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RE: [PWE3] Gen-ART review of draft-ietf-pwe3-mpls-eth-oam-iwk-06

2013-01-08 11:27:48
Hi Greg....

CC per se has little inherent value....but that is historical.  CV does have 
proper value.  CV and RDI however should NOT be mutually dependent messages as 
the latter cannot be meaningfully associated with (a CV flow on) p2mp 
connections.

And BTW AIS (or FDI) has no value whatsoever in any pkt networks....obvious for 
cl-ps but this is just as true for co-ps.  It has limited value in the co-cs 
mode with PVCs, where its origins stem from the fact that (i) the fixed time 
resource (time-slot) allocated by a server to a client link-connection has to 
be filled with something and (ii) that 'something' became binary all 1s simply 
because that was what the early TTL silicon technology in the PDH produced on 
failure, ie + 5V.  But when one considers co-cs SVCs then AIS even here starts 
to look very silly....the underlying key point being that *unless* there is a 
permanently fixed binding between a server and its clients (even after server 
failure, ie client does not attempt to re-route in *its* layer network) then 
where does the server know who to send the AIS (FDI) to?  AIS (FDI) should be 
strongly deprecated in all future work on OAM.  It took me a little time to 
fully realise this point.

regards, Neil

From: pwe3-bounces(_at_)ietf(_dot_)org 
[mailto:pwe3-bounces(_at_)ietf(_dot_)org] On Behalf Of Greg Mirsky
Sent: 07 January 2013 20:51
To: Bitar, Nabil N
Cc: sajassi(_at_)cisco(_dot_)com; ietf(_at_)ietf(_dot_)org; 
dinmohan(_at_)hotmail(_dot_)com; pwe3(_at_)ietf(_dot_)org; 
gen-art(_at_)ietf(_dot_)org
Subject: Re: [PWE3] Gen-ART review of draft-ietf-pwe3-mpls-eth-oam-iwk-06

Dear Nabil,
can we avoid different interpretation of the same abbreviation (RDI):

   RDI   Remote Defect Indication for Continuity Check Message

   RDI   Reverse Defect Indication

AFAIK, the latter form is the interpretation used by both IEEE 802.1ag and 
Y.1731. How useful is the first form?

Regards,

Greg

On Fri, Jan 4, 2013 at 8:17 AM, Bitar, Nabil N 
<nabil(_dot_)n(_dot_)bitar(_at_)verizon(_dot_)com<mailto:nabil(_dot_)n(_dot_)bitar(_at_)verizon(_dot_)com>>
 wrote:
Hi Dave,
Related to abbreviations comment below and to be clearer, I renamed the 
original terminology section to "Abbreviations and Terminology". I also created 
a subsection called "Abbreviations" ,and "Terminology" became the second 
subsection.  Here iis how the edits look

3. Abbreviations and Terminology
3.1. Abbreviations

        AIS   Alarm Indication Signal

   AC    Attachment Circuit

   BFD   Bidirectional Forwarding Detection

   CC    Continuity Check

   CCM   Continuity Check Message

   CE    Customer Equipment

   CV    Connectivity Verification

   E-LMI Ethernet Local Management Interface

   EVC   Ethernet Virtual Circuit

   LDP   Label Distribution Protocol

   LoS   Loss of Signal

   MA    Maintenance Association

   MD    Maintenance Domain

   ME    Maintenance Entity

   MEG   Maintenance Entity Group

   MEP   Maintenance End Point

   MIP   Maintenance End Point

   MPLS  Multiprotocol Label Switching

   MS-PW Multi-Segment Pseudowire

   NS    Native Service

   OAM   Operations, Administration, and Maintenance

   PE    Provider Edge

   PSN   Packet Switched Network

   PW    Pseudowire

   RDI   Remote Defect Indication for Continuity Check Message

   RDI   Reverse Defect Indication

   S-PE  Switching Provider Edge

   TLV   Type Length Value

   T-PE  Terminating Provider Edge

3.2. Terminology
This document uses the following terms with corresponding definitions:
- MD Level:  Maintenance Domain (MD) Level which identifies a value in the 
range of 0-7 associated with Ethernet OAM frame. MD Level identifies the span 
of the Ethernet OAM frame.
 - MEP:    Maintenance End Point is responsible for origination and termination 
of OAM frames for a given MEG.
 - MIP:      Maintenance Intermediate Point is located between peer MEPs and 
can process OAM frames but does not initiate or terminate them.
Further, this document also uses the terminology and conventions used in 
[RFC6310].


Thanks,
Nabil

From: <Bitar>, Nabil N 
<nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com<mailto:nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com>>
Date: Wednesday, January 2, 2013 11:28 AM
To: "Black, David" 
<david(_dot_)black(_at_)emc(_dot_)com<mailto:david(_dot_)black(_at_)emc(_dot_)com>>,
 "dinmohan(_at_)hotmail(_dot_)com<mailto:dinmohan(_at_)hotmail(_dot_)com>" 
<dinmohan(_at_)hotmail(_dot_)com<mailto:dinmohan(_at_)hotmail(_dot_)com>>, 
"Bitar, Nabil N" 
<nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com<mailto:nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com>>,
 Sagessi <sajassi(_at_)cisco(_dot_)com<mailto:sajassi(_at_)cisco(_dot_)com>>, 
"gen-art(_at_)ietf(_dot_)org<mailto:gen-art(_at_)ietf(_dot_)org>" 
<gen-art(_at_)ietf(_dot_)org<mailto:gen-art(_at_)ietf(_dot_)org>>
Cc: "pwe3(_at_)ietf(_dot_)org<mailto:pwe3(_at_)ietf(_dot_)org>" 
<pwe3(_at_)ietf(_dot_)org<mailto:pwe3(_at_)ietf(_dot_)org>>, 
"ietf(_at_)ietf(_dot_)org<mailto:ietf(_at_)ietf(_dot_)org>" 
<ietf(_at_)ietf(_dot_)org<mailto:ietf(_at_)ietf(_dot_)org>>
Subject: Re: Gen-ART review of draft-ietf-pwe3-mpls-eth-oam-iwk-06

Hi Dave,
Sorry for a late reply addressing your comments. Please, see inline.

Thanks,
Nabil

From: "Black, David" 
<david(_dot_)black(_at_)emc(_dot_)com<mailto:david(_dot_)black(_at_)emc(_dot_)com>>
Date: Monday, August 20, 2012 8:57 PM
To: "dinmohan(_at_)hotmail(_dot_)com<mailto:dinmohan(_at_)hotmail(_dot_)com>" 
<dinmohan(_at_)hotmail(_dot_)com<mailto:dinmohan(_at_)hotmail(_dot_)com>>, 
"Bitar, Nabil N" 
<nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com<mailto:nabil(_dot_)n(_dot_)bitar(_at_)one(_dot_)verizon(_dot_)com>>,
 Sagessi <sajassi(_at_)cisco(_dot_)com<mailto:sajassi(_at_)cisco(_dot_)com>>, 
"gen-art(_at_)ietf(_dot_)org<mailto:gen-art(_at_)ietf(_dot_)org>" 
<gen-art(_at_)ietf(_dot_)org<mailto:gen-art(_at_)ietf(_dot_)org>>
Cc: "Black, David" 
<david(_dot_)black(_at_)emc(_dot_)com<mailto:david(_dot_)black(_at_)emc(_dot_)com>>,
 "pwe3(_at_)ietf(_dot_)org<mailto:pwe3(_at_)ietf(_dot_)org>" 
<pwe3(_at_)ietf(_dot_)org<mailto:pwe3(_at_)ietf(_dot_)org>>, 
"ietf(_at_)ietf(_dot_)org<mailto:ietf(_at_)ietf(_dot_)org>" 
<ietf(_at_)ietf(_dot_)org<mailto:ietf(_at_)ietf(_dot_)org>>
Subject: Gen-ART review of draft-ietf-pwe3-mpls-eth-oam-iwk-06

I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, 
please
see the FAQ at <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Please resolve these comments along with any other Last Call comments you may 
receive.

Document: draft-ietf-pwe3-mpls-eth-oam-iwk-06
Reviewer: David L. Black
Review Date: August 20, 2012
IETF LC End Date: August 20, 2012

Summary:
This draft is basically ready for publication, but has nits that
should be fixed before publication.

<NB> Thanks.



This draft covers defect behavior for Ethernet pseudowires,

including defect state mapping and PE defect reporting behavior.

The draft is generally in good shape.  I found a few minor nits.



1) The draft uses a lot of acronyms - while each acronym appears to

be expanded on first use, an additional section near the start of the

draft listing all of them would be helpful.

<NB> Done.



2) There's a typo in the first paragraph of section 2:



     covers the following Ethernet OAM (Opertaions, Administration and



Opertaions -> Operations.

<NB> Thanks. Done.



3) The following normative reference is incomplete - please add additional

information that will enable a reader to locate the referenced document:



     [MEF16] "Ethernet Local Management Interface", MEF16, January 2006.

[MEF16] "Ethernet Local Management Interface", Metro Ethernet Forum Technical 
Specification MEF16, January 2006.

<NB> changed it to :



4) idnits 2.12.13 did not like the pagination:



  == The page length should not exceed 58 lines per page, but there was 22
     longer pages, the longest (page 1) being 61 lines
<NB> That will be fixed.

Thanks,
--David
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
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