Samita Chakrabarti wrote:
... That way, periodic RA will not wake up all the nodes in the 6lowpan. ...
To the best of my knowledge, 802.15.4 implementations power-down the radio when the system sleeps. As such, a broadcast packet does not wake a sleeping 802.15.4 node. Rather, the packet is simply never received by the sleeping node. If my understanding about this behavior is incorrect, someone please correct me. I have been meaning to check and see what the spec says about this, but haven't yet... Given that the response to broadcast packets differs in 802.16 networks (where an idle node wakes to process the packet) and 802.15.4 networks (where a sleeping node is never even aware of the packet), different solutions are probably required. To reiterate what I have said before, I believe that we must explicitly specify the behavior we expect of multicast in 6lowpan networks that contain sleeping nodes. In particular, does multicast mean "received by the potentially very small percentage of the nodes that aren't currently sleeping" or might it mean "received by every node after they wake up [whenever day that might be]"? After we specify the behavior of multicast, then we can then try to figure out whether we can actually implement that behavior in a useful way. In the interim, I suggest a moratorium on simply assuming that multicast is a potential solution to any of the challenges we face (e.g., duplicate address detection, router announcements, neighbor discovery, ...) -tjs _______________________________________________ 6lowpan mailing list [email protected] https://www1.ietf.org/mailman/listinfo/6lowpan
