Re: Can Multihop BFD be protected using RLFA backup?

Muthu Arul Mozhi Perumal <muthu.arul@gmail.com> Thu, 17 January 2019 11:02 UTC

Return-Path: <muthu.arul@gmail.com>
X-Original-To: rtg-bfd@ietfa.amsl.com
Delivered-To: rtg-bfd@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2065A130DD8 for <rtg-bfd@ietfa.amsl.com>; Thu, 17 Jan 2019 03:02:38 -0800 (PST)
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, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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 IA3JfgKfPyA2 for <rtg-bfd@ietfa.amsl.com>; Thu, 17 Jan 2019 03:02:35 -0800 (PST)
Received: from mail-lf1-x130.google.com (mail-lf1-x130.google.com [IPv6:2a00:1450:4864:20::130]) (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 3E07612F1AC for <rtg-bfd@ietf.org>; Thu, 17 Jan 2019 03:02:35 -0800 (PST)
Received: by mail-lf1-x130.google.com with SMTP id e26so7458268lfc.2 for <rtg-bfd@ietf.org>; Thu, 17 Jan 2019 03:02:35 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=w8jQMfzztMN8ieTNew2RYQBx31G2eVSZThtO6OHJMq4=; b=YDQiOXd6mltRdXwTgqcrDFcXAIss0Xi/Q6ajsOoFTNtPyPz2S4KEIn3K5zzNlMKKB4 jpZ0L7qXhc42/esT7G6mkmy0SDz/fJdLvuJckdSvoBoLBfAtaRqQ+jOFdoDKJBia0hC3 HKXQlVJUxx3+pPypPOl9c/N1HY2n/cnzOTz6ZWhoqez+8aN3rS8qLHtrIocS0HLsTEeN WydJigFtixPsT3BBiu3wuXKIcHFpQOKzQO5Z0TJOeleHYOqjxv4Uj7uXSJLvAznXrnGq H3YdrrV/IhaZ3/LNlE0MEy76LatxnuQ1Cl5UpjD2rU0y7a3T4Qq3TsCOrRAOs5e7gzYO zRXw==
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=w8jQMfzztMN8ieTNew2RYQBx31G2eVSZThtO6OHJMq4=; b=guu1GysQV7EyfFUgBGVy8XhCLh2snae96FSyZnh31TGGcI+zLV0U9JGNlSDpYA1OC0 dQLJvzE7y4t5lc7jFAafPJfxrxou1iHV2KabLdjgn5fiHmaGpK7k/vMK3cQPiNi3cnnA BdQYUIdJdVpB12OS4LlzWzVHILlk1MUBDB057+gTT4wzUSt1s6SjvlLz1DJgLErCMS+V d651R4yh4xs2BV+MFIxxNJ4EJAVqRR0G/QqtVEIV+N1Deb3eeFw4pcXtjVxwgqumgxIh iQsHHogw53EcLGu1XqO4pFIMmzZiK5DulPvj3U95Rirlvr4p9g1wub1sd1md8ylQes0m 5t6g==
X-Gm-Message-State: AJcUukftbZQPYw55V1kkrvbu995hlsp37CLbO8GANbUJlwRLGOtD7ocS T/smnOKnNCk3vpEChYQYpnsuPf/amrxTnd9a/t+FwHEd
X-Google-Smtp-Source: ALg8bN7fJv3fZJ5oX1xtI/6jOsMKdQSVMusD+u6l9f+uSdjd8/dRdVtjTuHUSdEkXxegf0bXCxQy80wXtCNVSyTKmXo=
X-Received: by 2002:a19:d619:: with SMTP id n25mr9586781lfg.91.1547722953220; Thu, 17 Jan 2019 03:02:33 -0800 (PST)
MIME-Version: 1.0
References: <CAKz0y8xNcx9AmS-kx4nM1YXnqk8+PDPrPrdBhMs4jtYVegoz8g@mail.gmail.com> <25009_1547719034_5C40517A_25009_420_1_9E32478DFA9976438E7A22F69B08FF924B78E8A2@OPEXCLILMA4.corporate.adroot.infra.ftgroup>
In-Reply-To: <25009_1547719034_5C40517A_25009_420_1_9E32478DFA9976438E7A22F69B08FF924B78E8A2@OPEXCLILMA4.corporate.adroot.infra.ftgroup>
From: Muthu Arul Mozhi Perumal <muthu.arul@gmail.com>
Date: Thu, 17 Jan 2019 16:32:21 +0530
Message-ID: <CAKz0y8yuVJ7t31OKKm7F1G1aGYMOyFqdE=5JWjWeBBTH_-9OQQ@mail.gmail.com>
Subject: Re: Can Multihop BFD be protected using RLFA backup?
To: stephane.litkowski@orange.com
Cc: "rtg-bfd@ietf.org" <rtg-bfd@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000d66e17057fa554e1"
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtg-bfd/_24lShr9crwsDv_YhsKjEJblbRk>
X-BeenThere: rtg-bfd@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "RTG Area: Bidirectional Forwarding Detection DT" <rtg-bfd.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtg-bfd>, <mailto:rtg-bfd-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rtg-bfd/>
List-Post: <mailto:rtg-bfd@ietf.org>
List-Help: <mailto:rtg-bfd-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtg-bfd>, <mailto:rtg-bfd-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 17 Jan 2019 11:02:38 -0000

Hi Stephane,

Thanks for your response. Please see inline..

On Thu, Jan 17, 2019 at 3:27 PM <stephane.litkowski@orange.com> wrote:

> Hi,
>
>
>
> I think that the fact that “control” packets can benefit of FRR is really
> implementation dependent. It is also linked to the place where BFD packets
> are created (RP or LC).
>
> From a theoretical point of view, nothing prevents FRR to be used as for
> any packet generated by the router itself.
>

Do we know of any implementation that provides RLFA FRR protection to
multihop BFD packets?


> Regarding the encapsulation, if your BFD client is using RFC5883, this
> will not change during FRR, the FRR will just push labels on top
> independently.
>

The primary reason for my question on encapsulations is because RFC 4379
has the foll. as one of the reasons for using the destination address
in 127/8 range for IPv4 (0:0:0:0:0:FFFF:7F00/104 range for IPv6) for
diagnostic packets sent over MPLS LSP:
   1. Although the LSP in question may be broken in unknown ways, the
      likelihood of a diagnostic packet being delivered to a user of an
      MPLS service MUST be held to an absolute minimum.

Since multihop BFD uses a routable destination address, wondering whether
there would be any issues if multihop BFD packets are sent over the RLFA
backup path without following RFC 5884 encapsulation..

Regards,
Muthu

>
>
> Again, the possibility to get FRR is really implementation dependent, as
> the forwarding decision of the BFD packet may not be taken by the network
> processor of the LC.
>
>
>
> Brgds,
>
>
>
> *From:* Rtg-bfd [mailto:rtg-bfd-bounces@ietf.org] *On Behalf Of *Muthu
> Arul Mozhi Perumal
> *Sent:* Thursday, January 17, 2019 10:16
> *To:* rtg-bfd@ietf.org
> *Subject:* Can Multihop BFD be protected using RLFA backup?
>
>
>
> Hi All,
>
>
>
> Multihop BFD (RFC 5883) packets are sent over UDP/IP. The encapsulation
> used is identical to single hop BFD (RFC 5881) except that the UDP
> destination port is set to 4784.
>
>
>
> Now, suppose on the ingress node there is no IP/LFA backup path for the
> destination address tracked by multihop BFD, but there exists an an RLFA
> backup path to that destination. In this case, is multihop BFD expected to
> be protected using the RLFA backup path i.e should multihop BFD packets be
> sent over the RLFA backup path if the primary path goes down?
>
>
>
> If multihop BFD packets are to be sent over the RLFA backup path, what
> encapsulation should the ingress use? The encapsulation specified in RFC
> 5883 or the encapsulation specified in RFC 5884 (MPLS BFD)?
>
>
>
> Please let me know you opinion.
>
>
>
> Regards,
>
> Muthu
>
> _________________________________________________________________________________________________________________________
>
> Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc
> pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler
> a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,
> Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.
>
> This message and its attachments may contain confidential or privileged information that may be protected by law;
> they should not be distributed, used or copied without authorisation.
> If you have received this email in error, please notify the sender and delete this message and its attachments.
> As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.
> Thank you.
>
>