Re: 64share v2

[Alexandre Petrescu <[e-mail]>]

Le 11/11/2020 à 00:06, Brian E Carpenter a écrit :
> 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.)
 >
 >
> 
> 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 agree.

> 
> 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.

I agree.

But it comes down again to the problem of length of an 'IID'.

Alex

> 
>     Brian
> 
>>
>>
>>
>>      Perhaps someone familiar with 3GPP internals, e.g. the authors
>>      of RFC6459, can comment?
>>
>>      Regards
>>          Brian
>>
> 
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