RE: [mobile-ip] Re: FW: I-D ACTION:draft-tsirtsis-dsmip-problem-0 0.txt

[Soliman Hesham <H.Soliman@flarion.com>]

 > > - half the signalling in the local and home domain
 > 
 > Assuming the signalling is identical enough that they could 
 > be bundled 
 > together, and only one protocol could be used.  I don't 
 > believe this is 
 > the case..

=> Why not? Let's take a simple example:
A dual stack node that wants to be reachable on IPv4
and IPv6 addresses. It gets one v4 and one v6 home 
address. If it uses both MIP versions, every time
it moves it will send two separate messages to its
HA. Even worse, if we try to get a decent handover performance
then another two messages will need to be sent to
routers in the local network. 


 > 
 > > - One mobility management protocol is used.
 > 
 > These mobility management protocols are not interchangeable. 
 >  They have 
 > significant differences.  I do not think it is appropriate 
 > to think that 
 > we could accomplish the functions of one with the other.  If 
 > so, it would 
 > certainly require some (even a great deal of) glue to hold 
 > it together, 
 > and the end result might be even worse than the other alternatives.

=> We're not trying to get the full advantage of each
one, this is a transition mechanism. Just like any
tunnelling mechanism will make you lose some of IPv6's
feature. This mechanism is not a goal, it's a mean to short
term deployment for mobile nodes. 

 > 
 > > - IPv6 Connections survive moving from a dual stack network
 > > to a V4 only network.
 > 
 > Already happens if you enable e.g. 6to4 to gain IPv6 
 > connectivity.  If you 
 > had IPv6 connectivity in the past, but move somewhere where 
 > there is none, 
 > I think surviving the connections is not your biggest worry.

=> What is your biggest worry then? I can't imagine a wireless
operator deploying a service that works sometimes. This is
a key problem to address.

 > > => Only one MIP version is needed. Of course a dual stack
 > > is needed in the HA and MNs but _not_ dual MIP versions.
 > 
 > Which means the one MIP version would have to include all 
 > the features of 
 > the other MIP version because otherwise it would not work?

=> Absolutely not our intention. We're trying to walk first
then run. Meaning, get basic connectivity and handover working
then worry about optimal communication. Like I said above, 
this is a transitional issue, ultimately (I hope) only
MIPv6 will be used and we can get all the benefits.

  I.e., in 
 > practice dual MIP versions but just glued together in one?

=> Not really, George and I are working on two solutions
and we'll publish them soon and hopefully this will
be clarified.

Hesham

 > 
 > -- 
 > Pekka Savola                 "You each name yourselves king, yet the
 > Netcore Oy                    kingdom bleeds."
 > Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
 > 
 >