Subject: [mobile-ip] Suggested revisions to HMIPv6

From: Charlie Perkins <[email-masked]>
Date: Fri, 16 Mar 2001 15:27:15 -0800

Hello folks,

Here are some suggestions about possible revisions to the
HMIPv6 draft that merit consideration.

- Discussion about smooth handovers (e.g., section 10) should
  be deleted.  It is not the purpose of a document about
  localizing binding update delivery to do that.

- Load balancing should not be part of HMIPv6.  It does not
  belong, and the particular methods chosen may need to be
  refined independently of the discussion about localizing
  the delivery of binding updates.  So, for instance, the
  'L' bit should be eliminated.

  So, for instance, we may wish to have load balancing in
  domains that do not implement any regionalized bindings.
  Separation of concerns is important.

- There should be only one kind of care-of address, and it
  should belong to the node which makes the address look
  topologically correct.  Thus, a mobile node SHOULD NOT
  have an address on the MAP's subnet, unless of course
  the mobile node is running applications that appear to
  be attached to that network.

  I think this means that the "basic mode" should be
  deleted.  Even without the abovementioned considerations,
  it is an unnecessary complication to have two modes of
  care-of address management for the mobile node.

- If, as just mentioned, basic mode is deleted, then
  HMIPv6 suggests modifications to the operation of the
  home agent.  These modifications should be avoided.

- MAP advertisements should not have preference values.
  The use of preferences is very fragile in any sort of
  dynamic situation such as is described within the HMIP
  draft.

- Using router renumbering for establishing MAP discovery
  techniques is highly speculative.  Creating a new message
  type greatly diminishes the claim of re-use of existing protocols.

- The 'T' bit for the Neighbor Discovery extension is either
  confusing, or should be eliminated (or both).

- How often does the 'M' bit force the mobile node to re-register
  with its home agent?  Presumably, not every time the
  advertisement is received.

- In section 7, the HA should not be tunneling things to
  the mobile node's site-local address.

- In section 7.3, mention about policy restrictions should
  be deleted.  This would also include discussion about
  authorization.

- Contrary to the statement in section 13.1, there are
  benefits to having multiple "levels" of care-of address
  locality.

- Section 15 should be deleted.

- There should be a very clear statement, perhaps in an
  appendix, about exactly which parts of the protocol
  specification are covered by Ericsson patents.

Regards,
Charlie P.

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From: Claude Castelluccia <[email-masked]>
Date: Sat, 17 Mar 2001 14:49:50 +0100

Hello Charlie,

>   localizing binding update delivery to do that.

I don't understand why? Why don't you need to worry about smooth
handovers between MAPs? We actually usually standard MIP mechanisms..
this section just clarifies how to use it in the context of HMIPv6....
we should
keep it...

>   Separation of concerns is important.

you are right but HMIPv6 (because of the MAP makes it easier
and more efficient....

> - There should be only one kind of care-of address, and it

why ? we propose 2 kinds of CoA for different purposes/applications....
Both modes have their own pros and cons (see section 8 for more
details...)..

>   be attached to that network.

why? Why can't you use an address belonging to the MAP's subnet?

Could you be more specific and give technical reasons...

>   care-of address management for the mobile node.

both modes are very useful as explained in the draft...if you remove one
of the
modes you just weaken the proposal...unless you give us valid technical
reasons I
will suggest to keep both modes...

>   advertisement is received.

of course not..only once and then periodically like in MIPv6...

> - Section 15 should be deleted.

In the last version of the draft, Section 15 is the acknowledgements
session...
do you actually mean to delete it ;-)

>   specification are covered by Ericsson patents.

I'll let Hesham or Karim answer this point...

Thanks Charlie for your comments eventhough I am not convinced about
their
technical validity (or you need to be more precise ...) ...

regards,

Claude.

--

----------------------------------------
Claude CASTELLUCCIA, INRIA Rhone-Alpes
ph:  +33 4.76.61.52.15 (fax: 52.52)
http://www.inrialpes.fr/planete/

---

From: Erik Nordmark <[email-masked]>
Date: Mon, 19 Mar 2001 19:27:49 +0000 (PST)

Hi Charlie,

> HMIPv6 draft that merit consideration.

Seems like a fair number of your suggested changes have to do
with disagreement about the problem statement.

Does the WG have a written and agreed upon problem statement for
handover?

  Erik