IETF Logo Mail Archive

Re: IPv6 Link Local Addresses [was Re: Is 1111 1110 10 equal to 0xfe80 or 0x3fa?]

Dennis Ferguson <dennis.c.ferguson@gmail.com> Mon, 10 June 2019 18:18 UTC

Return-Path: <dennis.c.ferguson@gmail.com>
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 98E52120233 for <ipv6@ietfa.amsl.com>; Mon, 10 Jun 2019 11:18:17 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Level:
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
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 vohYJijdTjKb for <ipv6@ietfa.amsl.com>; Mon, 10 Jun 2019 11:18:15 -0700 (PDT)
Received: from mail-it1-x136.google.com (mail-it1-x136.google.com [IPv6:2607:f8b0:4864:20::136]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id C1CF012021C for <ipv6@ietf.org>; Mon, 10 Jun 2019 11:18:15 -0700 (PDT)
Received: by mail-it1-x136.google.com with SMTP id r135so576852ith.1 for <ipv6@ietf.org>; Mon, 10 Jun 2019 11:18:15 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=EtxfooKBl78MtNv0Rf3D/u7NNV3v4W7pXNeHXqLTWro=; b=kYJSedt/lRjT+FwkEX+79kH5fZGELGeQdJn2s2xNoTQzmkIOhIExKxRfzuG40dWf+t YAisdz+1xpXcr8+LjnCIniCosWq3eJopV1GYrPEOHyF3t/WYMbQ1jknU3SsFk+dRNpmc WC4hKAtHYE/bXyuCYJ/ic9SxEPox8Gbsc5UsxVJOsjwB6I5w+ZYDpmmuR+rGhVQe304y kOV99ecM6oHb8EuNTtIOaU/PScQwdGeSc2l7fk4UQemwuVmXwk25YyZuVjsz2PZaabJl 8W/lawJvmDFLi8NXvuQ49REIeKLIU+1UvuX1hBAv5tvz65cTg8ITWNJigiLLKW8bSm7U lg3Q==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=EtxfooKBl78MtNv0Rf3D/u7NNV3v4W7pXNeHXqLTWro=; b=JwuNG+DxIuVTe4POXhbwsthLutyvtIB/dXcua76KslxX/23ihIXafzWIz97IxcD7A9 aOTftTONn7xtPuvFmVu5zyCyPBSkuTXmM6w/v4MOmK+w7h6/Y0xWVOKYeyqtvHjkPsvN F6AZ0/t+44J29K92zQvPSFq/DYXqqK9JFZdVyvvNe1bIM0ifU3J2DyYR0//adt1M8MK3 pmPOFgsl8uybgrOTVGqBvIW5Pg8V/YcYNY6sG1L7oK34WhpjHeL4z+wox464jprAKbbu 9xTh3fNzqSfuU7CEXvIB4mgxAWCJO5BL5/dTaS3g22MNFxAIZgyXZJcK1c3qL19V9ivl K72g==
X-Gm-Message-State: APjAAAUFodclhMG1AzAFU8y90AgA/SQ2OtQ0eo2fHV63CAAI2xUZWHKR Cb5wbguJUfvq9lo4VPeLsgM=
X-Google-Smtp-Source: APXvYqwB2ffiZlrw2SL/qZDSbwsQH4rpLJBLgV8l/U/eB4ieZjWMCHmmtRctb+Ie8VzB0OIr36glpQ==
X-Received: by 2002:a24:1d01:: with SMTP id 1mr9696215itj.83.1560190694794; Mon, 10 Jun 2019 11:18:14 -0700 (PDT)
Received: from [172.20.60.27] (69-165-184-254.dsl.teksavvy.com. [69.165.184.254]) by smtp.gmail.com with ESMTPSA id j127sm122697itj.32.2019.06.10.11.18.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 11:18:14 -0700 (PDT)
Content-Type: text/plain; charset="us-ascii"
Mime-Version: 1.0 (Mac OS X Mail 12.2 \(3445.102.3\))
Subject: Re: IPv6 Link Local Addresses [was Re: Is 1111 1110 10 equal to 0xfe80 or 0x3fa?]
From: Dennis Ferguson <dennis.c.ferguson@gmail.com>
In-Reply-To: <7E03089C-8429-4B56-96D6-441490C850B2@gmail.com>
Date: Mon, 10 Jun 2019 14:18:13 -0400
Cc: IPv6 List <ipv6@ietf.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <B3D43A45-5E90-4D04-BA64-17150EE6D2AA@gmail.com>
References: <DM6PR15MB2506E62560613C85F74A1FF8BB100@DM6PR15MB2506.namprd15.prod.outlook.com> <CALx6S36vVpD9bAPSBQmhV+daR0Yr4heQ-LaiB4hABAs8ofVfNQ@mail.gmail.com> <DM6PR15MB25063BAF058C1825E2B63E30BB130@DM6PR15MB2506.namprd15.prod.outlook.com> <CAKQ4NaW-QRZDO52zDZTSqz_MsfrS1uQHdz6zFjo+gXvtYVnFxA@mail.gmail.com> <DM6PR15MB2506E06165EA22E66BBB9524BB130@DM6PR15MB2506.namprd15.prod.outlook.com> <7E03089C-8429-4B56-96D6-441490C850B2@gmail.com>
To: Bob Hinden <bob.hinden@gmail.com>
X-Mailer: Apple Mail (2.3445.102.3)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/-qbiJndE9RKx_sPT2WROdx9Ii54>
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: Mon, 10 Jun 2019 18:18:18 -0000

> On Jun 10, 2019, at 12:44, Bob Hinden <bob.hinden@gmail.com> wrote:
> 
> This means that link local addresses have a 10 bit prefix (1111111010) followed by 54 bits of zeros.  That is it, nothing more.   Address with different prefixes or with a 1111111010 prefix followed by non-zero 54 bits are not link local addresses.
> 
> This is not ambiguous.  

So if an application asks my implementation to send a packet addressed to fe80:1::1 out a particular link what should the implementation do with it? It seems like there are only 3 choices:

   1. Run ND on that link to see if it can find a neighbor there with that address to send the packet to.

   2. Send the packet to the current default router.

   3. Something else (what?).

I had though 1. was the answer since that is what is done with packets addressed to link-local unicast destinations (which is what that address is according to RFC4191 section 2.4), but that now seems to be ambiguous.

Dennis Ferguson

v2.23.0 | Report a Bug | By Email