Subject: [Last-Call] Rtgdir last call review of draft-ietf-babel-v4viav6-07

From: Himanshu Shah via Datatracker <[email-masked]>
Date: Tue, 08 Feb 2022 16:34:09 -0800

Reviewer: Himanshu Shah
Review result: Ready

The draft is written well and easy to follow the proposed extensions for those
who are familiar with the Babel Protocol as described in RFC 8966.

In my view,  a couple of minor updates would read better for the novice reader.

In the Introduction, section 1, last but one paragraph -
--
 We call a route towards an IPv4 prefix that uses an IPv6 next hop a
   "v4-via-v6" route.  This document describes an extension that allows
   the Babel routing protocol [RFC8966] to announce v4-via-v6 routes
   across interfaces that have no IPv4 addresses assigned
(suggested append..)
"and are capable of forwarding IPv4 traffic over non-IPv4 interfaces".
(end of suggestion - or something similar to that effect..).
--
On support for ICMPv4 packet generation by Babel node that has IPv6 interfaces..
While this topic is covered, it would be nice if its importance is mentioned
somewhere in introduction or in section 3.

Such as -
"For hop-by-hop reachability distribution, it is important to facilitate
ICMPv4 "destination unreachable" from non-IPv4 Babel router to notify the
source about incomplete IPv4 path (i.e. dangling IPv4 path)."

Again these are suggestions to improve readability and author(s) can provide
the right text if applicable.

I must admit that I am not intimate with Babel protocol so take above
suggestions with a pinch of salt..

---

From: Juliusz Chroboczek <[email-masked]>
Date: Thu, 24 Feb 2022 17:46:24 +0100

> Review result: Ready

Thanks for your review.

> (end of suggestion - or something similar to that effect..).

Right.  Done roughly what you suggest.

> source about incomplete IPv4 path (i.e. dangling IPv4 path)."

I most respectfully disagree.  The issue of ICMPv4 is a complex one, and
I'd rather not try to (mis-)summarise it in one sentence.  There's a whole
section devoted to it, and it's referenced from the introduction.

(I am actually sympathetic to Warren Kumari's opinion that it's complex
enough to deserve a whole document.)

-- Juliusz