Subject: RE: [nemo] Re: is global HAHA so complex?

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Thu, 27 Apr 2006 09:42:07 +0200

>> [Pascal] I fail to see why a telephone needs to be multihomed?
>>
>
>4G telephones are multihomed by definition. besides, the end device
[Pascal] 
[Pascal] I am afraid there is some confusion here. I think we were
talking about multiple Home Networks not multiple interfaces on the
phone. In that context, could you please elaborate why 4G phones are
multi-homed by definition? 

>itself does need to be multihomed in order to need ths shim6 support,
>just attaching it to a multihomed network will imply multiple HoAs and
>you need something like SHIM6 to support this...
[Pascal] And if a Home Link fails what happens to the connections from
these non SHIM6 end devices?

>
>> And there are other things you can do than SHIM6 to benefit from
>> multihoming. For instance you can use MIP/NEMO to get back to ISP-B
via
>> ISP-A. While this is hardly a generic multihoming solution, this is
>> acceptable when you are already in the MIP/NEMO context.
>>
>
>no, this doesn't work
>multihoming is about fault tolerance and mip relies in going through
>the HA, (i guess you know this already)
[Pascal] 
[Pascal] Again we are off sync. I meant NEMO can be used similarly to a
good old ISDN call when your direct link to your ISP dies. But, agreed,
nothing can save you if the home link craches. 

>
>So mip and nemo is not enough... so need something else for this, shim6
>or global haha for instance :-)

[Pascal] Back in sync. 
Though I need to read your draft because I do not have a 100 percent
clear view on your proposal. 
I'm not convinced by the answers on my issues (which RO do you get, how
it works with stupid LFN, complexity of having multiple Home prefix on
each phone).

>
>>>
>>>> - And that gives you a very limited RO since you still do not have
>> the
>>>> proxies, which are the real reason why global HAHA improves the
path.
>>>>
>>>
>>> not sure about this one... i mean you can use the closest HA which
is
>>> similar to what you achieve in global HAHA (you could also expose
CoAs
>>> to the LFN, and you would achieve optimal path, but this is other
>>> discussion, i guess)
>>
>> [Pascal] How many prefixes do you have in your MR in the SHIM6
>> approach?
>
>shim6 relies on PA addressing, so you need one prefix per ISP serving
>the home netowrk.
[Pascal] That was not my question. The RO ypu get with this depends on
how close from your location the closest HA is. The SHIM approach needs
one prefix in the MR per such location. So you end up with 1-3
locations, and that does not give you Route Optimization. Distributing
the same Home does better, and multiplying proxies does even better.
That was my point.

>This is so becasue shim6 is gloabl routing table friendly and it does
>not requires additional bgp entries
[Pascal] There a 170K entries in the V4 tables. If NEMO RO is for all
Phones and cars and trucks and planes is obtained at the expense of
1-100 more entries, no one will complain. 

>
>> If you do not get rid of the home link, then that is as many anchor
>> points for MR to reattach. Not even one per continent. I do not call
>> that RO. This is why global HAHA removes the geographical constraint
of
>> the home link.
>>
>
>not sure what your point is here...
[Pascal] See just above. SHIM does not give you any RO. Proxies do.
 
>
>> But there is a long long history in NEMO about requirements (ask
>> Thierry). After that, we went into a long and difficult work on
Problem
>> Statement (RO-PS). And since people had worked on RO for years, we
also
>> compiled the RO SA, solution space analysis.
>>
>> Global HAHA builds on all that and sorry, I do not wish to start
>> over...
>>
>
>I am sorry but we are discussing rechartering at this very moment
>My point is that if we are going to work on a solution we need to agree
>on the requiremetns for that solution and then define the solution. I
>don't we are ready to accept a full fleshed solution like global haha
>that implies at least a liability to the gloabl routing health without
>proper assesment of the requirements that justify the need for that
>specific solution and that other alternatives need to be ruled out.
[Pascal] 
[Pascal] I understand that and would not oppose in general; that'd be
the normal way for a new WG. 

But we are not chartering and starting from scratch, we are
re-chartering to cover an evolution. What I am saying is that the
requirements are pretty much the same as when NEMO was created. We
restrained ourselves to do basic as a protocol while doing only PS for
RO.

If you think we need to evolve the requirements as well then you need to
post to Thierry. The feeling there was that the charter needed polishing
but that the requirements held still.

Pascal

---

From: marcelo bagnulo braun <[email-masked]>
Date: Thu, 27 Apr 2006 11:32:36 +0300

> multi-homed by definition?

Ok, you mean why a telephone may need multiple Home Networks?

Well, i guess that if you have a 4G phone and you have multiple 
provider, you want to be able to be reachable through all the 
providers.

We do agree that is a desired feature to be able to have differetn 
providers for different technologies, right? So that you don't have to 
rely on a single provider giving UMTS, WIFI services for instance.

In this scenario, you probably also want to have a stable address from 
each of the providers, so that you can by pass any of the providers. I 
mean if you are going to have a communication through the WiFI 
interface, you don't want to have to exchange the initial packets and 
the HoTI packets through the UMTS interface, right?

So i really think that it is a very useful feature that 4G phones hame 
multiple Home Addresses associated to different providers and different 
technologies

makes sense to you?

> these non SHIM6 end devices?

shim6 requires support from both peers of the communication, that is 
for sure.

but shim6 is used to provide multihoming support for fixed scenarios, 
so there other reasons that just RO to implement and support the shim6 
(I do agree that the deployment time frames for shim6 and a global HAHA 
solution are different and that shim6 requires modification of more 
devices, but as i already mention, i still not convinced that the 
timing required for this solution is so tight, i mean i haven't heard 
that airlines will provide v6 support anytime soon)

> nothing can save you if the home link craches.

ok, we agree then that mip/nemo approach cannot be used to provide home 
network fault tolerance

> the same Home does better, and multiplying proxies does even better.

well with a shim6 approach you would get as many prefixes as 
distributed locations and you would be able to use the prefix 
associated with the closer location. So you end up suing the HA which 
is closer to the MR. That should provide the same level of RO than 
global HAHA...

> 1-100 more entries, no one will complain.

why do these guys get to pollute the global routing table and others 
don't?
being a small number of entries is not enough justification
what need to be explained is why other solutions that do not pollute 
the global routing table fail to meet the requirements that this 
problem has. hence the need for explicitly flesh out the requirements

> requirements are pretty much the same as when NEMO was created.

so what is the document describing the requirements of gloablly moving 
networks? I mean what is the document that define the requirements for 
the problem that global HAHA is solving and that cannot be solved with 
a solution that does not pollute the global routing table?

I mean, global HAHA is not a general RO mechanism, as i been told, so 
what is the requirements for the specific problem that is being solved 
by global HAHA?

> We

the requirements for what? for RO? for nemo?

i guess nemo is addressed in the basic spec and global HAHA is not a 
general RO mechanism, so i fail to see where are the requirements for 
the problem that global HAHA is solving

rgeards, marcelo