[Gen-art] Gen-ART Last Call review of draft-ietf-opsawg-service-assurance-architecture-11

[Paul Kyzivat <[e-mail]>]

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.

Document: draft-ietf-opsawg-service-assurance-architecture-11
Reviewer: Paul Kyzivat
Review Date: 2022-11-15
IETF LC End Date: 2022-11-20
IESG Telechat date: ?

Summary:

This draft is on the right track but has open issues, described in the 
review.

Issues: 1
Nits: 8

1) ISSUE: Section 3.6: ambiguity

As best I understand the text "Under Maintenance" is being used in two 
different ways that can cause ambiguity:

- "When a service or subservice is flagged as under maintenance, it must 
report a generic "Under Maintenance" symptom, for propagation towards 
subservices that depend on this specific subservice: any other symptom 
from this service, or by one of its impacting dependencies must not be 
reported."

-  " In more complex cases, for instance with a primary and backup path 
... In such cases, the status of the service instance might include the 
"Under Maintenance" as well as other symptoms (e.g. from the backup path)"

In the latter case, if nothing is wrong with the backup path then there 
might only be the "Under Maintenance" from the primary path, and it 
would be indistinguishable from a case where there was no backup path.

IIUC it is important that these cases be distinguishable.


2) NIT: Section 3: missing word

"Based on the service configuration provided by the service 
orchestrator, the SAIN orchestrator decomposes the assurance graph. It 
then sends to the SAIN agents the assurance graph along some other 
configuration options."

s/along some other/along with some other/


3) NIT: Section 3.3.3: Improper DNS name in example

"Assume that we want to assure a kubernetes cluster https://kubernetes.io."

Examples like this should only use DNS domains intended for examples, 
such as kubernetes.example.org.


4) NIT: Section 3.1.1: missing word

"The status of a should depend on the status of c, d, e, f, g, and h"

s/status of a should/status of a ???? should/


5) NIT: Section 3.6: confusing wording

"Symptoms related to the device-specific subservices, such as the 
interfaces, might be ignored as well as their state changes is probably 
the consequence of the maintenance."

Hard to parse. Does the following work?

"Symptoms related to the device-specific subservices, such as the 
interfaces, might also be ignored because their state changes are 
probably the consequence of the maintenance."


6) NIT: Section 3.6: punctuation

Odd punctuation in:

"... subservices that depend on this specific subservice: any other 
symptom ..."

I think this would be better as two sentences:

"... subservices that depend on this specific subservice. Any other 
symptom ..."


7) NIT: Section 3.7: bad syntax

Syntax problems with:

"One of them is the domain of service management on network elements, 
with also requires its own assurance."

Does the following express the intent?

"One of them is the domain of service management on network elements, 
that also require their own assurance."


8) NIT: Section 3.7: awkward language

The following language is quite awkward:

" Exactly like ...
, exactly like ...
, exactly like ...
. Exactly like ... .

I suggest breaking this out as a list.


9) NIT: Section 3.9: unusual language

The following is IMO unusual phrasing:

"The assurance graph will change along the time"

I think the following would be a better phrasing:

"The assurance graph will change over time"