Subject: [Mip6] Some comments on draft-ietf-mip6-dsmip-problem-00.txt

From: [email-masked]
Date: Tue, 18 Oct 2005 08:37:26 +0300

George & Hesham,

A couple of points on the draft:

> 2.4. The impossibility of maintaining connectivity
>
>   A final point to consider is that even if both mobility protocols
are
>   supported by a mobile node seamless connectivity would not in fact
be
>   guarantied since that also depends on the IPv4/IPv6 capabilities of
>   the networks the mobile is visiting i.e.: a dual stack node
>   attempting to connect via a IPv4 only network would not be able to
>   maintain connectivity of its IPv6 applications and vice versa.

I guess the section title should really be 'The Impossibility of
maintaining
seamless connectivity.' Of course the mobile node can still be connected
to the network, but session continuity make break for some applications.

> 3. Conclusion and recommendations

I found this section a bit weak.  The document does discuss the problem
space quite well, but it seems like you jump into the bulleted list
seems
like you've jumped to conclusions.  I don't necessarily disagree with
the
points, but I think some additional text is needed with some analysis
why those bullets would be useful. I think the overall point you are
making is
that you want to make the MIP signaling to be IP version agnostic, so
that
a Mobile Node can HoAs independent of the MIP version used for
signaling.
The other point of having an single CoA (v4 or v6) seems a bit more
fuzzy 
for me, so I'd like a bit more background on what you are exactly
getting 
at.  From a certain perspective, it sounds like you want to make a sort
of
Mobile IP relay, but it isn't entirely clear to me.

thanks,
John

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---

From: "Soliman, Hesham" <[email-masked]>
Date: Tue, 18 Oct 2005 12:36:02 -0400

Hi John,

 > to the network, but session continuity make break for some 

=> That's true. We were talking about IP connectivity, which, in a 
mobile environment is practically non-existent if you're not 
reachable on your home address. But I agree that the wording can be 
made clearer.

 > that you want to make the MIP signaling to be IP version agnostic, 

=> Yes. 

   so
 > a Mobile Node can HoAs independent of the MIP version used for

=> Yes.

 > at.  

=> Basically, we are trying to highlight two problems that result from
tying MIP to a particular IP version/address family:

A. One home address cannot be used all the time. 
B. The MN-HA tunnel cannot be established if the MN is located
in a network that doesn't support the IP version associated 
with MIP. I.e. MIPv6 cannot setup an MN-HA tunnel in an IPv4-only
network and the same goes for MIPv4. 

The two points above lead to the need for an IP version agnostic
MIP that can handle IPv4/v6 home addresses, as well as, IPv4/v6
CoAs. And the different permutations of both.  
We'll try to do a better job in the conclusions section to reflect
that.

   From a certain perspective, it sounds like you want to 
 > make a sort

=> Not at all. We still want to keep MIP e2e. You'll soon
see the DSMIPv6 solution and hopefully MIP4 will go in a similar
direction. 

thx, 
Hesham

 > John

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