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

From: Stuart Cheshire <[email-masked]>
Date: Thu, 6 May 2004 22:49:28 -0700

>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.

Also, "Terminology" needs to be updated to incorporate the "not a 
loopback address" restriction.

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

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer, Inc.
 * www.stuartcheshire.org