Subject: [Detnet] RtgDir Review: draft-ietf-detnet-mpls-over-udp-ip

From: Harish Sitaraman <[email-masked]>
Date: Sun, 22 Dec 2019 11:03:02 -0800

Hello,

I have been selected as the Routing Directorate reviewer for this
draft. The Routing Directorate seeks to review all routing or
routing-related drafts as they pass through IETF last call and IESG
review, and sometimes on special request. The purpose of the review is
to provide assistance to the Routing ADs. For more information about
the Routing Directorate, please see
http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir

Although these comments are primarily for the use of the Routing ADs,
it would be helpful if you could consider them along with any other
IETF Last Call comments that you receive, and strive to resolve them
through discussion or by updating the draft.

Document: draft-ietf-detnet-mpls-over-udp-ip-04.txt
Reviewer: Harish Sitaraman
Review Date: Dec 22, 2019
IETF LC End Date: date-if-known
Intended Status: Standards Track

Summary:
I have some minor concerns about this document that I think should be
resolved before publication.

Comments:
The document is concise and focussed. I'm not as familiar with the
work of the DetNet WG so I quickly skimmed through some of the related
drafts.

Major Issues:
No major issues found.

Minor Issues:
Section 1, last paragraph:
"These requirements are satisfied by the DetNet over MPLS
Encapsulation described in [I-D.ietf-detnet-mpls] and they are partly
satisfied by the DetNet IP data plane defined in [I-D.ietf-detnet-ip]"

Please explicitly mention which subset of the requirements are
satisfied by ietf-detnet-ip since the text mentions "partly
satisfied"?
For MPLS, it seems apparent since prior to listing the requirements,
the text says "(these are a subset of the requirements for MPLS
encapsulation listed in [I-D.ietf-detnet-mpls])".

Section 3:
"In case of aggregates the A-Label is treated as an S-Label and it too
is not modified."
I couldn't understand the usage of "aggregates" here - Is this
referring to A-label used only at the aggregation end-point but not as
dis-aggregation end-point? If there is not distinction, the maybe
A-label can be clubbed into the previous sentence as not being
modified.

Section 4:
"The headers for each outgoing packet MUST be formatted according to
the configuration information and as defined in [RFC7510], with one
exception. Note that the UDP Source Port value MUST be set to uniquely
identify the DetNet flow."

The MUST in the first sentence above is used along with an exception,
which I think the next sentence "Note that..." clarifies on how the
source port should be set. Would it be possible to remove "with one
exception" and stitch the two sentences together to be more more
precise?

"This includes QoS related traffic treatment." - I assume this is IP
ToS/DSCP and not MPLS EXP? Is traffic treatment relevant for receive
processing in the next paragraph?

Section 5:
"e.g., via the controller or management plane"
Would it be better to use "...via the controller plane [RFC8655]"
since the next paragraph starts using controller plane?

Nits:
Section 4:
"To support receive processing an implementation" - add a comma after
'processing'. It might be preferable to replace "receive processing"
(I noticed a prior use in the DetNet MPLS draft and not in the base
RFC) with "To support processing incoming DetNet MPLS over UDP/IP
encapsulation..." to be specific.

Section 4:
The packet MUST then be handed as
                                           ^^^^^^^
Section 5:
multiple sets of UPD/IP information
                          ^^^^
needed to provided the traffic treatment => s/provided/provide
                 ^^^^^^^^
Section 9,  References:
Re-run to pull in latest versions of drafts.

--
Harish