RE: DHCP failures (was RE: Do you want to have more meetings outsi de US ?)

["Tony Hain" <alh-ietf@tndh.net>]

Jari Arkko wrote:

> Tony,
> 
> > Absolute BS. There is no need for those to communicate. A host needs
> to be able to get configuration from either mechanism.
> 
> A host needs to get the configuration from either one, yes. If the host
> can see (e.g. from the RA) what it should do AND both ways are
> implemented, then we are fine. I worry about cases where network
> implements just one way and the host the other. Granted, there are ways
> to deal with these, depending a little bit what one find acceptable -
> but I think it is a real issue to worry about. If not, please explain.

It is very unlikely that a device would only implement DHCP, so the only
case to worry about is a device that does not implement DHCP (being a
slightly more complex message exchange), while the network operator insists
that their network only supports that. 

I am not particularly concerned about that case. The reason a manufacturer
would choose to not implement DHCP would be that it is a simple node (light
switch or the like), and the most likely case is that the network operator
that insists on DHCP would not want to allow these trivial devices anyway
because they will not have the UI to deal with the rest of the
DHCP-as-a-trust-anchor scenarios. Multi-purpose OSs will easily do both, and
are most likely to need the ability to switch as they move between
operational environments. 

Get over it and define both mechanisms. Let the operational community decide
what they will and will not support in their deployments. If the device
manufacturers want to deploy into networks that use DHCP-as-a-trust-anchor,
they will have to implement DHCP. If that is not worth their time, the
network needs to support a full set of services via the RA approach that is
more likely in networks without an elite network management staff that likes
to get paid well for their arcane knowledge of a more complex environment. 

I am not saying DHCP is wrong, just that forcing a one-size-fits-all answer
is wrong.

Tony