Hi all,
(changing the subject to ease tracking the discussion)
At least from where I sit, I think that that the inputs from Andy/ Matthew
kindly helped to clarify the assumptions on the QoS treatment.
Now, focusing on this part of the discussion where Greg suggests:
* In-flow OAM is an active or hybrid OAM method, as defined in
[RFC7799], that traverses the same set of links and interfaces and
receives the same Quality of Service treatment as the monitored
object.
Which is inspired by RFC9772:
* In-band OAM is an active or hybrid OAM method, as defined in
[RFC7799], that traverses the same set of links and interfaces and
receives the same Quality of Service treatment as the monitored
object. In this context, the monitored object refers to either
the entire Geneve tunnel or a specific tenant flow within a given
Geneve tunnel.
I have some clarification questions for Greg:
* is this a proposal for replacement to the following terms or are these
new terms?
CURRENT:
Path-Congruent OAM:
The OAM information follows the exact same path as the observed
data traffic. This was sometimes referred to as "in-band".
Non-Path-Congruent OAM:
The OAM information does not follow the exact same path as the
observed data traffic. This can also be called Path-
Incongruent OAM, and was sometimes referred to as "out-of-
band".
* If so, taking into account the feedback received in the discussion with
with Andy, why the assumption on QoS is part of the definition?
* Being part of a flow (as suggested by in-flow) does not guarantee that
the same path will be followed, for reasons that you know (multipathing,
load-balancing, etc.).
In order to make progress here, can I suggest that:
* @Adrian/Tal/Carlos propose a definition of what they put behind
“congruent”
* @All: discuss the definition and converge
* See if we need a better term to capture that definition
Thank you.
Cheers
Med
De : Greg Mirsky <[email protected]>
Envoyé : vendredi 6 juin 2025 06:37
À : [email protected]
Cc : Matthew Bocci (Nokia) <[email protected]>; Andrew G. Malis
<[email protected]>; Ops Area WG <[email protected]>; Carlos Pignataro
<[email protected]>
Objet : [OPSAWG]Re: RFC 5085/PALS/PWE3 (RE: Re: WG LAST CALL: Guidelines for
Charactering "OAM"
Hi Adrian,
Thank you for your detailed and thoughtful response. Please find my notes below
tagged GIM2>>.
Regards,
Greg
On Thu, Jun 5, 2025 at 7:24 PM Adrian Farrel
<[email protected]<mailto:[email protected]>> wrote:
Geometry may possibly be a rather specialist use of an English language term.
The usage here is not colloquial.
Picking an online dictionary at random…
(The American Heritage® Dictionary of the English Language, 5th Edition)
adjective
1. Corresponding; congruous
1. Possessing congruity; suitable; agreeing; corresponding.
1. Corresponding in character
GIM>> Synchronizing disctionaries is very helpful for a productive discussion.
I looked at the interpretation of "congruent" in the Cambridge
disctionary<https://dictionary.cambridge.org/dictionary/english/congruent> One
of the examples seems very relevant to our discussion:
Congruent segments geometry
Congruent segments are segments (= parts of a line) that are the same length.
The Merriam-Webster
dictionary<https://www.merriam-webster.com/dictionary/congruent> gives the
following very generic interpretation:
congruent
adjective
con·gru·ent kən-ˈgrü-ənt ˈkäŋ-grə-wənt
: having the same size and shape : capable of being placed over another figure
and exactly matching
My understanding of how "congruent" is used in IETF documents differs
significantly from the interpretation outside the IETF. If that is the case,
how is defining the IETF-specific interpretation of "congruent" more and more
advantageous, a better way to use consistent and intuitive terminology compared
to describing the IETF-specific interpretation of "in-band"?
Further, as indicated in the draft, this term is used (and defined) in RFC 6669.
GIM>> Unless I am missing it, in RFC 6669 congruent is defined through
"in-band":
OAM packets and the user traffic are congruent (i.e., OAM packets
are transmitted in-band) ...
The concept of “congruent routes” is found in RFC 2362, and congruent
topologies in RFC 2796 and RFC 4257/8.
There are many other RFCs that talk about congruent topologies, and I don’t
think any of them means, “Of the same shape or connectivity so that one could
be mapped to the other through an isomorphic transposition.”
GIM>> If we compare number of RFCs that use "congruent" and use "in-band", I
think that it will be pretty close outcome.
Notwithstanding this, if Greg finds this word to be confusing we should assume
that other readers of similar education may be similarly confused.
I think the best solution is to include a careful definition of “congruent”.
GIM>> Thank you for your kind consideration, Adrian. I proposed a pair of new
terms, "in-flow/out-of-the-flow", defined, with minor update, as in RFC 9772:
* In-flow OAM is an active or hybrid OAM method, as defined in
[RFC7799], that traverses the same set of links and interfaces and
receives the same Quality of Service treatment as the monitored
object.
Hybrid OAM natively is in-flow OAM. Ensuring the active OAM method is used as
in-flow OAM usually requires special considerations. What are your thoughts?
Cheers,
Adrian
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