Subject: RE: [Mip6] RR Security and DNS HA Discovery

From: Gerardo Giaretta <[email-masked]>
Date: Thu, 17 Mar 2005 18:45:34 +0100

> Hi Gerardo,
> 
> Gerardo Giaretta wrote:
> >> HA assignment during bootstrapping relates to HAs on same link, I 
> >> hope I'm not wrong on this one.
> > 
> > I'm not sure I got your point. What do you mean by "on same link"? 
> > During bootstrapping, the HA could be assigned anywhere, both in the
> >  visited domain and back in the home domain.
> 
> Oh?  Both in the visited _and_ in the home?  Assigning a HA in a
> different domain at each bootstrap implies that MN is no longer
> reachable at its previously assigned HA's Home Address.  
> After only two
> such alternating bootstraps the MN is no longer reachable at its
> permanent DNS name either (MN bootstrapping is too frequent 
> an operation
> to be allowed to do DNS updates I think).
> 

I meant at each Mobile IPv6 bootstrapping, not at each MN bootstrap.
How often MIPv6 bootstrapping will happen is still an open issue (also
in DT discussion). And it could also depend on provider's policies, IMO.

> Anyways, I think my point was that if the MN is to continue using a
> unique same HoA between bootstraps, the assigned HA should be 
> on a same
> unique link (there may be several HAs on that link, and the 
> assigned HA
> may be any of these HAs).  I think... or I may miss something.
> 

This means (but please correct me if I'm worng) that in your view the MN
performs MIPv6 bootstrapping at each bootstrap, but these bootstrapping
operations do not change the HoA and the home link. If so, how does the
MN discover the new HA? Using DHAAD?

--Gerardo

> Alex

Gruppo Telecom Italia - Direzione e coordinamento di Telecom Italia S.p.A.

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From: Alexandru Petrescu <[email-masked]>
Date: Thu, 17 Mar 2005 19:37:44 +0100

Gerardo Giaretta wrote:
>> Assigning a HA in a different domain at each bootstrap implies that
>>  MN is no longer reachable at its previously assigned HA's Home 
>> Address. After only two such alternating bootstraps the MN is no 
>> longer reachable at its permanent DNS name either (MN bootstrapping
>>  is too frequent an operation to be allowed to do DNS updates I 
>> think).
>> 
> 
> How often MIPv6 bootstrapping will happen is still an open issue 
> (also in DT discussion). And it could also depend on provider's 
> policies, IMO.

Ok, no intention to interfere to DT discussion (DT members: please 
ignore this!).

>>  unique same HoA between bootstraps, the assigned HA should be on a
>>  same unique link (there may be several HAs on that link, and the 
>> assigned HA may be any of these HAs).  I think... or I may miss 
>> something.
>> 
> 
> This means (but please correct me if I'm worng) that in your view the
>  MN performs MIPv6 bootstrapping at each bootstrap, but these 
> bootstrapping operations do not change the HoA and the home link.

Yes, that's what I thought.

> If so, how does the MN discover the new HA? Using DHAAD?

Discovering HA with DHAAD assumes a certain prefix.  DHAAD answers to
"what's the best HA of this prefix"...

So MN can't discover a HA with DHAAD for a prefix in the foreign network
because MN can't be pre-configured with all prefixes it will ever visit.

How would an MN discover a new HA (offering it a new HoA) depends on the
use scenarios, basically answering the question of why would MN need a
new HA in every network it visits.

If the answer if for MN to be able to continuously use a particular HoA
while visiting that foreign network, then HA discovery should happen
just like DHCP Discovery, the HA address could eventually be in the DHCP
Offer, or in the RA.  HMIPv6 comes to mind (RA MAP options, the MAP 
itself, etc.)

The third case - to have the HA address in the DNS - what would the FQDN
associated to this address be?  Something like ha.domain?  Is the
procedure something like: MN obtains the domain name from DHCP, prefix
it with "ha." and then interrogate the DNS?

Sorry for the verbiage, actually I should get updated with the drafts
before posting... I'll check back.

Alex