Subject: Fwd: New Version Notification for draft-petrescu-6man-ll-prefix-len-15.txt

From: Alexandre Petrescu <[email-masked]>
Date: Mon, 29 Apr 2019 15:47:14 +0200

Hi participants to 6MAN,

We would like to briefly inform you that we updated the draft about the 
prefix length of the LL addresses.

It reflects arguments made during recent threads.

This is the change log:

-15: added references to draft-farmer-6man-exceptions-64-09 and
      draft-farmer-6man-routing-64-02, and interpreted them;
      added explanations of the solutions mentioned in WG discussion;
      added a use-case of car convoy with details about current 
restrictions of LL
      addressing and how a variable len plen for LL can improve the
      situation.
-14: updated authorship.
-13: added a Problem Statement section;
      added the name of the Organisation of one co-author;
      distinguished between 'need' and 'would need' a draft.

Alex

-------- Message transféré --------
Sujet : 	New Version Notification for 
draft-petrescu-6man-ll-prefix-len-15.txt
Date : 	Mon, 29 Apr 2019 03:05:17 -0700
De : 	[email-masked]
Pour : 	Naveen Kottapalli <[email-masked]>, Loganaden Velvindron 
<[email-masked]>, Alexandre Petrescu <[email-masked]>, 
Gyan Mishra <[email-masked]>, Alexandre Petrescu 
<[email-masked]>

A new version of I-D, draft-petrescu-6man-ll-prefix-len-15.txt
has been successfully submitted by Alexandre Petrescu and posted to the
IETF repository.

Name: draft-petrescu-6man-ll-prefix-len
Revision: 15
Title: The length of the prefix of an IPv6 link-local address ranges 
from 10 to 127
Document date: 2019-04-29
Group: Individual Submission
Pages: 13
URL: 
https://www.ietf.org/internet-drafts/draft-petrescu-6man-ll-prefix-len-15.txt
Status: https://datatracker.ietf.org/doc/draft-petrescu-6man-ll-prefix-len/
Htmlized: https://tools.ietf.org/html/draft-petrescu-6man-ll-prefix-len-15
Htmlized: 
https://datatracker.ietf.org/doc/html/draft-petrescu-6man-ll-prefix-len
Diff: https://www.ietf.org/rfcdiff?url2=draft-petrescu-6man-ll-prefix-len-15

Abstract:
A rejected Erratum to RFC4291 "IPv6 Addr Archi" on the topic of link-
local addresses 'would need' a draft. This draft is an answer to
that need.

The length of the prefix of an IPv6 link-local address is variable.
The minimal value is 10 decimal. The maximum value is 127 decimal.

Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

The IETF Secretariat

---

From: Philip Homburg <[email-masked]>
Date: Tue, 30 Apr 2019 11:07:49 +0200

>prefix length of the LL addresses.

After reading draft-petrescu-6man-ll-prefix-len-15, this is my impression of
the draft:

Section 3, Problem Statement, limits itself to manual configuration. Then
it describes how manual configuration sometimes benefits from a Subnet ID.

This is fine. In the case of manual configuration, there is no need to judge
how the subnet ID is allocated or kept consistent. At the same time, manual
configuration is a very limited use case.

Then Section 4, Kinds of Solutions, gives a description of using fe80::1:2/64
where '1' is the subnet ID and '2' an interface ID.

The only comment on using this apporach is 'invade the IID with a Subnet ID'.
To me that doesn't seem to be a technical issue. The total IID space is
64 bits. We are talking about manual configuration. So even if the lower
32 bits would be used for an IPv4 address there is still plenty of space
for a subnet ID. It is very unlikely that with manual configuration it would
be impossible to find a split between the subnet ID and any other ID that is
required.

So it seems to me that the problem described in Section 3 can be solved using
fe80::1:2/64 and this draft is unnecessary.

Alternatively, the authors can explain how they tried to use fe80::1:2/64
in practice and it lead to problems.

There is one statement that I found confusing: "Other solutions involve a
hidden 'scope_id' and the use of special syntax ('%') to denote an interface."

As far as I know, in all operating systems, the use of a link local address
requires the use of a scope_id. This is because exactly the same prefix is
implicitly configured on all interface. So scope_id is far from hidden. It
is required.