Subject: WG Review: IPv6 Site Renumbering (6renum)

From: IESG Secretary <[email-masked]>
Date: Thu, 2 Jun 2011 10:54:54 -0700 (PDT)

A new IETF working group has been proposed in the Operations and 
Management Area.  The IESG has not made any determination as yet. The 
following draft charter was submitted, and is provided for informational 
purposes only. Please send your comments to the IESG mailing list 
([email-masked]) by Thursday, June 9, 2011                            

IPv6 Site Renumbering (6renum) 
-------------------------------
Last Modified: 2011-06-02

Current Status: Proposed Working Group

Chairs: TBD

Area Director: Ron Bonica

Mailing list
  Address: [email-masked]
  To Subscribe: https://www.ietf.org/mailman/listinfo/renum
  Archive: http://www.ietf.org/mail-archive/web/renum/

Description of Working Group
-----------

As outlined in RFC 5887, renumbering, especially for medium to large 
sites and networks, is currently viewed as an expensive, painful, and 
error-prone process, avoided by network managers as much as possible. 

As IPv6 adoption begins to gather momentum, those managers may turn to
PI addressing for IPv6 to attempt to minimise the need for future 
renumbering. However, such an approach would create very serious BGP4
scaling problems if used by millions of end sites; it is thus desirable 
to develop tools, techniques and practices that may make renumbering a
simpler process, to reduce demand for IPv6 PI space. In addition, as
RFC 5887 describes, there are other triggers that mean some cases of
renumbering are unavoidable, so it should be considered a given that
a site may need partial or complete renumbering at some stage.   

Strategically it is thus important to implement and deploy techniques 
that facilitate simpler IPv6 site renumbering, so that as IPv6 becomes 
universally deployed, renumbering can be viewed as a more routine event.
This includes consideration of how the initial assignment and subsequent
management of address information is performed, as this will affect 
future renumbering operations.

For renumbering to become more routine, a systematic address management 
approach will be essential. A large site with a short prefix will be 
divided into subnets with longer prefixes. In this scenario, renumbering 
or partial renumbering can be complicated. Aggregation, synchronisation, 
coordination, etc., need to be carefully managed, and the use of 
manually inserted address literals minimised. In unmanaged scenarios, 
consideration may need to be made for 'flag day' renumbering (in 
contrast to the procedure described in RFC4192).

The task of the 6RENUM working group is to document existing renumbering
practices for managed (enterprise) and unmanaged (SOHO) networks, to 
identify specific renumbering problems in the context of site-wide 
renumbering, and to then recharter with a view to develop point 
solutions and system solutions to address those problems or to stimulate 
such development in other working groups if appropriate.  The principal 
target will be solutions for IPv6.

RFC 4192, RFC 5887, and draft-jiang-ipv6-site-renum-guideline are 
starting points for this work.

Goals/deliverables
------------------

The goals of the 6RENUM working group are:

1. To undertake scenario descriptions, including documentation of 
   current capability inventories and existing BCPs for managed 
   (enterprise) and unmanaged (SOHO) networks.  These texts should 
   contribute towards the gap analysis and provide an agreed basis for 
   subsequent WG rechartering towards development of solutions 
   (potentially in other WGs) and improved practices. Operator input 
   will be of particularly high value for this stage.

2. To examine fully automatic, self-organising networks (manet/autoconf) 
   as a possible third scenario. 

3. To perform a gap analysis for renumbering practices, drawing on RFCs
   4192 and 5887, to identify generic issues for network design, network
   management, and renumbering operations. The scenario texts will
   contribute to the analysis.

4. To document existing IP address management models and practices with
   a view to proposing (at a high level) an appropriate model to allow
   simplification of any partial or full site renumbering process
   (this would likely be applicable to managed rather than unmanaged
   scenarios).

The general methodology for the WG will be to first build managed and
unmanaged baseline scenario descriptions, while in parallel undertaking 
an initial gap analysis from existing work in (at least) RFC4192 and 
RFC5877. As the scenario texts harden, their contributions will be 
incorporated into the gap analysis, which can be published once the 
scenarios are completed.   

The following topics are out of scope for the working group:

1. Renumbering avoidance; this can perhaps be considered by appropriate 
   IRTF groups.  As documented in RFC5887, renumbering cannot be 
   completely avoided. The WG is limited to dealing with how to renumber 
   when it is unavoidable.

2. IPv4 renumbering.  While many sites are likely to run dual-stack, 
   IPv6 is the future and, especially given concerns over extensive use 
   of IPv6 PI, the most appropriate place to focus effort.

3. ISP renumbering; this is potentially the most complex renumbering 
   case.  More benefit can be achieved by focusing effort on site 
   renumbering.  The site analysis should include the ISP's role in its 
   own renumbering event.

A recharter of the WG will be possible once the gap analysis and 
scenario descriptions are completed, and the IP address management 
('numbering tool') review and (high level) proposal have been published.   
The rechartering will identify more specific work items within the 
6RENUM WG or appropriate protocol WGs. 

Milestones
----------

Aug 2011    managed (enterprise) scenario draft ready for WG adoption 
            (partly based on draft-jiang-ipv6-site-renum-guideline)

Aug 2011    unmanaged (SOHO) scenario draft ready for WG adoption

Oct 2011    gap analysis document ready for WG adoption (already some 
            considerations in RFC5887 and 
            draft-jiang-ipv6-site-renum-guideline)

Oct 2011    management model draft ready for WG adoption

Jan 2012    managed (enterprise) scenario draft ready for WGLC

Jan 2012    unmanaged (SOHO) scenario draft ready for WGLC

Feb 2012    management model ready for WGLC

Mar 2012    gap analysis document ready for WGLC

Apr 2012    recharter WG towards solution space