Re: Proposed Resolution of Issues [1-37]

[Fred Baker <fred@cisco.com>]

On Sep 2, 2005, at 1:33 AM, Tim Chown wrote:
> Issues 32&33:  ULAs *may* help renumbering, not *will*.  There is  
> baggage
> with ULAs and as such their use is a tradeoff not a given, I feel.

I very much agree. I had the same debate with Pekka and Thomas when  
the renumbering procedure draft went in. Thomas filed a 'discuss'  
requiring me to say that ULAs would simplify renumbering, but without  
saying how. I told them:

On Jan 15, 2005, at 5:46 PM, Fred Baker wrote:
> Listen. If ULAs simplify the procedure of renumbering a network  
> without a flag day, then there should be several places in the  
> document where a few sentences of the following form can be added.
>
>   "if the old prefix..." or "if the new prefix..."
>   "is a ULA prefix then"
>   "...this step may be skipped" or "...this step may be simplified  
> <in this way>"
>   "and it still allows you to renumber a network without a flag day  
> for <this> reason."
>
> Present me with those sentences, and I will include them.

On Jan 15, 2005, at 9:34 AM, Fred Baker wrote:
> > This said, I think it's still good idea to _mention_ ULAs, but  
> > treat them with sufficient skepticism at this point.  The text you  
> > proposed, and which I modified, and suggested in the previous  
> > message:
> >
> > > This document describes issues related to renumbering a network,  
> > > where network addresses need to be changed because the old  
> > > numbers will no longer be usable in the future. Readers should be  
> > > aware that a form of local addressing, Unique Local Addressing  
> > > (ULA) [ULA].  Using ULA addresses doesn't obviate the need to  
> > > renumber networks, but are another tool that may reduce the need  
> > > for or complexity of renumbering networks.
>
> This document, first and foremost, is about a procedure for  
> renumbering a network. Both you and Thomas suggest that ULAs might  
> reduce the complexity involved in numbering networks, but I am at a  
> loss to say how - and in the end, when people ask that question,  
> they will ask it of the authors. In neither the text you propose  
> nor the text Thomas proposes do I see any suggestion of a way that  
> ULAs might alter that procedure in any way. Am I missing something?
>
> If you can't tell me *how* ULAs reduce the complexity in the  
> procedure of renumbering a network, I don't see the mention as  
> relevant.

I have heard a fair bit of dogma about ULAs to the effect that they  
solve something, but have never been presented with those sentences,  
and am not convinced on the rest either. They look to me like a re- 
invention of site-local with many of the same problems.

And by the way, if ULAs are global, they are global addresses... What  
does the "L" stand for?