Re: [mpls] MPLS WG adoption call for draft-mirsky-mpls-p2mp-bfd

Loa Andersson <loa@pi.nu> Tue, 06 November 2018 04:50 UTC

Return-Path: <loa@pi.nu>
X-Original-To: mpls@ietfa.amsl.com
Delivered-To: mpls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E766F130E16; Mon, 5 Nov 2018 20:50:03 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=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 J2ng-MLCQBYF; Mon, 5 Nov 2018 20:50:00 -0800 (PST)
Received: from pipi.pi.nu (pipi.pi.nu [83.168.239.141]) (using TLSv1.1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 6E30F12D4EA; Mon, 5 Nov 2018 20:50:00 -0800 (PST)
Received: from [31.133.148.96] (dhcp-9460.meeting.ietf.org [31.133.148.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: loa@pi.nu) by pipi.pi.nu (Postfix) with ESMTPSA id 78B4D1802AAA; Tue, 6 Nov 2018 05:49:56 +0100 (CET)
To: "Carlos Pignataro (cpignata)" <cpignata@cisco.com>, Greg Mirsky <gregimirsky@gmail.com>
Cc: mpls <mpls@ietf.org>, rtg-bfd WG <rtg-bfd@ietf.org>, "mpls-chairs@ietf.org" <mpls-chairs@ietf.org>
References: <CA+RyBmVDvb6t3rh3sZUHrsApfJRb9A8GCLxPCe9b=tcvZz6J3w@mail.gmail.com> <15CB10A6-6AF4-460F-A71D-56F28D9D7784@cisco.com> <CA+RyBmVbWkDK3o2ZREv2jat++O3hNWBA4_Yn-ynyDdjpG+GjXw@mail.gmail.com> <5BFD9FF7-DBF8-48E6-BF45-1D29AFB90034@cisco.com>
From: Loa Andersson <loa@pi.nu>
Message-ID: <212c9ad1-e932-9e0e-626f-39d13e18f7a1@pi.nu>
Date: Tue, 6 Nov 2018 11:49:54 +0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <5BFD9FF7-DBF8-48E6-BF45-1D29AFB90034@cisco.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/mpls/RdLKx5UEksfmc_whHTaplXBohbc>
Subject: Re: [mpls] MPLS WG adoption call for draft-mirsky-mpls-p2mp-bfd
X-BeenThere: mpls@ietf.org
X-Mailman-Version: 2.1.29
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: Tue, 06 Nov 2018 04:50:05 -0000

Carlos,

Since the a wg adoption poll I read your comments as that we are doing
progress, and that we can address the rest during the wg process,
correct?

/Loa

On 2018-11-06 00:11, Carlos Pignataro (cpignata) wrote:
> Hi Greg,
> 
> Many thanks for your response and suggestions! Please see inline.
> 
>> On Nov 2, 2018, at 6:13 AM, Greg Mirsky <gregimirsky@gmail.com 
>> <mailto:gregimirsky@gmail.com>> wrote:
>>
>> Hi Carlos,
>> thank you for your comments. Please find my notes, answers in-line 
>> tagged GIM>>.
>>
>> Regards,
>> Greg
>>
>> On Thu, Oct 25, 2018 at 8:47 PM Carlos Pignataro (cpignata) 
>> <cpignata@cisco.com <mailto:cpignata@cisco.com>> wrote:
>>
>>     Hi,
>>
>>     Cc BFD WG
>>
>>     It would be useful to understand the use case motivation or
>>     applicability of this draft, other than it can be done.
>>
>> GIM>>  The motivation can be seen in the following (from another draft 
>> that discusses OAM over G-ACh:
>>   In some
>>    environments, the overhead of extra IP/UDP encapsulations may be
>>    considered as overburden and make using more compact G-ACh
>>    encapsulation attractive.
>> Will add text in the draft.
> 
> CMP: Thank you very much. This is a good start, although it would be 
> useful to add precision into which environments specifically, and the 
> burden comparison between IP/UDP and G-ACh.
> 
>>
>>     I’m also increasingly concerned by confusing scope and definition
>>     of specifications.
>>
>>     For example:
>>
>>     https://tools.ietf.org/html/draft-mirsky-mpls-p2mp-bfd-04#section-3.2
>>
>>     3.2.  Non-IP Encapsulation of Multipoint BFD
>>
>>        Non-IP encapsulation for multipoint BFD over p2mp MPLS LSP MUST use
>>        Generic Associated Channel (G-ACh) Label (GAL) [RFC5586] at the
>>        bottom of the label stack followed by Associated Channel Header
>>        (ACH).  Channel Type field in ACH MUST be set to BFD CV [RFC6428].
>>
>>
>>     First, there’s no definition for non-IP BFD in RFC 5586 — only in
>>     RFC 5885.
>>
>> GIM>> RFC 5586 defined the use of GAL. I think that this reference is 
>> appropriate. I agree that the second reference should be to RFC 5885, 
>> not RFC 6428. Will make the change.
> 
> CMP: Thank you. However, RFC 5885 is in the context of PW VCCV — is 
> there a missing definition in the specs for BFD over G-ACh generically?
> 
>>     Second, the specification in RFC 6428 applies to MPLS Transport
>>     Profile only. NOT for MPLS, and explicitly NOT for P2MP!
>>
>>     https://tools.ietf.org/html/rfc6428#section-1
>>
>>        This document specifies the BFD extension and behavior to
>>     satisfy the
>>        CC, proactive CV monitoring, and the RDI functional
>>     requirements for
>>        both co-routed and associated bidirectional LSPs.  Supported
>>        encapsulations include Generic Associated Channel Label (GAL) /
>>        Generic Associated Channel (G-ACh), Virtual Circuit Connectivity
>>        Verification (VCCV), and UDP/IP.  Procedures for unidirectional
>>        point-to-point (P2P) and point-to-multipoint (P2MP) LSPs are for
>>        further study.
>>
>>
>>     So, no, this does not work.
>>
>>     RFC 6428 does not have scope for P2MP.
>>     And RFC 5586 does not specify anything for BFD. Instead, what
>>     needs to be cited (appropriately and expanded) is RFC 5885
>>
>> GIM>> RFC 5586 specifies the use of GAL and G-ACh and the reference is 
>> used in this context.
> 
> CMP: This is the same comment as above.
> 
>>
>>     https://tools.ietf.org/html/rfc6428#section-4
>>           RFC 5884 - BFD CC in UDP/IP/LSP
>>           RFC 5885 - BFD CC in G-ACh
>>
>> GIM>> I'd point that it is for p2p BFD CC, and p2mp BFD uses different 
>> from p2p BFD method to demultiplex BFD control packets.
> 
> 
> CMP: Apologies I did not understand this response.
> 
> CMP: Thanks again for considering the comment to improve the document.
> 
> Thanks,
> 
> Carlos.
> 
> 
>>           RFC 5085 - UDP/IP in G-ACh
>>            MPLS-TP - CC/CV in GAL/G-ACh or G-ACh
>>
>>
>>
>>     Thanks,
>>
>>     — Carlos Pignataro
>>
>>>     On Oct 13, 2018, at 4:24 PM, Greg Mirsky <gregimirsky@gmail.com
>>>     <mailto:gregimirsky@gmail.com>> wrote:
>>>
>>>     Dear WG Chairs, et al.,
>>>     as the author of the BFD for Multipoint Networks over
>>>     Point-to-Multi-Point MPLS LSP (draft-mirsky-mpls-p2mp-bfd) I
>>>     would like to ask you to consider WG adoption call of the draft.
>>>     The document addresses non-IP encapsulation of p2mp BFD over MPLS
>>>     LSP that may be useful if the overhead of IP, particularly IPv6,
>>>     encapsulation is the concern. The base specification of BFD for
>>>     Multipoint Networks is at this time in IESG LC.
>>>
>>>     Regards,
>>>     Greg
>>>     _______________________________________________
>>>     mpls mailing list
>>>     mpls@ietf.org <mailto:mpls@ietf.org>
>>>     https://www.ietf.org/mailman/listinfo/mpls
>>
> 
> 
> 
> _______________________________________________
> mpls mailing list
> mpls@ietf.org
> https://www.ietf.org/mailman/listinfo/mpls
> 

-- 


Loa Andersson                        email: loa@pi.nu
Senior MPLS Expert
Bronze Dragon Consulting             phone: +46 739 81 21 64