handoff and
initial registration scenarios. This handoff indication can be available
to the MAG. MAG can include an indication to the LMA in the same option
which include the access type if the registration is due to a handoff
scenario. That in addition to LMA policy will make the solution more
reliable and efficient. Not only that but this way we are customizing
the solution to work as efficiently as the access technology is capable
of. i.e. Access type and handoff indication are sent in the same option
+ LMA local policy makes a very reliable solution!

>   via any of L1/2/3 means) prior to assigning the interface via MAG2

[Ahmad]
In case of having the optimization proposed above, when LMA receive an
indication from the MAG that registration is due to handoff, LMA can
assign the same prefix and does not need to wait for a de-registration
from the pMAG.

> LMA (to which the above solution is proposed). In the case where the 
> MN attaches via another interface is a different PMIP6 domain from the

> domain which serves the earlier interface, the MN is assigned a unique

> prefix.
> solution to multihomed hosts in a

[Ahmad]
I believe we have a solution and it is time to close this issue and move
forward.
> -Basavaraj> >

---

From: Jari Arkko <[email-masked]>
Date: Sat, 13 Oct 2007 11:59:52 -0500

Basavaraj,

I think this solution is promising. There are some
details to work out, but you are on the right track.

Jari