Subject: [mobile-ip] Sub: Identifying link changes

From: [email-masked]
Date: Tue, 18 Jun 2002 15:25:03 +0530

Hi all,

Consider the case where MN is in a foreign network, which has 2 default
routers.
Each router, advertises 2 global unicast address prefixes. Hence there are
4 global networks on a single link.

Consider that one of the default router becomes unreachable. So, MN
switches to the next default router. Here, MN considers the router change
as network change and sends BU to the Previous network's HA, which is
nothing but the HA in the same link as MN is currently in. This BU will be
sent with 'D' bit set. HA will perform DAD which will be a problem since MN
is also on the same network.

Is there any other way of identifying the link changes, to avoid sending BU
to HA on the same link where MN is currently in.

Thanks
Srinivasan

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From: Jari Arkko <[email-masked]>
Date: Tue, 18 Jun 2002 14:11:12 +0300

> to HA on the same link where MN is currently in.

First, is this a legal or useful scenario? Since the MN is still on the
link, it would be receiving packets destined to it even at the old care-of
address. Of course, if the old router does not work at all any more, then
the MN would not get its packets. But if it doesn't work e.g. due to a
connectivity failure, wouldn't it also be unable to forward the packets using
MIPv6?

But if this is a useful scenarion, then the MN could leave the D bit to zero.
There is no text in the current draft, however, to describe this particular
reason for leaving it to zero.

Jari