Subject: [RRG] Mobility in the future -- civil aviation mobility

From: "Fleischman, Eric" <[email-masked]>
Date: Thu, 6 Dec 2007 10:45:09 -0800

I strongly resonate with Jari's posting. Over the past few months I have
been considering how aircraft mobility would work in an IPv6 variant of
the Aeronautical Telecommunications Network (ATN; i.e., civil aviation's
proposed air-ground and possibly air-air communications). I have become
very aware of the diverse range of opinions about the underlying
operative requirements -- differences which influence technology
preferences.

More to the point: many hypothesize direct aircraft connectivity to
ground-based entities via techniques such as NEMO, Mobile IP (MIP),
Wi-Fi, or MANET. On the other hand, the FAA's Networked LAN Security
study concluded that air-ground and air-air links (at least for
avionics) need to occur within the context of partitioned networks
(i.e., virtual private networks) for security and safety reasons. 

While considering these issues, I have formed the tentative opinion that
unanticipated requirements such as VPN-hosted communications radically
change mobility considerations. That is, if one presumes non-partitioned
communications, then NEMO, MIP, or MANET look much more attractive than
if one insists that the communications must be partitioned into VPNs. In
the latter case, I tend to think of variants of L3VPN or maybe even
L2VPN. As far as I know, the PE-CE interface of L3VPN was not designed
with mobility in mind. However, I personally don't know why it couldn't
handle mobility (e.g., for an IP in IP interface) as long as the
mobility occurred within the context of a single ISP and the mobility
rate was low enough not to deprecate the convergence of that ISP's
routing tables. 

My point being that Robin Whittle's original posting (which started this
thread) presumed MIP but MIP is by no means the only mobility
alternative. Rather, as Jari pointed out, the choice of mobility
solutions is a function of the environment's requirements and concept of
operations. And who knows, perhaps even L3VPN variants may some day
become viewed as a viable mobility solution along with the more
traditional mobility protocols?

--Eric

From: Jari Arkko [mailto:[email-masked]] 
>What type of mobility are you trying to solve? 
>Networks moving around? Hosts moving around? 
>The implications for what the global routing 
>system must know about the moving entities are big. 
>Also, what are the requirements for speed of updates? 
>The type of mobility that is requested in today's 
>networks goes all the way to up to the speed that 
>is capable of avoid interruptions in VoIP calls. This 
>may be possible to do in the routing system, too, but 
>the requirements are very different from merely 
>supporting, say, site multihoming.

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---

From: Roland Dobbins <[email-masked]>
Date: Thu, 6 Dec 2007 10:53:43 -0800

On Dec 6, 2007, at 10:45 AM, Fleischman, Eric wrote:

> That is, if one presumes non-partitioned
> if one insists that the communications must be partitioned into VPNs.

I don't follow the logic.  Does it make sense to do this for all  
comms to/from the aircraft (so, the aircraft will encrypt/tunnel my  
traffic, and then I encrypt/tunnel the traffic, on top of that?

It's off-topic for this group, but I think this is a questionable  
requirement for this application and I don't know whether it will be  
implemented, once folks start to understand its implications.  So, as  
an input for this group's considerations, I'd suggest taking this  
'requirement' with a grain of salt.

-----------------------------------------------------------------------
Roland Dobbins <[email-masked]> // 408.527.6376 voice

	Culture eats strategy for breakfast.

            -- Ford Motor Company

---

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 6 Dec 2007 10:55:06 -0800

Eric,

> -----Original Message-----
> From: Fleischman, Eric 
> Sent: Thursday, December 06, 2007 10:45 AM
> To: Jari Arkko; Robin Whittle
> Cc: Routing Research Group list; Russ White
> Subject: [RRG] Mobility in the future -- civil aviation mobility
> 
In
> traditional mobility protocols?

Just to add, we have also been discussing MOBIKE to manage
mobility for VPNs as an alternative for this use case.

Thanks - Fred
[email-masked]

---

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 6 Dec 2007 11:23:48 -0800

Roland,

> From: Roland Dobbins [mailto:[email-masked]] 
> Sent: Thursday, December 06, 2007 10:54 AM
> To: Routing Research Group list
> Subject: Re: [RRG] Mobility in the future -- civil aviation mobility
> 
> 

There are different domains within the aircraft, i.e.,
those that are critical to the operation of the aircraft
and the saftey of all aboard, those that provide a
nice-to-have service to the passengers, etc.

Clearly those domains cannot interfere with one another,
and clearly there are mobility considerations for all of
the domains that relate to routing and addressing.

Fred

---

From: Jari Arkko <[email-masked]>
Date: Thu, 06 Dec 2007 11:36:22 -0800

FWIW, we have an existing WG in the IETF to look at the aviation
mobility case, MEXT. They are in stage 1, understanding what the
requirements are.

Jari

---

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 6 Dec 2007 11:39:14 -0800

Are routing and addressing implications of the mobility management
scheme considered?

Thanks - Fred

> Sent: Thursday, December 06, 2007 11:36 AM
> To: Templin, Fred L
> Cc: Roland Dobbins; Routing Research Group list

---

From: Roland Dobbins <[email-masked]>
Date: Thu, 6 Dec 2007 11:40:09 -0800

> the domains that relate to routing and addressing.

Sure - I understand VPNning aircraft stuff (though there's no reason  
this can't work with MANET).  I don't understand VPNning
  passenger stuff.

            -- Ford Motor Company

---

From: Jari Arkko <[email-masked]>
Date: Thu, 06 Dec 2007 11:47:35 -0800

The group's charter restricts them to NOT consider solutions that would
impact global Internet routing tables or dynamics in any way.

Jari

---

From: "Fleischman, Eric" <[email-masked]>
Date: Thu, 6 Dec 2007 13:24:41 -0800

The VPN requirement recommendation was for air-ground and air-air
communications of devices or systems that have safety importance to
aircraft. 

I am not aware of a security or safety reason that would require VPNing
passenger communications from aircraft. One may debatably want to do it
for non-security or non-safety reasons such as consistency or
performance (e.g., an ATM study has tentatively concluded that there are
performance reasons to use VPN).

-----Original Message-----
> Clearly those domains cannot interfere with one another, and clearly 
> there are mobility considerations for all of the domains that relate 
> to routing and addressing.

---

From: Roland Dobbins <[email-masked]>
Date: Thu, 6 Dec 2007 13:30:00 -0800

On Dec 6, 2007, at 1:24 PM, Fleischman, Eric wrote:

> One may debatably want to do it for non-security or non-safety  
> reasons such as consistency or
> performance (e.g., an ATM study has tentatively concluded that  
> there are performance reasons to use VPN).

If one is using some sort of compression scheme, maybe.  Whether any  
purported benefits outweigh path agility via MANET-type ad hoc  
connectivity is of course a whole other discussion.

At any rate, this group should not assume that VPN-type traffic  
engineering technology is being used to aggregate the traffic to/from  
large numbers of mobile nodes in transit.

            -- Ford Motor Company

---

From: Tony Li <[email-masked]>
Date: Thu, 6 Dec 2007 13:44:28 -0800

Hi guys,

<co-chair>

Can we please get back to talking about routing architecture, please?

</co-chair>

Thanks,
Tony

---

From: "Fleischman, Eric" <[email-masked]>
Date: Thu, 6 Dec 2007 13:45:51 -0800

I believe that MEXT is inherently off topic for this list because MEXT
relies upon NEMO and NEMO does not cause mobility impacts upon the
Internet scaling that I am aware of -- possibly unlike the other
mobility alternatives.

However, the MEXT work presumes using NEMO and solely limits
considerations of civil aviation requirements to NEMO solutions. It is
accurate to say that there are individuals within the civil aviation
community who are interested in NEMO and MEXT as possible solutions for
aircraft mobility, but any assertion that MEXT represents a civil
aviation consensus would be very inaccurate at this current time.

-----Original Message-----

>FWIW, we have an existing WG in the IETF to 
>look at the aviation mobility case, MEXT. They 
>are in stage 1, understanding what the requirements are.

---

From: Jari Arkko <[email-masked]>
Date: Thu, 06 Dec 2007 13:49:05 -0800

Yes, of course. Thanks for the clarification.

Jari

---

From: [email-masked]
Date: Thu, 6 Dec 2007 16:51:40 -0500

> Are routing and addressing implications of the mobility management

It depends on what you mean by "routing and addressing implications".
We're working on *NEMO* "route optimization" techniques there, but
that doesn't have anything to do with the BGP routing system.

Regarding addressing, this is something for the regulatory bodies
in the aeronautics world to work out, not the IETF or IRTF, but it is
worth noting that with either multiple NEMO MNPs assigned to an MR for
the different classes of onboard networks, or multiple MRs using
different MNPs, partitioning of the address space can be performed
onboard without jumping to the conclusion of VPNs.  Current regulations
restrict air-traffic control data from even sharing the same physical
links as more mundane traffic, so it's possible that concerns about
partitioning are somewhat different than what you expect.

RRG is not the right place to talk about this, in any case ... come
over to MEXT if you want to discuss the NEMO RO techniques.

---

From: Marshall Eubanks <[email-masked]>
Date: Thu, 6 Dec 2007 16:58:54 -0500

> performance reasons to use VPN).

While some of the documents are old now, you might find some useful  
background at

http://www.multicasttech.com/mpi/

Regards
Marshall

---

From: "Fleischman, Eric" <[email-masked]>
Date: Thu, 6 Dec 2007 14:10:53 -0800

Roland,

Please don't interpret my postings as evaluating MANET, MIP, NEMO,
MOBIKE, etc. Until our civil aviations community creates stable set of
ATN IPv6 requirements, I don't know how any viable technical analysis
can be done that could favor or preclude any mobility alternative. 

Rather, the point of my postings was to state my tentative conclusion
that requirements such as whether avionics communications must be
partitioned (VPN) or not influences the relative desirability of various
mobility alternatives. It is my perception that some of those
alternatives potentially may impact Internet scaling, depending upon how
they are designed. 

It is of course commonplace to use VPNs over MANETs (e.g., military
deployments).

I disagree with your final paragraph: VPN aggregations are definitely
still on the table within elements of our community. However, RRG may --
or may not -- choose to consider that issue as we see fit.

--Eric

-----Original Message-----
> One may debatably want to do it for non-security or non-safety reasons

> such as consistency or performance (e.g., an ATM study has tentatively

> concluded that there are performance reasons to use VPN).

---

From: Roland Dobbins <[email-masked]>
Date: Thu, 6 Dec 2007 14:20:31 -0800

> or may not -- choose to consider that issue as we see fit.

We're all quite familiar with the use of VPNs in many contexts,  
thanks.  The initial post in this sub-thread seemed to imply that  
large numbers of aerially-mobile nodes would have their traffic  
aggregated together within some sort of tunnel, to wit:

 >change mobility considerations.

I disagree with the statement that VPN-hosted communications are  
unanticipated, and I further disagree with the statement that they  
radically change mobility considerations for this WG.  VPNs will be  
used in some instances, they won't be in others; irrespective of  
their use or non-use in any given circumstance, I don't believe  
there's any significance for this WG.

            -- Ford Motor Company