Subject: RE: Proposed "IPv4-compatible IPv6" Deprecation text

From: "Gray, Eric" <[email-masked]>
Date: Wed, 23 Mar 2005 17:29:59 -0500

In this context, it is fairly self explanatory. "Deprecate" in 
the IETF means "no longer recommended usage, may not be supported
in the future".  The term is frequently used in a MIB-related 
context.  The text proposed reflects this meaning.

--
Eric

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Iljitsch van Beijnum
Sent: Wednesday, March 23, 2005 4:58 PM
To: Bob Hinden
Cc: IETF IPv6 Mailing List
Subject: Re: Proposed "IPv4-compatible IPv6" Deprecation text

On 23-mrt-05, at 20:54, Bob Hinden wrote:

>> > 2.5.5.1 IPv4-Compatible IPv6 Address

>> >     The "IPv4-compatible IPv6 address" is now deprecated because the
>> >     current IPv6 transition mechanisms no longer use them.  New or
>> >     updated implementations are not required to support this address
>> >     type.  Existing implementations and deployments may continue to 
>> use
>> >     these addresses.

>> Can we just drop that last sentence altogether as it seems somewhat
>> contrary to the rest of the paragraph?

> I don't have a strong opinion and would be happy to remove it.  I will 
> plan to do that unless I hear lots of disagreement.

Is there a place where it is explained what "deprecate" means in the 
IETF context? Looking the word up in the dictionary won't help people 
who don't understand it...

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---

From: Bob Hinden <[email-masked]>
Date: Wed, 23 Mar 2005 15:29:07 -0800

Hi,

OK, I think that is a "wrap".  I just submitted it to be an ID.

Thanks for the comments and editorial suggestions.  The deprecation text is 
much improved.

The updated deprecation and IANA text that will be in the new draft is 
include below.

Thanks,
Bob

----------------

2.5.5 IPv6 Addresses with Embedded IPv4 Addresses

    Two types of IPv6 addresses are defined that carry an IPv4 address in
    the low-order 32 bits of the address.  These are the "IPv4-Compatible
    IPv6 Address" and the "IPv4-Mapped IPv6 Address".

    The "IPv4-compatible IPv6 address", was defined to assist in the IPv6
    transition.  The format of the "IPv4-compatible IPv6 address" is:

    |                80 bits               | 16 |      32 bits        |
    +--------------------------------------+--------------------------+
    |0000..............................0000|0000|    IPv4 address     |
    +--------------------------------------+----+---------------------+

    Note: The IPv4 address used in the "IPv4-compatible IPv6 address"
    must be a globally-unique IPv4 unicast address.

    The "IPv4-compatible IPv6 address" is now deprecated because the
    current IPv6 transition mechanisms no longer use these addresses.
    New or updated implementations are not required to support this
    address type.

2.5.5.2 IPv4-Mapped IPv6 Address

    A second type of IPv6 address that holds an embedded IPv4 address is
    defined.  This address type is used to represent the addresses of
    IPv4 nodes as IPv6 addresses.  The format of the "IPv4-mapped IPv6
    address" is:

    |                80 bits               | 16 |      32 bits        |
    +--------------------------------------+--------------------------+
    |0000..............................0000|FFFF|    IPv4 address     |
    +--------------------------------------+----+---------------------+

    See [RFC4038] for background on the usage of the "IPv4-mapped IPv6
    address".

------------------------

4. IANA Considerations

    The "IPv4-compatible IPv6 address" is deprecated by this document.
    The IANA should continue to list the address block containing this
    address as "Reserved by IETF" and not reassign it for any other
    purpose.

    The IANA should update the references for the IPv6 Address
    Architecture in the IANA registries to this RFC when it is published.

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