Subject: [netlmm] Review of PMIPv6-MIPv6 Interworking Docs

From: Christian Vogt <[email-masked]>
Date: Fri, 04 May 2007 12:24:38 +0300

There are currently two documents [1, 2] describing different
PMIPv6-MIPv6 interworking scenarios and one document [3] focusing on
interworking issues:

  [1] devarapalli-netlmm-pmipv6-mipv6
  [2] giaretta-netlmm-mip-interactions
  [3] weniger-netlmm-pmipv6-mipv6-issues

I think these documents do a good job in analyzing the matter at hand.
Two comments, though:

(1)  IMO it would be good to more clearly explain the overhead involved
in different interworking scenarios, specifically WRT to (possibly
nested) payload packet tunneling.

(2)  One additional interworking scenario that I could think of is where
a MN moves between two PMIPv6 domains, one of which (domain A) comprises
the MN's home network, while the other (domain B) is a foreign network.
 The LMA in domain A is in this case colocated with the HA and it
provides the CMIPv6 home address.  Domain B provides a (regional)
care-of address from the perspective of CMIPv6.  The MN is at home while
in domain A, although it has a transparent registration with domain A's
LMA at that time.  When moving to domain B, the MN registers a binding
with its HA in domain A in addition to the transparent binding at domain
B's LMA.  This is one way of realizing inter-domain roaming.

Regards,
- Christian

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From: Ashutosh Dutta <[email-masked]>
Date: Fri, 04 May 2007 07:46:25 -0400

Christian, yes, I think we should consider inter-domain roaming scenario 
  for both types, a) When client is equipped with CMIPv6 and b) When 
client is not equipped with CMIPv6.

Thanks
Ashutosh

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From: Christian Vogt <[email-masked]>
Date: Fri, 04 May 2007 16:24:05 +0300

> Christian, yes, I think we should consider inter-domain roaming
> scenario for both types, a) When client is equipped with CMIPv6 and
> b) When client is not equipped with CMIPv6.

Hello Ashutosh,

the scenario you are having in mind is actually an additional one:
Roaming between administratively separate PMIPv6 domains without the use
of CMIPv6 on the MN.  In this case, the foreign PMIPv6 domain advertises
the MN's home address just like the home domain.  So from the
perspective of the MN it makes no difference which domain it attaches to
(barring possibly some higher roaming charges in the foreign domain).

The above scenario is actually not an PMIPv6/CMIPv6 "interworking"
scenario, but in any case I very much agree that it is important.  In a
sense, the scenario is very similar to how roaming is done in today's
cellular networks.

Best,
- Christian

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From: "Vijay Devarapalli" <[email-masked]>
Date: Fri, 4 May 2007 10:53:08 -0700

Hi Christian, 

> -----Original Message-----
> From: Christian Vogt [mailto:[email-masked]] 
> Sent: Friday, May 04, 2007 2:25 AM
> To: Netlmm
> Subject: [netlmm] Review of PMIPv6-MIPv6 Interworking Docs
> 

We briefly touch upon this. From draft-devarapalli-netlmm-pmipv6-mipv6

   When the mobile moves away from its home domain and enters another
   domain where network-based mobility management is enabled, the mobile
   node obtains an address from the new PMIPv6 domain, and uses that
   address as the care-of address for Mobile IPv6 registration.  The
   earlier MN-HoA address is now treated as the MIPv6 home address
   (MIPv6-HoA).  This is similar to the scenario described in
   Section 3.1.

We basically say if the MN moves and enters another domain where
PMIPv6 is enabled, but not emulating the home link, then it
becomes similar to hierarchical use of PMIPv6 and MIPv6.

Vijay

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From: Christian Vogt <[email-masked]>
Date: Fri, 04 May 2007 22:06:16 +0300

Hi Vijay,

yes, you are actually right.

- Christian

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From: "Gerardo Giaretta" <[email-masked]>
Date: Wed, 9 May 2007 05:17:39 +0200

Hi Christian,

how is your scenario different from the scenario C described in our draft?

Gerardo

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From: Christian Vogt <[email-masked]>
Date: Wed, 09 May 2007 10:14:38 +0300

> how is your scenario different from the scenario C described in our draft?

Hi Gerardo,

in scenario C in your draft, the MN moves from a PMIPv6 domain to a
non-PMIPv6 domain.  In the scenario that I was describing, the MN moves
between two PMIPv6 domains, exactly one of which provides the CMIPv6
home address.

The possible scenarios partly appear very similar, and sometimes it is
hard for the reader to see a difference between two scenarios without
re-reading the respective descriptions.  Maybe it makes things a bit
easier if, instead of enumerating all possible scenarios, the
PMIPv6-CMIPv6 drafts would look at the deployment options at a somewhat
higher level.  Maybe something along these lines:

1.  PMIPv6 operation in home domain (PMIPv6_h)
1.1.  PMIPv6_h HoA == CMIPv6 HoA
1.2.  PMIPv6_h HoA != CMIPv6 HoA => PMIPv6_h HoA == CMIPv6 CoA

Co-location of HA and LMA makes sense only with option 1.1.

2.  PMIPv6 operation in visited domain (PMIPv6_v)
2.1.  PMIPv6_v HoA == PMIPv6_h HoA
      => CMIPv6 not needed with 1.1 in home domain, needed with 1.2
2.2.  PMIPv6_v HoA != PMIPv6_h HoA
      => CMIPv6 needed & PMIPv6_v HoA == CMIPv6 CoA

Option 2.1 is a roaming scenario, whereas PMIPv6 operation is
transparent to other domains in option 2.2.

Combine either of 1.1 and 1.2 with either of 2.1 and 2.2.

Best,
- Christian