Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save?

"Andrew G. Malis" <agmalis@gmail.com> Thu, 23 July 2015 20:33 UTC

Return-Path: <agmalis@gmail.com>
X-Original-To: mpls@ietfa.amsl.com
Delivered-To: mpls@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A61F21A8A9C for <mpls@ietfa.amsl.com>; Thu, 23 Jul 2015 13:33:09 -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, HTML_MESSAGE=0.001, SPF_PASS=-0.001] autolearn=ham
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 DtdYlBpJFAGm for <mpls@ietfa.amsl.com>; Thu, 23 Jul 2015 13:33:08 -0700 (PDT)
Received: from mail-wi0-x22a.google.com (mail-wi0-x22a.google.com [IPv6:2a00:1450:400c:c05::22a]) (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 00EA51A009E for <mpls@ietf.org>; Thu, 23 Jul 2015 13:33:08 -0700 (PDT)
Received: by wibxm9 with SMTP id xm9so649419wib.1 for <mpls@ietf.org>; Thu, 23 Jul 2015 13:33:06 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=r9h4eFuDpcHkMN5V58RrdelvnAlcPXP7Sjdatgp1VXM=; b=vQcI4/fp6XgfCk5KbJaPEP/8Zr7o8BRXgDCO2WqmG2yCw3n1W+/efYGTvaUGBdzC8Z hzyL8HGTa75mp8e7pBwOHclw9wZvcK9SMwGqdLfKFC8ukqslAwEJeqC97FMDzDJtA8iA QPX67+CmCbllUlfxdPiZ+dz5wOE/yQniYmMMIe4U82k6V7RdqOi4SLIDnc4UcKA63+aA h26YPUMvDaL2dspF5Fc0bjz+A/yOn3+hGrVMEIFukERPQpIGlTm1Jsnp2Vd/MRHJfI1t JCrzl262S7/4i1XdesbQvlP/HgjsLpeUbFagEetJ1OcXkKeKDZYofn7onAgPXQ5s+Smp 92vQ==
X-Received: by 10.194.89.72 with SMTP id bm8mr19684116wjb.116.1437683586767; Thu, 23 Jul 2015 13:33:06 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.28.87.18 with HTTP; Thu, 23 Jul 2015 13:32:47 -0700 (PDT)
In-Reply-To: <4A6CE49E6084B141B15C0713B8993F2831F7A156@SJEXCHMB12.corp.ad.broadcom.com>
References: <DB3PR03MB078098C91E8D3C7DCDCCF8C39D840@DB3PR03MB0780.eurprd03.prod.outlook.com> <EA360A7AB9D90D4B9E9173B6D27C371EE3F6038F@MTKMBS61N1.mediatek.inc> <55B11D6D.2040102@pi.nu> <4A6CE49E6084B141B15C0713B8993F2831F7A156@SJEXCHMB12.corp.ad.broadcom.com>
From: "Andrew G. Malis" <agmalis@gmail.com>
Date: Thu, 23 Jul 2015 22:32:47 +0200
Message-ID: <CAA=duU1oKDWn5wWtunfUffQR5HSGBqaOh_+aMZbDkTBQXLHVKQ@mail.gmail.com>
To: Shahram Davari <davari@broadcom.com>
Content-Type: multipart/alternative; boundary=089e010d868c7d2286051b90cb20
Archived-At: <http://mailarchive.ietf.org/arch/msg/mpls/adn4Qo_uGJysz93Ipgz3JZG4rMo>
Cc: "mpls@ietf.org" <mpls@ietf.org>
Subject: Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save?
X-BeenThere: mpls@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Multi-Protocol Label Switching WG <mpls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mpls>, <mailto:mpls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/mpls/>
List-Post: <mailto:mpls@ietf.org>
List-Help: <mailto:mpls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mpls>, <mailto:mpls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 23 Jul 2015 20:33:09 -0000

Sharam,

The point was made during the meeting that on the wire, "no swap" (but
still decrement TTL, etc.) is indistinguishable from "swap to the same
label". So this really is a local optimization in the switch, and not
subject to standardization.

Cheers,
Andy

On Thu, Jul 23, 2015 at 7:18 PM, Shahram Davari <davari@broadcom.com> wrote:

> I thought the idea was to decrement TTL and consider EXP bits for queuing
> and count as a hop so you can do OAM, etc.. Basically swap to itself.
>
> Thx
> Shahram
>