Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Brian,

> -----Original Message-----
> From: ipv6 [mailto:ipv6-bounces@ietf.org] On Behalf Of Brian E Carpenter
> Sent: Thursday, February 18, 2021 12:27 PM
> To: ipv6@ietf.org
> Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-
> ipv6-ula-scope-00.txt)
> 
> On 19-Feb-21 09:11, Templin (US), Fred L wrote:
> > Fernando,
> >
> > Then, let's have a scope for "MANET-local" scope which is what you get when
> > you have a small collection of (probably) mobile nodes that form a network
> > between themselves without the support of any infrastructure. I think HITs
> > would make for fine IPv6 addresses within the MANET-local scope, but if the
> > MANET ever connects to the global Internet then nodes will also want to get
> > a *real* GUA (served by the infrastructure) to go along with the HIT they
> > already have.
> >
> > Did I mention HITs are self-generated, and not delegated by some
> > infrastructure node?
> 
> Therefore, presumably, they are only statistically unique, even though
> there are 100 pseudo-random bits. ULAs on steroids.

4 bits are used to encode the cryptographic algorithm type, so there are
really 96 pseudo-random bits. But, yes that means they are statistically
unique and like ULAs on steroids.

I know the HIP people have done a lot of thinking about the uniqueness
of HITS, and I am probably grossly under-representing all of the aspects
they have considered by what I am saying here. But, I do see a use case.

Fred

>    Brian
> 
> >
> > Fred
> >
> >> -----Original Message-----
> >> From: Fernando Gont [mailto:fgont@si6networks.com]
> >> Sent: Thursday, February 18, 2021 11:53 AM
> >> To: Templin (US), Fred L <Fred.L.Templin@boeing.com>; IPv6 Operations <v6ops@ietf.org>; 6man@ietf.org
> >> Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-
> >> ipv6-ula-scope-00.txt)
> >>
> >>
> >> On 18/2/21 16:46, Templin (US), Fred L wrote:
> >> [...]
> >>>>
> >>>> Hi, Fred,
> >>>>
> >>>> On 18/2/21 16:11, Templin (US), Fred L wrote:
> >>>> [...]
> >>>>>> On 18/2/21 14:37, Templin (US), Fred L wrote:
> >>>>>>> Another aspect I failed to mention is that the use of (H)HITs does not
> >>>>>>> necessarily  mean that all aspects of the HIP protocol must be used. (H)HITs could be
> >>>>>>> used with the AERO/OMNI services instead, for example.
> >>>>>>
> >>>>>> Questions: Are these addresses globally-unique?
> >>>>>
> >>>>> Yes - global uniqueness is a key objective of (H)HIT. Aggregation is not within
> >>>>> scope, however.
> >>>>
> >>>> If that's the case, then, according to RFC4007, they are global addresses.
> >>>
> >>> I actually think HITs are a bit of a gray area. According to RFC7343, they are
> >>> formed from the GUA prefix 2001:20::/28 but the remaining bits following
> >>> the ::/28 prefix are cryptographically generated and hence non-aggregatable.
> >>
> >> BUt according to RFC4007, the scope is defined by the topological span
> >> where the address is meaningful....
> >>
> >>
> >>> That means that there is no way to represent a group of them in the routing
> >>> system using any other prefix length than /128.
> >>
> >> That's not a requirement when it comes to "scope".
> >>
> >>
> >>
> >>>> (I'd argue that if they cannot be aggregated, that's because they
> >>>> resulting "addresses" are not really topologically-dependent, in which
> >>>> case you might probably argue that they are not addresses in the first
> >>>> place :-) )
> >>>
> >>> Not in terms of routing across the global Internet, no, because it would not
> >>> scale to inject large numbers of /128's into the global Internet routing system.
> >>
> >> The thing is that if they don't represent a location in the network
> >> topology, they don't seem to qualify as an address, anyway.
> >>
> >> An address is supposed to be a topologically-dependent identifier --
> >> i.e., to convey information of location ("where?").
> >>
> >> Thanks,
> >> --
> >> Fernando Gont
> >> SI6 Networks
> >> e-mail: fgont@si6networks.com
> >> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
> >>
> >>
> >>
> >
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