Re: [v6ops] Next step? [Re: The bottom is /112]

[Mark Smith <[e-mail]>]

On Sat, 21 Nov 2020, 14:00 Brian E Carpenter, <[e-mail]>
wrote:

> Joel,
>
> It seems to me that it's high time to draft a liaison statement to 3GPP,
> observing that:
>
> (1) There is a serious problem for the design and implementation of
> 5G-based IPv6 "hot spots" and CEs [which is where this conversation
> started];
>

I think it is also important to find out why they haven't deployed DHCPv6
to solve this problem.

Don't they think DHCPv6 infrastructure will scale? Is it just that they
don't know how to scale it?

Is it a vendor / mobile operator / handset developer DHCPv6
capability chicken-and-egg problem?

Is there an overriding business or industry reason?

The mobile industry has been resistant to tethering over the years, and
probably only came to begrudgingly accept it because they couldn't prevent
phone vendors from implementing Wifi and NAT, and couldn't very effectively
stop their customers from using that capability (One trick I've heard of to
prevent tethering working was to check if an IPv4 packet's TTL value was 64
when it arrived at the network, meaning it originated from the directly
attached handset. Packets from tethered devices had a TTL of 63 so were
dropped. Of course, you could set the default TTL on a tethered PC to 65 to
get around that.)

I guess there might be a fairly strong mindset that there must be a fee per
device attached to the network in addition to a fee for network
utilisation. Providing multiple /64s would be formally acknowledging that
multiple devices can be attached and a fee per device isn't and can't ever
be charged, counter to the mindset.

Regards,
Mark.


> (2) Although the best solution is not yet obvious, defining and
> standardizing it will require a joint effort by the IETF and 3GPP.
>
> Followed by a proposal to form an ad hoc joint design team.
>
> Regards
>    Brian Carpenter
> On 21-Nov-20 14:46, Joel M. Halpern wrote:
> > The nesting got me lost, so I will top post my take on the answer to the
> > one quesiton I could understand.
> >
> > I believe you asked what I think would need to be changed to permit the
> > delegation.
> > As with anything, the real things that need to change are the devices in
> > the network.
> >
> > With regard to IETF standards, what is proposed is a change to RA.
> > There are several possible changes.  None of them require a change to
> > the IPv6 addressing archtiecture, as the addressing structure remains as
> > it is.
> > As for the exact mechanism, at the moment I lean towards Ole's proposal
> > of using a new option in his generic option mechanism.  But I am not
> > wedded to that answer.
> >
> > And of course, to get this supported in mobile environments we will have
> > to work with 3GPP and make sure there are no other hidden issues.
> > That's the way we do things.  Work together.
> >
> > Changing the prefix length to /80 is technically also possible.  It does
> > a lot more violence to my understanding of the architecture and software
> > structures that go with it, and is a very limited and narrow solution to
> > the problem.
> >
> > Yours,
> > Joel
> >
> > On 11/20/2020 7:58 PM, Gyan Mishra wrote:
> >> Hi Joel
> >>
> >> In-line
> >>
> >> On Fri, Nov 20, 2020 at 6:02 PM Joel M. Halpern <[e-mail]
> >> <mailto:[e-mail]>> wrote:
> >>
> >>     Gyan, separate from Ole's comments about the difference between
> address
> >>     assignment and delegation, I have another problem following the
> >>     reasoning below.
> >>
> >>     Yes, the proposal for using shorter prefixes to enable UE to perform
> >>     delegation will require changes to the UE.
> >>
> >>      Gyan> Agreed.  So that change would be to RFC 4291 64 bit boundary
> >> to allow for longer prefix.  Do you agree?
> >>
> >> If you don’t agree what do think the change would be to allow the UE to
> >> accept shorter prefix from the 3GPP gateway?
> >>
> >>
> >>     But I do not see how that is relevant to any choice we are trying to
> >>     make.
> >>     Any solution that enables UE to delegate addresses (in the sense
> that
> >>     they lack the capability now) willr equire changes to the UE.
> >>
> >>
> >>
> >>     Gyan> If the UE receives a /56 via RA it could delegate /64 to
> >>     downstream devices.  No change needed to delegate  /64, however a
> >>     change is needed to accept /56 via RA.
> >>
> >>
> >>      If 3GPP gateway supported PD - problem solved but that’s not the
> >> case and that does not sound like it will ever change even with 5G.
> >>
> >>     Gyan> The UE needs to be able to accept shorter prefix.  That’s the
> >> IPV6 specification change that requires removal of the 64 bit boundary.
> >>
> >>     Yoru
> >>     proposed change to the SLAAC length if anything does more violence
> to
> >>     the software (depending upon the exact software architecture.)
> >>
> >>
> >>     Gyan> What violence to software.  There would be more violence to
> >> software if we removed the 64 bit boundary and allowed slaac to support
> >> any vlsm prefix lengths.
> >>
> >> My /80 proposal would just shift the boundary 16 bits to /80.
> >>
> >> Hosts on the same subnet with two different masks would not be on-net
> to
> >> each other as on different subnets.  The router would be configured
> with
> >> the two subnets /64 and /80 subnet to support the two device types.
> >> The solution would be a simple RA PIO flag that is set and older hosts
> >> not upgraded would be backwards compatible and so would only support 64
> >> bit boundary by ignoring flag. Hosts upgraded to support would
> >> understand the flag and be able to support longer mask up to /80.
> >>
> >>
> >>
> >>     So I do not follow how you got to your conclusion.
> >>
> >>     Yours,
> >>     Joel
> >>
> >>     On 11/20/2020 5:27 PM, Gyan Mishra wrote:
> >>      >
> >>      > (top posting)
> >>      >
> >>      > As I would like to clear the air as well as get to the crux of
> >>     the v6ops
> >>      > presentation development results as well as next steps for this
> >>     draft
> >>      > and the 6man variable slaac solutions draft:
> >>      >
> >>      >
> >>      > This thread was in light of Lorenzo kindly pointing out that
> >>     upgrading
> >>      > 3GPP is not all that needs be done for Cameron’s 64share v2 to
> >>     work - as
> >>      > all mobile devices would stop working- as slaac would not would
> be
> >>      > effectively broken.
> >>      >
> >>      > The mobile device would receive a shorter prefix let’s say /56
> >>     but not
> >>      > know what to do with it since it’s expecting a /64.
> >>      >
> >>      > So that a major gap and the only solution is updating RFC 4291
> >>     removing
> >>      > the 64 bit boundary allowing for shorter prefix and now as well
> >>     longer
> >>      > prefixes to work and in that respect now provide the much needed
> >>     parity
> >>      > with static and DHCPv6 which can do any prefix length.
> >>      >
> >>      > So that is a drastic change to RFC 4291.  However, in light of
> this
> >>      > development on the v6ops 109 call, my balancing act of best of
> both
> >>      > worlds and also to keep everyone happy to make this a WG effort
> >>     for this
> >>      > change by proposing in the subject heading /80 fixed boundary and
> >>     not a
> >>      > variable slaac change allowing all bits vlsm.
> >>      >
> >>      > Basically stealing 16 bits for network prefix out of the IID,
> still
> >>      > keeping the fixed boundary so longer than 80 would NOT  be
> allowed.
> >>      >
> >>      > A /64 would now be equivalent to a /48 with now 64k /80’s.
> >>      >
> >>      > This /80 would keep the operators and law enforcement happy as
> >>     now 16
> >>      > bits less helps traceability but is still long enough for 48
> bits of
> >>      > privacy to IP correlation by attackers.
> >>      >
> >>      > This /80 would be a nice optimal balance as it would keep wired
> >>      > broadband and mobile handset customers happy respecting their
> >>     privacy as
> >>      > the 16 bits less of heuristics is minimal change that will
> impact IP
> >>      > correlation by attackers.
> >>      >
> >>      > The IID as it’s less than the current 64 bit cannot use MAC based
> >>     EUI64
> >>      > IID, which is not a problem as Mac based IID is not recommended
> >>     as most
> >>      > all manufacturers use RFC 4941 and I believe Linux flavors some
> use
> >>      > stable IID RFC 7217.
> >>      >
> >>      > So now the 48 bit IID would require a random IID generation
> >>     schema so
> >>      > can use either RFC 4941 privacy extension or RFC 7217 stable IID
> to
> >>      > generate the 48 bit IID.
> >>      >
> >>      > 3GPP subtending would now work issue mentioned in the problem
> >>     statement
> >>      > draft without even having to use 64share as now longer prefixes
> >>     up to
> >>      > /80 would be supported allowing for further segmentation of
> >>     downstream
> >>      > devices.
> >>      >
> >>      > This also would help wired broadband and soon fixed 5G broadband
> >>      > proliferation where operators in light of BCP RIPE-690, are sill
> >>      > allocation via BNG gateways a /64, now operators  can stay as-is,
> >>     as the
> >>      > /64 would now be allowed to be further segmented supporting 64k
> >>     /80s,
> >>      > way more then enough for SOHO.
> >>      >
> >>      > This would allow 64share if used by 3GPP operators to work and
> >>     would not
> >>      > require the 3GPP specification to be updated.  We don’t know even
> >>     if the
> >>      > 3GPP architecture specification can be updated to support shorter
> >>      > prefixes and if the 3GPP consortium of operators would agree to
> >>     it.  So
> >>      > that is all theoretical of that change is possible.
> >>      >
> >>      > As with 5G with Enhanced VPN framework SR steering of high
> priority
> >>      > traffic, traffic isolation and Network slicing capabilities
> becomes
> >>      > mainstream and will soon be a real world reality and as fixed 5G
> >>      > broadband proliferation takes off and mobile 5G == the idea of a
> >>      > wearable /48 will really be many /48s.
> >>      >
> >>      > As this paradigm shift takes place, operators around the world
> >>     will be
> >>      > clamoring after the RIR for massive blocks, I would say less
> than /8
> >>      > more like a /5 or /4.  If you do the math on the way high side a
> /10
> >>      > yields 7 bits so 128 divided by 5 RIRs yields 24 ISPs per RIR
> >>     which is
> >>      > tiny number with the number of large size operators worldwide.
> >>      >
> >>      > With the massive proliferation of IOT devices and just about
> >>     every home
> >>      > or office appliance on 5G, the problem now gets way exacerbated.
> >>      >
> >>      > As this evolution unfolds IANA will be scrambling to release all
> >>      > remaining /3 as well as all unallocated blocks to subvert RIR
> IPv6
> >>      > address space depletion.
> >>      >
> >>      > Playing Monday night quarterbacking in hindsight we would never
> >>     think
> >>      > this would happen in a million years, but we would see IPv6 on
> >>     the verge
> >>      > of address space depletion.  Unheard of but it can happen as the
> >>     saying
> >>      > goes “when you build - they will come”.
> >>      >
> >>      > It is true as history has taught that very important lesson.
> >>      >
> >>      > The answer to this real world problem is in the subject heading
> >>     of this
> >>      > thread.
> >>      >
> >>      > This would also fix the day 1 issue I mentioned allowing mix of
> >>     slaac
> >>      > devices with static and DHCPv6 up to /80.
> >>      >
> >>      > The variable slaac solution draft proposes a new  RA PIO flag
> >>     that would
> >>      > be used to signal longer prefixes, and would provide backwards
> >>      > compatibility so that devices not supporting woud ignore the flag
> >>       and
> >>      > devices on newer code supporting would use the flag.  We
> definitely
> >>      > don’t want to impact any existing devices on the existing 64 bit
> >>     slaac
> >>      > boundary standard.
> >>      >
> >>      > Dmytro has tested the solution on Linux kernel signaling RA PIO
> >>     flag and
> >>      > was able to successfully test any length mask and random IID
> >>     generation
> >>      > both RFC 4941 privacy extension as well as stable IID RFC 7217.
> >>      >
> >>      >
> >>     https://datatracker.ietf.org/doc/draft-mishra-6man-variable-slaac/
> >>     <https://datatracker.ietf.org/doc/draft-mishra-6man-variable-slaac/
> >
> >>      >
> >>     <https://datatracker.ietf.org/doc/draft-mishra-6man-variable-slaac/
> >>     <https://datatracker.ietf.org/doc/draft-mishra-6man-variable-slaac/
> >>
> >>      >
> >>      > If everyone is in agreement with what I have stated on this
> >>     thread, I
> >>      > would like to ask the chairs for WG adoption as this is a WG
> effort.
> >>      >
> >>      > I would like to garner support from all 6MAN members with full
> >>     consensus
> >>      > to change the existing RFC 4941 /64 fixed boundary to /80 fixed
> >>     boundary.
> >>      >
> >>      > Kind Regards
> >>      >
> >>      > Gyan
> >>      >
> >>      > On Thu, Nov 19, 2020 at 5:14 PM Joel M. Halpern
> >>     <[e-mail] <mailto:[e-mail]>
> >>      > <mailto:[e-mail] <mailto:[e-mail]>>>
> wrote:
> >>      >
> >>      >     I am missing something in your reasoning.
> >>      >     You seem to say at one point that (to paraphrase) "we can't
> >>     do this
> >>      >     because it does not work with the existing UE software".
> >>      >     Any new solution where a UE delegates based on any change of
> >>     any kind
> >>      >     (including lengthening the prefix, shortening the prefix, or
> >>     magically
> >>      >     incanting new prefixes) requires that the UE be upgraded to
> know
> >>      >     what to
> >>      >     do with the information.  I do not see how that
> >>     differentiates any of
> >>      >     the solutions. (Except "don't do anything", which I think we
> >>     do not
> >>      >     want
> >>      >     to take.)
> >>      >
> >>      >     Yours,
> >>      >     Joel
> >>      >
> >>      >     On 11/19/2020 5:03 PM, Gyan Mishra wrote:
> >>      >      >
> >>      >      >
> >>      >      > On Thu, Nov 19, 2020 at 10:33 AM <[e-mail]
> >>     <mailto:[e-mail]>
> >>      >     <mailto:[e-mail] <mailto:[e-mail]>>
> >>      >      > <mailto:[e-mail] <mailto:[e-mail]
> >
> >>     <mailto:[e-mail] <mailto:[e-mail]>>>>
> wrote:
> >>      >      >
> >>      >      >
> >>      >      >
> >>      >      >      > On 19 Nov 2020, at 14:58, Gyan Mishra
> >>      >     <[e-mail] <mailto:[e-mail]>
> >>     <mailto:[e-mail] <mailto:[e-mail]>>
> >>      >      >     <mailto:[e-mail]
> >>     <mailto:[e-mail]>
> >>      >     <mailto:[e-mail]
> >>     <mailto:[e-mail]>>>> wrote:
> >>      >      >      >
> >>      >      >      > You would need a new option. It would likely be
> >>     useful for the
> >>      >      >     requesting router to indicate interest in the option.
> Even
> >>      >     hinting
> >>      >      >     at what prefix size it was expecting.
> >>      >      >      > Now can you explain to me again the reasons why
> this
> >>      >     approach is
> >>      >      >     better than using the existing DHPCv6 protocol
> packets?
> >>      >      >      >
> >>      >      >      >     3GPP gateway does not support DHCPv6
> >>      >      >
> >>      >      >     3GPP gateway doesn't support new option. What's your
> >>     point?
> >>      >      >
> >>      >      >
> >>      >      >
> >>      >      >      The point of the v6ops presentation and this email
> >>     thread is
> >>      >     how to
> >>      >      > “extend a /64” in the 3GPP use case  in slide 1 of the
> >>     deck you
> >>      >     compiled
> >>      >      > a list of options and of the two I had highlighted in red
> >>     were the
> >>      >      > 64share v2 Cameron’s option and the variable slaac
> >>     option.  So on
> >>      >     the
> >>      >      > call this morning Lorenzo shot down 64share v2 shorter
> prefix
> >>      >     option as
> >>      >      > even if the 3GPP architecture was updated to support
> longer
> >>      >     prefixes and
> >>      >      > even is the 3GPP gateway was able to send a shorter prefix
> >>     with A
> >>      >     flag
> >>      >      > not set, all mobile devices per Lorenzo’s point would be
> >>     broken
> >>      >     as they
> >>      >      > would not accept the shorter let’s say /56 prefix to
> build the
> >>      >     slaac 128
> >>      >      > bit address.  So the bottom line is the 64share v2 won’t
> work
> >>      >     unless we
> >>      >      > update RFC 4291 and remove the 64 bit boundary.
> >>      >      >
> >>      >      >   So we are back to square uno - no viable solution
> >>      >      >
> >>      >      >   So now we had thrown out the longer >64 due to race to
> >>     bottom
> >>      >     worries
> >>      >      > which I and others believe is Fud and as described in
> >>     slide 10 of
> >>      >     the
> >>      >      > v6ops “race to the bottom slide”.
> >>      >      >
> >>      >      > So a happy medium /80 fixed boundary I came up with that I
> >>     think
> >>      >     solves
> >>      >      > a lot of the issue and not just the 3GPP initial
> >>     segmentation of
> >>      >      > downstream devices problem statement.
> >>      >      >
> >>      >      > Since we have to update RFC 4291 for 64share v2 to work
> >>     anyways
> >>      >     to allow
> >>      >      > for shorter prefixes, why not instead create a new bottom
> >>     at /80
> >>      >     giving
> >>      >      > 16 bits more of prefix length and shrinking the IID down
> >>     to 48 bits.
> >>      >      > Doing so you would not even have to update the 3GPP
> >>     architecture
> >>      >     as I
> >>      >      > don’t know if that would fly or not.  Also this solves a
> >>     few other
> >>      >      > problems at the same time.
> >>      >      >
> >>      >      >
> >>      >      > As I mentioned in the v6ops deck presented that vlsm 0 to
> >>     128 is
> >>      >      > mainstream for operators for static addressing on router
> >>     and switch
> >>      >      > infrastructure and dhcpv6 subnets longer prefixes for
> network
> >>      >      > infrastructure appliance clusters, NFV/VNF virtualization
> >>     and server
> >>      >      > farms.  On host subnets where there is a chance of mix of
> >>     slaac
> >>      >     hosts
> >>      >      > with dhcpv6  devices the prefix length is stuck at /64.
> So on
> >>      >     these mix
> >>      >      > addressing host subnets we cannot do longer prefixes
> following
> >>      >     our ND
> >>      >      > cache hard limit mantra to prevent ND cache exhaustion
> >>     issues as
> >>      >      > described in RFC 6164.
> >>      >      >
> >>      >      > So with the /80 new fixed boundary shifting prefix length
> >>     16 bits
> >>      >     longer
> >>      >      > and shortening the IID by 16 bits gives resolved the 3GPP
> >>     issue
> >>      >     which
> >>      >      > 64share can work as is and subtending to downstream
> >>     devices will now
> >>      >      > work as a /64 is now equivalent to a /48 with 64k /80s.
> Also
> >>      >     BCP-690
> >>      >      > for broadband not all operators have adopted the shorter
> >>     prefix
> >>      >     lengths
> >>      >      > /56 or /48 recommendations  and now that’s not an issue
> as the
> >>      >     /64 would
> >>      >      > now suffice.
> >>      >      >
> >>      >      >  From an operators perspective that gain allows at least
> >>     for 3GPP
> >>      >      > massive growth and subtending with a single /64 allows the
> >>     operators
> >>      >      > such as Verizon with massive subscriber base worldwide can
> >>     stay with
> >>      >      > current allocations and don’t have to ask
> >>     <
> https://www.google.com/maps/search/ent+allocations+and+don%E2%80%99t+have+to+ask?entry=gmail&source=g
> >
> >>     for /10.
> >>      >      >
> >>      >      > As 5G gets rolled out with Enhanced VPN framework and
> Network
> >>      >     slicing
> >>      >      > paradigm, the demand for shorter blocks and wearable
> >>     multiple /48
> >>      >     will
> >>      >      > be our new reality.
> >>      >      >
> >>      >      > Making that 16 bit shift now to /80 making a /64 the new
> >>     /48 will
> >>      >     give
> >>      >      > broadband and 3GPP subscribers a ton of space to
> >>     subtending their
> >>      >      > networks we would be set for the future.  Especially with
> >>     IOT the
> >>      >     demand
> >>      >      > for subtending will continue to grow astronomically.
> >>      >      >
> >>      >      > Also IANA does not have to get start in allocating the
> >>     other /3 and
> >>      >      > other available blocks.
> >>      >      >
> >>      >      > Lots of problems being solved here with a fixed /80 new
> >>     boundary.
> >>      >      >
> >>      >      > Also with the existing random IID generation schemes which
> >>     we have
> >>      >      > tested on Linux kernel can do longer p
> >>      >
> >>       <
> https://www.google.com/maps/search/tested+on+Linux+kernel+can+do+longer+p?entry=gmail&source=g
> <
> https://www.google.com/maps/search/tested+on+Linux+kernel+can+do+longer+p?entry=gmail&source=g
> >>refixes
> >>      >     using RFC 4941 privacy
> >>      >      > extension or RFC 7217 stable IID.
> >>      >      >
> >>      >      > Win-Win for all.
> >>      >      >
> >>      >      >     Ole
> >>      >      >
> >>      >      > --
> >>      >      >
> >>      >      > <http://www.verizon.com/ <http://www.verizon.com/>
> >>     <http://www.verizon.com/ <http://www.verizon.com/>>>
> >>      >      >
> >>      >      > *Gyan Mishra*
> >>      >      >
> >>      >      > /Network Solutions A//rchitect /
> >>      >      >
> >>      >      > /M 301 502-1347
> >>      >      > 13101 Columbia Pike
> >>      >      > /Silver Spring, MD
> >>      >      >
> >>      >      >
> >>      >      >
> >>      >      > _______________________________________________
> >>      >      > v6ops mailing list
> >>      >      > [e-mail] <mailto:[e-mail]>
> >>     <mailto:[e-mail] <mailto:[e-mail]>>
> >>      >      > https://www.ietf.org/mailman/listinfo/v6ops
> >>     <https://www.ietf.org/mailman/listinfo/v6ops>
> >>      >     <https://www.ietf.org/mailman/listinfo/v6ops
> >>     <https://www.ietf.org/mailman/listinfo/v6ops>>
> >>      >      >
> >>      >
> >>      > --
> >>      >
> >>      > <http://www.verizon.com/ <http://www.verizon.com/>>
> >>      >
> >>      > *Gyan Mishra*
> >>      >
> >>      > /Network Solutions A//rchitect /
> >>      >
> >>      > /M 301 502-1347
> >>      > 13101 Columbia Pike
> >>      > /Silver Spring, MD
> >>      >
> >>      >
> >>
> >> --
> >>
> >> <http://www.verizon.com/>
> >>
> >> *Gyan Mishra*
> >>
> >> /Network Solutions A//rchitect /
> >>
> >> /M 301 502-1347
> >> 13101 Columbia Pike
> >> /Silver Spring, MD
> >>
> >>
> >
> > _______________________________________________
> > v6ops mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/v6ops
> >
>
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