Re: comments on draft-larsson-v6ops-mip-scenarios-00.txt

[Henrik Levkowetz <henrik@levkowetz.com>]

on 2004-11-19 9:37 pm Pekka Savola said the following:
> On Fri, 19 Nov 2004, Henrik Levkowetz wrote:
>> on 2004-11-19 9:03 pm Pekka Savola said the following:
>>>> => And? Actually, HMIPv6 has this feature already. So it's not
>>>> entirely new to MIPv6.
>>>
>>> This doesn't help because it seems to be kind of using stateless
>>> address autoconfiguration mechanisms, so it's entirely dependant on
>>> v6.  You cannot deploy similar technology for v4.
>>>
>>> With v4, at least (and possibly with v6, depending on the solution),
>>> the home agent will have to keep some DHCP-like "address pool".
>>> Putting that code in the MIPv6 HA function is a non-trivial exercise.
>>
>> Actually, MIP4 simply defines the protocol for delivering the dynamic
>> address to the mobile node.  Whether it is handled by the HA through
>> an address poll, through interaction with a DHCP server etc, isn't
>> defined.
>>
>> People have implemented several different solutions, which all work;
>> this is good, and I don't see why we in discussing a draft laying out
>> the playing field have to go into details which hasn't even been
>> specified by the base protocol (in the MIP4 case) ??
> 
> Because adding v4 address assignment to MIPv6 is a relatively weighty 
> operation; whether the code or even specification already exists for 
> _MIPv4_ seems irrelevant.  MIPv6 just hasn't been designed with 
> address assignment, and stateful address assignment by the HA in 
> particular, in mind.  If a particular solution would force one to 
> specify and implement something like that on MIPv6 HAs, some people 
> might get excited.

Hm.  I worked on the MIP4 address assignment code in the ipUnplugged
HA, and did the dhcp-client part which we used to get the addresses.

I really can't see that what you say here makes sense as a big and
heavy thing from an implementation viewpoint, and especially not it
being relevant until we get to a specific problem statement.  Do you
have any particular implementation knowledge which makes you say this?

> The same applies, possibly to a lesser degree, with MIPv4. 'Lesser 
> degree' because IPv6 assignment can be stateful while IPv4 assignment 
> cannot. 'Possibly' depending if some spec already existed how exactly 
> to do it; Hesham seems to be saying yes, you seem to be saying no.  I 
> guess this means implementation(s) exist but the spec does not.

Hesham may be right, I don't know MIP6 as well as I do MIP4.  But
I still think this is a way, way smaller issue than you seem to
think it is...

	Henrik