Re: [Rescert] Another attempt to round off the IR-ISP protocol

[Rob Austein <sra@hactrn.net>]

At Tue, 05 Jun 2007 14:23:23 +1000, Geoff Huston wrote:
> Rob Austein wrote:
> > 
> > With the scheme as I described it a few hours ago the msg_ref never
> > needs to be reset, full stop.  So there's no need for a reset timer,
> > 24 hour or otherwise.
> > 
> > Yes this is a change from what I wrote up on Saturday.
> 
> Are you referring to this scheme?
> 
> 1) On the replay protection thing: Randy and I have been talking to
>     Steve Bellovin, and while we haven't quite converged yet it looks
>     like the simplest answer is to follow RobK's earlier suggestion:
>     just make the msg_ref a monotonically increasing integer, no CMS
>     timestamp required, no reset mechanism required, done, full stop.
>     The likely implementation would be to generate the msg_ref value
>     from a clock on the sender side, eg, nanoseconds since epoch, but
>     it really doesn't matter so long as it's monotonically increasing.
>     The CMS timestamp doesn't isn't fine enough for this, and combining
>     CMS timestamp with an additional value has timing screws, so let's
>     just keep this simple and go with the counter.
> 
>     Steve Bellovin doesn't quite believe this yet but I think that
>     Randy and I can convince him.  We'll keep you posted.

Yes.