Last Call Review of draft-ietf-lwig-tcp-constrained-node-networks-10
review-ietf-lwig-tcp-constrained-node-networks-10-genart-lc-dunbar-2020-09-24-00

Request Review of draft-ietf-lwig-tcp-constrained-node-networks
Requested rev. no specific revision (document currently at 11)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2020-09-30
Requested 2020-09-16
Authors Carles Gomez, Jon Crowcroft, Michael Scharf
Draft last updated 2020-09-24
Completed reviews Genart Last Call review of -10 by Linda Dunbar (diff)
Intdir Telechat review of -11 by Bernie Volz
Iotdir Telechat review of -11 by Ines Robles
Tsvart Telechat review of -11 by Mirja K├╝hlewind
Assignment Reviewer Linda Dunbar 
State Completed
Review review-ietf-lwig-tcp-constrained-node-networks-10-genart-lc-dunbar-2020-09-24
Posted at https://mailarchive.ietf.org/arch/msg/gen-art/D4Pe7uUxLdlBTrZ9Qj0o-KHJkPs
Reviewed rev. 10 (document currently at 11)
Review result Almost Ready
Review completed: 2020-09-24

Review
review-ietf-lwig-tcp-constrained-node-networks-10-genart-lc-dunbar-2020-09-24

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-lwig-tcp-constrained-node-networks-10
Reviewer: Linda Dunbar
Review Date: 2020-09-24
IETF LC End Date: 2020-09-30
IESG Telechat date: Not scheduled for a telechat

Summary:
This document describes the guidance on how to configure TCP parameters in the Constrained-Node-Networks. 

Major issues:
4.1.2. recommends ECN to be used  in the Constrained Node networks. In any network, especially when many IoT devices are attached , the congestion can be very short lived. Having Constrained node supporting ECN can cause traffic oscillation.  In addition, not many deployed internet supports ECN, it can be waste of processing of the CNN nodes.  

Section 4.1.1 recommend packet size to be 1280 for IPv6 to avoid the need to support Path MTU Discovery. it is problematic.  There are many layers of tunneling and encapsulation in today's network, (let's not even assume SR), the actual packet size can be much larger.  Supporting Path MTU Discovery is far less processing intensive than supporting ECN. 


Minor issues:

Nits/editorial comments:

Cheers, 

Linda Dunbar