Early Review of draft-ietf-manet-dlep-credit-flow-control-15
review-ietf-manet-dlep-credit-flow-control-15-opsdir-early-boucadair-2024-07-24-00

Hi all,

Thanks for the authors for the effort put into this well-written document.

First, I'm always impressed by authors who persevere and push for a
specification over many years. I checked the archives to see whether there were
contentious points that would justify the long development process, but I
didn't find something meaningful other than some discussions on how the various
pieces (this I-D, classification, etc.) can be documented. That discussion
answered a comment I had about the need to separate the classification spec
from this. I won't thus raise that point in my review. However, it seems weird
(at least to me) to define objects and put in the abstract that future
documents "will mandate the use".

I was also expecting to see a discussion on how this flow-control is superior
compared to the pause approach specified in RFC 8651, including a discussion
about co-existence considerations and which one will take precedence.

Overall, the document (seems) to reason following the model in Figure 1 of RFC
8175, while it should be applicable as well for the configuration in Figure 2
of 8175. For example, the FID uniqueness (at the router side) should be
associated with the link over which the packets will be sent.

From a protocol machinery standpoint, there are some few cases where I think
the MUST behavior is not justified. Please refer to the link below for more
details on this.

From an ops standpoint, the document includes a dedicated section on
management. However, I think that more concrete implementation behavior should
be provided, e.g.,

* how to report errors?

* expose configuration knobs to control many of the parameters there. Also,
exposing implementation default would be helpful when operating the system.

* technically characterize some events (e.g., transient events) and provide a
minimum value for how frequent messages can be sent.

More detailed comments can be found at:

https://github.com/boucadair/IETF-Drafts-Reviews/blob/master/2024/draft-ietf-manet-dlep-credit-flow-control-15-rev%20Med.pdf

hope this helps

Cheers,
Med