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RE: [mpls] LastCall: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt> (Proactive Connectivity Verification, Continuity Check and Remote Defect indicationfor MPLS Transport Profile) to Proposed Standard

2011-07-08 10:36:29
Hi,
Just to make it clear, this is not a discussion on the requirements. I
would like to encourage this kind of discussion but in the right
context.
The CC-CV-RDI draft aims to satisfy the OAM requirements which are
specified in RFC 5860. One of the requirements there is to provide a
tool for CC as well as for CV. 
In the context of this LC, we should focus now on the proposed solution.
Best regards,
Nurit

-----Original Message-----
From: mpls-bounces(_at_)ietf(_dot_)org 
[mailto:mpls-bounces(_at_)ietf(_dot_)org] On Behalf Of
ext Thomas Nadeau
Sent: Friday, July 08, 2011 6:27 PM
To: neil(_dot_)2(_dot_)harrison(_at_)bt(_dot_)com
Cc: mpls(_at_)ietf(_dot_)org; ietf(_at_)ietf(_dot_)org; 
ietf-announce(_at_)ietf(_dot_)org;
stbryant(_at_)cisco(_dot_)com
Subject: Re: [mpls] LastCall: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification,Continuity Check and Remote Defect
indicationfor MPLS Transport Profile) to Proposed Standard


On Jul 8, 2011, at 3:15 AM, <neil(_dot_)2(_dot_)harrison(_at_)bt(_dot_)com> 
wrote:

Got to say I agree with Rui on much of what he says here.  And I
absolutely resonate with his point on the need for simplicity.  The
reason OAM needs to be as simple as possible is because it must be super
reliable....we do not want to consciously build in weaknesses, esp
unnecessary ones.... this also implies minimal config.  We could all do
better on this.  For example:

-       Rui is dead right a CC function is fairly useless, we only
need a CV function...the ATM OAM in I.610 suffers from this problem (and
few others like AIS and the assumed use of request/response MLT to
diagnose leaking/mismerging traffic...request/response OAM won't work
with unidirectional defects).

        While you are entitled to your opinion, I personally think there
are enough requirements elsewhere to have both CC and CV functions.  But
we digress. Are you actually asking that the CC functionality be removed
from the draft or just making a general comment?

-       all packet layer networks should not have an AIS OAM
message....very obvious for the cl-ps mode of course.  The co-ps mode is
also not like the co-cs mode.  One has to consciously manufacture AIS
messages and target them to specific clients in the co-ps mode....who
may have taken action in their own layer network and 'moved elsewhere'
anyway, ie a total waste of time now.  AIS is actually unnecessary wrt
providing information anyway, it simply represents an in-built weakness
of just something else to go wrong which itself will create problems.

        What does that comment have to do with the actual draft in
question?

-       creating preconfigured TCM sublayers is just asking for
trouble IMO.  It is far smarter to simply create a single end-end OAM CV
(and when required PM) flow and tap this off at intermediate nodes on
the *rare* occasions one wants to do.

        Again, what does this have to do with the actual draft in
question?

        --tom





regards, Neil

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-----Original Message-----
From: mpls-bounces(_at_)ietf(_dot_)org 
[mailto:mpls-bounces(_at_)ietf(_dot_)org] On Behalf
Of
Rui Costa
Sent: 08 July 2011 01:15
To: David Allan I; Stewart Bryant
Cc: ietf(_at_)ietf(_dot_)org; IETF-Announce; mpls(_at_)ietf(_dot_)org
Subject: Re: [mpls] Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

David,

Reading something, keeping it on record, without effect in the draft
and "ignoring comments" have IMHO similar outcomes. As author of the
draft you are free to do it. These standards have a great impact in
our
work, so i'm also free to write what i did.




Stewart,

My technical concerns regarding this draft were expressed...
...in the (ITU-T -> IETF, Feb/2011) liaison regarding it (LS281, i
believe);
...in operators' meetings' that took place during ITU-T's Feb/2011
plenary meeting;
...in a comparison session that took place during that same ITU-T
meeting.
Some:

CC/CV
I don't understand the need for 2 types of packets: a single type
allows CC; mismatching identifiers in the same CC packets allow CV.
Besides adding complexity, we whether always activate both or
potentiate undetected mismerges.
(BTW: can't understand how we propose one ACH codepoint to CC,
another
for CV, [counting other drafts, another for frame loss ...] but don't
consider assigning 1 single ACH protocol identifier codepoint as
requested by ITU-T)

Uni P2P / P2MP
I can't see how BFD will support unidir and hence P2MP other than...

...eliminating the session "state variable" (down, init, up), aiming
just the state variables we really need, bringing us to something
similar to 1731, eventually with other bits on the wire or...
...using IP to create the reverse way, which we cannot assume per
requirements;
Will we create a complete different tool for that?
(BFD's B="bidirectional")

Provisioning list
This is an MPLS profile/subset (and i heard) achievable through a
particular configuration. So, i expect each draft-ietf-mpls-TP-* to
focus on that profile/configuration. However, i keep seeing
references
f.i. to IP encapsulations unexpected under TP's OAM.
I don't thus understand what the aim is: do we expect this in TP, are
we talking about MPLS in general?... The TP profile is never quite
delimited.
Does chapter 4 contain ALL the configurable parameters list agreed to
provide in the comparison session?

Backwards compatibility
This was the main argument risen to ground MPLS-TP OAM on BFD. It's
not
a better argument than grounding MPLS-TP OAM on 1731 due to its ETH
deployment plus coherence with SDH, OTN, as defended by ITU-T.
For reasons like the above, however, MPLS-TP BFD won't be backwards
compatible with previous BFD (even considering just CC/CV). They
don't
even share the same codepoint.

Simplicity
Whether we look to PDH, SDH, OTN or ETH, ITU-T's approach to CC is
simpler: in each flow, a standard defined nr of constant heartbeat
signals (with standard constant or provisioned period - no
auto/negotiated -) means OK. A standard defined number of misses
means
lost Rx connection. An RDI, the only articulation between Rx and Tx
flows, meaningful in bidirectional applications, allows each pear to
identify Tx problems.
This OAM simplicity is the key for reliable fail finger pointing,
performance reports and protection. Also to allow scaling, more
implementation opportunities/manufacturers, which is valuable for
operators.


IMHO, between your MPLS-TP view and MPLS/IP, it becomes more and more
difficult to tell which is which.

Regards,
Rui









-----Original Message-----
From: David Allan I 
[mailto:david(_dot_)i(_dot_)allan(_at_)ericsson(_dot_)com]
Sent: quarta-feira, 6 de Julho de 2011 19:25
To: erminio(_dot_)ottone_69(_at_)libero(_dot_)it; Rui Costa; 
ietf(_at_)ietf(_dot_)org; IETF-
Announce
Cc: mpls(_at_)ietf(_dot_)org
Subject: RE: [mpls] R: Re: Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-
05.txt> (Proactive Connectivity Verification, Continuity Check and
Remote Defect indication for MPLS Transport Profile) to Proposed
Standard

Hi Erminio:

<snipped>
Several service providers regarded this draft as not meeting their
transport networks' needs.

E> This is a true statement: the solution in this draft is useless
for
many MPLS- TP deployments.

The two statements do not necessarily follow.

What we established during discussions at the SG15 plenary in
February
was that the issue some service providers had was that the IETF BFD
solution exceeded their requirements in that there was additional
functionality they did not see a need for, and that they considered
any
additional functionality parasitic.

However this is a consequence of adapting an existing technology to a
new application. I do not see any way around that. And the entire
joint
project was based on the premise of engineering re-use not greenfield
design. That is what it said on the tin up front, and IMO why when
the
IETF started down this path packet transport transitioned from being
a
minority sport to mainstream, so it is a bit late to cry foul....

My 2 cents
Dave




-----Original Message-----
From: David Allan I 
[mailto:david(_dot_)i(_dot_)allan(_at_)ericsson(_dot_)com]
Sent: quarta-feira, 6 de Julho de 2011 18:36
To: erminio(_dot_)ottone_69(_at_)libero(_dot_)it; loa(_at_)pi(_dot_)nu; Rui 
Costa
Cc: mpls(_at_)ietf(_dot_)org; ietf(_at_)ietf(_dot_)org; IETF-Announce
Subject: RE: [mpls] R: Re: Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-
05.txt> (Proactive Connectivity Verification, Continuity Check and
Remote Defect indication for MPLS Transport Profile) to Proposed
Standard

Hi Erminio:

Two of the three document editors were present at SG15 plenary in
February where the comments originated. The revised meeting schedule
resulted in a day spent going through the document with the editors.
IMO there were lots of discussion and legitimate issues with the
document identified and corrected so it was a useful session. The
liaison of same was in many ways *after the fact*.

Cheers
Dave




-----Original Message-----
From: erminio(_dot_)ottone_69(_at_)libero(_dot_)it
[mailto:erminio(_dot_)ottone_69(_at_)libero(_dot_)it]
Sent: quarta-feira, 6 de Julho de 2011 18:34
To: Rui Costa; ietf(_at_)ietf(_dot_)org; IETF-Announce
Cc: mpls(_at_)ietf(_dot_)org
Subject: R: Re: [mpls] Last Call:
<draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

The way this draft has been developed is a bit strange.

The poll for its adoption as a WG document was halted by the MPLS WG
chair
because "it is not possible to judge consensus":

http://www.ietf.org/mail-archive/web/mpls/current/msg04502.html

The lack of consensus was motivated by serious technical concerns
raised by
several transport experts during the poll.

Nevertheless the MPLS WG chair decided to adopt the draft as a WG
document:

http://www.ietf.org/mail-archive/web/mpls/current/msg04512.html

After several WG revisions and WG LCs, the technical issues have not
been
resolved.

Several service providers regarded this draft as not meeting their
transport
networks' needs.

This is a true statement: the solution in this draft is useless for
many MPLS-
TP deployments.


-----Original Message-----
From: erminio(_dot_)ottone_69(_at_)libero(_dot_)it
[mailto:erminio(_dot_)ottone_69(_at_)libero(_dot_)it]
Sent: quarta-feira, 6 de Julho de 2011 18:26
To: loa(_at_)pi(_dot_)nu; Rui Costa
Cc: mpls(_at_)ietf(_dot_)org; ietf(_at_)ietf(_dot_)org; IETF-Announce
Subject: R: Re: [mpls] Last Call:
<draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

Version -04 of the document was published June 28th.

The publication request for draft-ietf-mpls-tp-cc-cv-rdi was  sent
June 29th.


So when the WG LC to confirm the LC comment resolution has been
launched?

The proto write-up says:

           It has also passed a working roup call to verify that LC
comments
were correctly with minor comments.

It also says:

           The comments has been
           carefully discussed between the authors and people making
the
comments and
           has been resolved.

But it seems that some comments have not been discussed with the
authors of
the comments. When ITU-T Q10/15 has been involved in discussing its
comments?




-----Original Message-----
From: Loa Andersson [mailto:loa(_at_)pi(_dot_)nu]
Sent: quarta-feira, 6 de Julho de 2011 16:44
To: Rui Costa
Cc: ietf(_at_)ietf(_dot_)org; IETF-Announce; mpls(_at_)ietf(_dot_)org
Subject: Re: [mpls] Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

All,

Since someone has commented about the process used for resolving
questions on
draft-ietf-mpls-tp-cc-cv-rdi I am supplying some details below.

The history of draft-ietf-mpls-tp-cc-cv-rdi working group review
process is:

On February 3rd 2011 the working group last call was issued
on version -03

     This was copied to the the Ad Hoc Team List
     and liaised to SG15 also on February 3rd

     This working group last call ended om Feb 28


     On Feb 28 we also received a liaison with comments from SG15


The authors compiled a list of all comments received  as part the
MPLS
working group last call; these  comments - and the intended
resolution
-
is included in the meeting minutes from the Prague meeting:


     http://www.ietf.org/proceedings/80/slides/mpls-9.pdf


 During the IETF meeting in Prague, we agreed with the BFD working
 group to do a separate working group last callfor the BFD working
 group

The (BFD) working group last call was started on March 30th and ran
for 13 days. The last call ended on April 11th.

 The authors have since worked hard to resolve comments, some
 issue has been brought to the working group mailing list for
 resolution.

 Version -04 of the document was published June 28th.

 The publication request for draft-ietf-mpls-tp-cc-cv-rdi was  sent
 June 29th.

 The AD review resulted in a "New ID needed" due to mostly editorial
 comments. Version -05 was published on June 29 and the IETF last
call
 started as soon as the new ID was avaialbe.

 The current list of Last Call Comments resoltion is also avaiable
at:
 http://www.pi.nu/~loa/cc-cv-rdi-Last-Call-Comments.xls

 The list of issues that the authors kept very carefully, shows
without
doubt
 that no comments been ignored.

 Loa
 mpls wg document shepherd







-----Original Message-----
From: David Allan I 
[mailto:david(_dot_)i(_dot_)allan(_at_)ericsson(_dot_)com]
Sent: quarta-feira, 6 de Julho de 2011 14:58
To: Rui Costa; ietf(_at_)ietf(_dot_)org; IETF-Announce
Cc: mpls(_at_)ietf(_dot_)org
Subject: RE: [mpls] Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

Hi Rui:

The comments were not ignored, the resolution of the Q10 comments as
well as those collected from the MPLS WG was presented at the last
IETF. My spreadsheet from which that report was generated and has
been
augmented to include the BFD WG comments is available at
http://www.pi.nu/~loa/cc-cv-rdi-Last-Call-Comments.xls

So you know...
Dave


-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org 
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On Behalf
Of
Rui Costa
Sent: segunda-feira, 4 de Julho de 2011 23:03
To: ietf(_at_)ietf(_dot_)org; IETF-Announce
Cc: mpls(_at_)ietf(_dot_)org
Subject: RE: [mpls] Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard

IMHO and for the record:

ITU-T comments regarding this draft haven't been discussed with ITU-T
but were simply ignored. No LS describing these comments' resolution
was sent.

Several service providers regarded this draft as not meeting their
transport networks' needs.

[The v03 draft was published in Feb and went to WG LC.
The v04 draft addressing WG LC comments was published on the 28th
June
(same date as the proto write-up).
When was the WG LC launched, to verify LC comments resolution?]

Regards,
Rui


-----Original Message-----
From: mpls-bounces(_at_)ietf(_dot_)org 
[mailto:mpls-bounces(_at_)ietf(_dot_)org] On Behalf
Of
The IESG
Sent: quinta-feira, 30 de Junho de 2011 14:47
To: IETF-Announce
Cc: mpls(_at_)ietf(_dot_)org
Subject: [mpls] Last Call: <draft-ietf-mpls-tp-cc-cv-rdi-05.txt>
(Proactive Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile) to Proposed Standard


The IESG has received a request from the Multiprotocol Label
Switching
WG
(mpls) to consider the following document:
- 'Proactive Connectivity Verification, Continuity Check and Remote
  Defect indication for MPLS Transport Profile'
 <draft-ietf-mpls-tp-cc-cv-rdi-05.txt> as a Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to
the
ietf(_at_)ietf(_dot_)org mailing lists by 2011-07-14. Exceptionally, comments
may
be
sent to iesg(_at_)ietf(_dot_)org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract

  Continuity Check, Proactive Connectivity Verification and Remote
  Defect Indication functionalities are required for MPLS-TP OAM.

  Continuity Check monitors the integrity of the continuity of the
  label switched path for any loss of continuity defect. Connectivity
  verification monitors the integrity of the routing of the label
  switched path between sink and source for any connectivity issues.
  Remote defect indication enables an End Point to report, to its
  associated End Point, a fault or defect condition that it detects
on
  a pseudo wire, label switched path or Section.

  This document specifies methods for proactive continuity check,
  continuity verification, and remote defect indication for MPLS-TP
  label switched paths, pseudo wires and Sections using Bidirectional
  Forwarding Detection.


The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-mpls-tp-cc-cv-rdi/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-mpls-tp-cc-cv-rdi/


No IPR declarations have been submitted directly on this I-D.
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