[Gen-art] Genart last call review of draft-ietf-lwig-tcp-constrained-node-networks-10

Linda Dunbar via Datatracker <noreply@ietf.org> Thu, 24 September 2020 17:34 UTC

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Subject: [Gen-art] Genart last call review of draft-ietf-lwig-tcp-constrained-node-networks-10
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Reviewer: Linda Dunbar
Review result: Almost Ready

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


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

This document describes the guidance on how to configure TCP parameters in the

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:


Linda Dunbar