"T.J. Kniveton" wrote:
>
> [I am crossposting to Mobile-IP since I am throwing in some info about
> mobiles]
> >
> > Also, doesn't the node's stack need to allow for the possibility that
> > when it is powered back on, it is connected to a different link entirely?
>
> Good point. I didn't even get into the problems with mobile nodes. Imagine,
> for instance the following twist:
>
> The mobile node had one global address based on its home prefix. It was
> turned off on July 31st. The mobile's Home Network was renumbered, as
> described in RFC 2461, between August 1st and September 1st. Mappings from
> the old prefix to the new prefix were removed from routers on September
> 15th. The old prefix is dead.
>
> Now the mobile node is turned on, on September 25th, in a visited network.
> It starts receiving router advertisements for the local link. It configures
> a link-local care-of address. It wants to contact its Home Agent to register
> a binding for its care-of address.
>
> "I can't contact my home agent."
> "I can't contact any routers on my home network to do Home Agent Discovery."
> "My cached home address has not expired...but my home network has
> disappeared."
> "Help!"
>
> Hmmm. This could be a problem. I am writing a draft to address possible
> courses of action at this point..unless anyone can provide a good, clear,
> obvious answer.
Are your prefix lifetimes not supposed to be in the same order as the
renumbering period? If your renumbering takes one month, set valid
lifetime to one month for prefixes announces long before the renumbering
phase starts. In this way you won't end up in situations like this.
Next, I wouldn't be sure that a Mobile Node would remember it's home
prefix lifetime if it was switched off.
One requirement that we came up to when writing Mobile IPv6 i-d v13 was
that the Mobile Node must somehow know its home prefix or a DNS name
representing the home prefix or home agents anycast address. How the
Mobile Node learns this is out of scope of the draft. Thus, the upper
layer that provides the Mobile Node with the home prefix in the first
place, must also provide the new renumbered home prefix in cases like
this when the Mobile Node is switched off during renumbering.
/Mattias
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