Re: [v6ops] How do you solve 3GPP issue if neither operator nor handset supports PD?

otroan@employees.org Tue, 24 November 2020 12:40 UTC

Return-Path: <otroan@employees.org>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 234623A0AD4 for <ipv6@ietfa.amsl.com>; Tue, 24 Nov 2020 04:40:33 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 0
X-Spam-Level:
X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CxQcF1cE8YOm for <ipv6@ietfa.amsl.com>; Tue, 24 Nov 2020 04:40:28 -0800 (PST)
Received: from clarinet.employees.org (clarinet.employees.org [198.137.202.74]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 587383A0AC7 for <ipv6@ietf.org>; Tue, 24 Nov 2020 04:40:27 -0800 (PST)
Received: from astfgl.hanazo.no (77.16.72.77.tmi.telenormobil.no [77.16.72.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by clarinet.employees.org (Postfix) with ESMTPSA id 740C54E11AEC; Tue, 24 Nov 2020 12:40:27 +0000 (UTC)
Received: from [IPv6:::1] (localhost [IPv6:::1]) by astfgl.hanazo.no (Postfix) with ESMTP id 97D6245DE79F; Tue, 24 Nov 2020 13:40:22 +0100 (CET)
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.20.0.2.21\))
Subject: Re: [v6ops] How do you solve 3GPP issue if neither operator nor handset supports PD?
From: otroan@employees.org
In-Reply-To: <m1khXWs-00007wC@stereo.hq.phicoh.net>
Date: Tue, 24 Nov 2020 13:40:21 +0100
Cc: 6man WG <ipv6@ietf.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <47150D97-27D7-4AFD-8418-692D68D09828@employees.org>
References: <CABNhwV2-dH81CY4wSisV8BU-7H9m5a1xYMqTMecRxhNqZe=ApQ@mail.gmail.com> <CAKD1Yr1xV179LZ7Kxtk5mGruJcJ+BpGb2heBBy4ORtRU7bfvqw@mail.gmail.com> <CAMGpriWqnmL0qo0Hm=b+GbzcdCuXz6PM5aq8owE7-=ty5pDFsw@mail.gmail.com> <1DB65027-BEF2-4C0A-ACF4-C979DA7444C2@employees.org> <m1khXWs-00007wC@stereo.hq.phicoh.net>
To: Philip Homburg <pch-ipv6-ietf-6@u-1.phicoh.com>
X-Mailer: Apple Mail (2.3654.20.0.2.21)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/dM6-coS6Q4591WtTQ-sQHOC8Doc>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 24 Nov 2020 12:40:33 -0000

Philip,

>> In the P2P Ethernet/3GPP case it says:
>> This prefix is not used on the link between us.
>> The prefix is dedicated to you, and I promise to install a route like:
>> ipv6 route <prefix> p2p-interface | interface, NH pointing at you.
>> You can if you like configure an address on the interface on the upstream lin
>> k,
>> as the router will forward traffic to anything in that prefix blindly.
>> (you aren't strictly doing SLAAC at that point though.)
> 
> In my experience, many true point-to-point links (such as ppp, but also
> tunnels) are like this.
> 
> The reason is that in theory you should do neighbor discovery even if a link
> has no L2 addresses. I found that many implementations just don't react
> to an NS or send any themselves.

That is correct for any implementation I have written.

> So all traffic is just sent to the other side of the link. I.e., the route
> could actually point to the link, but you can't really tell the difference.
> 
> In theory you could try to see if the router has an address on the link, but
> I never tried that experiment.
> 

And my point was that this is the desired behaviour in this case.
At least we should explore the consequences of not treating the nodes on each end as having a directly connected shared subnet (apart from fe80::/10) and what that does for address assignment/pd.

Best regards,
Ole