RE: [EXTERNAL] Re: Extending a /64 (The most welcome comment)

["Pascal Thubert (pthubert)" <[e-mail]>]

Hello Tony

Just to clarify I expect that by Mobile IP you specifically mean NEMO (RFC 3963), which is for a mobile router that carries an MNP, correct?

Keep safe;

Pascal 

> -----Original Message-----
> From: ipv6 <[e-mail]> On Behalf Of Tony Whyman
> Sent: jeudi 19 novembre 2020 09:42
> To: Templin (US), Fred L <[e-mail]>; Brian E Carpenter
> <[e-mail]>; [e-mail]
> Subject: Re: [EXTERNAL] Re: Extending a /64 (The most welcome comment)
> 
> On 18/11/2020 22:27, Templin (US), Fred L wrote:
> > Brian,
> >
> >> How about an ops Area draft describing how the proposal works with BGP4
> and how many new BGP routes it will create?
> > I am not well liked in ops, but if Tony is up for another document and
> > has enjoyed the IETF "ride" thus far sure why not. What do you think, Tony?
> >
> > Fred
> 
> Fred,
> 
> Not sure if I really understand the question. As we both know, BGP routes to
> mobiles are not readily aggregatable. They are also subject to an unusually high
> rate of change resulting in potential forwarding table volatility. If you go down
> the BGP path then some sort of containment strategy is required, as you have
> specified for AERO and which itself draws on the way the ATN/OSI works with
> IDRP routes. Outside the containment area only a highly aggregated route to all
> mobiles is ever advertised.
> 
> Alternatively, Mobile IP avoids the problem by aggregating mobile routes
> effectively within the Home Agent and advertising only an aggregated route to
> some collective Home Network. A LISP based approach does not even work
> with BGP in the EID-space, although an xTR Proxy might advertise a highly
> aggregated route to all mobiles to the wider internet.
> 
> As for the "ride" - next time I'll confine myself to the simpler problem of
> delivering World Peace.
> 
> Tony
> 
> 
> >
> >> -----Original Message-----
> >> From: Brian E Carpenter [mailto:[e-mail]]
> >> Sent: Wednesday, November 18, 2020 2:20 PM
> >> To: Templin (US), Fred L <[e-mail]>; Tony Whyman
> >> <[e-mail]>; [e-mail]
> >> Subject: [EXTERNAL] Re: Extending a /64 (The most welcome comment)
> >>
> >> Fred,
> >>
> >> My concern isn't about what happens inside the ICAO limited domain.
> >> What you say makes complete sense there. It's about how these
> >> prefixes (fail to) aggregate in what we used to call the default-free zone.
> (RFC1888 probably would have had that problem too, but as far as I know,
> nobody ever implemented it.) If there was a bgpops WG, that would be the
> place to discuss it.
> >>
> >> If the plan creates a new DFZ route for each airline, that's a
> >> negligible number in the BGP4 context. If it creates a new DFZ route for each
> aircraft, that could be problematic.
> >>
> >> How about an ops Area draft describing how the proposal works with BGP4
> and how many new BGP routes it will create?
> >>
> >> Regards
> >>     Brian
> >>
> >> On 19-Nov-20 10:27, Templin (US), Fred L wrote:
> >>> Brian, there will be many non-airplane users of the ATN/IPS
> >>> top-level IPv6 prefix allocation - often in fixed and non-mobile
> >>> environments - and we can expect them to conform to CIDR
> >>> conventions. We are only talking here about the airplanes, which are
> always mobile and always away from "home".
> >>>
> >>> I have shown how we can route their prefixes using scalable
> >>> de-aggregation, and you seemed to concur. So, why can't we tolerate
> >>> a 24-bit portion of the airplane's prefix that does not come from a strict
> CIDR hierarchy?
> >>>
> >>> Fred
> >>>
> >>>> -----Original Message-----
> >>>> From: ipv6 [mailto:[e-mail]] On Behalf Of Brian E
> >>>> Carpenter
> >>>> Sent: Wednesday, November 18, 2020 12:10 PM
> >>>> To: Tony Whyman <[e-mail]>;
> [e-mail]
> >>>> Subject: [EXTERNAL] Re: Extending a /64 (The most welcome comment)
> >>>>
> >>>> Tony,
> >>>>
> >>>> I don't like the argument that people are arguing for either "purity"
> >>>> or "perfection". That is not the issue. The issue is doing
> >>>> something that matches how IPv6 wide-area routing actually works,
> >>>> and that is by CIDRised prefix allocation.
> >>>>
> >>>> Now you have peeled back the onion to this point:
> >>>>
> >>>>> we have to have an addressing plan (for
> >>>>> aircraft) that is canonical with the existing NSAP Address.
> >>>> I understand that as a perceived requirement; it's more or less why
> >>>> we wrote RFC1888, although mapping US GOSIP addresses was the
> >>>> target then. I don't know how the ICAO lays out its NSAPA
> >>>> addresses, but I imagine that the aircraft ID is towards the low-order bits?
> >>>> That's where it should be in an IPv6 address, IMNSHO.
> >>>>
> >>>> The current proposal seems to be limited to 16 subnets on an
> >>>> aircraft and that is highly likely to come back and bite you.
> >>>>
> >>>> Regards
> >>>>     Brian Carpenter
> >>>>
> >>>> On 18-Nov-20 22:33, Tony Whyman wrote:
> >>>>> On 18/11/2020 03:30, Michael Richardson wrote:
> >>>>>> When we designed IPv6, we assumed that everyone would get some,
> >>>>>> even if they didn't connect.
> >>>>>>
> >>>>>>       > ULAs only have the first property.
> >>>>>>       > If a device doesn't need the second property, the device doesn't
> need a GUA.
> >>>>>>
> >>>>>> Again, what is this business of trying to ration IPv6?
> >>>>>> Do they really need 39 bits? I don't know.
> >>>>>>
> >>>>>> Our entire Ipv6 architecture ENCOURAGES entities to ask for the
> >>>>>> amount of space that they think they might need over the lifetime
> >>>>>> of their effort and NEVER COME BACK for more.
> >>>>>>
> >>>>>> That's why /64 for IIDs, and /48s for every site.
> >>>>> If there is another edition of RFC 8200 then the sentence
> >>>>> beginning "Our entire.." should be copied to the front page of the
> >>>>> new edition. Yes, we all get the idea that addressing plans should
> >>>>> be as elegant as possible
> >>>>> - but IPv4-think should have no place in this. But, perhaps the
> >>>>> most important notion that comes through in the above is that each
> >>>>> industry ultimately knows best when it comes to the compromises
> >>>>> that have to be made to create an industry specific addressing plan.
> >>>>>
> >>>>> Over the last few days, I have been happy to try and peel away the
> >>>>> issues that lay behind our proposed IPv6 addressing plan and to
> >>>>> use it as an opportunity to spread understanding of the ATN/IPS
> >>>>> and the constraints under which we are working. However, there is
> >>>>> one point that it seems to be too difficult for some to get their
> >>>>> head around and that is that we are not starting with a "clean
> >>>>> sheet of paper". We have to respect the constraints that we have
> >>>>> and sometimes arguably poor decisions that were made in the past
> >>>>> and the result is a compromise. It will offend those who demand purity -
> but purity is not the objective.
> >>>>> The objective is to deploy a working IPv6 based system.
> >>>>>
> >>>>> In the ICAO Working Groups, we are writing the 3rd edition of the
> >>>>> ATN/IPS Manual. There were two earlier versions and both represent
> >>>>> failed attempts to deliver an IPS based ATN. They failed - not
> >>>>> necessarily for technical reasons - but because there was no
> >>>>> business case. This is a very hard nosed industry and, unless its
> >>>>> use is commanded by regulation, if a new technology does not
> >>>>> deliver more passengers or raise the profit/passenger then it ain't going
> to happen.
> >>>>>
> >>>>> Even now, I am hard pressed to see any business case for an
> >>>>> ATN/IPS replacing the venerable ATN/OSI. The ATN/OSI is a CLNP
> >>>>> overlay on top of an IPv4 network, it works, with some
> >>>>> limitations, and will support the current generation of
> >>>>> applications. With nugatory upgrades it could support the next
> >>>>> generation. Some might point to presumed cost savings by replacing
> >>>>> CLNP with something that is industry mainstream - but the truth is
> >>>>> that the CLNP bits are, by and large, in systems that perform
> >>>>> functions that are unique to civil aviation, while the rest is catalogue
> item routers.
> >>>>>
> >>>>> However, looking to the long term, it will be increasingly
> >>>>> difficult to develop new applications on the ATN/OSI base and we
> >>>>> should seize the first opportunity that we can find to move on to an
> ATN/IPS.
> >>>>>
> >>>>> A funding window has opened up with the European Space Agency
> >>>>> (ESA) and the EU's SESAR research programme putting in the funds
> >>>>> to develop a prototype SATCOM service for the ATN/IPS. This should
> >>>>> just about extend to cover initial avionics on a single aircraft
> >>>>> type (different generations of aircraft have different
> >>>>> communication architectures and everything has to be type approved
> >>>>> before it can be used). The funding should also cover a protocol
> >>>>> gateway allowing the prototype to interwork with ATC Centres i.e.
> >>>>> to at least demonstrate an operational service using the ATN/IPS.
> >>>>>
> >>>>> Even stretching the funding envelope this far is optimistic.
> >>>>> Adding in anything else like a new registration scheme for
> >>>>> aircraft and lookup tables in the protocol gateway will kill the
> >>>>> project financially. Yes, I know that these are not technically
> >>>>> difficult, but when you work in an environment where every new
> >>>>> function has to be subject to a hazard analysis, a safety case, a
> >>>>> high end develop lifecycle and rigorous testing then, what looks
> >>>>> like a simple function on paper, quickly gets replaced by a dollar sign
> followed by lots of digits.
> >>>>>
> >>>>> To keep this project feasible, we have to have an addressing plan
> >>>>> (for
> >>>>> aircraft) that is canonical with the existing NSAP Address. You
> >>>>> may prefer purity and demand that we have a perfect addressing
> >>>>> plan. But you are not helping.
> >>>>>
> >>>>> Our goal is to get a working ATN/IPS on to a single aircraft type
> >>>>> with minimum change to the existing system. Once this has been
> >>>>> demonstrated to be feasible and "industry mainstream" then the
> >>>>> case can be made for rolling it out to other aircraft types and,
> >>>>> may be, one day, even the ATC Centre's will get upgraded - but
> >>>>> that will probably have wait until a new application provides the
> business case.
> >>>>>
> >>>>> Perhaps another aphorism that could be put on the front page of a
> >>>>> future version of RFC 8200 is "never let the perfect be the enemy of the
> good".
> >>>>>
> >>>>> Regards
> >>>>>
> >>>>> Tony Whyman, MWA
> >>>>>
> >>>>> PS: we could always declare the ATN as a closed network and use
> >>>>> our own addressing plan - but does not help make the "industry
> >>>>> mainstream" case, does it.
> >>>>>
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