There are clearly some strong opinions both ways on this issue. I plan
to raise the issue during the discussion of this draft at IETF and I
hope we can discern WG consensus then.

Thanks,
Rich

> -----Original Message-----
> From: Robert Elz [mailto:[EMAIL PROTECTED]] 
> Sent: Friday, December 07, 2001 2:12 AM
> To: Alain Durand
> Cc: Richard Draves; [EMAIL PROTECTED]
> Subject: Re: "Default Address Selection for IPv6" 
> 
> 
>     Date:        Thu, 06 Dec 2001 22:29:36 -0800
>     From:        Alain Durand <[EMAIL PROTECTED]>
>     Message-ID:  
> <[EMAIL PROTECTED]>
> 
>   | In the case they don't, the system will rely on longest 
> prefix match
>   | with the problematic behavior I exposed earlier.
> 
> As I recall it, it wasn't really problematic, just strange.
> 
>   | Doing a longest prefix match on something longer than the actual
>   | prefix length is always meaningless.
> 
> Yes, but at least, deterministic meaningless, rather than random.
> 
>   | I would rather have longest prefix match limited to the 
> prefix length
>   | (that is /64 in the normal case) and, in the end, all 
> things being equal,
>   | suggest to use a deterministic tie breaker,
> 
> like using the following bits in the address...
> 
>   | like using the first
>   | interface or address the system has configured.
> 
> Neither of those is deterministic.   Especially the address, which can
> determine upon the order in which RAs are received (and how 
> long since an address there was last deprecated).
> 
>   | The alternative you mention, that is to use the order 
> returned by the DNS
> 
> which is also not deterministic.
> 
>   | is in my opinion more suitable than sorting interfaces on 
> the particular
>   | brand of NIC card they are using.
> 
> There's certainly nothing to commend using the MAC addresses, 
> other than that they simplify the algorithm (no special 
> cases), and most particularly avoid building in any knowledge 
> of 64 in places where it does not belong.
> 
> If you can specify this such that it actually uses the 
> currently configured prefix lengths (no mention of the number 
> 64 anywhere) and actually find a way to make the outcome 
> predictable, then I'd be more inclined to accept it
> as a reasonable change.   Otherwise not.
> 
> kre
> 
> 
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