Subject: [MEXT] Comments on draft-ng-nemo-ce-req-01

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Thu, 06 Dec 2007 01:27:46 +0100

Hi,

	I've read the draft and I have some questions/comments:
- (general comment) I've honestly always have doubts about the
feasibility of real deployments of LMMs. In the scenario described in
the draft, a laptop or WLAN-enabled PDA can break off from the personal
area network and the connect to the Internet on its own. To do that, is
the HA of that node located on the mobile network? If so, given the
particular characteristics of this mobile network (it is a PAN, can
present discontinuos connectivity), the laptop may experience
connectivity problems as that connectivity would depend on the PAN
reachability. If a different deployment is possible (e.g., the HA
located at the Home Network of the MR, not on the NEMO itself), then I'm
fine.

- In the scenario described in Figure 6, how do you LFNs on the Car
Sensors network from configuring an IP address from the MNP of the PAN
and using this as source address for communications with CNs in the
Internet. If the PAN detaches, these communications would break, right? 

- Regarding the requirements, I find some of them vague. For example,
Req2: Low Processing Load, what does "increase the processing load of
the MR significantly" mean? is linear increase with the number of
nodes/communications Route Optimised/etc acceptable? You might consider
also include a requirement regarding signalling load.

- I'd consider adding a requirement regarding modification of
correspondent nodes. Another thing that does not seem completely clear
to me is: to which devices RO should be provided? only LFNs and LMNs or
also VMNs?.

- Do you want to be able to enable RO for some nodes and use plan NEMO
B.S. for others? I think this is called separability in other
requirements drafts.

- For the MR-to-MR optimisation, is there any difference -- significant
for the personal MR scenario -- when the MRs are attached to the same
link vs the general case?

	Well, I might come up with more comments later on.

	Thanks for writing this draft.

	Regards,

	Carlos

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From: Alexandru Petrescu <[email-masked]>
Date: Wed, 05 Dec 2007 17:17:43 -0800

Carlos Jesús Bernardos Cano wrote:
> Hi,
> 
> I've read the draft and I have some questions/comments: - (general 
> comment) I've honestly always have doubts about the feasibility of 
> real deployments of LMMs.

Not sure what you mean by LMM but I also have doubts about deploying
protocols designed to work on paper not according to some user needs.

> In the scenario described in the draft, a laptop or WLAN-enabled PDA 
> can break off from the personal area network and the connect to the 
> Internet on its own.

[You mean Figure 4 "Switching of Roles"?]

> To do that, is the HA of that node located on the mobile network? If
> so, given the particular characteristics of this mobile network (it
> is a PAN, can present discontinuos connectivity), the laptop may
> experience connectivity problems as that connectivity would depend on
> the PAN reachability. If a different deployment is possible (e.g.,
> the HA located at the Home Network of the MR, not on the NEMO
> itself), then I'm fine.

Sorry, if you mean Figure 4, then the intention was to not picture HA at 
all and to not assume Mobile IPv6 at all.  This is something that can be 
fixed by MIPv6, NEMOv6, NEMOV6-RO or something else.  Just the scenario 
is there.

I felt like if I added a HA somewhere then I already made some decision.

If someone feels like adding a HA somewhere then I'd ask which software 
(like when you ask which CN would RO).

> Sensors network from configuring an IP address from the MNP of the 
> PAN and using this as source address for communications with CNs in 
> the Internet. If the PAN detaches, these communications would break, 
> right?
> 
>  Req2: Low Processing Load, what does "increase the processing load 
> of the MR significantly" mean? is linear increase with the number of
>  nodes/communications Route Optimised/etc acceptable? You might 
> consider also include a requirement regarding signalling load.
> 
> correspondent nodes. Another thing that does not seem completely 
> clear to me is: to which devices RO should be provided? only LFNs and
>  LMNs or also VMNs?.
> 
> - Do you want to be able to enable RO for some nodes and use plan 
> NEMO B.S. for others? I think this is called separability in other 
> requirements drafts.
> 
> - For the MR-to-MR optimisation, is there any difference -- 
> significant for the personal MR scenario -- when the MRs are attached
>  to the same link vs the general case?

I think (but will let Chan-Wah clarify) that MR-to-MR optimisation is 
pretty much the same whether vehicle or Personal Area Networks or more 
general case.

Alex

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---

From: Thierry Ernst <[email-masked]>
Date: Thu, 06 Dec 2007 02:27:54 +0100

> pretty much the same whether vehicle or Personal Area Networks or more 

I wouldn't think so. For car-to-car communications, there is a will to 
allow direct MR-to-MR communication (that gets us into a MANEMO type of 
situation) or undirectly via the ARs to which each MR is connected to. 
There are scenarios where both types would be needed simultaneously for 
different types of applications.

I haven't seen that for CE.

Thierry

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Thu, 06 Dec 2007 18:15:04 +0100

Hi Alex,

	Comments below...

> protocols designed to work on paper not according to some user needs.

I wanted to say "LMNs" (Local Mobile Nodes), not LMMs (my mistake).

> [You mean Figure 4 "Switching of Roles"?]

No, I tried to mean the LMN scenario, where a MNN connected to a NEMO
then moves away from the NEMO and becomes a Mobile Node, whose HoA
belongs to the MNP.

> fixed by MIPv6, NEMOv6, NEMOV6-RO or something else.  Just the scenario 

(I didn't mean Figure 4)

> pretty much the same whether vehicle or Personal Area Networks or more 

Well, I guess that in the solution space it might be different, but it
was just a comment.

	Regards,

	Carlos

---

From: Chan-Wah Ng <[email-masked]>
Date: Fri, 07 Dec 2007 01:48:00 +0800

Hello Carlos,

Thanks for the reading and commenting, responses in line.

/rgds
/cwng

> located at the Home Network of the MR, not on the NEMO itself), then I'm

That actually may be a requirement coming out of this scenario.  If the
LMN wishes to enjoy continuous reachability of its address (configured
from PAN's MNP), then there is no choice but for someone in PAN to
perform ND proxy for the LMN when it moves away and forward the packet
to the LMN's current location.  One way to reduce the reliance on the
PAN's reachability is for HA of MR to become the HA of LMN, and MR to
perform ND-Proxy on the NEMO link.  But that is treading into solution
space.

> Internet. If the PAN detaches, these communications would break, right? 
Right.  So, in my first draft, I just write the scenario where the two
network are actually inter-nested within each other instead of merged.
However, in Chicago, most of the comments are that it should be a merged
network.  That's why I included that scenario, but I don't see a
compelling use case for that, unless the future of in-car sensor network
are all going to be all wireless (eg W-USB).  As I see it now, the PAN
is using wireless, the car sensors are using the CAN wired network.
They would be disjoint.  Perhaps the car industry people would like to
provide some insight?

> also include a requirement regarding signalling load.

Sure.  I will try to provide more numbers in the next version.  However,
as a thought experiment, the CE industry largely wants RO for better
quality AV streaming.  So, I would expect the signaling load to a, say,
typical H.263/4 stream.  For instance, if a hypothetical RO solution
required MR to include signaling for every data packet, that is
unacceptable.

> correspondent nodes.

I would not :).  Consumer electronics industries is changing at a rapid
pace.  How long did you use your last handphone/laptop?  3 years? 2?  I
know of people who upgrades their phones every year.  CN modification is
not a concern.  Plus, most of the scenarios indicate a strong need for
RO with MR-to-MR communications, much less MR-to-CN.

>  Another thing that does not seem completely clear
I think there are some text in the use case scenario that rule out VMNs.
Most users will not allow VMN in their PANs.  RO will be provided to any
nodes that needs it.

> B.S. for others? I think this is called separability in other

Yes, I will add that in the next version.
> link vs the general case?

What do you mean by "general case"?  As in for Avionics, Car, and CE
industries?  If so, then there is a big difference.  Most use cases
indicates a strong need for MR-to-MR optimization in CE, whereas not so
in avionics.  For car industry, as Thierry pointed out, the c2ccc has
defined their own layer 2 manet-like route optimization for car-to-car
communications.  So, they have zero needs for MR-to-MR optimization.

Again, thanks for the comments.

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Thu, 06 Dec 2007 19:10:12 +0100

Hi Chan-Wah,

	Comments below...

> perform ND-Proxy on the NEMO link.  But that is treading into solution

OK, if it's possible to configure the HA of the MR as the HA of the LMN,
then I'm fine with the feasibility of the scenario. I know that goes
into the solution space, but for me it was important to check :-).

> required MR to include signaling for every data packet, that is

OK.

> RO with MR-to-MR communications, much less MR-to-CN.

	Well, if all the potential use cases of interests are MR-to-MR, I'm
fine, but if there is also a bunch of scenarios involving MR-to-CN, then
I disagree that modifying the CN is not a problem. For instance, do you
expect youtube servers to be modified just to support NEMO RO?

> Most users will not allow VMN in their PANs.  RO will be provided to any

	Yes, there is text, but it would be nice to include that also on the
list of requirements, IMHO.

> Yes, I will add that in the next version.

OK, thanks.

> communications.  So, they have zero needs for MR-to-MR optimization.

	Well, I'm not so sure that the car industry is assuming any particular
solution yet. They are working on the requirements, the solution should
come after that. I think there might be a difference in requiring
MR-to-MR optimisation when these two MRs are directly one-hop connected
and when they are not.

> Again, thanks for the comments.

	You're welcome :-D

	Regards,

	Carlos

---

From: Thierry Ernst <[email-masked]>
Date: Thu, 06 Dec 2007 19:23:11 +0100

> communications.  So, they have zero needs for MR-to-MR optimization.

This is wrong ChanWah, I didn't say that and if it was interpreted as 
such I didn't express me clearly.

I said there is:

- 1: a need for direct MR-MR communication (over a direct wireless link 
when vehicles are in short range) but I didn't say layer 2, though this 
is what the C2C-CC is looking at for safety applications and no, Carlos 
they do have a solution. The requirements is a document for the IETF to 
focus its work. But the C2C-CC  vision is not the only one in the car 
industry and for non-safety application it's not a L2 solution.

- 2: a need for MR-MR communication via the access network: for instance 
  when vehicles are not in the same communication range over a physical 
medium. It is clearly not acceptable to have such communication going 
through the HA (or 2 HAs if they don't have the same).

Thierry

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Thu, 06 Dec 2007 19:32:35 +0100

Hi Thierry,

> industry and for non-safety application it's not a L2 solution.
	I said "car industry" not C2C-CC. I know C2C-CC does have a solution,
but I was trying to mean that we (IETF) are now working on the
requirements, not yet in the solutions. So basically, I think we agree
on this ;-).

> through the HA (or 2 HAs if they don't have the same).

	Yes, I agree on that.

	Regards,

	Carlos

---

From: Chan-Wah Ng <[email-masked]>
Date: Fri, 07 Dec 2007 02:33:22 +0800

> through the HA (or 2 HAs if they don't have the same).

Ah, I stand corrected.  However, my response was based on the (only)
available draft from the car industry.  The question is whether is there
a use-case for car-to-car comm`unications that requires RO for
car-to-car that are not in range using the sub-IP solution.  I don't see
that (at least from the c2ccc draft).

/rgds
/cwng

---

From: Chan-Wah Ng <[email-masked]>
Date: Fri, 07 Dec 2007 02:44:45 +0800

> expect youtube servers to be modified just to support NEMO RO?

There are two related question here.  

#1) is RO needed for viewing youtube? 

#2) Would YouTube server support MIPv6 RO?  If it does, why not NEMO
RO? :)

The first question is more relevant here.  As I mentioned in the draft,
it is all about use-cases.  We would of-course like to have the best
quality of communications for everything. But is RO required for
web-browsing, You-tube viewing, checking Google Maps?  I don't see a
need here.  The most important use-case right now is real-time
interactive applications (gaming, video/audio conferencing).  These
involve CNs that are willing to be modified because it is mutually
beneficial.

/rgds
/cwng

---

From: Carlos Jesús Bernardos Cano <[email-masked]>
Date: Thu, 06 Dec 2007 19:52:20 +0100

Hi Chan-Wah,

> #1) is RO needed for viewing youtube? 
(see below)

> #2) Would YouTube server support MIPv6 RO?  If it does, why not NEMO

Well, probably it will not support MIPv6 RO :-(. But if it does, it's
obviously easier to assume that the smaller the number of changes we
require, the bigger are the probabilities to get NEMO RO deployed.

> involve CNs that are willing to be modified because it is mutually

I completely agree on the real-time comment, you want to perform RO to
reduce the e2e delay, but it's also mentioned in the draft that another
nice feature brought by RO is that you avoid problems related to home
network congestion (and broadband residential access asymmetry). In the
later case, optimising youtube (or this kind of applications) might be
interesting as well.

Regards,

Carlos

---

From: Christophe Janneteau <[email-masked]>
Date: Fri, 07 Dec 2007 10:34:11 +0100

Hi Thierry, All,

> I said there is:
[snip]
> through the HA (or 2 HAs if they don't have the same).
I share your view on this form of RO being needed for the automotive use
case; and also think there is the very same need in the consumer
electronic space: allowing RO between two handheld devices (acting as
MR/PAN) connected to the (typically same operator's) network.

Christophe

---

From: "Roberto Baldessari" <[email-masked]>
Date: Thu, 13 Dec 2007 09:58:51 +0100

Hi all,

> > indicates a strong need for MR-to-MR optimization in CE, 
> whereas not 
> > so in avionics.  For car industry, as Thierry pointed out, 
> the c2ccc 
> > has defined their own layer 2 manet-like route optimization for 
> > car-to-car communications.  So, they have zero needs for 
> MR-to-MR optimization.
> 
> This is wrong ChanWah, I didn't say that and if it was 
> interpreted as such I didn't express me clearly.
> 
> I said there is:
> 
> - 1: a need for direct MR-MR communication (over a direct 
> wireless link when vehicles are in short range) but I didn't 
> say layer 2, though this is what the C2C-CC is looking at for 
> safety applications and no, Carlos they do have a solution. 
> The requirements is a document for the IETF to focus its 
> work. But the C2C-CC  vision is not the only one in the car 
>   when vehicles are not in the same communication range over 
> a physical medium. It is clearly not acceptable to have such 
> communication going through the HA (or 2 HAs if they don't 
> have the same).
> 
> 
> Thierry

I agree that these are 2 separeted issues and somehow complementary:

1) MR-to-MR when no infrastructure is available: this is out of scope of MEXT WG. C2C-CC considers a sub-IP approach for that since C2C-CC already has sub-IP routing. But C2C-CC is not the only automotive consortium. I expect others to need signaling at IP layer (which should probably come from another WG)

2) MR-to-MR when infrastructure is available: this is what RO requirements are for 

How 2 solutions for these 2 issues coexist and complement each other is deployment-specific and again out of scope of this WG. I think the discussion here should only focus on 2). The description of the sub-IP approach in the c2c draft is only to describe the deployment scenario and clarify that C2C-CC needs RO, not ad hoc routing. 

Best regards,

Roberto