Subject: on the need for documentation addresses of all types

From: Michael Richardson <[email-masked]>
Date: Mon, 27 Feb 2017 09:23:54 -0500

rfc3849 gives us 2001:DB8::/32 for use in documentation.

I find that I am often giving example addresses in fe80:: (Link Local), and
fd00::/8 (ULA) addresses when those prefixes are appropriate for the
protocol.   I worry that someone will think the numbers I've chosen are
special in some way.  There are clearly far less concern about duplication
since both spaces are designed to be duplicated (LL) and
not-guaranteed-to-be-unique (ULA).

I'd still be happier if someone google'ed the prefixes in the document, and
found that they were documentation examples.

I'd also like to have three additional documentation prefixes from GUA
space so that examples involving inner and outer addresses, and senders and
receivers could be better distinguished.  Yes, we currently can carve
/48 blocks out of 2001:DB8::/32 for this purpose, but it would be nice if
the pattern was even more unique.

Would it also be useful to have documentation addresses for the multicast
ranges, and the like?

--
Michael Richardson <[email-masked]>, Sandelman Software Works
 -= IPv6 IoT consulting =-

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From: Tim Chown <[email-masked]>
Date: Mon, 27 Feb 2017 14:36:42 +0000

> found that they were documentation examples.

I guess it’s tricky to reserve any documentation range when those could be genuinely used anyway?

> Would it also be useful to have documentation addresses for the multicast

There are multicast documentation prefixes - see RFC 6676.

Tim

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From: Michael Richardson <[email-masked]>
Date: Mon, 27 Feb 2017 11:02:43 -0500

> be genuinely used anyway?

yes, agreed, it would have to say that.

    > There are multicast documentation prefixes - see RFC 6676.

Argh. 6676 should have updated 3849, so that there would be a forward link,
and I wouldn't suggest such duplication :-)

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     [email-masked]  http://www.sandelman.ca/        |   ruby on rails    [

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From: Brian E Carpenter <[email-masked]>
Date: Tue, 28 Feb 2017 08:47:07 +1300

On 28/02/2017 03:23, Michael Richardson wrote:
> special in some way.

I've thought about that from time to time, but what's the harm in these
cases? Does it matter if someone sees fe80::28cc:dc4a:9703:6871%12
or fd63:45eb:de13:0:28cc:dc4a:9703:6871 in an example and copies them?

   Brian

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From: Michael Richardson <[email-masked]>
Date: Tue, 28 Feb 2017 13:38:29 -0500

> or fd63:45eb:de13:0:28cc:dc4a:9703:6871 in an example and copies them?

It's more of the:
     "Oh, I have to configure **fe80::28cc:dc4a:9703:6871** on my interface
      to make the service run"

(which is wrong!)
which I worry about.  If someone puts into service, and is then surprised
that they can not run two of them on the same LAN, the message back to the
developers is that they didn't understand what a documentation address is.