Eric and Martin: 

I have received email back from Glenn Parsons regarding the sys-mac-address - 
who is in charge of the IEEE Yang modules for TSN PAR (time sensitive network). 

The email started with a rant regarding the lack of coordination over this 
model occurring at the last minute, and 
a request to delay final review of this model until the july 20th IEEE 802.1 
meeting.   Since the first WG publication of 
draft-ietf-i2rs-yang-l2-network-topology-00.txt  in 2015 predates the IEEE 
802.1 Yang models for the bridge, it seems any coordination for the last 5 
years regarding this model has gone to /dev/null.  

In order to keep harmonious working between IEEE 802.1 and IETF for this I2RS 
model,  it may be necessary for this review and delay to occur.   Qin, his 
co-authors, and I have repeatedly tried to make sure this coordination has 
occurred.  We have received "acks" from internal IETF sources that were 
supposedly knowledgeable. 

I recommend that you and Martin communicate with Glenn Parsons in order to 
foster a good review.  Since the virtual models of I2RS for IETF NM are not 
well understood in the IESG,  you may need my help or members of the I2RS WG to 
help explain the basic concept of the I2RS Virtual models.  

By the way, Glenn did not provide any new data on the sys-mac-address concept.  

Sue 

-----Original Message-----
From: Eric Vyncke (evyncke) [mailto:evyn...@cisco.com] 
Sent: Thursday, July 9, 2020 4:33 AM
To: Qin Wu; Susan Hares; 'Eric Vyncke (evyncke)'; 'The IESG'
Cc: draft-ietf-i2rs-yang-l2-network-topol...@ietf.org; i2rs@ietf.org; 
i2rs-cha...@ietf.org
Subject: Re: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

Qin,

Honestly, I do not mind too much about "system-mac-address" (and the LLDP was 
just an example) but per symmetry with other leaves, adding a 
'management-mac-address' could be useful. But, again, I do not mind too much.

About the link rate... whether it is Sigfox or other data link does not really 
mater but I keep wondering why not having a minimum lower than 10 kbps is such 
a problem for the authors/WG... Why not simply augment the number of decimals 
on this leaf ? It is a decimal64 and by looking at RFC 6020 section 9.3.4 is 
seems that even using 3 decimals for Mbps (or simply using rate in kbps) will 
not limit the upper rate. 

In short, I am still really puzzled why this lower bound on rate is in the 
model.

-éric



-----Original Message-----
From: iesg <iesg-boun...@ietf.org> on behalf of Qin Wu <bill...@huawei.com>
Date: Thursday, 9 July 2020 at 08:40
To: Susan Hares <sha...@ndzh.com>, "'Eric Vyncke (evyncke)'" 
<evyncke=40cisco....@dmarc.ietf.org>, 'The IESG' <i...@ietf.org>
Cc: "draft-ietf-i2rs-yang-l2-network-topol...@ietf.org" 
<draft-ietf-i2rs-yang-l2-network-topol...@ietf.org>, "i2rs@ietf.org" 
<i2rs@ietf.org>, "i2rs-cha...@ietf.org" <i2rs-cha...@ietf.org>
Subject: RE: [i2rs]  Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

    Hi, Eric:
    Sorry for late reply, your question on wireless is difficult to me,:-)
    Regarding Key editorial additions:
    Sure, we should replace CRC with RCS and fix inconsistency on L2 vs Layer 2.
    Regarding key technical changes:
    I think system-mac-address will be used for sending LLDP frames, we don't 
need another management MAC address, maybe we use different terminology to talk 
about the same thing.
    As for speeds for IoT and wireless,
    I am using figure 1 in draft-ietf-lpwan-schc-over-sigfox as an example, I 
still believe we should not model the link between Device and Sigfox BS (RG) in 
the Layer 2 network topology, bear in mind, L2 topo focuses network side 
topology.
    see reference 
https://www.ietf.org/id/draft-ietf-lpwan-schc-over-sigfox-02.txt
    Do you think the link speed of wired line between Sigfox BS and Sigfox 
network should be less than 10 kbps? No?
    Anyway if the wireless can benefit from L2 topology, I hope it could take 
augmentation approach.

    -Qin
    -----邮件原件-----
    发件人: Susan Hares [mailto:sha...@ndzh.com] 
    发送时间: 2020年7月7日 22:20
    收件人: 'Eric Vyncke (evyncke)' <evyncke=40cisco....@dmarc.ietf.org>; Qin Wu 
<bill...@huawei.com>; 'The IESG' <i...@ietf.org>
    抄送: draft-ietf-i2rs-yang-l2-network-topol...@ietf.org; i2rs@ietf.org; 
i2rs-cha...@ietf.org
    主题: RE: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

    Eric: 

    Another round of comments are below.   

    As to the  IEEE review, this goes through the IETF-IEEE liaison.     I'm 
happy to have this yang model reviewed by the IEEE liaison is in 2020.   Qin's 
review occurred late 2019.  I'm unclear who the 2020 liaison is from IETF to 
IEEE.  Asking specifically about the Ethernet is useful.  Martin/Alvaro/Deborah 
may know who to ask. 

    FCS is a more generic term.  I'm sure that Qin will agree to utilize this 
term. 
    Qin response may come in 2-3 hours. 

    More comments below to your questions.   [Sue2] indicates the next round of 
answers. 

    Key editorial additions: 
    1) FCS replacing CRC
    2) Inconsistent use of L2 versus Layer 2. 

    Key technical changes: 
    1) management-mac-address - used for sending LLDP frames. 
    2) Speeds for IoT and the Wireless - could we get an expert from Internet 
on IoT directorate, and Any suggestions on 802.11 person?  
    I have managed a team that wrote code for early 802.11 code in L2 switches, 
but I have not done that since 2010.   If you do not have a key person, Qin or 
Donald Eastlake or other 802.11 people can help me. 

    Thanks for going through the model carefully. 

    Susan Hares 

    -----Original Message-----
    From: i2rs [mailto:i2rs-boun...@ietf.org] On Behalf Of Eric Vyncke (evyncke)
    Sent: Tuesday, July 7, 2020 8:39 AM
    To: Qin Wu; Susan Hares; 'The IESG'
    Cc: draft-ietf-i2rs-yang-l2-network-topol...@ietf.org; i2rs@ietf.org; 
i2rs-cha...@ietf.org
    Subject: Re: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

    Hello Qin

    Long time not talked ☹

    Satisfied to read that IEEE has reviewed the document as this was a major 
concern of mine. If IEEE reviewers do not mind about using the old 'ethernet' 
word rather than 'ieee802', then I can only respect your and their choice.

    About the Ethernet frame length, your suggested text is improved but you 
may want to also specify for IEEE 802.11 whether the 'frame control' and other 
fields are also counted. I know, L2 is a pain __ Also (and my bad), please use 
FCS rather than CRC.

    About the rate, AFAIK, SigFox is below 1 kbps and LoRa is just a little 
faster. So, why not covering those rates ? Except if there is another 
limitation that I am not aware of

    Sincerely hope it helps

    -éric


    -----Original Message-----
    From: Qin Wu <bill...@huawei.com>
    Date: Tuesday, 7 July 2020 at 14:22
    To: Eric Vyncke <evyn...@cisco.com>, Susan Hares <sha...@ndzh.com>, 'The 
IESG' <i...@ietf.org>
    Cc: "draft-ietf-i2rs-yang-l2-network-topol...@ietf.org" 
<draft-ietf-i2rs-yang-l2-network-topol...@ietf.org>, "i2rs@ietf.org" 
<i2rs@ietf.org>, "i2rs-cha...@ietf.org" <i2rs-cha...@ietf.org>
    Subject: RE: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

        Hi, Eric:
        Thanks Sue for helping clarification. See followup comments inline 
below.
        -----邮件原件-----
        发件人: Eric Vyncke (evyncke) [mailto:evyn...@cisco.com] 
        发送时间: 2020年7月7日 15:36
        收件人: Susan Hares <sha...@ndzh.com>; 'The IESG' <i...@ietf.org>
        抄送: draft-ietf-i2rs-yang-l2-network-topol...@ietf.org; i2rs@ietf.org; 
i2rs-cha...@ietf.org
        主题: Re: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

        Hello Sue,

        Thank you for your reply; no surprise, you take your document shepherd 
role seriously.

        About the YANG validations, I was indeed suspecting something about the 
tool itself rather with the document: thank you for clearing my concerns. Your 
statement obviously clears my semi DISCUSS.

        Please find below some more comments prefixed with EV> (mainly about 
IEEE and indeed my lack of knowledge about the IETF topology model)

        All the best,

        -éric

        -----Original Message-----
        From: Susan Hares <sha...@ndzh.com>
        Date: Monday, 6 July 2020 at 22:40
        To: Eric Vyncke <evyn...@cisco.com>, 'The IESG' <i...@ietf.org>
        Cc: "draft-ietf-i2rs-yang-l2-network-topol...@ietf.org" 
<draft-ietf-i2rs-yang-l2-network-topol...@ietf.org>, "i2rs@ietf.org" 
<i2rs@ietf.org>, "i2rs-cha...@ietf.org" <i2rs-cha...@ietf.org>
        Subject: RE: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

            Eric: 

            <shepherd hat on> 

            Thank you for being concerned about the errors reported by the 
tools.  These errors have been growing with each revision of the yang tools kit 
without any change to the Yang.  

            Yang doctors have OKed the draft.  We have asked the Yang Doctors 
to address this issue and the ADs.    It is hard to fix ghost bugs.   The 
authors will fix anything that is a real bug rather than a ghost bug. 

            Other comments are below. 
             I will answer quickly because Authors are in China.   They may 
correct me - as it is there document. 


            Sue 

            -----Original Message-----
            From: i2rs [mailto:i2rs-boun...@ietf.org] On Behalf Of Éric Vyncke 
via Datatracker
            Sent: Friday, July 3, 2020 6:21 AM
            To: The IESG
            Cc: draft-ietf-i2rs-yang-l2-network-topol...@ietf.org; 
i2rs@ietf.org; i2rs-cha...@ietf.org
            Subject: [i2rs] Éric Vyncke's No Objection on 
draft-ietf-i2rs-yang-l2-network-topology-14: (with COMMENT)

            Éric Vyncke has entered the following ballot position for
            draft-ietf-i2rs-yang-l2-network-topology-14: No Objection

            When responding, please keep the subject line intact and reply to 
all email addresses included in the To and CC lines. (Feel free to cut this 
introductory paragraph, however.)


            Please refer to 
https://www.ietf.org/iesg/statement/discuss-criteria.html
            for more information about IESG DISCUSS and COMMENT positions.


            The document, along with other ballot positions, can be found here:
            
https://datatracker.ietf.org/doc/draft-ietf-i2rs-yang-l2-network-topology/



            
----------------------------------------------------------------------
            COMMENT:
            
----------------------------------------------------------------------

            Thank you for the work put into this document.

            Please find below a couple on non-blocking COMMENTs (and I would 
appreciate a reply to each of my COMMENTs because for some of them I was close 
to ballot a DISCUSS).

            I hope that this helps to improve the document,

            Regards,

            -éric

            == DISCUSS ==

            == COMMENTS ==

            Generic: is there a reason why the YANG validation results in 19 
errors and 4 warnings? Sue Harres (the shepherd) mentions in her write-up that 
9 errors are linked to missing IEEE but what about the 10 remaining errors ?

            Has there been a review by IEEE of this YANG model? While the 
shepherd is extensive and detailed, there is no mention of a coordination with 
IEEE.

        EV> I still would like to have a confirmation that IEEE has also 
reviewed this YANG module.
        [Qin]:All IEEE references has been reviewed by IEEE folks during WGLC 
and cross posted to the netmod mailing list for IEEE folks to chime in by Sue 
and Rob help relay the discussion between IETF and IEEE.
        This is one of links related to IEEE part, can't remember other links.
        https://mailarchive.ietf.org/arch/msg/i2rs/nVPOs8oBHwk5AFQlwyaVYRvoEnk/
        Hope this address your comment.
            -- Section 3 --

              "The Layer 2 (L2) network topology YANG module is designed to be
               generic and applicable to Layer 2 networks built with different 
L2
               technologies."
            Is this statement correct? What about LoraWAN, Sigfox, and other 
LP-WAN technologies? Or technologies that may be using different MTU sizes on 
each direction? or having more parameters than this (such as being NBMA that 
should be captured).

            [Sue:   It is generic abstract representation just like the network 
topology is a generic abstract representation. 
            Abstract models can be augmented with specific details.  See TEAS 
augmentation of the abstract network topology model.   As a chair, I delayed 
this model until it was implemented on a set of topologies.  

            If we can get proposals from running code or people plan running 
code for yang models,  I will glad work on augmentations for any of these 
topologies.  The only caveat is if my AD agrees to this work. 

        EV> Ack. I am trusting you about the YANG augment facility

            Should "sys-mac-address? " rather be "management-mac-address? "

            [Sue: My understanding from building switches is that the 
sys-mac-address may be different than the 
            management-mac-address.   The system processor may have a different 
chip that the management processor. 
            Therefore, based on the plan implementations - I would have to 
object to a change. 

        EV> Good point. But, then should there be  'management-mac-address' 
added to the model? I.e., used as a source for LLDP frames ?

        [Qin]: In most cases I have seen, only management IP address is used as 
a source for LLDP frames. Do you have other case in mind?
    [Sue2]:   Do you wish us to add a management IP address for LLDP frames?  
Most switches do support LLDP. 

            I must admit that I am not familiar with the ietf-topology YANG 
model, so, the following COMMENTs can be plain wrong :-( ... It is unclear to 
me the difference between 'node' and 'termination-point'. If not defined in the 
ietf-topology, then please define before first use (I had to read the YANG 
module to understand).


            [Sue:  This shows a misunderstand of the base topology model.  May 
I politely suggest that I will cover this offline with you or that you discuss 
this with Alvaro or Martin or Rob Wilton [NM/OPS]?  ]

        EV> I had confessed my ignorance before __ so bear with me __

            Why is 'ethernet' used rather than 'ieee802', notably to cover IEEE 
802.11 ?
            [Sue: The  IEEE 802.1 is now linking multiple IEEE 802.11 segments 
using IEEE 802.11 segments.  Donald Eastlake was a part of that process in 
802.11 specification.    In my limited understanding, it is correct to use 
ieee802 as ieee802.1 is provides the linkage.   

            The use of the term Ethernet was vetted by several discussions 
regarding the 802.1 models this links to.   If the IEEE and the IETF suggest 
something else  (in their harmonization of this model between groups), the 
authors will change to.  We've put in the draft what all parties agreed to 
(i2rs participants and IETF yang experts with IEEE knowledge) suggested.   If 
you have a concrete alternate proposal the same groups agree to, we will 
adjust.  We've been trying to do the best to stay aligned to the best common 
practices of both groups. 

        EV> my point was that the current use of 'ethernet' appears outdated 
and I would have preferred 'ieee802' (covering a lot of technologies including 
the good old Ethernet). Nothing blocking on my side, but, I would like that 
authors/WG have a 2nd thought on this name.
        [Qin]: I understand what you ask is allow ieee802.11 technology series 
specific parameters can be augmented into L2 topology model. The current model 
doesn't prevent you from doing that, e..g,
                 choice l2-termination-point-type {
                   description
                     "Indicates termination-point type
                      specific attributes.";
                   case ethernet {
                     leaf mac-address {
                       type yang:mac-address;
                       description
                         "Interface MAC address.";
                     }
                     ...
                    }
                  Case 802.11 {
                  }
               If we rename Ethernet as 'ieee802', do you think all the 
parameters under etherent case can be reused by IEEE802.11?
            While most termination points have a single MAC address, are we 
sure that no termination point will ever have more than one MAC address ?
            [Sue: Multiple termination points are possible in the basic 
topology model.  Again, I suggest a review of the basic topology model concepts 
may be useful.  ] 

            'rate' leaf is in Mbps and with 2 decimals, i.e., the lowest rate 
is 10 kbps and this is already higher than some layer-2 links. Any reason to 
ignore lower rate links ?
            [Sue: Implementation reports gave us the lowest current rate of 10 
kbps.  
            If you believe that this lower link boxes will implement yang 
models, we are glad to adjust this rate.  
            L2 model are difficult because there are so many things out there.] 
 

        EV> agreed on the diversity of L2... Hence, why limiting the rate to a 
multiple of 10 kbps? Even if I do not envision IoT devices on low rate link 
being provisioned by NETCONF/YANG, there could be NMS/OPS/??? systems using 
this YANG module to model the actual topology for their own purposes.
        [Qin]: Do we need to model IoT device and wireless link as part of 
network topology? Suppose wireless link should be modelled, data rate is 
usually in Mbps, see
        
https://www.intel.com/content/www/us/en/support/articles/000005725/network-and-i-o/wireless-networking.html
 


    [Sue2]:  IoT devices and wireless links are part of the 802.1 model.  As 
shepherd/chair I had resisted adding 
    these features because we did not have an implementation.   I suggest 
allowing different data rates at least. 
    Adding the IoT and wireless portions of the model without implementations 
concerned me. 
    However, Wireless links are part of all switches.  Many switches are 
deployed for sensors. 

    Eric - if you could provide us a link to an expert in either of these 
features, we can add this intelligently. 
    Otherwise, it would be better to allow a short draft to augment this model 
rather than be incorrect In the modeling
    [Sue2 ends] 

            -- Section 4 --
            "leaf maximum-frame-size" please specify whether Ethernet 
pre-amble, inter-frame gap, and CRC should be included. The text for Ethernet 
and for PPP are identical, so, why repeating it ?

            [Sue:  I will let the authors take a first pass on why they left 
out Ethernet pre-amble, inter-frame gap, and CRC.  After they comment, I will 
provide a comment on the repetition. ] 

        [Qin]: Based on our analysis, maximum-frame-size should include CRC but 
not include preamble, inter-frame gap, 
https://en.wikipedia.org/wiki/Ethernet_frame
        we can clarify this in the text. Based on your comment, how about the 
following change:
                 leaf maximum-frame-size {
                   type uint32;
                   description
                     "Maximum L2 frame size that can be transported on 
                                 the data link layer, e.g. Ethernet frame. 
                                 If L2 frame is an Ethernet frame, the maximum 
frame size
                                 should include CRC and should not include 
preamble,Start 
                                 Frame Delimiter and Inter frame gap.";
                 }
            == NITS ==

            Sometimes 'L2' is used, sometimes 'Layer 2' is used. Not very 
consistent ;-) I am not an English speaker, but, I believe 'Layer 2 topology' 
should be written
            'layer-2 topology'

            [Good catch - Sometimes, the obvious aids to clarity get missed 
after you read a document long enough. ] 
        [Qin]:Thanks Eric.


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