[DNA] Re: Alternatives to "just send RS" when DNA starts

[JinHyeock Choi <jinchoe@gmail.com>]

Dear Thomas

> > I think 2461bis allows an immideate RS for mobile nodes.
>
> Can you cite text? And I hope they don't make an exception just for
> "mobile nodes".

9th bullet of APPENDIX F: CHANGES FROM RFC 2461 from 2461 bis

    o Allowed mobile nodes to be exempt from adding random delays before
      sending an RS during a handover.

> But one can also imagine parallel approaches. E.g, for the default
> routers on the list, measure the actual observed RTTs during NS/NA
> exchanges. Then, for DNA, send out an NS, using that RTT as an
> estimate of how long you are willing to wait (and I'd expect this to
> be very short, like 10ms or less). If that doesn't work, then fall
> back to RS. One can imagine other optimizations.

Allow me to clarify the above. I understand that, according to your suggestion,

Upon receiving link-up indication, an MN sends an unicast NS to a
known router (or routers) and waits for a certain amount of time
(based on measured RTT value). Upon the time expiration, the MN sends
an RS to get an RA.

Am I right?

If so, this will certainly save packets in case the MN stays at the
same link. But in case of a link change, there will be an additional
delay for NS/ NA exchange and we need to measure RTT which may vary
drastically in wireless environment.

Thanks for your kind consideration.

Best Regards

JinHyeock