Subject: [MOBILE-IP] How to determine the Home Address in Mobile IPv6?

From: Florian Heissenhuber <[email-masked]>
Date: Fri, 15 Oct 1999 08:49:45 +0000

How determines a Mobile Node in Mobile IPv6 its home address? Is it
possible to use Address Autoconfiguration or has it to be configured
manually?

If you use Address Autoconfiguration, then it is neccessary for a
mobile system to boot on its home link. Otherwise if the mobile node
comes up on a foreign link, it performs Address Autonconfiguration
and uses the prefix of the foreign link as the prefix for its home
address.

If the home address has to be configured manually, then you loose one
of the benefits of IPv6. But section 9.7 says that Address
Autoconfiguration of the Mobile Node is used in case of renumbering
the home subnet. Hence, Address Autoconfiguration for the home
address of the Mobile Node should be possible.

Thus, how is the home address of Mobile Node configured?

Best regards,

Florian Heissenhuber

---

From: Linfeng Yang <[email-masked]>
Date: Fri, 15 Oct 1999 11:54:48 +0300

> possible to use Address Autoconfiguration or has it to be configured

Since Mobile IPv6 draft does not address this issue, I suppose both method
can be used.
>
> If you use Address Autoconfiguration, then it is necessary for a
> comes up on a foreign link, it performs Address Autoconfiguration
Here as I understand, boot means the procedure performed when you turn on
your computer. But is there a difference between the first time boot and
later time boot (reboot)? I suppose so. I mean first time boot is the boot
you turn on a new computer, there is no any home address record in home
address entry. So with Address Autoconfiguration, you get one. If this is
done in home network, it is fine. But if this first time boot happens to
be done in a foreign network, and later when you reboot in real home
network, you should have possibility to change the care-of address you get
then to home address. Is this one area the author of the draft should
clarify in the later version?

> address of the Mobile Node should be possible.
Another issue here in Section 9.7, if renumbering happened when mobile
node was in foreign network, but mobile node was not turned on, should
home agent continue periodical retransmit the tunneled Router
Advertisement? Is it wise to put some time limit here? I remember in early
version of draft, it is required for mobile node to send Binding Update to
home agent whenever it turned on the power, but I couldn't find it in
latest version. Maybe I remembered wrong, but it seems necessary to do
this Binding Update. If this is the case, then home agent could return
Binding Request at this time.

> Thus, how is the home address of Mobile Node configured?
Maybe I raised more question than answered yours :-)

> Florian Heissenhuber
Best Regards,

Linfeng Yang
http://www.tcm.hut.fi/~lyang/

---

From: Francis Dupont <[email-masked]>
Date: Fri, 15 Oct 1999 11:22:52 +0200

In your previous mail you wrote:

=> the only reasonnable choice is a manual configuration.

   If you use Address Autoconfiguration, then it is neccessary for a
   mobile system to boot on its home link.

=> then my answer.

   of the benefits of IPv6.

=> in fact only the home prefix is needed but this doesn't change
the issue...

   But section 9.7 says that Address Autoconfiguration of the Mobile Node
   is used in case of renumbering the home subnet.

=> if the Mobile Node is connected during the home subnet renumbering
then it is possible to update the home address configuration...

=> manually because only the user knows if the node is at home or in visit
and in the second case what is the home prefix (needed for the home
address and home agent discovery...): zero config can't work.

Regards

[email-masked]