Re: 64share v2

[Ca By <[e-mail]>]

On Tue, Nov 10, 2020 at 3:06 PM Brian E Carpenter <
[e-mail]> wrote:

> On 11-Nov-20 11:03, Ca By wrote:
> >
> >
> > On Tue, Nov 10, 2020 at 1:49 PM Brian E Carpenter <
> [e-mail] <mailto:[e-mail]>> wrote:
> >
> >     On 10-Nov-20 21:10, Ca By wrote:
> >     > Folks,
> >     >
> >     > In an effort to progress the conversation, i created a simple and
> rough pre-00 i-d (as ietf is not accepting submissions now) for your review
> and comment
> >     >
> >     > https://pastebin.com/duyYRkzG
> >
> >     I'm having difficulty reconciling that with what I read at:
> >
> https://mailarchive.ietf.org/arch/msg/v6ops/0d7lSiP_78td3vWBlMnVvmp7UAo/
> >
> >
> >     If that email is correct, the 3GPP model is tightly bound to
> >     the /64 boundary and to the notion of giving a single address
> >     and predefined Interface ID to the UE.
> >
> >
> >
> > This is not a correct summary. I believe rfc6459 describes it clearly.
> The ue receives an off-link  /64, the iid is simply a hint and typically
> not used. This is why rfc7278 works.
>
> Thanks for the clarification.
>
> >
> >     Also, since /64
> >     is still fixed by the addressing architecture, and RA PIOs
> >     are constrained by that architecture, I don't understand how
> >     a UE can be "given a prefix such as a /56 using RA".
> >
> >
> > The i-d is to requests the 3gpp to make a change to allow < 64 via RA
>
> RFC 6459 says "The 3GPP network allocates each default bearer a
> unique /64 prefix" but doesn't seem to explain how that prefix is
> conveyed to the UE. It does say that the suggested IID is conveyed
> by "layer-2 signaling". If the allocated prefix is only conveyed
> by an RA/PIO there is something unconventional going on, i.e. the
> UE is allowed to deduce *from the RA* that it owns the entire /64,
> which is not all what applies on a conventional LAN. (Yes, I do see
> how that enables RFC 7278, but this unconventional semantic is
> not all obvious from RFC 6459.)
>

Yes, it is conveyed only using RA

On the wire(less), it looks like this (image of pcap)

https://imgur.com/a/p6dBy3d


> So if that's right, I think we do have a problem. If we (=IETF+3GPP)
> decide to allow <64 prefixes in RA/PIO during the establishment of
> a PDP context, that seems to be not only an unconventional use
> of RA but also one that directly contravenes the /64 rule in the
> addressing architecture.
>
> I'm not against either of those things, but I think some very
> explicit wording is needed to explain what's going on and how it
> is different from a conventional LAN.
>
>    Brian
>
> >
> >
> >
> >     Perhaps someone familiar with 3GPP internals, e.g. the authors
> >     of RFC6459, can comment?
> >
> >     Regards
> >         Brian
> >
>
>