Subject: Fwd: New Version Notification for draft-petrescu-6man-ll-prefix-len-02.txt

From: Alexandre Petrescu <[email-masked]>
Date: Mon, 24 Sep 2018 12:40:56 +0200

Hi 6manners,

I submitted a new version of this draft about prefix length of the link 
local addresses.

- it still says the ll plen is 64.

- it adds some of the points about the context that were said on the 
list recently.

Alex

-------- Message transféré --------
Sujet : 	New Version Notification for 
draft-petrescu-6man-ll-prefix-len-02.txt
Date : 	Mon, 24 Sep 2018 03:39:56 -0700
De : 	[email-masked]
Pour : 	Alexandre Petrescu <[email-masked]>, Alexandre 
Petrescu <[email-masked]>

A new version of I-D, draft-petrescu-6man-ll-prefix-len-02.txt
has been successfully submitted by Alexandre Petrescu and posted to the
IETF repository.

Name:		draft-petrescu-6man-ll-prefix-len
Revision:	02
Title:		The length of the IPv6 link-local prefix
Document date:	2018-09-24
Group:		Individual Submission
Pages:		5
URL:            https://www.ietf.org/internet-drafts/draft-petrescu-6man-ll-prefix-len-02.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-02
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-02

Abstract:
    The length of the IPv6 link-local prefix is 64 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: Wilco Baan Hofman <[email-masked]>
Date: Mon, 24 Sep 2018 12:56:02 +0200

I oppose a change in the IANA assignment.

There is no ambiguity. fe80::/10 is reserved at IANA for IPv6 link 
local. Only IPv6 *OVER ETHERNET* should use 64-bit IID and thus 
fe80::/64. IPv6 over other media are free to use longer IIDs and thus 
more link-local bits.

IPv6 may be transported over a non-ethernet medium with up to 118 bit 
addresses, that is fine. Use 118-bit IIDs for link-local. Using 118-bit 
IIDs with SLAAC then later presents a bit of a challenge with routing in 
only 10 bits, but link-local should work. Other address assignment 
schemes can be used for globally scoped addresses.

I don't see a problem with the current state of affairs. Alexandre: What 
are you trying to solve? Why do you want to get rid of a futureproofing 
IANA assignment that doesn't hurt anyone?

-- Wilco

On 24/09/2018 12:40, Alexandre Petrescu wrote:
>
> Hi 6manners,
>
> I submitted a new version of this draft about prefix length of the 
> link local addresses.
>
> URL:https://www.ietf.org/internet-drafts/draft-petrescu-6man-ll-prefix-len-02.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-02
> 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-02
>
> Abstract:
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [email-masked]
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------

---

From: Mark Smith <[email-masked]>
Date: Mon, 24 Sep 2018 21:24:37 +1000

> fe80::/64. IPv6 over other media are free to use longer IIDs and thus

That's not correct. See RFC4291, 2.5.6.

> then later presents a bit of a challenge with routing in

---

From: Alexandre Petrescu <[email-masked]>
Date: Mon, 24 Sep 2018 13:37:00 +0200

Le 24/09/2018 à 12:56, Wilco Baan Hofman a écrit :
[...]

> Alexandre: What 

In the text, I do not want IANA to change the assignment of the 10 
leading bits of link-local addresses.

But IANA should change the name it uses to call these 10 leading bits, 
instead of calling them an "IPv6 prefix".

Because link-local addresses are only valid  on a link (or on a subnet) 
and "fe80::/10" is neither a "subnet prefix", nor a "on-link prefix".

draft says:
>    IANA is requested to change the name of the column head in the table
>    that depicts the "Internet Protocol Version 6 Address Space".  The
>    name should be "The n leading bits of an address" instead of "IPv6
>    Prefix".

Alex

---

From: Fernando Gont <[email-masked]>
Date: Fri, 28 Sep 2018 21:06:38 -0300

Alexandre,

I read your I-D, but found it hard to parse, for numerous reasons.

1) You refer to an IANA page, but you never reference it. I *assume* you
mean
<https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml>.
 But then that page never talks about "prefixes".

2) My mental model for the LL prefix is that it is fe80::/64, which is
taken from the reserved block fe80::/10

3) In practice, you cannot use any fe80::/10 for anything else: at least
BSDs internally employ bits in such "prefix" to store e.g. interface
indexes (since they are expected to be zero, and hence you don't need to
actually use them for anything else). Try communicating with a BSD using
yourself e.g. fe80:1234:5678:90ab:[IID]/64 and see what happens. Jinmei
will probably expand better on this.

Thanks,
Fernando

-- 
Fernando Gont
SI6 Networks
e-mail: [email-masked]
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492