Subject: RE: Source Address Selection (was Re: [nemo] crossover tunnel....)

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Tue, 2 Sep 2003 10:58:55 +0100

> -----Original Message-----
> From: Jongkeun Na [mailto:[email-masked]]
> Sent: mardi 2 septembre 2003 11:14
> To: Pascal Thubert (pthubert); 'Vijay Devarapalli'
> Cc: [email-masked]
> Subject: RE: Source Address Selection (was Re: [nemo] crossover
tunnel....)
> 
> Thanks for your explanation.
> >
> > The remote end may be on the visited link or some hops away. The key
> is whether
> > the route to the remote end is via the MRHA or not. If the route is
> via MRHA, then
> > the home address should be used as the global address on that link,
> that's all I'm
> > saying.
> Yes, I agree. But, how can MR decide to choose it's CoA of visited
link
> to send some packets to a node on some hops away? If MR can be
> configured by static routes, it's possible. However, I don't think
that
> is a thing we really want to find. There is something we should think
> about. There is some benefit if MR can use it's CoA for the outgoing
> connection that has the destination node on global internet, not just
> some hops away. That is because most of applications of Mobile Network
> will be client type except sort of emerging services like VoIP that is
> required to accept an incoming connection. Is there any problem in
using
> it's CoA for outgoing connections? Any difference in doing for nodes
on
> some hops away?

I meant hops away but known by a local routing protocol (eg MANET). In
that case, a routing protocol has injected a best match than whatever
goes via MRHA (usually ::/0). Note that a MR could be configured with a
route via MRHA that's not ::/0 (for instance just your company's
prefix), in which case ::/0 would be via the access router using the
CareOf.

If you mean that packet sourced by MR over MRHA may use CareOf as
source, yes, it's possible but it violates SAS. It may be interesting
for some application in a Mobile Host, but I do not perceive any point
for MRs. I believe that the SAS I described in a generic MN thing, not
just a MR thing. This is what I said at last IETF.

> >
> > The MR has a connected route to the prefix of the CareOf. In your
case
> 2 (LFN to
> > end node in the visited network) the packets will not be routed via
> MRHA because
> > there is a better prefix match. Consequence the packets from the LFN
> will reach
> > the destination. But the end node will not have a route to the LFN
so
> the return
> > connectivity will be broken if there's no MRHA tunnel.
> >
> > We still have to find a solution for that. Maybe some proxy by the
MR,
> or some
> > advertisement of its MNP on the visited link?
> 
> Yes, I agree. There are some points we need to come up with for route
> optimization.
> 

It's a very open question with many options. MR RA's and proxies MNP on
the visited link, MR RA's visited link in MNet and proxies the visited
prefix, etc... We need to think whether we want just one level of
bridging or if we can cover a mobile tree. And to which extend this goes
before global RO (MR-CN tunnel) takes over. I do not think it's a
priority for the WG at the moment, though.

Pascal

---

From: "Jongkeun Na" <[email-masked]>
Date: Tue, 2 Sep 2003 21:29:32 +0900

Please see inline.
> From: Pascal Thubert (pthubert) [mailto:[email-masked]]
> Sent: Tuesday, September 02, 2003 6:59 PM
> To: Jongkeun Na; Vijay Devarapalli
> Cc: [email-masked]
tunnel....)
> just a MR thing. This is what I said at last IETF.

I meant just for local and short-lived outgoing connection and in case
having best matched routes other than MRHA tunnel(default route ::/0). 
I can see your point generally. One comment regarding to SAS, in respect
of MN, we need some sort of user preference about applying or not SAS
for outgoing connection because doing it means no guarantee of session
continuity. In some scenarios with no MRHA tunnel or unreachable HA,
this option maybe helpful to user. In other words, my point is that
applying SAS without considering mobility or user preference would break
the continuity of session for Mobile Node.

/Jongkeun

---

From: "Jongkeun Na" <[email-masked]>
Date: Tue, 2 Sep 2003 21:29:32 +0900

Please see inline.
tunnel....)

/Jongkeun