Re: [mpls] Progressing Resdience Time Measurement draft

Lou Berger <> Sun, 31 January 2016 14:27 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id F1E021AD33F for <>; Sun, 31 Jan 2016 06:27:32 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.667
X-Spam-Status: No, score=-1.667 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, IP_NOT_FRIENDLY=0.334, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001] autolearn=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id UbYQvQKuhkm8 for <>; Sun, 31 Jan 2016 06:27:31 -0800 (PST)
Received: from ( []) by (Postfix) with SMTP id 448411AD338 for <>; Sun, 31 Jan 2016 06:27:31 -0800 (PST)
Received: (qmail 13272 invoked by uid 0); 31 Jan 2016 14:27:26 -0000
Received: from unknown (HELO CMOut01) ( by with SMTP; 31 Jan 2016 14:27:26 -0000
Received: from ([]) by CMOut01 with id CeTH1s00M2SSUrH01eTLXX; Sun, 31 Jan 2016 07:27:25 -0700
X-Authority-Analysis: v=2.1 cv=FuSWoQbq c=1 sm=1 tr=0 a=h1BC+oY+fLhyFmnTBx92Jg==:117 a=IkcTkHD0fZMA:10 a=-NfooI8aBGcA:10 a=uEJ9t1CZtbIA:10 a=7aQ_Q-yQQ-AA:10 a=48vgC7mUAAAA:8 a=0FD05c-RAAAA:8 a=VYftjG--RY8hbhC1RNsA:9 a=Hwm-rIzr9CuGOSFS:21 a=3RmREeOJRhj8Ri5d:21 a=QEXdDO2ut3YA:10
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:Cc:References:To:Subject; bh=lbn/YEaOH/EqQGd2Qyqnq49AUNnY4x/Yvb1zKtAzkkw=; b=yT1re1RXwYKa5BX7YGGJv5aHyWel1JKQAX2tG2pgwXds3ztWaeoEXcP/Zb2TFmRzUyzY4vpXP6v011dH4pHEMIU6+9WsUeyNkbHD4nuFqFy6SoTNuKa2M4rrC4Nb0QYg;
Received: from ([]:44586 helo=[]) by with esmtpa (Exim 4.84) (envelope-from <>) id 1aPsyE-00024E-Gy; Sun, 31 Jan 2016 07:27:18 -0700
To: "Acee Lindem (acee)" <>, Gregory Mirsky <>, Loa Andersson <>,
References: <> <> <>
From: Lou Berger <>
X-Enigmail-Draft-Status: N1110
Message-ID: <>
Date: Sun, 31 Jan 2016 09:27:07 -0500
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
X-Identified-User: {} {sentby:smtp auth authed with}
Archived-At: <>
Cc: "" <>
Subject: Re: [mpls] Progressing Resdience Time Measurement draft
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Multi-Protocol Label Switching WG <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Sun, 31 Jan 2016 14:27:33 -0000

So this thread triggered me to reread the draft.  I don't really have
any time sync experience, so won't be commenting on those aspects of the
draft - but I did just send a message off to the DetNet WG as they be
interested in using this at some point and are likely to have some folks
with 1588 knowledge. 

The following comment is independent of which LSA types are used, as
discussed below, but others may feel it impacts the choice.

Should the solution really scoped to just RSVP controlled TE LSPs?  It
seems to me it should work for any TE LSP, and any TE LSP setup
mechanism that can provide the participating nodes with the required
information.  Does this make sense?

I think the following changes are one way to make this change:

    The scope of
   this document is on LSPs instantiated using RSVP-TE [RFC3209 <>] because
   the LSP's path can be determined.

    The scope of this document is on TE LSPs, e.g., those  instantiated
     RSVP-TE [RFC3209 <>], because
the LSP's path can be determined.

And add text that describes the following in a new section, perhaps at
4.6 or 4.8 "Non-RSVP controlled LSPs"
  When the TE LSP is controlled via mechanisms other than RSVP-TE, the
following information needs to be provided to the RTM capable nodes
along the LSP path:
   - RTM role (ingress, transit, egress)
   - RTM neighbors
   - RTM hop counts (as needed)
  - Anything else I'm sure I missed!
  The method used to convey this information is out of scope of this

I have an RSVP specific comment that I'll send separately.


PS I think this is important work and hope to see it completed soon.

On 1/31/2016 7:50 AM, Acee Lindem (acee) wrote:
> Hi Greg, 
> That sounds like a good plan.
> Thanks,
> Acee
> On 1/30/16, 8:36 PM, "Gregory Mirsky" <> wrote:
>> Hi Acee,
>> thank you for your thorough review and OSPF insights.
>> I've updated reference to RFC 7684 in the new -01 version.
>> When we were starting work on RTM we intended to address LDP signaled
>> IP/MPLS networks as well and that, as I recall, was the reason to use
>> more generic IGP TLVs rather than TE-specific. Since LDP drifted out of
>> scope, I agree, use of TE advertisements is more suitable. We'll work on
>> that and share new update with you and the IGP WGs.
>> 	Regards,
>> 		Greg
>> -----Original Message-----
>> From: mpls [] On Behalf Of Acee Lindem (acee)
>> Sent: Thursday, January 28, 2016 4:55 PM
>> To: Loa Andersson
>> Cc:;
>> Subject: Re: [mpls] Progressing Resdience Time Measurement draft
>> I’ve read the subject draft and think it offers a useful function to
>> facilitate more accurate time synchronization in NTP/PTP deployments. One
>> question I have is why the capability is signaled in the generic IGP TLV
>> LSAs and LSPs rather than the TE advertisements when the document is
>> scoped to RSVP-TE [RFC3209] LSPs? One reason I ask is that we are waiting
>> on implementations of the OSPFv3 Extended LSAs draft. Having said that,
>> OSPFv2 and OSPFv3 have separate registry for the TLV LSAs and section 8
>> should reflect this. Also, OSPF Prefix/Link Attributes is now RFC 7684.
>> Thanks,
>> Acee
>>> -----Original Message-----
>>> From: Loa Andersson []
>>> Sent: Monday, December 14, 2015 7:23 PM
>>> To: Gregory Mirsky;;
>>> Cc:
>>> Subject: Re: [mpls] Progressing Resdience Time Measurement draft
>>> Working Group and authors, <chair hat off> As a matter of fact I
>>> believe this document should be progressed.
>>> <chair hat on>
>>> This draft has been a working group document since early August, but
>>> there has been no discussion on the document on the wg mailing list.
>>> There are of course two ways if interpreting this.
>>> - there is total agreement on the draft
>>> - there is no intrest in the draft
>>> I have no basis to decide which is the case.
>>> Can we plese have at least a few (non-author) comments on the mailing
>>> list if it is time to start the wglc.
>>> /Loa
>>> mpls wg co-chair
>>> On 2015-12-15 07:21, Gregory Mirsky wrote:
>>> Dear Chairs of the MPLS WG,
>>>> authors of the Residence Time Measurement in MPLS Network draft
>>>> believe that all comments received during the WG adoption call been
>>>> addressed.
>>>> Thus, authors would like to ask the WG Chairs to consider WG LC as the
>>>> next step.
>>>>                 Regards,
>>>>                                 Greg
>>>> _______________________________________________
>>>> mpls mailing list
>> _______________________________________________
>> mpls mailing list
> _______________________________________________
> mpls mailing list