Re: [spring] Beyond SRv6.

Robert Raszuk <robert@raszuk.net> Fri, 13 September 2019 09:33 UTC

Return-Path: <robert@raszuk.net>
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 9247C1200B9 for <ipv6@ietfa.amsl.com>; Fri, 13 Sep 2019 02:33:26 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.998
X-Spam-Level:
X-Spam-Status: No, score=-1.998 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=raszuk.net
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 sWv31ONvVcLn for <ipv6@ietfa.amsl.com>; Fri, 13 Sep 2019 02:33:24 -0700 (PDT)
Received: from mail-qk1-x72b.google.com (mail-qk1-x72b.google.com [IPv6:2607:f8b0:4864:20::72b]) (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 AA10712006A for <6man@ietf.org>; Fri, 13 Sep 2019 02:33:24 -0700 (PDT)
Received: by mail-qk1-x72b.google.com with SMTP id f16so1173188qkl.9 for <6man@ietf.org>; Fri, 13 Sep 2019 02:33:24 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=raszuk.net; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=l1eWEvF5IRKzHhNgOeb4zjvfYdwhO4/9E+CE4pi8hZo=; b=TK8TDQvZPhXFBhJiCXkp129X2cs0PjFAdN1jGVgqhsZ6laTgqZPZkTdoU00Gk4GLWi t7tkSUXbp+gs77CIVXa3qK9AyaKi8LLsyMj3GkY3vugjSStUoONzxAnQE1JzhNdDG8r0 oRHWL2qlBbSvwEBrobI2FoHLlzD8Gy/yjvL/KvJWZDmJ7qw8Ga8pZXjVQoABByHro1/v kXNAbSkYiJz/numtfA6qMFOW7pSmIiZcsGMF+LkAdslFPLNUMlhXDXYG95rozV79eVN2 q2hg4eoXkFhnq3A3itfIEwTvI+x2V9gV/+B8wBAl/lkKE3VrgGxwFxhbDRfVhEUyyHK5 CP+Q==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=l1eWEvF5IRKzHhNgOeb4zjvfYdwhO4/9E+CE4pi8hZo=; b=ZJicMWsyVFBT8jaDFtSg8/ltvhTdZbY9s4McdG7Gw+lPnomFXPFq/FsezjktZl+y15 lOE2n0jTkUOCTiKOuorNifmqIviu+whT91NPl00vT5AdHuR57T/7u30aRcjy7sMALEn3 TeF75oGd60e6YXeukwUUcrI74glmH8mde7B8bkXkQHKkW5nTXYmFrEgUADjHN6fZzIcg z7G352mq9J7zVD8iVOSs6IINyOQakhUZTOxsOForsBxczaNoEtdmiCrEVag+nKMGb0wb U8cdyR7Xa1p3uPL+72PBIfFVCkI+mlSjikvops8fTSvFAt8DxUn5cpD+ox9wVnGB74JI CnYg==
X-Gm-Message-State: APjAAAXx0QBW/wJM2V7bteabLmG5IpGyGOf5K4hZwIacQCLsRFgt0fyy J6IVG6cbpbdgur8cWxKRv7mXWMFzHENAQBwpGXtF5g==
X-Google-Smtp-Source: APXvYqwzBPbhn9ynbOe7oPTZWnC0Lgvmtv9z8sOqdD0sXjKcA9ZRU7lbHPsJZ1DxqVM3e3EVGgzqLz65V9PfXLhd6qk=
X-Received: by 2002:a37:6144:: with SMTP id v65mr44253665qkb.465.1568367203591; Fri, 13 Sep 2019 02:33:23 -0700 (PDT)
MIME-Version: 1.0
References: <5B57874F-8C54-4E82-BB55-A2B6585B6AE6@bell.ca> <BYAPR05MB5463BA9F2C38745F4BDF5C28AEB00@BYAPR05MB5463.namprd05.prod.outlook.com> <CAOj+MMHvc-P=j0dvs0uMS+NmapQ-RbcgzC4OLg5evUjYpcaoQQ@mail.gmail.com> <704dbd1e-b1e6-0924-42b1-6bf19fa785fe@gmail.com> <CAOj+MMExK2hkex0SiMPZf-XtXstSoibBWSrmXqtazjCS6xUS-A@mail.gmail.com> <CALx6S366sSE1nxqWrx0YsK6OAUvoCAW5cHGo9LSEdCnM0bM4tA@mail.gmail.com>
In-Reply-To: <CALx6S366sSE1nxqWrx0YsK6OAUvoCAW5cHGo9LSEdCnM0bM4tA@mail.gmail.com>
From: Robert Raszuk <robert@raszuk.net>
Date: Fri, 13 Sep 2019 11:33:14 +0200
Message-ID: <CAOj+MMHCzevD0WKQiRKtjSexwzi_YMD1_wAL+oP4L05pLqUhmA@mail.gmail.com>
Subject: Re: [spring] Beyond SRv6.
To: Tom Herbert <tom@herbertland.com>
Cc: Brian E Carpenter <brian.e.carpenter@gmail.com>, Rob Shakir <robjs@google.com>, SPRING WG <spring@ietf.org>, 6man <6man@ietf.org>, "xiechf@chinatelecom.cn" <xiechf@chinatelecom.cn>, Tarek Saad <tsaad.net@gmail.com>
Content-Type: multipart/alternative; boundary="0000000000000c3dc905926bf2e9"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/8237YuqUesT2SVIUah1_FqF9tNI>
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: Fri, 13 Sep 2019 09:33:26 -0000

Hi Tom,

Robert,
>
> Right, but isn't that precisely one of the arguments that 16 byte SIDs are
> a problem? For instance, if my parsing buffer is 128 bytes then that allows
> an SRH with at most four or maybe five SIDs if I'm not mistaken. It seems
> like the smaller SID size of SRV6+, even with the DOH PSSI, option still
> would produce smaller a header chain than SRV6 and thereby allow more
> segments in the header.
>

Let me just send a ref to one of the IETF emails from eng of one of the
major NPU data plane vendor ...

He said:

    It clearly depends on the device capabilities. For a device with a
parsing buffer of *256 bytes*
    that should be plenty of room for HBH options, SR header,
transport layer, etc.

https://mailarchive.ietf.org/arch/msg/ippm/RapEwM8JcMZjFZtqcsF1NqXWDUI#

I also know from other direct discussions that 256 bytes is the defacto
standard in modern chips.

But the reality is and this has been already said as well that most use
cases use just a few SIDs say anywhere from 1-4. Beyond that while of
course you will find customer stating I need 10 you can use uSID or
draft-li-spring-compressed-srv6-np

Thx,
R.