What is necessity for SRH, and other EH, insertion/removal?

Tom Herbert <tom@herbertland.com> Sat, 07 December 2019 17:17 UTC

Return-Path: <tom@herbertland.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 B7BCF1200C7 for <ipv6@ietfa.amsl.com>; Sat, 7 Dec 2019 09:17:29 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level:
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=herbertland-com.20150623.gappssmtp.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 b7E2M1AjKHNK for <ipv6@ietfa.amsl.com>; Sat, 7 Dec 2019 09:17:28 -0800 (PST)
Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) (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 165BD120019 for <ipv6@ietf.org>; Sat, 7 Dec 2019 09:17:28 -0800 (PST)
Received: by mail-ed1-x535.google.com with SMTP id e10so8689575edv.9 for <ipv6@ietf.org>; Sat, 07 Dec 2019 09:17:28 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=herbertland-com.20150623.gappssmtp.com; s=20150623; h=mime-version:from:date:message-id:subject:to; bh=mOlva8vDVqRNs7FqMqqG+Xb4R3zCB6w0Vuqx1BbjcS8=; b=ug6khQQqSiJzhlLpRr3vhuHbo41svqxCq6eO+rorzArUTUCozbPam4xb/D8kgctpus t8zt7qewCizT4z1MXlaQpGci3sDZPfa43a3cI7s0tTN5NE0kQWreYwC46qXXfJnikXvF OOZYekqsESK3J+E6+Y72zinqaL7gg2ce+Cp5GkCrk30Agma0YEC1stI+b+NyVZ/UQG1n S75AfDrj/N9WevjBBxYUptDn8h+9xyGNaP6IcLZwP8LORpuCmoXEzgEiVX0CDYMLqm9c EEco2JEPiKxJk2XpxYorR9yFFxJwX81NnplK3DOJ/UdE1btR/RcYKcdQDDPiD/EdvTm9 QTXg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=mOlva8vDVqRNs7FqMqqG+Xb4R3zCB6w0Vuqx1BbjcS8=; b=cP0vLAYg1zy+aEZMuenhuU1qHWyR2YommZ6zpyfcgDKbNiOen7TiJbJ7PUfKu1DQdW 7jk33wiJ8QcqM+gyDubHaITZy+vFJSRx/0hFB/F+JpEHLnFBFQTYfyhUlJ4ZWCr437+b +wKdvFL3nKuvOBKwNnzgIXzeuSxAYIx44+l7io/bEQhw/HnkbqQzSNH9lbP+huX/Lrsv Thyb/eebAXqgDB8Wlxms01zYSEvRCK3E8ZLlEnZSYZEEPSbtXgz/wqWu+TKYrPqd06Iw gfN1EF5R9oyDV4Fc2Ucd9FkJOXFGaDdMWFdv08Na1phv7mtF01KalwVrz1niBJAT2Db2 2dvw==
X-Gm-Message-State: APjAAAX6fyfrvy/2rB7pfnOyhDipHBPLF1GhvYWjJi/Lcas/GegcvA5Z zvgru0ZJYeyjZW85tAo2xiytAgUi5S5Sceo84El4buWC
X-Google-Smtp-Source: APXvYqx8JfKx0G1Puiy2tsMREWo792dMvWajbJRRujflaW/SPj9y4Krby3212UEF8kaWjg6NM/DRz8I2crSIgGEMC/U=
X-Received: by 2002:a17:906:a444:: with SMTP id cb4mr22481079ejb.42.1575739046076; Sat, 07 Dec 2019 09:17:26 -0800 (PST)
MIME-Version: 1.0
From: Tom Herbert <tom@herbertland.com>
Date: Sat, 07 Dec 2019 09:17:15 -0800
Message-ID: <CALx6S34vG=L_5nw_FzxHBUy+7tbWH4dhOh8xodOfKf2oOdrarg@mail.gmail.com>
Subject: What is necessity for SRH, and other EH, insertion/removal?
To: 6man <ipv6@ietf.org>
Content-Type: text/plain; charset="UTF-8"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/cbF_KKWlGq1JKSgg0m72FQVp-Xw>
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: Sat, 07 Dec 2019 17:17:30 -0000

Pulling this out into a separate thread. Pertinent questions are:

Why is extension header insertion and removal at necessary?

Why isn't the proposed alternative of IPIP encapsulation sufficient?
(where the encapsulating headers contain the extension headers that
would otherwise be inserted)

Please note, I'm asking for the technical justification of the
protocol design, saying that it's necessary because it's already being
deployed isn't useful in this regard.

Tom