Subject: [MOBILE-IP] Changing networks - Learning new prefixes ?

From: Jeroen Van Beirendonck <[email-masked]>
Date: Tue, 9 May 2000 20:31:18 +0200

Hello,

I'm having a bit of trouble understanding the Mobile IPv6 protocol as
stated in the current
draft. Is there anyone that could help me with these questions ? :

The draft clearly states that it isn't a fault that routers on the same
network may advertise different prefixes.
But if a mobile node that starts on it's home link, can NEVER be sure that
it has gotten ALL prefixes
from all available routers that it should consider on-link, how can it
detect then the fact that it has moved
to a different link ? Because it it is allowed (for e.g. wireless links) to
be in transmission range
of different routers serving on different links, she can get RA's from both
routers, but the
fact that the prefixes are different can't make her decide that they are on
different links ...

Is the mobile node supposed to keep a seperate prefix-list of all valable
home subnet prefixes ?
That is if it is able to get a 100% complete & certain list of that ?

thanx,

Jeroen Van Beirendonck
Computer Science Student
UIA University, Antwerp
Belgium
email : [email-masked]

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From: "Hesham Soliman (EPA)" <[email-masked]>
Date: Wed, 10 May 2000 10:51:15 +1000

> fact that the prefixes are different can't make her decide that they are
        Receiving RAs with new prefixes should not be an indication of
movement. However receiving new prefixes combined with the fact that your
default router has disappeared IS in fact an indication of movement. Of
course you can easily find out if your default router disappeared or not by
probing its link local address.