host-identifier with IPv6

[Ted Lemon]

On Mar 2, 2009, at 2:12 PM, Simon Hobson wrote:
> This may be a fundamental difference of opinion, but the MAC address
> of the devices interfaces is probably as stable as anything you are
> likely to get on current devices. [...]

You make some good points here, Simon, but it all boils down to the  
life cycle of your typical client, and we can't optimise the protocol  
to support one particularly broken client (the one that requires  
frequent O.S. reinstalls that would wipe out the DUID - I won't name  
it, but you know which one I'm talking about).

By far the majority of IP addresses served by centralized DHCP servers  
are served by large ISPs to residential gateways of various kinds.    
The next biggest majority would be IP addresses served by residential  
gateways to clients inside the home.   Corporate and similar sites  
might be next, but they're a much, much smaller group.

I won't argue that ISPs don't want the kind of identifiers you're  
talking about, because ISPs each have their own needs that vary quite  
widely.   But what I will say is that the devices they are talking to  
by and large do not see frequent O.S. reinstalls that would wipe out a  
stored identifier.   So for those sites, if they need a stable  
identifier, they already have one.

I don't mean to minimize the needs of sites that happen to run the  
type of client that requires frequent O.S. reinstalls, but my point is  
that we can't design network protocols around those clients.