Re: [DNA] RE: Review of draft-krishnan-dna-simple-01.txt

[JinHyeock Choi <jinchoe@gmail.com>]

Bernard

now I come to understand simple DNA procedures the better. thanks for
your clarification.

> The host verifies a subset of routers which generated valid addresses by
> doing
> NUD to them and sending an RS.  Verifying reachability via NUD confirms all
> prefixes formerly advertised by that router, so it can validate
> multiple addresses at once.

ok. Simple DNA verifies addresses per a router, whereas previous DNA
verifies addresses per a link.

> > IMO, the host can verify address B based on the verification of
> > address A. If address A and B were valid in the same link and address
> > A is proven still valid, it's reasonable to assume that address B also
> > is still valid (except in some corner cases.)
>
> If router B is no longer present, and does not answer NS or send
> RAs for prefix B, then the host probably should not conclude that
> address B is still valid, even if router A is present and sends NA or RA.

The above will happen only when router B becomes out of order during
DNA procedure. It may be a corner case which simple DNA don't have to
worry.

> > I have in mind the following example.
> >
> > Assume a host is attached to a link
> > with two access router R1 and R2
> > which advertise prefix 1 and prefix 2 respectively.
> >
> > The host autoconfigures address 1 with prefix 1.
> >
> > After a while, the host executes DNA and performs NUD with R1 and R2.
> >
> > When a solicited NA from R2 arrives to confirm R2's reachability,
> > IMO, it's reasonable to assume that
> > address 1 with prefix 1 is still valid,
> > even though a solicited NA from R1 didn't arrive yet (or never).
>
> Simple DNA will perform NUD to R1 and R2 simultaneous with sending an
> RS.  When the solicited NA arrives from R1 it will autoconfigure address 1.
> If R2 answers the NS, it will autoconfigure address 2.   It will also
> process
> the RAs from R1 and/or R2.  However, if R2 doesn't answer the unicast NS
> or the RS, then it won't auto-configure address 2 until it hears evidence
> that
> R2 is still there.

The example above is not about
how a host would autoconfigure a new address in relationship with DNA
operation but about
how a host would verify (already autoconfigured) existing addresses.

IMO, when the host receives a solicted NA from R1,
the host can use the existing address 2 (configured with the
information from R2)
even if it hears no evidence that R2 is still there.
At least, that's how current DNA operates.

Thanks for your kind consideration.

Best Regards

JinHyeock