Re: [dhcwg] Please review version -07 of draft-ietf-dhc-dhcpv6-stateful-issues

[神明達哉 <[e-mail]>]

At Fri, 17 Oct 2014 19:01:30 +0000,
"Bernie Volz (volz)" <[e-mail]> wrote:

> We have to handle EXISTING servers which I believe base the T1/T2 times on each IA separately - though that is just my assumption -- I haven't analyzed all of the servers. Obviously this also depends on the lifetimes configured (i.e., if they are all the same and the server assigns the addresses/PDs are the same time, the lifetimes should generally all be identical and hence so should the T1/T2 times).
>
> This is the point about the client text - it is there to handle the case where the client is communicating with an older (3315 compliant) server. If we required all servers to be magically updated, we wouldn't need the client text.

I thought the mixed use of different IAs (especially of different
types) is largely unspecified and we cannot reasonably expect
interoperability anyway (in fact, hence this draft, right?).  And, if
we cannot expect a specific behavior from the server side, I don't see
much point in trying to specify how the client should deal with them.
It seems to be simpler if we just say

- if you want to deploy mixed use of IAs in an interoperable manner,
  make sure all servers and clients are updated according to this
  clarification.
- otherwise, such mixed use may or may not work.  do it at your own
  risk.

> Perhaps that is a way to solve this problem - perhaps the text should focus on the behavior to say that:
>
> "The client SHOULD Renew (or Rebind) all of the bindings at once, whatever the individual IA T1/T2 times might have been. How a client handles this (whether it determines one set of T1/T2 values to use across all bindings, initiates independent timers and the first one to go off results in a Renew (or Rebind) with all bindings, or some other approach), is up to the client implementation."

Looks good (enough) to me.  I'd also note that as long as servers are
implemented (and operated) based on this update (and that's the
recommended way of operation with mixed use of IAs), T1 and T2 should
have the same values for all IAs, and the client behavior should be
trivial and deterministic.

--
jinmei