Subject: RE: About route aggregation in global HAHA(was Re:draft-thubert-nemo-global-haha-01.txt (was:[nemo] Charter proposal)

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Sun, 16 Apr 2006 10:06:29 +0200

>> well, we still need to inject one bgp route per distributed
>> home network, right?
>
>I think I'm getting confused on the terminology.  I tried going back to
the nemo-terminology draft
>but that didn't help...  :(

[Pascal] This one comes from HAHA. HAHA removes the home link centric
behaviour which attaches home to a link. Some home is now distributed,
but it is still one Home (one SP say) as opposed to a consortium formed
by the aggregation of ISPs.

>
>We need to inject at least 1 BGP route.  Theoretically all mobile nodes
could be aggregated into a
>single route, however that isn't likely.  The best case that I see
happening is an aggregated prefix
>per "mobile-network operator".  Where a "mobile network operator" is
responsible for the provisioning
>an providing service to a large number of mobile platforms.
>
>Make sense?
>
[Pascal] Well, the hope is to find a place somewhere between the 2,
closer to the one route model, for a large consortium of SPs. In the
best case, that single route is advertised ubiquitously, from all
accesses to a second, parallel Internet, dedicated to mobility.

In that parallel Internet, you find BGP between SPs, and maybe between
sites of a distributed Home, though the latter can also be IGP. Those
routes are injected in the traditional sense, and refer to Homes, which
are not mobile. But they do not leak to the main Internet.

And you find NEMO for route projection. This happens between a proxy HA
and either a HA or another proxy. In that model, the route is just sent
to where is it is needed, over a tunnel that is built on demand. NEMO
basic already uses route projection, and HAHA is widening the scope.
Projected routes do not leak at all (a proxy does not redistribute a
projected route it got from another proxy). 

>>
>> >
>> ...
>> >
>> > Third, if the two ISPs are tightly linked together somehow (because
>> > they advertise same /32) then it would be sufficient for
>> them to run
>> > route updates between them to point exactly where the /48 is, thus
>> > avoiding core-BGP injections _and_ Mobile IP tunnelling.
>> >
>
>Advertising BGP routes between providers certainly is an option, but
the complexity can really grow
>when there are more than two providers.  My concern about that is that
you are now seperating the
>mobility signalling between the NEMO and BGP.  It seems like it would
be easier operationally if your
>mobility signalling was in one protocol not two.
>
[Pascal] Agreed. It is difficult, almost impossible, to configure
similar rules in 2 protocols, so we can not expect to see parallel
sessions in BGP and NEMO. But maybe, if they happen between different
set of peers having different set of policies, it could happen; and
establishing BGP sessions on the fly between proxies might be a bit of
overkill. 

Anyway, global HAHA describes a model, it does not force you to use NEMO
signaling, though it proposes one because sometimes it can be mush
simpler and more efficient that way.

>>
>> good point,
>>
>> basically if the aircraft already knows what ISPs it will be
>> visiting and it has some commercial arrangement with it, it
>> is likely that the ISP can accept routes from the aircraft
>> when it is visiting, so no mobile is required whatsoever
>>
>> I guess that the bottom line is that the trust/commercial
>> model in the case of an aircraft visiting an ISP is different
>> from the one assumed in mobile IP. I mean, i guess we can
>> assume a much more higher level of trust between the aircraft
>> and the visited ISP, so that route injection is an option (we
>> can see that from boeing presentation, i guess)
>>
>
>I can see there being a higher level of trust as you describe.  Route
injection could be an option.
>I don't necessarily think that is the best option though.  Route
injection similar to what we are
>doing today requires a high level of integration between ISPs.
>
>
>Andrew
>
[Pascal] Note that route projection is a bit different. 

Initially, proxy trusts HA (and other proxies), and MR's HA trusts MR.
MR binds to proxy which binds to MR's HA. As part of that flow, MR's
credentials and ownership on MNP can be verified by proxy as part of the
binding to HA. Now proxy trusts MR for its ownership of MNP.

If the same thing happens to that other MR and the proxies can find and
trust each other, then proxies can project to each other the routes to
the MNPs of their respective MRs. Those routes are never injected
anywhere.

This makes the trust model significantly simpler than if the route had
to we injected and accepted all the way through between the proxies.
Also route projection does not have the scalability issues that we see
with route injection.

Pascal