Re: [Time] MEP and maintenance domain boundary

Huub van Helvoort <huubatwork@gmail.com> Mon, 30 June 2014 12:58 UTC

Return-Path: <huubatwork@gmail.com>
X-Original-To: time@ietfa.amsl.com
Delivered-To: time@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0C33A1A02BB for <time@ietfa.amsl.com>; Mon, 30 Jun 2014 05:58:27 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.276
X-Spam-Level:
X-Spam-Status: No, score=-1.276 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, MIME_HTML_ONLY=0.723, SPF_PASS=-0.001] autolearn=no
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 ppV2D9iokPZ4 for <time@ietfa.amsl.com>; Mon, 30 Jun 2014 05:58:25 -0700 (PDT)
Received: from mail-we0-x22e.google.com (mail-we0-x22e.google.com [IPv6:2a00:1450:400c:c03::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 655D81A02C2 for <time@ietf.org>; Mon, 30 Jun 2014 05:58:25 -0700 (PDT)
Received: by mail-we0-f174.google.com with SMTP id u57so8265098wes.33 for <time@ietf.org>; Mon, 30 Jun 2014 05:58:24 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:disposition-notification-to:date:from:reply-to :user-agent:mime-version:to:subject:references:in-reply-to :content-type:content-transfer-encoding; bh=pxZxDls0EbQxRTEh/bUxJ8EMq2ydVeClPXpNUK7wDgs=; b=AHmomTAxwyJtqpcqgezImZBFdGVjrdQlB1CgC3eVwFVg5iq7c7fy4SzeIM7JaWW5TF xCPS5l49EzZIdtZJTihxA1eWAEUf9myBbj4AOWP+OUdqJdn+/1dJyvxyuJSYGXXxhT2w mP81kpYR52mz+rpl9QVojHmDaacrea0+mQCWeakSeFOJv56tJxSb7hFd7uOsUNflIHCv C2J8pOCOXnvkv0qkCU+lVzEf5sAzhGMrks646k/+4eSg01cS2IuLimBsZCeATZQMdk7b K+/0xlLXdzSzk7bBS1+UnlJ8SupviYRSXAW4wgJKPHG+diG4pkVL4T7dmockJIh6dOs0 Mv4A==
X-Received: by 10.180.211.71 with SMTP id na7mr20905606wic.55.1404133103724; Mon, 30 Jun 2014 05:58:23 -0700 (PDT)
Received: from McAsterix.local (g215085.upc-g.chello.nl. [80.57.215.85]) by mx.google.com with ESMTPSA id q11sm31204237wib.14.2014.06.30.05.58.22 for <time@ietf.org> (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 30 Jun 2014 05:58:23 -0700 (PDT)
Message-ID: <53B15EED.2020701@gmail.com>
Date: Mon, 30 Jun 2014 14:58:21 +0200
From: Huub van Helvoort <huubatwork@gmail.com>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0
MIME-Version: 1.0
To: time@ietf.org
References: <B8F9A780D330094D99AF023C5877DABA8457B6A4@nkgeml501-mbs.china.huawei.com>
In-Reply-To: <B8F9A780D330094D99AF023C5877DABA8457B6A4@nkgeml501-mbs.china.huawei.com>
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Archived-At: http://mailarchive.ietf.org/arch/msg/time/8tkFUHjCCwh9iVcVbyG_XJHKSnc
Subject: Re: [Time] MEP and maintenance domain boundary
X-BeenThere: time@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
Reply-To: huubatwork@gmail.com
List-Id: "Transport Independent OAM in Multi-Layer network Entity \(TIME\) discussion list." <time.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/time>, <mailto:time-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/time/>
List-Post: <mailto:time@ietf.org>
List-Help: <mailto:time-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/time>, <mailto:time-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 30 Jun 2014 12:58:27 -0000

Hello Qin,

You wrote:

Hi, Greg:

Thanks for your review to problem statement draft.

http://tools.ietf.org/html/draft-ww-opsawg-multi-layer-oam-01" rel="nofollow">http://tools.ietf.org/html/draft-ww-opsawg-multi-layer-oam-01

Section 4 gives an architecture overview of management plane OAM,

You comment on the following quoted sentence

“MEP is a maintenance functional entity that is implemented into

   network entity at the maintenance domain boundary 

as “Not necessarily, e.g. MEP at Level < 7 in Ethernet Service OAM as CFM or Y.1731.

Unfortunately MPLS-TP has only one MEL, fixed at "7".

Are you saying MEP can be placed either at the maintenance domain boundary or within maintenance domain?

First of all you have to correct the expansion of MEP and MIP:
MEP = Maintenance entity End Point
MIP = Maintenance entity Intermediate Point.
MEPs and MIPs that belong to the same Maintenance Entity (ME) are not
aware of any MEPs or MIPs outside the ME they belong to.

A Maintenance Entity can be any path, tunnel or section in the
network.
So it can exist between domain boundaries (NNIs) but also inside
a domain, or across multiple domains (end-to-end ME).

In section 4 I notice:
   MEP is a maintenance functional entity that is implemented
   into a Network Element either at the maintenance domain boundary or
   in the maintenance domain and can generate, send and receive OAM
   packets.

What is the difference between generate and send OAM packets?

   MIP is a maintenance functional entity that is implemented
   into a Network Element in the maintenance domain and can forward OAM
   packets.

A MIP can also respond to OAM messages sent by the source MEP.

   Either MEP or MIP may be at different layer and use various
   different encapsulating protocols.

This is confusing, as I explained above.
MEPs and MIPs can exist in different layers/technologies.
However in the same layer ME MIPs cannot exist without MEPs.
MEPs and MIPs in the same ME in a layer are not aware of 
MEPs and MIPs other ME in the same layer, nor in other layers.

Best regards, Huub.

-- 
*****************************************************************
              请记住,你是独一无二的,就像其他每一个人一样