Subject: WG ACTION: 2 weeks to discuss [LL58] Duplicate inconsistent routable address definition

From: Erik Guttman <[email-masked]>
Date: Wed, 5 May 2004 01:03:37 +0200

Please post discussion of this issue to the mailing list over the 
next two weeks
ending May 18, 2004.  In order to accept this issued, we will need a strong WG
consensus given that this is very late in the process.

Please see http://www.drizzle.org/~aboba/ZEROCONF/issues.html for a list of
current issues and their status.

[LL58]

Description of Issue:		Duplicate inconsistent routable 
address definition
Submitter Name:                 Stuart Cheshire
Submitter Email Address:        [email-masked]
Date first submitted:           04 May 04
Reference:
Comment Type ['t'ech|'e'dit]:	t
Prio ['S' Must|1 should|2 may]:	1
Section:			1.2, 1.9
Rationale/Explanation:
Lengthy Description:

>    A routable address is any address that is:
>
>    * a unicast address (see Section 1.2)
>    * not a loopback address
>    * not contained within the 169.254/16 prefix reserved for IPv4 Link-
>       Local addresses

This duplicates (but not entirely agrees with) Section 1.2.

Requested Change:

From

1.9.  When to configure a Link-Local IPv4 address

    Having addresses of multiple different scopes assigned to an
    interface, with no adequate way to determine in what circumstances
    each address should be used, leads to complexity for applications and
    confusion for users.  A host with an address on a link can
    communicate with all other devices on that link, whether those
    devices use Link-Local addresses, or routable addresses.  For these
    reasons, a host SHOULD NOT have both a valid routable address and a
    Link-Local IPv4 address configured on the same interface.

    A routable address is any address that is:

    * a unicast address (see Section 1.2)
    * not a loopback address
    * not contained within the 169.254/16 prefix reserved for Link-Local
       IPv4 addresses

To

1.9.  When to configure an IPv4 Link-Local address

    Having addresses of multiple different scopes assigned to an
    interface, with no adequate way to determine in what circumstances
    each address should be used, leads to complexity for applications and
    confusion for users.  A host with an address on a link can
    communicate with all other devices on that link, whether those
    devices use Link-Local addresses, or routable addresses.  For these
    reasons, a host SHOULD NOT have both a valid routable address and an
    IPv4 Link-Local address configured on the same interface.

---

From: "Philip Nye" <[email-masked]>
Date: Fri, 7 May 2004 11:47:37 -0000

> Section 1.9 duplicates (but not entirely agrees with) Section 1.2.

Stuart is right that there is an issue and in fact the definition of 1.9 is better than that of 1.2.

I agree with the proposed change and the additional modification in Stuarts subsequent email:

Replace

   This document uses the term "routable address" to refer to all
   unicast IPv4 addresses outside the 169.254/16 prefix, including
   global addresses and private addresses such as Net 10/8 [RFC1918],
   all of which may be forwarded via routers.

with

   This document uses the term "routable address" to refer to all valid
   unicast IPv4 addresses outside the 169.254/16 prefix that may be
   forwarded via routers. This includes all global IP addresses and
   private addresses such as Net 10/8 [RFC1918], but not loopback
   addresses such as 127.0.0.1

Philip