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

Philip Homburg <> Wed, 25 November 2020 12:08 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 922E53A0FEC for <>; Wed, 25 Nov 2020 04:08:09 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.499
X-Spam-Status: No, score=-1.499 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, KHOP_HELO_FCRDNS=0.399, SPF_HELO_NONE=0.001, SPF_NONE=0.001] autolearn=no autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 0RrvKDhZVjkH for <>; Wed, 25 Nov 2020 04:08:07 -0800 (PST)
Received: from ( [IPv6:2001:888:1044:10:2a0:c9ff:fe9f:17a9]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 5C9633A0FE4 for <>; Wed, 25 Nov 2020 04:08:06 -0800 (PST)
Received: from (localhost [::ffff:]) by with esmtp (TLS version=TLSv1.2 cipher=ECDHE-RSA-CHACHA20-POLY1305) (Smail #157) id m1khtaY-0000JoC; Wed, 25 Nov 2020 13:07:58 +0100
Message-Id: <>
Subject: Re: [EXTERNAL] Re: [v6ops] How do you solve 3GPP issue if neither operator nor handset supports PD?
From: Philip Homburg <>
References: <> <> <> <> <> <> <> <> <> <> <> <> <> <>
In-reply-to: Your message of "Tue, 24 Nov 2020 17:33:25 +0000 ." <>
Date: Wed, 25 Nov 2020 13:07:54 +0100
Archived-At: <>
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 25 Nov 2020 12:08:10 -0000

> Philip, obviously I do
> not agree to your position and ask that you have a further
> consideration of the "LLA Type" draft. IPv6 interfaces may assign
> multiple IPv6 addresses, and even multiple IPv6 link-local address
> which may be created by multiple means (e.g., RFC4941(bis), RFC7217,
> RFC3972, admin config, OMNI etc.).  By placing a "Type" code in
> bits 56-63 of the LLA the different types can be differentiated
> without there being a chance for mutual interference or collisions
> that might require DAD. 

That doesn't make any sense to me. Outside OMNI, this type of interference
just doesn't exist.

If it does, then please give numbers. How often does adding the flag prevent
interference or collisions outside OMNI? Did anyone ever spotted interference
between different types of addresses on ethernet?

I can see how it is an issue for OMNI, but that just means that OMNI is

> Then, by also including a Prefix Length
> value in bits 48-55 of the LLA we can have a PD exchange without
> having to include any form of PIO* in the RS/RA message, which
> saves some bits over low-end links.  

Compression for low-bandwidth links should be done in IPv6-over-foo documents,
not as general changes to the architecture.

In particular, we are discussing prefix delegation in mobile networks,
which as not low-end by any sensible definition of low-end.

> Finally, when the mobile node
> gets its prefix delegation its LLA encodes the prefix so that PD
> and IPv6 ND are inherently linked instead of having to map the PD
> to some other form of LLA through a lookup table.

This seems to be a bogus argument to me. The router needs to map the GUA
prefix to an outgoing interface, so you get the link-local next hop for free.

A transmission function on a point-to-point interface doesn't a next hop
unless you run NUD on the link, which as far as I know, mobile doesn't.