Re: [Last-Call] Tsvart telechat review of draft-ietf-sfc-oam-framework-13

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Thanks Frank.  Both for the review, and the discussion.
Yours,
Joel

On 5/22/2020 11:03 AM, Frank Brockners (fbrockne) wrote:
Per what I mentioned below - the below is my personal take, taking the position of a reader, who might not be aware of WG structures, WG scopes etc. Personally, I don't think that a reader of the SFC OAM framework document would expect the SFC WG to address all of the dimensions of SFC OAM, even if the document lays them out.

That said, I do understand your concern about WG structures and scope. Looks like we (sadly) need to follow Conway's law ...
So in general terms, I'm ok with Nagendra's approach.

Cheers, Frank


-----Original Message-----
From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx>
Sent: Freitag, 22. Mai 2020 16:49
To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar Nainar
(naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx
Cc: sfc@xxxxxxxx; last-call@xxxxxxxx; draft-ietf-sfc-oam-framework.all@xxxxxxxx
Subject: Re: Tsvart telechat review of draft-ietf-sfc-oam-framework-13

My basic concern is that if we go down the path you outline, it would suggest to
the reader that the SFC working group expected to address the SF dimensions of
the problem.  I grant that they are real problems.  But the SFC working group has
neither the charter nor the expertise to address those problems.  As far as I can
tell, ART may have the expertise, and may not.  And has shown no interest in the
problem.  So I am very reluctant to put a lot of verbiage into the RFC on SF
monitoring.

Given the above, can you live with Nagendra's text that you quote?

Yours,
Joel

On 5/22/2020 5:33 AM, Frank Brockners (fbrockne) wrote:
Joel,

Nagendra suggested "The task of evaluating the true availability of a
Service Function is a complex activity, currently having no simple,
unified solution.  There is currently no standard means of doing so.
Any such mechanism would be far from a typical OAM function, so it is
not explored as part of the analysis in Sections 4 and 5." in the
related thread for discussion on availability.
https://mailarchive.ietf.org/arch/msg/sfc/1ZsLw6m1OeJRJfHW2TygxOyKPJk/

It could well be that my expectations for a framework document differ from
that of others. So please take this as a personal perspective.
My expectation for a framework document is that it identifies and
describes the components for a solution. It can optionally also hint
at potential approaches to a solution (independently whether these
solution are already in scope of the WG or not), but does not have to
provide these solutions. The document does a good job at most of these
- but misses out on those things, where we currently don't really have
a solution available, which are questions like
* How do we define availability for a SFC at service level? How do we define
availability for a SF?
* How do we define performance for a SFC at service level? How do we define
performance for a SF?
Right now the document focuses on those pieces of SF/SFC availability and
performance that are connectivity related ("Packets traverse it").

A potential approach could be to decompose the problem, using the structure
the document lays out - and put this into the context of SLA definitions.

Why can we just say for e.g. SFC performance that SFC performance is a
composite of
* link layer performance,
* underlay performance,
* overlay performance,
* service layer performance.
A SFC OAM solution needs to consider the performance measures across all
those layers.
Consequently, for the performance of a SF, one needs to consider the aspects
at each layer:
* link layer - Example "how well is the SF connected at e.g. Ethernet
layer?" -> example: Leverage ITU-T Y.1731
* underlay - Example "how well is the SF connected at e.g. IP layer?"
-> example: Leverage OWAMP/TWAMP
* overlay - Example "how well is the SF connected at e.g. NSH layer?"
* service layer - Example "how well does the SF meet the criteria of an SLA?"
So e.g. 3.1.2 and 3.2.2 could explicitly expand on these aspects and state that
apart from connectivity level measures (loss, throughput), service level criteria,
typically defined as part of an SLA, are included in SFC performance
characterization. IMHO this is a better approach, than either say "SF availability
is a hard problem" (which is what Nagendra says in the above statement - and
which is of course true) or just define the service aspects as out of scope for SFC
OAM ("how clean are the clothes when returned from the laundry?").

My 2cents..

Cheers, Frank


-----Original Message-----
From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx>
Sent: Mittwoch, 20. Mai 2020 20:17
To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar
Nainar
(naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx
Cc: sfc@xxxxxxxx; last-call@xxxxxxxx;
draft-ietf-sfc-oam-framework.all@xxxxxxxx
Subject: Re: Tsvart telechat review of
draft-ietf-sfc-oam-framework-13

So the question now is whether the text Murray suggested suffices for
you?  (We are still waiting to hear from Alvaro.)

Yours,
Joel

On 5/20/2020 1:41 PM, Frank Brockners (fbrockne) wrote:
Thanks Joel. Per what I mentioned below, let's be clear that SF
performance is
out of scope for the doc.
And I think this was Alvaro's point as well.

Cheers, Frank

-----Original Message-----
From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx>
Sent: Mittwoch, 20. Mai 2020 19:21
To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar
Nainar
(naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx
Cc: sfc@xxxxxxxx; last-call@xxxxxxxx;
draft-ietf-sfc-oam-framework.all@xxxxxxxx
Subject: Re: Tsvart telechat review of
draft-ietf-sfc-oam-framework-13

Frank, regarding your comment about SF performance, I thought the
document was pretty clear that we consider that out of scope (c.f.
the discussions with the various ADs.)

If you can see a place to add text, please propose text.

Thank you,
Joel

On 5/20/2020 1:10 PM, Frank Brockners (fbrockne) wrote:
Hi Nagendra,

Thanks for the detailed reply. Please see inline (..FB).

-----Original Message-----
From: Nagendra Kumar Nainar (naikumar) <naikumar@xxxxxxxxx>
Sent: Samstag, 16. Mai 2020 16:16
To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>;
tsv-art@xxxxxxxx
Cc: sfc@xxxxxxxx; last-call@xxxxxxxx;
draft-ietf-sfc-oam-framework.all@xxxxxxxx
Subject: Re: Tsvart telechat review of
draft-ietf-sfc-oam-framework-13

Hi Frank,

Thank you for the review. Please see inline for the response..


        Reviewer: Frank Brockners
        Review result: Ready with Nits

        This document has been reviewed as part of the transport
area review
team's
        ongoing effort to review key IETF documents. These
comments were
written
        primarily for the transport area directors, but are copied
to the
document's
        authors and WG to allow them to address any issues raised
and also to the IETF
        discussion list for information.

        When done at the time of IETF Last Call, the authors
should consider
this
        review as part of the last-call comments they receive. Please always
CC
        tsv-art@xxxxxxxx if you reply to or forward this review.

        This document provides a reference framework for OAM for SFC.

        Comments:

        Section 3.1.1 SF availability: The text makes explicit
reference to
multiple
        instances of a SF. Consequently, it should be defined how
availability of a
SF
        is computed/determined in case multiple instances are deployed.

<Nagendra> This is already clarified in the section as below:

"For cases where
       multiple instances of an SF are used to realize a given SF for the
       purpose of load sharing, SF availability can be performed by checking
       the availability of any one of those instances, or the availability
       check may be targeted at a specific instance."

This further
        leads to the question, whether availability is always a "binary" state
        (available / not-available), or could a SF be e.g. 99% available?

<Nagendra>The availability is measured as binary state. I am not
sure what is 99% available. If it means getting 99 responses for
100 probes sent, I think it falls under packet loss category
which in turn is
performance measurement.

...FB: Thanks. Though I'm still not entirely following. If
availability is binary and
I put the statements above together, what would be the availability
of the following setup: There is an SF that is made up of 100
instances. 99 of these instances are powered down entirely. And the
1 instance that is "up" is alternating between servicing requests
for 10min followed by not servicing requests for 10min. Would the
SF be
considered "available"?


Section 3.1.2
        SF performance: What is the impact of a "multiple instance
SF deployment" on SF
        performance measurement?

<Nagendra>I think we covered this in SF availability but not here.
Does the below updated text look better?

OLD:
On the one hand, the performance of any specific SF can be quantified
       by measuring the loss and delay metrics of the traffic from SFF to
       the respective SF, while on the other hand, the performance can be
       measured by leveraging the loss and delay metrics from the
respective
       SFs.  The latter requires SF involvement to perform the measurement
       while the former does not.

NEW:
On the one hand, the performance of any specific SF can be quantified
       by measuring the loss and delay metrics of the traffic from SFF to
       the respective SF, while on the other hand, the performance can be
       measured by leveraging the loss and delay metrics from the
respective
       SFs.  The latter requires SF involvement to perform the measurement
       while the former does not. For cases where
       multiple instances of an SF are used to realize a given SF for the
       purpose of load sharing, SF performance can be quantified by
measuring
       the metrics for any one instance of SF or by measuring the metrics
for
       a specific instance.

The section only talks about loss and delay as
        performance criteria. It would be good to state that other
performance criteria
        (e.g. specific to the SF, throughput, etc.) exist.

<Nagendra> We can add the below to Section 3.1.2:

NEW:
"The metrics measured to quantify the performance of the SF
component is not just limited to loss and delay. Other metrics
such as throughout also exist and the choice of metrics for
performance measurement is outside the scope of this document."

Section 3.2.1 SFC
        availability: The current definition is very focused on connectivity
        verification, i.e. it tries to answer the question: "Does my SFC
transport
        packets?". IMHO we should also ask the question "Does my
SFC process
the
        packets correctly?" - because if packets are not processed per the
SFC
        definition, we might not call the SFC available.

<Nagendra> I think this is already handled by SF availability.
The end-to-end SFC availability is verified by steering the OAM
packet over the ordered set of SFs within the SFC. This is more
like daisy chaining the availability of SFs within the SFC to
determine end-to-end SFC availability. If the derived solution
verifies the SF availability not just based on the uptime but
based on the service treatment, it also answers the question
"Does my SFC process the packets
correctly". Let us know if there is any further clarity required.

While 3.2.2 states that "any
        SFC-aware network device should have the ability to make
performance
        measurements" a similar statement isn't found in 3.2.1.
IMHO the ability
for
        availability checks is probably a prerequisite for
performance
measurement.

<Nagendra> The ability to perform end-to-end or partial SFC
availability verification is already mentioned in section 3.2.1 as below:

" In order to perform service connectivity verification of an SFC/SFP,
       the OAM functions could be initiated from any SFC-aware network
       devices of an SFC-enabled domain for end-to-end paths, or partial
       paths terminating on a specific SF, within the SFC/SFP"

Please let us know if you have any suggestion to improve if there
is a lack of clarity.

        Section 3.2.2 SFC performance measurement: The section
only mentions the need
        for performance measurement. It misses the definition of
what SFC performance
        measurement is.

<Nagendra>

...FB: Thanks for the suggested updates, which would definitively
improve the
text. One problem about SFC performance remains though IMHO.
All the text so far is focused on the connectivity within a SFC -
not the service
itself. I.e. If you'd consider a "laundry service" - we focus a lot
on how long it takes to get the clothes shipped to and from the
washing machine, but we don't focus on how well the washing machine
washes the clothes.
IMHO we should either expand on the performance of the SFC and SF
wrt/ the
service (especially given that you define a service layer in
section
2) - or clearly state that the framework would just focus on
connectivity
between SFs.



Section 3.3. Classifier component: The section mentions the
        need for the ability to perform performance measurement of
the
classifier
        component. What is performance measurement of the classifier?
What
does
        performance measurement of the classifier component comprise?

<Nagendra>We can add the below text:

OLD:
Any SFC-aware network device should have the ability to perform
       performance measurement of the classifier component for each SFC.

NEW:
Any SFC-aware network device should have the ability to perform
       performance measurement of the classifier component for each SFC.
        The performance can be quantified by measuring the
performance metrics of the
         traffic from the classifier for each SFC/SFP.

Section 3.4. /
        3.5. Availability/PM of the underlay and overlay network:
It would be good
to
        add a sentence that states that the mechanisms for
availability/PM which
are
        offered by the technologies used by the overlay/underlay
are used, rather than
        new methods specifically for SFC would be defined.

<Nagendra>Yes, that makes sense. Please check the below text:

OLD:
Any SFC-aware network device may have the ability to perform
       availability check or performance measurement of the overlay
network.

NEW:
Any SFC-aware network device may have the ability to perform
       availability check or performance measurement of the overlay
network.
Any
       existing OAM tools and techniques can be leveraged for this purpose.

Section 4. SFC OAM
        Functions: It would be good, if examples in section 4
could also include
more
        "recent" methods such as OWAMP/TWAMP (RFC4656, RFC 5357).

<Nagendra>

OLD:
Delay within an SFC could be measured based on the time it takes for
       a packet to traverse the SFC from the ingress SFC node to the egress
       SFF.  As SFCs are unidirectional in nature, measurement of one-way
       delay [RFC7679] is important.  In order to measure one-way delay,
       time synchronization MUST be supported by means such as NTP, PTP,
       GPS, etc.

NEW:
Delay within an SFC could be measured based on the time it takes for
       a packet to traverse the SFC from the ingress SFC node to the egress
       SFF.  Measurement protocols such as One-way Active Measurement
        Protocol (OWAMP) [RFC4656], Two-way Active Measurement
Protocol
       (TWAMP) [RFC5357] can be used to measure the characteristics. As
       SFCs are unidirectional in nature, measurement of one-way
       delay [RFC7679] is important.  In order to measure one-way delay,
       time synchronization MUST be supported by means such as
NTP, Precision Time Protocol (PTP),
       GPS, etc.

Section 4.4.
        Performance Measurement: Focus is entirely on the PM of
the
connectivity,
        rather than on the SF. How about covering PM for the SF as well?

<Nagendra> I am not sure I understand what is missing. Do you
have any suggestion for the text improvement?.

...FB: See above. This would be about adding a capability to
assess how well
the washing machine washes my laundry.


Section 5.1
        OAM Tool Gap Analysis:
         - Not sure what "NVo3 OAM" refers to. Could that be
explained below the table
         and in section 1.2.1?

<Nagendra> Combining this with other below queries as they
appears to be related.

- E-OAM needs to be detailed. Is seems that CFM
         (802.1ag) and not 802.3ah is refered to here.

<Nagendra> Per my understanding, 802.ah is 1-hop while 802.3ag
can be more than 1 hop and both uses Ethernet frames. So I think
both are
applicable here.
My response regarding E-OAM details in this section is combined below.

...FB: Maybe I missed it - but I don't see text that refers to CFM
or EFM
OAM.
Where is this covered? IMHO we would need references to IEEE
standards to avoid confusion.


- "Trace" in the "Trace" column
         need to be extended on. Is this traceroute? Paris-Traceroute?
IOAM- Loopback?

         IPPM needs to be detailed, because IPPM is not a tool as
such but an IETF WG.
         Does this refer to OWAMP/TWAMP/etc. as defined by IPPM?

<Nagendra> Combining the above queries.

OLD:
There are various OAM tool sets available to perform OAM functions
       within various layers.  These OAM functions may be used to validate
       some of the underlay and overlay networks.  Tools like ping and trace
       are in existence to perform connectivity check and tracing of
       intermediate hops in a network.  These tools support different
       network types like IP, MPLS, TRILL, etc.  There is also an effort to
       extend the tool set to provide connectivity and continuity checks
       within overlay networks.  BFD is another tool which helps in
       detecting data forwarding failures.  Table 3 below is not
exhaustive

NEW:
There are various OAM tool sets available to perform OAM functions
       within various layers.  These OAM functions may be used to validate
       some of the underlay and overlay networks.  Tools like ping and trace
       are used to perform connectivity check and tracing of
       intermediate hops in a network.  These tools are already available for
       different types of networks such as IP, MPLS, TRILL, etc.

E-OAM offers OAM mechanisms such as an Ethernet continuity check
for Ethernet links. There is an effort around NVO3 OAM to provide
connectivity and continuity checks for networks that use NVO3.
BFD is used for the detection of data plane forwarding failures.

...FB: Check whether NVO3 WG will indeed deliver a solution and
"NVO3
OAM"
indeed existis. If in doubt, it might be better to avoid forward
looking references. Per my note above, it would be good to
explicitly refer to IEEE standards as opposed to introducing a new term like
"E-OAM".


The IPPM framework [RFC 2330] offers tools such as OWAMP
[RFC4656] and TWAMP [RFC5357] (collectively referred as IPPM in
this section) to measure various performance metrics. MPLS Packet
Loss Measurement
(LM) and Packet Delay Measurement (DM) (collectively referred as
MPLS_PM in this section) [RFC6374] offers the ability to measure
performance metrics in MPLS network.

Table 3 below is not exhaustive.

Section 6.4.3 IOAM:
        - The section states that IOAM "may be used to perform
various SFC
OAM
        functions as well". It would be good to expand on this statement:
E.g.
IOAM
        Trace-Option Type could be leveraged for SFC tracing. IOAM
Direct-Export Option
        Type could be leveraged. - How would we deal with the IOAM
Active
Flag
        (draft-ietf-ippm-ioam-flags-01) when used with SFC OAM?

<Nagendra> The intention of the section is to highlight the
applicability of different OAM toolsets for OAM functions at
service layer. I am not sure if we really should try explaining
all the possible options within each tool. But I agree that it is
worth clarifying the availability of IOAM options for tracing.
think we can clarify that different IOAM Option-Types are
available for OAM functions
such as SFC tracing. Can you check if the below looks ok?

OLD:
[I-D.ietf-sfc-ioam-nsh] defines how In-Situ OAM data fields are
       transported using NSH header.  [I-D.ietf-sfc-proof-of-transit]
       defines a mechanism to perform proof of transit to securely verify if
       a packet traversed the relevant SFP or SFC.  While the mechanism is
       defined inband (i.e., it will be included in data packets), it may be
       used to perform various SFC OAM functions as well.

NEW:
[I-D.ietf-sfc-ioam-nsh] defines how In-Situ OAM data fields are
       transported using NSH header.  [I-D.ietf-sfc-proof-of-transit]
       defines a mechanism to perform proof of transit to securely verify if
       a packet traversed the relevant SFP or SFC.  While the mechanism is
       defined inband (i.e., it will be included in data packets),
IOAM Option-
Types
      such as IOAM Trace Option-Types can also be used to perform
other SFC OAM function
      such as SFC tracing.

- The text states
        "In-Situ OAM could be used with O bit set": Why would IOAM
be used with
the
        overflow bit set for SFC OAM? For details on IOAM's O-bit,
see section
4.4.1 in
        https://tools.ietf.org/html/draft-ietf-ippm-ioam-data-09.

<Nagendra> The O bit referred here is not the O bit in IOAM but
the one in NSH/Overlay header. To avoid any confusion, this can
be updated as
below:

OLD:
In-Situ OAM could be used with O bit set to perform SF availability
       and SFC availability or performance measurement.

NEW:
In-Situ OAM could be used with O bit in the overlay header set,
to perform SF availability
       and SFC availability or performance measurement.

... FB: Ah, ok. Given that this section is about IOAM and not NSH,
I'd rather
explicitly refer to NSH here. E.g. If SFC is realized using NSH,
then the O-bit in the NSH header could be used to indicated OAM traffic.
You could refer to
https://tools.ietf.org/html/draft-ietf-sfc-ioam-nsh-03#section-4.2
explicitly.


Section 6.4.4 SFC
        Traceroute: - This section refers to an expired draft
(even calling out
the
        fact that the draft has exipred), but also mentions that functionality
is
        available and implemented in OpenDaylight. Consider
removing the references to
        the expired draft and rather add references to
OpenDaylight documents. - IOAM
        Loopback (see draft-ietf-ippm-ioam-flags-01) could apply
SFC Traceroute as well.

<Nagendra>Ok. Let me check if I can find some reference for ODL.

        Detailed set of nits that I encountered while reading
through the document ([x]
        references line number x) – hope that they are helpful in
further improving
the
        doc:

<Nagendra> Yes of course (.

        [global] s/an SF/a SF/ -- and similarly SFC/SFF

<Nagendra>Other RFCs uses "an SF/SFF". So the draft is updated
accordingly. If your suggestion is to substitute "a SF" to "an
SF",  it is done
(.

        [176] "OAM Controller" not defined

<Nagendra>We can change it as below:

OLD:
OAM controllers are assumed to be within the same administrative
       domain as the target SFC enabled domain.

NEW:
OAM controllers are SFC-aware network devices that are capable of
generating OAM packets. They are assumed to be within the same
administrative domain as the target SFC enabled domain.

        [202] Why just Virtual Machines and no containers? Suggest
to make
things
        generic and talk about virtual and physical entities.

<Nagendra> We changed this as virtual entities.

              This comment applies throughout the document.
        [216] Ethernet OAM: Add reference. Do you refer to
physical layer Ethernet OAM
        (802.3ah) or CFM (802.1ag)?

<Nagendra> The response was provided in the above comment section.

[243] s/uses the overlay network/uses the overlay
        network layer/

<Nagendra> Done.

[246] Could we add a few examples of "various overlay network
        technologies"? For the underlay network layer several
examples are
listed.

<Nagendra> Ok.

        [248] What does "mostly transparent" mean?

<Nagendra> The data plane elements connecting the overlay layer
nodes may not always process the overlay header.

...FB: How about we explain this in the document?


[254] What does "tight coupling"
        between the link layer and the physical technology mean?

<Nagendra>I am not sure I understand the nit here. Do you see any
difficulty in parsing the sentence?

...FB: Not sure what "tight coupling" means here. Could you
clarify what is
"tight coupling" vs. "not tight coupling"?


[255] Suggest to avoid
        terms like "popular" - popularity can change, standards
stay

<Nagendra> Ok. This is changed as "Ethernet is one such choice..."

[256] Acronyms
        "POS" and "DWDM" are not defined

<Nagendra> Added.

[274] Link start/end-points don't seem to
        always align with the underlay network in the diagram

<Nagendra> Fixed it.

[287] s/may comprise
        of/may consist of/

<Nagendra>We fixed it as "may comprise"..

[288] s/but not shown/but is not shown/

<Nagendra> We fixed this as "intermediate nodes not shown...:

[307]
        s/devices/device/

<Nagendra> Done.

[308] What is a "controller"?

<Nagendra> We discussed this in the above comment section.

[314] s/includes/include/

<Nagendra>Done.

[319]
        Add hSFC to list of acronyms in section 1.2.1

<Nagendra> This is expanded in the respective section. We added
it in the acronym section as well.

[320] Add IBN to list of acronyms
        in section 1.2.1

<Nagendra> Ok, Done.

[325] s/includes/include/

<Nagendra> Done.
[359] The function/term "controller"
        requires definition.

<Nagendra> Done, as mentioned in the above comment section.

[383] s/?./?/

[398] s/get the got/got/

<Nagendra> Done.

     [461]
        s/devices/device/

<Nagendra> Done.

     [469] Does it have to be equal cost multipath at the service
        layer, or could unequal cost multipath also be an option
for
load-
balancing?

<Nagendra>I didn’t see any discussion specific to ECMP/UCMP in
the architecture RFC.

...FB: Hmm. I did not see that RFC7665 is only about equal cost multipath.

     [521] Not sure whether the overlay network establishes the
service
plane.
Isn't
        it that the overlay network establishes connectivity for the SFC-
related
        functions in the service plane?

<Nagendra> The service layer is established over the overlay
network layer. I am not sure if it is right to say overlay
network provides connectivity for service layer (.

...FB: Overlay network is one component of the service layer,
isn't it. So it is
required but not sufficient.


[531] s/components/component/ [545] remove
        "underlay"

<Nagendra> Done.

[595] s/devices/device/

<Nagendra> Done.

[600] s/action/an action/

<Nagendra> Done.

[601] Expand on
        "TTL or other means" (TTL also needs to be added to
acronyms in 1.2.1). Is
this
        specific to NSH? Or specific to IPv4?

<Nagendra> TTL is listed as well-known abbrev in https://www.rfc-
editor.org/materials/abbrev.expansion.txt and so we left it as it is.
TTL in this document refers to NSH TTL field.

...FB: Let's ensure we refer to NSH TTL in this case. Given that
SFC can be done
with other means than NSH, implicit reference to NSH might be a problem.

     [630] Mention that for "approximation of
        packet loss for a given SFC can be derived" to be
applicable, SFC OAM
packets
        would need to be forwarded the same as live user traffic.

<Nagendra> As it is intending to derive the approximate loss
value, I am not sure if we need this additional consideration
that the OAM packet would need to follow the live user traffic.
Let me know if you think
otherwise.

...FB: IMHO we should - given that it is one potential complication.


     [636] Is uppercase
        "MUST" applicable to an informational document? Especially given
that
        RFC2119/RFC8174 is explicitly referenced by the draft.

<Nagendra> Based on various reviewer comments, we removed the use
of any normative statement.

[666] Add MPLS, TRILL to
        acronyms in 1.2.1

<Nagendra> Ok. Done.

[678] s/exhaustive/exhaustive./

<Nagendra> Done.

[720] Is uppercase "SHOULD" applicable to an informational document?
        Especially given that RFC2119/RFC8174 is explicitly
referenced by the
draft.

<Nagendra> Based on various reviewer comments, we removed the use
of any normative statement.

[722] Is uppercase "MAY" applicable to an informational document?
Especially
        given that RFC2119/RFC8174 is explicitly referenced by the draft.

<Nagendra> Based on various reviewer comments, we removed the use
of any normative statement.

[754]
        s/packet/packets/

[755] s/to next node/to the next node/

     [771] How does this
        requirement align with the earlier paragraph, e.g. in case
a node sends an ICMP
        reply? It would probably make sense to scope the statement to e.g.
NSH.

<Nagendra> As mentioned in the statement, the node that initiates
the OAM packet must set the marker and so this statement is
applicable for the initiating node.

[806]
        s/function/functions/

<Nagendra> Done

[809] s/from relevant node/from the relevant node/

<Nagendra> Done

[810]
        s/generate ICMP/generate an ICMP/

<Nagendra> Done

[812] s/from last/from the last/

<Nagendra> Done

[830]
        s/perform continuity/perform the continuity/

<Nagendra> Done

     [834] s/with relevant/with the
        relevant

<Nagendra> Done

[835] s/perform partial SFC availability./perform a partial SFC
        availability check./

<Nagendra> Done

[851] For "In-Situ OAM data fields" add a normative
        reference to draft-ietf-ippm-ioam-data

[905] Add "CLI" to section 1.2.1
        acronyms

<Nagendra> Done

[920] Add a reference for NETCONF ->RFC6241

<Nagendra> Done

Once again, thanks a lot for the great comments.

Regards,
Nagendra

Thanks again for considering the comments in great detail. Much
appreciated.

Cheers, Frank





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