Subject: RE: [Mip6] I-D ACTION:draft-ietf-mip6-nemo-v4traversal-00.txt

From: "Soliman, Hesham" <[email-masked]>
Date: Tue, 25 Oct 2005 16:42:02 -0400

> > => Please read the problem statement.
 > 
 > The problem statement mostly says "running MIP4 and MIP6 
 > simultaneously
 > is a burden" and the DSMIPv6 solution looks nothing short of a bigger
 > burden.
 > 
 > Would you please summarize your thoughts in a few lines about why not
 > using MIPv4 for v4 Home Addresses?  If it's not possible to have a 3
 > liner on that for a 30seconds elevator speech I don't think 
 > the problem
 > is valid.

=> Ok, then you don't think the problem is valid. I've summarized all
my thoughts in the problem statement. If you don't want to read it
that's too bad. If you have comments on it (like the one below)
then I'll be happy to discuss them.

 > A good problem shows that something breaks, while the only thing
 > mentioned in the Problem Statement that may seem to break is 
 > the following:
 > > 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.
 > 
 > which is basically presenting an apparent paradox: if both 
 > MIP6 and MIP4
 > are run then no seamless IPv4 and IPv6 connectivity, because an
 > application can't seamlessly switch its stream from v4 to 
 > v6.  Well, an
 > application seamlessly switching its streaming from a v4 
 > socket to a v6
 > socket is something not in the field of MIP I believe, and could be
 > achieved without MIP techniques.

=> I'm afraid you didn't understand the draft. We are working under
the premise that MIP is used to manage mobility. Other techniques
are outside the scope of this draft and this mailing list. 

Based on that, we state that if you have an IPv4 home address and 
you appear in an IPv6-only network you won't be able to maintain
connections using MIPv4 only. Similarly, if you have an IPv6
home address and you appear in an IPv4-only network, then you
won't be able to maintain connectivity to that address using 
MIPv4 as specified today. 

The same goes for CoAs.

 > I've just read.
 > 
 > The problem statement draft is not the problem I know.
 > 
 > I guess you won't agree to the relevance of the problem I know (MIPv6
 > MN, v6 app, connect to v4-only access network), so let me also say I
 > don't agree with the problem statement.

=> ok. 

Hesham

 > Alex

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---

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 25 Oct 2005 22:57:47 +0200

Soliman, Hesham wrote:

>> simultaneously is a burden" and the DSMIPv6 solution looks nothing
>>  short of a bigger burden.
>> 
>> Would you please summarize your thoughts in a few lines about why 
>> not using MIPv4 for v4 Home Addresses?  If it's not possible to 
>> have a 3 liner on that for a 30seconds elevator speech I don't 
>> think the problem is valid.
> 
> that's too bad. If you have comments on it (like the one below) then
>  I'll be happy to discuss them.

Good then.

>> mentioned in the Problem Statement that may seem to break is the 
>> following:
>>> 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.
>> 
>> which is basically presenting an apparent paradox: if both MIP6 and
>>  MIP4 are run then no seamless IPv4 and IPv6 connectivity, because
>>  an application can't seamlessly switch its stream from v4 to v6. 
>> Well, an application seamlessly switching its streaming from a v4 
>> socket to a v6 socket is something not in the field of MIP I 
>> believe, and could be achieved without MIP techniques.
> 
> the premise that MIP is used to manage mobility. Other techniques are
>  outside the scope of this draft and this mailing list.
> 
> Based on that, we state that if you have an IPv4 home address and you
>  appear in an IPv6-only network you won't be able to maintain 
> connections using MIPv4 only.

Absolutely.  Note though that the urgency of a solution for this
scenario is much lower than the urgency of a solution for a v6 MN
connecting to a v4-only network, simply because there are much more
v4-only wireless access networks (than v6), no?

> Similarly, if you have an IPv6 home address and you appear in an 
> IPv4-only network, then you won't be able to maintain connectivity to
>  that address using MIPv4 as specified today.

Absolutely.  And this scenario is more urgent to be solved.

And the two scenarios lead to the immediate question: why not running
both MIP4 and MIP6 on the mobile, so that when it connects to the
v4-only access it uses MIP4 and when it connects to the v6-only access
it uses MIP6.  This would not solve the second scenario you've described
above, though, but it would solve the problem of "MIP6 node on v6
network" and the problem of "MIP4 node on v4 network".

I hope the answer is not 'because it is a burden'.  Running both MIP4
and MIP6 on a same MN should break something, which we could identify
and try to solve.  Currently it doesn't break anything, no?

Alex